EFM32LG-MCP3650 - Silicon Labs

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EFM32LG Reference Manual

Leopard Gecko Series

• 32-bit ARM Cortex-M3 processor running at up to 48 MHz

• Up to 256 kB Flash and 32 kB RAM memory

• Energy efficient and autonomous peripherals

• Ultra low power Energy Modes with Sub µ operation

• Fast wake-up time of only 2 µs

The EFM32LG microcontroller series revolutionizes the 8- to 32-bit market with a

combination of unmatched performance and ultra low power consumption in both

active- and sleep modes. EFM32LG devices consume as little as 211 µA/MHz in run

mode.

EFM32LG's low energy consumption outperforms any other available 8-, 16-,

and 32-bit solution. The EFM32LG includes autonomous and energy efficient

peripherals, high overall chip- and analog integration, and the performance of the

industry standard 32-bit ARM Cortex-M3 processor.

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1 Energy Friendly Microcontrollers

1.1 Typical Applications

The EFM32LG microcontroller is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive

applications. These devices are developed to minimize the energy consumption by lowering both the

power and the active time, over all phases of MCU operation. This unique combination of ultra low energy

consumption and the performance of the 32-bit ARM Cortex-M3 processor, help designers get more out

of the available energy in a variety of applications.

Ultra low energy EFM32LG microcontrollers are perfect for:

• Gas metering

• Energy metering

• Water metering

• Smart metering

• Alarm and security systems

• Health and fitness applications

• Industrial and home automation

01 2 3 4

1.2 EFM32LG Development

Because EFM32LG use the Cortex-M3 CPU, embedded designers benefit from the largest development

ecosystem in the industry, the ARM ecosystem. The development suite spans the whole design

process and includes powerful debug tools, and some of the world’s top brand compilers. Libraries with

documentation and user examples shorten time from idea to market.

The range of EFM32LG devices ensure easy migration and feature upgrade possibilities.

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2 About This Document

This document contains reference material for the EFM32LG series of microcontrollers. All modules and

peripherals in the EFM32LG series devices are described in general terms. Not all modules are present

in all devices, and the feature set for each device might vary. Such differences, including pin-out, are

covered in the device-specific datasheets.

2.1 Conventions

TIMERn_CTRL - Control Register

The "n" denotes the numeric instance for modules that might have more than one instance.

Some registers are grouped which leads to a group name following the module prefix:

GPIO_Px_DOUT - Port Data Out Register,

where x denotes the port instance (A,B,...).

Bit Fields

Registers contain one or more bit fields which can be 1 to 32 bits wide. Multi-bit fields are denoted with

(x:y), where x is the start bit and y is the end bit.

Address

The address for each register can be found by adding the base address of the module (found in the

Memory Map), and the offset address for the register (found in module Register Map).

Access Type

The register access types used in the register descriptions are explained in Table 2.1 (p. 3) .

Table 2.1. Register Access Types

Access Type Description

R Read only. Writes are ignored.

RW Readable and writable.

RW1 Readable and writable. Only writes to 1 have effect.

RW1H Readable, writable and updated by hardware. Only writes to

1 have effect.

W1 Read value undefined. Only writes to 1 have effect.

W Write only. Read value undefined.

RWH Readable, writable and updated by hardware.

Number format

0x prefix is used for hexadecimal numbers.

0b prefix is used for binary numbers.

Numbers without prefix are in decimal representation.

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Reserved

Registers and bit fields marked with reserved are reserved for future use. These should be written to 0

unless otherwise stated in the Register Description. Reserved bits might be read as 1 in future devices.

Reset Value

The reset value denotes the value after reset.

Registers denoted with X have an unknown reset value and need to be initialized before use. Note

that, before these registers are initialized, read-modify-write operations might result in undefined register

values.

Pin Connections

Pin connections are given as a module prefix followed by a short pin name:

USn_TX (USARTn TX pin)

The pin locations referenced in this document are given in the device-specific datasheet.

2.2 Related Documentation

Further documentation on the EFM32LG family and the ARM Cortex-M3 can be found at the Silicon

Laboratories and ARM web pages:

www.silabs.com

www.arm.com

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3 System Overview

3.1 Introduction

The EFM32 MCUs are the world’s most energy friendly microcontrollers. With a unique combination of

the powerful 32-bit ARM Cortex-M3, innovative low energy techniques, short wake-up time from energy

saving modes, and a wide selection of peripherals, the EFM32LG microcontroller is well suited for

any battery operated application, as well as other systems requiring high performance and low-energy

consumption, see Figure 3.1 (p. 5) .

3.2 Block Diagram

Figure 3.1 (p. 5) shows the block diagram of EFM32LG. The color indicates peripheral availability

in the different energy modes, described in Section 3.4 (p. 7) .

Figure 3.1. Block Diagram of EFM32LG

Clock Management Energy Management

Serial Interfaces

I/O Ports

Core and Memory

Timers and Triggers Analog Interfaces Security

32-bit bus

Peripheral Reflex System

ARM Cortex ™-M3 processor

Flash

Program

Memory

LESENSE

High Freq.

Oscillator

High Freq.

Crystal

Oscillator

Timer/

Counter

Low Energy

Timer

Pulse

Counter

Real Time

Counter

Low Freq.

Crystal

Oscillator

Low Freq.

Oscillator

Watchdog

Timer

RAM

Memory

Ext. Bus

Interface

General

Purpose

I/O

Memory

Protection

Unit

DMA

Controller

Debug

Interface

w/ ETM

External

Interrupts

Reset

Hardware

AES

Leopard Gecko

LCD

Controller

ADC

DAC Operational

Amplifier

USB

USART

Low

Energy

UART

Power-on

Reset

Voltage

Regulator

Back-up

Power

Domain

Voltage

Comparator

Brown-out

Detector

TFT

Driver

Back-up

RTC

Wakeup

Ultra Low Freq.

Oscillator

Analog

Comparator

Aux High Freq.

Oscillator

Figure 3.2. Energy Mode Indicator

01 2 3 4

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Note In the energy mode indicator, the numbers indicates Energy Mode, i.e EM0-EM4.

3.3 Features

3.3.1 MCU Features

•ARM Cortex-M3 CPU platform

• High Performance 32-bit processor @ up to 48 MHz

• Memory Protection Unit

• Wake-up Interrupt Controller

•Flexible Energy Management System

• 20 nA @ 3 V Shutoff Mode

• 0.4 µA @ 3 V Shutoff Mode with RTC

• 0.65 µA @ 3 V Stop Mode, including Power-on Reset, Brown-out Detector, RAM and CPU

retention

• 0.95 µA @ 3 V Deep Sleep Mode, including RTC with 32768 Hz oscillator, Power-on

Reset, Brown-out Detector, RAM and CPU retention

• 63 µA/MHz @ 3 V Sleep Mode

• 211 µA/MHz @ 3 V Run Mode, with code executed from flash

•256/128/64 KB Flash

•32 KB RAM

•Up to 90 General Purpose I/O pins

• Configurable push-pull, open-drain, pull-up/down, input filter, drive strength

• Configurable peripheral I/O locations

• 16 asynchronous external interrupts

• Output state retention and wake-up from Shutoff Mode

•12 Channel DMA Controller

• Alternate/primary descriptors with scatter-gather/ping-pong operation

•12 Channel Peripheral Reflex System

• Autonomous inter-peripheral signaling enables smart operation in low energy modes

•External Bus Interface (EBI)

• Up to 4×256 MB of external memory mapped space

• TFT Controller supporting Direct Drive

•Universal Serial Bus (USB)

• Fully USB 2.0 compliant

• On-chip PHY and embedded 5V to 3.3V regulator

•Integrated LCD Controller for up to 8×36 Segments

• Voltage boost, adjustable contrast adjustment and autonomous animation feature

•Hardware AES with 128/256-bit Keys in 54/75 cycles

•Communication interfaces

• 3× Universal Synchronous/Asynchronous Receiver/Transmitter

• UART/SPI/SmartCard (ISO 7816)/IrDA (USART0)/I2S (USART1+USART2)

• Triple buffered full/half-duplex operation

• 4-16 data bits

• 2× Universal Asynchronous Receiver/Transmitter

• Triple buffered full/half-duplex operation

• 8-9 data bits

• 2× Low Energy UART

• Autonomous operation with DMA in Deep Sleep Mode

• 2× I2C Interface with SMBus support

• Address recognition in Stop Mode

•Timers/Counters

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• 4× 16-bit Timer/Counter

• 3 Compare/Capture/PWM channels

• Dead-Time Insertion on TIMER0

• 16-bit Low Energy Timer

• 1× 24-bit and 1× 32-bit Real-Time Counter

• 3× 8/16-bit Pulse Counter

• Asynchronous pulse counting/quadrature decoding

• Watchdog Timer with dedicated RC oscillator @ 50 nA

•Backup Power Domain

• RTC and retention registers in a separate power domain, available in all energy modes

• Operation from backup battery when main power drains out

•Ultra low power precision analog peripherals

• 12-bit 1 Msamples/s Analog to Digital Converter

• 8 input channels and on-chip temperature sensor

• Single ended or differential operation

• Conversion tailgating for predictable latency

• 12-bit 500 ksamples/s Digital to Analog Converter

• 2 single ended channels/1 differential channel

• Up to 3 Operational Amplifiers

• Supports rail-to-rail inputs and outputs

• Programmable gain

• 2× Analog Comparator

• Programmable speed/current

• Capacitive sensing with up to 8 inputs

• Supply Voltage Comparator

•Ultra low power sensor interface

• Autonomous sensor monitoring in Deep Sleep Mode

• Wide range of sensors supported, including LC sensors and capacitive buttons

3.3.2 System Features

•Ultra efficient Power-on Reset and Brown-Out Detector

•Debug Interface

• 2-pin Serial Wire Debug interface

• 1-pin Serial Wire Viewer

• Embedded Trace Module v3.5 (ETM)

•Temperature range -40 - 85°C

•Single power supply 1.98 - 3.8 V

•Packages

• QFN64

3.4 Energy Modes

There are five different Energy Modes (EM0-EM4) in the EFM32LG, see Table 3.1 (p. 8) . The

EFM32LG is designed to achieve a high degree of autonomous operation in low energy modes. The

intelligent combination of peripherals, RAM with data retention, DMA, low-power oscillators, and short

wake-up time, makes it attractive to remain in low energy modes for long periods and thus saving energy

consumption.

Tip

Throughout this document, the first figure in every module description contains an Energy Mode

Indicator showing which energy mode(s) the module can operate (see Table 3.1 (p. 8) ).

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Table 3.1. Energy Mode Description

Energy Mode Name Description

01 2 3 4 EM0 – Energy Mode 0

(Run mode)

In EM0, the CPU is running and consuming as little as 211 µA/MHz, when

running code from flash. All peripherals can be active.

01 2 3 4 EM1 – Energy Mode 1

(Sleep Mode) In EM1, the CPU is sleeping and the power consumption is only 63 µA/MHz.

All peripherals, including DMA, PRS and memory system, are still available.

01 2 3 4 EM2 – Energy Mode 2

(Deep Sleep Mode)

In EM2 the high frequency oscillator is turned off, but with the 32.768 kHz

oscillator running, selected low energy peripherals (LCD, RTC, LETIMER,

PCNT, LEUART, I2C, LESENSE, OPAMP, USB, WDOG and ACMP) are still

available. This gives a high degree of autonomous operation with a current

consumption as low as 0.95 µA with RTC enabled. Power-on Reset, Brown-

out Detection and full RAM and CPU retention is also included.

01 2 3 4 EM3 - Energy Mode 3

(Stop Mode)

In EM3, the low-frequency oscillator is disabled, but there is still full CPU

and RAM retention, as well as Power-on Reset, Pin reset, EM4 wake-up and

Brown-out Detection, with a consumption of only 0.65 µA. The low-power

ACMP, asynchronous external interrupt, PCNT, and I2C can wake-up the

device. Even in this mode, the wake-up time is a few microseconds.

01 2 3 4 EM4 – Energy Mode 4

(Shutoff Mode)

In EM4, the current is down to 20 nA and all chip functionality is turned off

except the pin reset, GPIO pin wake-up, GPIO pin retention, Backup RTC

(including retention RAM) and the Power-On Reset. All pins are put into their

reset state.

3.5 Product Overview

Table 3.2 (p. 8) shows a device overview of the EFM32LG Microcontroller Series, including

peripheral functionality. For more information, the reader is referred to the device specific datasheets.

Table 3.2. EFM32LG Microcontroller Series

EFM32LG Part

Flash

RAM

GPIO(pins)

USB

LCD

USART+UART

LEUART

I2C

Timer(PWM)

LETIMER

RTC

PCNT

Watchdog

ADC(pins)

DAC(pins)

ACMP(pins)

AES

EBI

LESENSE

Op-Amps

Package

230F256 256 32 56 - - 3 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y - Y 3 QFN64

232F256 256 32 53 - - 3 2 2 4

(11) 1 1311

(8) 2

(2) 2

(16) Y - Y 3 TQFP64

280F256 256 32 86 - - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 LQFP100

290F256 256 32 90 - - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 LFBGA112

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EFM32LG Part

Flash

RAM

GPIO(pins)

USB

LCD

USART+UART

LEUART

I2C

Timer(PWM)

LETIMER

RTC

PCNT

Watchdog

ADC(pins)

DAC(pins)

ACMP(pins)

AES

EBI

LESENSE

Op-Amps

Package

295F64 64 32 93 - - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 VFBGA120

295F128 128 32 93 - - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 VFBGA120

295F256 256 32 93 - - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 VFBGA120

330F64 64 32 53 Y - 3 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y - Y 3 QFN64

330F128 128 32 53 Y - 3 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y - Y 3 QFN64

330F256 256 32 53 Y - 3 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y - Y 3 QFN64

332F64 64 32 50 Y - 3 2 2 4

(11) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 TQFP64

332F128 128 32 50 Y - 3 2 2 4

(11) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 TQFP64

332F256 256 32 50 Y - 3 2 2 4

(11) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 TQFP64

360F64 64 32 65 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y - Y 3 CSP81

360F128 128 32 65 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y - Y 3 CSP81

360F256 256 32 65 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y - Y 3 CSP81

380F64 64 32 83 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y Y 3 LQFP100

380F128 128 32 83 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y Y 3 LQFP100

380F256 256 32 83 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y Y 3 LQFP100

390F64 64 32 87 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y Y 3 LFBGA112

390F128 128 32 87 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y Y 3 LFBGA112

390F256 256 32 87 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y Y 3 LFBGA112

395F64 64 32 93 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 VFBGA120

395F128 128 32 93 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 VFBGA120

395F256 256 32 93 Y - 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y Y 3 VFBGA120

840F256 256 32 56 - 8x20 3 2 2 4

(12) 1 1311

(8) 2

(2) 2

(8) Y - Y 3 QFN64

842F256 256 32 53 - 8x18 3 2 2 4

(11) 1 1311

(8) 2

(2) 2

(8) Y - Y 3 TQFP64

880F256 256 32 86 - 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 LQFP100

890F256 256 32 90 - 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 LFBGA112

895F64 64 32 93 - 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 VFBGA120

895F128 128 32 93 - 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 VFBGA120

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EFM32LG Part

Flash

RAM

GPIO(pins)

USB

LCD

USART+UART

LEUART

I2C

Timer(PWM)

LETIMER

RTC

PCNT

Watchdog

ADC(pins)

DAC(pins)

ACMP(pins)

AES

EBI

LESENSE

Op-Amps

Package

895F256 256 32 93 - 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 VFBGA120

900F256 256 32 93 Y 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 Wafer

940F64 64 32 53 Y 8x18 3 2 2 4

(12) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 QFN64

940F128 128 32 53 Y 8x18 3 2 2 4

(12) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 QFN64

940F256 256 32 53 Y 8x18 3 2 2 4

(12) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 QFN64

942F64 64 32 50 Y 8x16 3 2 2 4

(11) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 TQFP64

942F128 128 32 50 Y 8x16 3 2 2 4

(11) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 TQFP64

942F256 256 32 50 Y 8x16 3 2 2 4

(11) 1 1311

(8) 2

(2) 1

(4) Y - Y 3 TQFP64

980F64 64 32 83 Y 8x34 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y1Y 3 LQFP100

980F128 128 32 83 Y 8x34 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y1Y 3 LQFP100

980F256 256 32 83 Y 8x34 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y1Y 3 LQFP100

990F64 64 32 87 Y 8x34 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y1Y 3 LFBGA112

990F128 128 32 87 Y 8x34 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y1Y 3 LFBGA112

990F256 256 32 87 Y 8x34 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(12) Y Y1Y 3 LFBGA112

995F64 64 32 93 Y 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 VFBGA120

995F128 128 32 93 Y 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 VFBGA120

995F256 256 32 93 Y 8x36 3+2 2 2 4

(12) 1 1311

(8) 2

(2) 2

(16) Y Y1Y 3 VFBGA120

1EBI and LCD share pins in the part. Only a reduced pin count LCD driver can be used simultaneously with the EBI.

3.6 Device Revision

The device revision number is read from the ROM Table. The major revision number and the chip family

number is read from PID0 and PID1 registers. The minor revision number is extracted from the PID2 and

PID3 registers, as illustrated in Figure 3.3 (p. 11) . The Fam[5:2] and Fam[1:0] must be combined

to complete the chip family number, while the Minor Rev[7:4] and Minor Rev[3:0] must be combined to

form the complete revision number.

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Figure 3.3. Revision Number Extraction

PID1 (0xE00FFFE4)

31:4 3:0

PID0 (0xE00FFFE0)

31:8 7:6 5:0

Major Rev[5:0]

PID3 (0xE00FFFEC)

31:8 7:4 3:0

Minor Rev[3:0]

Fam[1:0] Fam[5:2]

PID2 (0xE00FFFE8)

31:8 7:4 3:0

Minor Rev[7:4]

For the latest revision of the Leopard Gecko family, the chip family number is 0x02 and the major revision

number is 0x02. For earlier revisions of the Leopard Gecko family, the chip family number is 0x03

and the major revision number is 0x01. The minor revision number is to be interpreted according to

Table 3.3 (p. 11) .

Table 3.3. Minor Revision Number Interpretation

Minor Rev[7:0] Revision

0x00 A

0x01 B

0x02 C

0x03 D

0x04 E

3.6.1 Revision Specific Behaviour

Some functional differences exist between the revisions and the user is referred to the errata document

for an overview of erratas that apply to the EFM32LG. This document can be found in Simplicity Studio

and online at:

http://www.silabs.com/support/pages/document-library.aspx?p=MCUs--32-bit

In addition, there are a couple of differences not covered by any errata, as new functionality is added

to later revisions. Those differences are listed here.

3.6.1.1 Revision E

EMU_BUCTRL_BUMODEBODEN is added. This enables the BUBODUNREG-bod to be sensing on

BU_VIN in backup mode, and when it senses a brown-out it should trigger a reset (and switch back to

main power). Setting this bit on previous revisions will not enable this BOD in backup mode.

USART_CTRL_SMSDELAY/SSSEARLY is added. USART_CTRL_SMSDELAY allows the master to

delay the sampling to the next setup edge while USART_CTRL_SSSEARLY will make the slave setup

data on the sample edge. Setting this bit on previous revisions will not enable this functionality.

The maximum clock frequency for the Low Energy (LE) peripherals is now 12 MHz. For earlier chip

revisions the max LE peripheral clock frequency was 16 MHz. This means the CMU_CTRL_HFLE bit

needs to be set when using HFCORECLK above 24 MHz and this is selected as the clock source for

the LE peripherals.

The reset-value of CMU_CTRL_LFXOBOOST is changed to 0x1.

Chip family number is 0x02. Major revision number is 0x02.

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4 System Processor

01 2 3 4

CM3 Core

32-bit ALU

Control Logic Thumb & Thumb-2

Decode

Instruction Interface Data Interface

NVIC Interface

Single cycle

32-bit multiplier

Hardware divider

Memory Protection Unit

Quick Facts

What?

The industry leading Cortex-M3 processor

from ARM is the CPU in the EFM32LG

microcontrollers.

Why?

The ARM Cortex-M3 is designed for

exceptional short response time, high

code density, and high 32-bit throughput

while maintaining a strict cost and power

consumption budget.

How?

Combined with the ultra low energy

peripherals available, the Cortex-M3 makes

the EFM32LG devices perfect for 8- to 32-

bit applications. The processor is featuring a

Harvard architecture, 3 stage pipeline, single

cycle instructions, Thumb-2 instruction set

support, and fast interrupt handling.

4.1 Introduction

The ARM Cortex-M3 32-bit RISC processor provides outstanding computational performance and

exceptional system response to interrupts while meeting low cost requirements and low power

consumption.

The ARM Cortex-M3 implemented is revision r2p1.

4.2 Features

• Harvard Architecture

• Separate data and program memory buses (No memory bottleneck as for a single-bus system)

• 3-stage pipeline

• Thumb-2 instruction set

• Enhanced levels of performance, energy efficiency, and code density

• Single-cycle multiply and efficient divide instructions

• 32-bit multiplication in a single cycle

• Signed and unsigned divide operations between 2 and 12 cycles

• Atomic bit manipulation with bit banding

• Direct access to single bits of data

• Two 1MB bit banding regions for memory and peripherals mapping to 32MB alias regions

• Atomic operation which cannot be interrupted by other bus activities

• 1.25 DMIPS/MHz

• Memory Protection Unit

• Up to 8 protected memory regions

• 24-bit System Tick Timer for Real-Time Operating System (RTOS)

• Excellent 32-bit migration choice for 8/16 bit architecture based designs

• Simplified stack-based programmer's model is compatible with traditional ARM architecture and

retains the programming simplicity of legacy 8- and 16-bit architectures

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• Unaligned data storage and access

• Continuous storage of data requiring different byte lengths

• Data access in a single core clock cycle

• Integrated power modes

• Sleep Now mode for immediate transfer to low power state

• Sleep on Exit mode for entry into low power state after the servicing of an interrupt

• Ability to extend power savings to other system components

• Optimized for low latency, nested interrupts

4.3 Functional Description

For a full functional description of the ARM Cortex-M3 (r2p1) implementation in the EFM32LG family,

the reader is referred to the EFM32 Cortex-M3 Reference Manual.

4.3.1 Interrupt Operation

Figure 4.1. Interrupt Operation

Module Cortex-M3 NVIC

IEN[n]

IF[n]

set clear

IFS[n] IFC[n]

Interrupt

condition IRQ

SETENA[n]/CLRENA[n]

Interrupt

request

SETPEND[n]/CLRPEND[n]

set clear

Active interrupt

Software generated interrupt

The EFM32LG devices have up to 38 interrupt request lines (IRQ) which are connected to the Cortex-

M3. Each of these lines (shown in Table 4.1 (p. 13) ) are connected to one or more interrupt flags in

one or more modules. The interrupt flags are set by hardware on an interrupt condition. It is also possible

to set/clear the interrupt flags through the IFS/IFC registers. Each interrupt flag is then qualified with its

own interrupt enable bit (IEN register), before being OR'ed with the other interrupt flags to generate the

IRQ. A high IRQ line will set the corresponding pending bit (can also be set/cleared with the SETPEND/

CLRPEND bits in ISPR0/ICPR0) in the Cortex-M3 NVIC. The pending bit is then qualified with an enable

bit (set/cleared with SETENA/CLRENA bits in ISER0/ICER0) before generating an interrupt request to

the core. Figure 4.1 (p. 13) illustrates the interrupt system. For more information on how the interrupts

are handled inside the Cortex-M3, the reader is referred to the EFM32 Cortex-M3 Reference Manual.

Table 4.1. Interrupt Request Lines (IRQ)

IRQ # Source

0 DMA

1 GPIO_EVEN

2 TIMER0

3 USART0_RX

4 USART0_TX

5 USB

6 ACMP0/ACMP1

7 ADC0

8 DAC0

9 I2C0

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IRQ # Source

10 I2C1

11 GPIO_ODD

12 TIMER1

13 TIMER2

14 TIMER3

15 USART1_RX

16 USART1_TX

17 LESENSE

18 USART2_RX

19 USART2_TX

20 UART0_RX

21 UART0_TX

22 UART1_RX

23 UART1_TX

24 LEUART0

25 LEUART1

26 LETIMER0

27 PCNT0

28 PCNT1

29 PCNT2

30 RTC

31 BURTC

32 CMU

33 VCMP

34 LCD

35 MSC

36 AES

37 EBI

38 EMU

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5 Memory and Bus System

01 2 3 4

ARM Cortex-M3

DMA Controller

RAM

Peripherals

Flash

EBI

Quick Facts

What?

A low latency memory system, including low

energy flash and RAM with data retention,

makes extended use of low-power energy-

modes possible.

Why?

RAM retention reduces the need for storing

data in flash and enables frequent use of the

ultra low energy modes EM2 and EM3 with

as little as 0.65 µA current consumption.

How?

Low energy and non-volatile flash memory

stores program and application data

in all energy modes and can easily be

reprogrammed in system. Low leakage RAM,

with data retention in EM0 to EM3, removes

the data restore time penalty, and the DMA

ensures fast autonomous transfers with

predictable response time.

5.1 Introduction

The EFM32LG contains an AMBA AHB Bus system allowing bus masters to access the memory mapped

address space. A multilayer AHB bus matrix, using a Round-robin arbitration scheme, connects the

master bus interfaces to the AHB slaves (Figure 5.1 (p. 16) ). The bus matrix allows several AHB

slaves to be accessed simultaneously. An AMBA APB interface is used for the peripherals, which are

accessed through an AHB-to-APB bridge connected to the AHB bus matrix. The AHB bus masters are:

•Cortex-M3 ICode: Used for instruction fetches from Code memory (0x00000000 - 0x1FFFFFFF).

•Cortex-M3 DCode: Used for debug and data access to Code memory (0x00000000 - 0x1FFFFFFF).

•Cortex-M3 System: Used for instruction fetches, data and debug access to system space

(0x20000000 - 0xDFFFFFFF).

•DMA: Can access EBI, SRAM, Flash and peripherals (0x00000000 - 0xDFFFFFFF).

•USB DMA: Can access EBI, SRAM and Flash (0x80000000 - 0xDFFFFFFF, 0x00000000 -

0x3FFFFFFF), and the AHB-peripherals: USB and AES.

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Figure 5.1. EFM32LG Bus System

Cortex AHB Multilayer

Bus Matrix

DCode

System

USB DMA

Flash

RAM

EBI

AHB/APB

Bridge

ICode

AES

Peripheral 0

Peripheral n

DMA

USB

5.2 Functional Description

The memory segments are mapped together with the internal segments of the Cortex-M3 into the system

memory map shown by Figure 5.2 (p. 17)

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Figure 5.2. System Address Space

The embedded SRAM is located at address 0x20000000 in the memory map of the EFM32LG. When

running code located in SRAM starting at this address, the Cortex-M3 uses the System bus to fetch

instructions. This results in reduced performance as the Cortex-M3 accesses stack, other data in SRAM

and peripherals using the System bus. To be able to run code from SRAM efficiently, the SRAM is also

mapped in the code space at address 0x10000000. When running code from this space, the Cortex-M3

fetches instructions through the I/D-Code bus interface, leaving the System bus for data access. The

SRAM mapped into the code space can however only be accessed by the CPU, i.e. not the DMA.

5.2.1 Bit-banding

The SRAM bit-band alias and peripheral bit-band alias regions are located at 0x22000000 and

0x42000000 respectively. Read and write operations to these regions are converted into masked single-

bit reads and atomic single-bit writes to the embedded SRAM and peripherals of the EFM32LG.

The standard approach to modify a single register or SRAM bit in the aliased regions, requires software

to read the value of the byte, half-word or word containing the bit, modify the bit, and then write the byte,

half-word or word back to the register or SRAM address. Using bit-banding, this read-modify-write can

be done in a single atomic operation. As read-writeback, bit-masking and bit-shift operations are not

necessary in software, code size is reduced and execution speed improved.

The bit-band regions allows addressing each individual bit in the SRAM and peripheral areas of the

memory map. To set or clear a bit in the embedded SRAM, write a 1 or a 0 to the following address:

Memory SRAM Area Set/Clear Bit

bit_address = 0x22000000 + (address – 0x20000000) × 32 + bit × 4, (5.1)

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where address is the address of the 32-bit word containing the bit to modify, and bit is the index of the

bit in the 32-bit word.

To modify a bit in the Peripheral area, use the following address:

Memory Peripheral Area Bit Modification

bit_address = 0x42000000 + (address – 0x40000000) × 32 + bit × 4, (5.2)

where address and bit are defined as above.

Note that the AHB-peripherals USB and AES does not support bit-banding.

5.2.2 Peripherals

The peripherals are mapped into the peripheral memory segment, each with a fixed size address range

according to Table 5.1 (p. 18) , Table 5.2 (p. 18) and Table 5.3 (p. 19) .

Table 5.1. Memory System Core Peripherals

Core peripherals

Address Range Module Name

0xE0041000 - 0xE0080FFF ETM

0x400E0000 - 0x400E03FF AES

0x400CA000 - 0x400CA3FF RMU

0x400C8000 - 0x400C83FF CMU

0x400C6000 - 0x400C63FF EMU

0x400C4000 - 0x400C43FF USB

0x400C2000 - 0x400C3FFF DMA

0x400C1C00 - 0x400C1FFF FPUEH

0x400C0000 - 0x400C03FF MSC

0x40008000 - 0x400083FF EBI

Table 5.2. Memory System Low Energy Peripherals

Low Energy peripherals

Address Range Module Name

0x4008C000 - 0x4008C3FF LESENSE

0x4008A000 - 0x4008A3FF LCD

0x40088000 - 0x400883FF WDOG

0x40086800 - 0x40086BFF PCNT2

0x40086400 - 0x400867FF PCNT1

0x40086000 - 0x400863FF PCNT0

0x40084400 - 0x400847FF LEUART1

0x40084000 - 0x400843FF LEUART0

0x40082000 - 0x400823FF LETIMER0

0x40081000 - 0x400813FF BURTC

0x40080000 - 0x400803FF RTC

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Table 5.3. Memory System Peripherals

Peripherals

Address Range Module Name

0x400CC000 - 0x400CC3FF PRS

0x40010C00 - 0x40010FFF TIMER3

0x40010800 - 0x40010BFF TIMER2

0x40010400 - 0x400107FF TIMER1

0x40010000 - 0x400103FF TIMER0

0x4000E400 - 0x4000E7FF UART1

0x4000E000 - 0x4000E3FF UART0

0x4000C800 - 0x4000CBFF USART2

0x4000C400 - 0x4000C7FF USART1

0x4000C000 - 0x4000C3FF USART0

0x4000A400 - 0x4000A7FF I2C1

0x4000A000 - 0x4000A3FF I2C0

0x40006000 - 0x40006FFF GPIO

0x40004000 - 0x400043FF DAC0

0x40002000 - 0x400023FF ADC0

0x40001400 - 0x400017FF ACMP1

0x40001000 - 0x400013FF ACMP0

0x40000000 - 0x400003FF VCMP

5.2.3 Bus Matrix

The Bus Matrix connects the memory segments to the bus masters:

• Code: CPU instruction or data fetches from the code space

• System: CPU read and write to the SRAM, EBI and peripherals

• DMA: Access to EBI, SRAM, Flash and peripherals

• USB DMA: Access to EBI, SRAM and Flash

5.2.3.1 Arbitration

The Bus Matrix uses a round-robin arbitration algorithm which enables high throughput and low latency

while starvation of simultaneous accesses to the same bus slave are eliminated. Round-robin does not

assign a fixed priority to each bus master. The arbiter does not insert any bus wait-states.

5.2.3.2 Access Performance

The Bus Matrix is a multi-layer energy optimized AMBA AHB compliant bus with an internal bandwidth

equal to 4 times a single AHB-bus.

The Bus Matrix accepts new transfers initiated by each master in every clock cycle without inserting

any wait-states. The slaves, however, may insert wait-states depending on their internal throughput and

the clock frequency.

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The Cortex-M3, the DMA Controller, and the peripherals run on clocks that can be prescaled separately.

When accessing a peripheral which runs on a frequency equal to or faster than the HFCORECLK, the

number of wait cycles per access, in addition to master arbitration, is given by:

Memory Wait Cycles with Clock Equal or Faster than HFCORECLK

Ncycles = 2 + Nslave cycles, (5.3)

where Nslave cycles is the wait cycles introduced by the slave.

When accessing a peripheral running on a clock slower than the HFCORECLK, wait-cycles are

introduced to allow the transfer to complete on the peripheral clock. The number of wait cycles per

access, in addition to master arbitration, is given by:

Memory Wait Cycles with Clock Slower than CPU

Ncycles = (2 + Nslave cycles) x fHFCORECLK/fHFPERCLK, (5.4)

where Nslave cycles is the number of wait cycles introduced by the slave.

For general register access, Nslave cycles = 1.

More details on clocks and prescaling can be found in Chapter 11 (p. 124) .

5.3 Access to Low Energy Peripherals (Asynchronous Registers)

5.3.1 Introduction

The Low Energy Peripherals are capable of running when the high frequency oscillator and core system

is powered off, i.e. in energy mode EM2 and in some cases also EM3. This enables the peripherals to

perform tasks while the system energy consumption is minimal.

The Low Energy Peripherals are:

• Liquid Crystal Display driver - LCD

• Low Energy Timer - LETIMER

• Low Energy UART - LEUART

• Pulse Counter - PCNT

• Real Time Counter - RTC

• Watchdog - WDOG

• Low Energy Sensor Interface - LESENSE

• Backup RTC - BURTC

All Low Energy Peripherals are memory mapped, with automatic data synchronization. Because the Low

Energy Peripherals are running on clocks asynchronous to the core clock, there are some constraints

on how register accesses can be done, as described in the following sections.

5.3.1.1 Writing

Every Low Energy Peripheral has one or more registers with data that needs to be synchronized into

the Low Energy clock domain to maintain data consistency and predictable operation. There are two

different synchronization mechanisms on the Leopard Gecko; immediate synchronization, and delayed

synchronization. Immediate synchronization is available for the RTC, LETIMER and LESENSE, and

results in an immediate update of the target registers. Delayed synchronization is used for the other

Low Energy Peripherals, and for these peripherals, a write operation requires 3 positive edges on the

clock of the Low Energy Peripheral being accessed. Registers requiring synchronization are marked

"Asynchronous" in their description header.

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5.3.1.1.1 Delayed synchronization

After writing data to a register which value is to be synchronized into the Low Energy Peripheral using

delayed synchronization, a corresponding busy flag in the <module_name>_SYNCBUSY register (e.g.

LEUART_SYNCBUSY) is set. This flag is set as long as synchronization is in progress and is cleared

upon completion.

Note Subsequent writes to the same register before the corresponding busy flag is cleared is not

supported. Write before the busy flag is cleared may result in undefined behavior.

In general, the SYNCBUSY register only needs to be observed if there is a risk of multiple

write access to a register (which must be prevented). It is not required to wait until the

relevant flag in the SYNCBUSY register is cleared after writing a register. E.g EM2 can be

entered immediately after writing a register.

See Figure 5.3 (p. 21) for a more detailed overview of the write operation.

Figure 5.3. Write operation to Low Energy Peripherals

Synchronizer 0

Synchronizer 1

Synchronizer n

Write[0:n]

Syncbusy Register 0

Syncbusy Register 1

Syncbusy Register n

Set 0

Set 1

Set n

Freeze

Synchronization Done

Clear 0

Clear 1

Clear n

Core Clock Low Frequency Clock Low Frequency Clock

Core Clock Domain Low Frequency Clock Domain

5.3.1.1.2 Immediate synchronization

Contrary to the peripherals with delayed synchronization, data written to peripherals with immediate

synchronization, takes effect in the peripheral immediately. They are updated immediately on the

peripheral write access. If a write is set up close to a peripheral clock edge, the write is delayed to after

the clock edge. This will introduce wait-states on peripheral access. In the worst case, there can be three

wait-state cycles of the HFCORECLK_LE and an additional wait-state equivalent of up to 315 ns.

For peripherals with immediate synchronization, the SYNCBUSY registers are still present and serve two

purposes: (1) commands written to a peripheral with immediate synchronization are not executed before

the first peripheral clock after the write. During this period, the SYNCBUSY flag in the command register

is set, indicating that the command has not yet been executed; (2) to maintain backwards compatibility

with the EFM32G series, SYNCBUSY registers are also present for other registers. These are however,

always 0, indicating that register writes are always safe.

Note If the application must be compatible with the EFM32G series, all Low Energy Peripherals

should be accessed as if they only had delayed synchronization, i.e. using SYNCBUSY.

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5.3.1.2 Reading

When reading from Low Energy Peripherals, the data is synchronized regardless of the originating clock

domain. Registers updated/maintained by the Low Energy Peripheral are read directly from the Low

Energy clock domain. Registers residing in the core clock domain, are read from the core clock domain.

See Figure 5.4 (p. 22) for a more detailed overview of the read operation.

Note Writing a register and then immediately reading back the value of the register may give the

impression that the write operation is complete. This is not necessarily the case. Please

refer to the SYNCBUSY register for correct status of the write operation to the Low Energy

Peripheral.

Figure 5.4. Read operation from Low Energy Peripherals

Synchronizer 0

Synchronizer 1

Synchronizer n

Freeze

Core Clock Low Frequency Clock Low Frequency Clock

Core Clock Domain Low Frequency Clock Domain

Low Energy

Peripheral

Main

Function

HW Status Register 0

HW Status Register 1

HW Status Register m

Read

Synchronizer

Read Data

5.3.2 FREEZE register

For Low Energy Peripherals with delayed synchronization there is a <module_name>_FREEZE register

(e.g. RTC_FREEZE), containing a bit named REGFREEZE. If precise control of the synchronization

process is required, this bit may be utilized. When REGFREEZE is set, the synchronization process is

halted, allowing the software to write multiple Low Energy registers before starting the synchronization

process, thus providing precise control of the module update process. The synchronization process is

started by clearing the REGFREEZE bit.

Note The FREEZE register is also present on peripherals with immediate synchronization, but

has no effect.

5.4 Flash

The Flash retains data in any state and typically stores the application code, special user data and

security information. The Flash memory is typically programmed through the debug interface, but can

also be erased and written to from software.

• Up to 256 kB of memory

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• Page size of 2048 bytes (minimum erase unit)

• Minimum 20 000 erase cycles

• More than 10 years data retention at 85°C

• Lock-bits for memory protection

• Data retention in any state

5.5 SRAM

The primary task of the SRAM memory is to store application data. Additionally, it is possible to execute

instructions from SRAM, and the DMA may used to transfer data between the SRAM, Flash and

peripherals.

• Up to 32 kB memory

• Bit-band access support

• Data retention of the entire memory in EM0 to EM3

5.6 Device Information (DI) Page

The DI page contains calibration values, a unique identification number and other useful data. See the

table below for a complete overview.

Table 5.4. Device Information Page Contents

DI Address Register Description

0x0FE08020 CMU_LFRCOCTRL Register reset value.

0x0FE08028 CMU_HFRCOCTRL Register reset value.

0x0FE08030 CMU_AUXHFRCOCTRL Register reset value.

0x0FE08040 ADC0_CAL Register reset value.

0x0FE08048 ADC0_BIASPROG Register reset value.

0x0FE08050 DAC0_CAL Register reset value.

0x0FE08058 DAC0_BIASPROG Register reset value.

0x0FE08060 ACMP0_CTRL Register reset value.

0x0FE08068 ACMP1_CTRL Register reset value.

0x0FE08078 CMU_LCDCTRL Register reset value.

0x0FE080A0 DAC0_OPACTRL Register reset value.

0x0FE080A8 DAC0_OPAOFFSET Register reset value.

0x0FE080B0 EMU_BUINACT Register reset value.

0x0FE080B8 EMU_BUACT Register reset value.

0x0FE080C0 EMU_BUBODBUVINCAL Register reset value.

0x0FE080C8 EMU_BUBODUNREGCAL Register reset value.

0x0FE081B0 DI_CRC [15:0]: DI data CRC-16.

0x0FE081B2 CAL_TEMP_0 [7:0] Calibration temperature (°C).

0x0FE081B4 ADC0_CAL_1V25 [14:8]: Gain for 1V25 reference, [6:0]: Offset for 1V25

reference.

0x0FE081B6 ADC0_CAL_2V5 [14:8]: Gain for 2V5 reference, [6:0]: Offset for 2V5

reference.

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DI Address Register Description

0x0FE081B8 ADC0_CAL_VDD [14:8]: Gain for VDD reference, [6:0]: Offset for VDD

reference.

0x0FE081BA ADC0_CAL_5VDIFF [14:8]: Gain for 5VDIFF reference, [6:0]: Offset for 5VDIFF

reference.

0x0FE081BC ADC0_CAL_2XVDD [14:8]: Reserved (gain for this reference cannot be

calibrated), [6:0]: Offset for 2XVDD reference.

0x0FE081BE ADC0_TEMP_0_READ_1V25 [15:4] Temperature reading at 1V25 reference, [3:0]

Reserved.

0x0FE081C8 DAC0_CAL_1V25 [22:16]: Gain for 1V25 reference, [13:8]: Channel 1 offset for

1V25 reference, [5:0]: Channel 0 offset for 1V25 reference.

0x0FE081CC DAC0_CAL_2V5 [22:16]: Gain for 2V5 reference, [13:8]: Channel 1 offset for

2V5 reference, [5:0]: Channel 0 offset for 2V5 reference.

0x0FE081D0 DAC0_CAL_VDD [22:16]: Reserved (gain for this reference cannot be

calibrated), [13:8]: Channel 1 offset for VDD reference, [5:0]:

Channel 0 offset for VDD reference.

0x0FE081D4 AUXHFRCO_CALIB_BAND_1 [7:0]: Tuning for the 1.2 MHZ AUXHFRCO band.

0x0FE081D5 AUXHFRCO_CALIB_BAND_7 [7:0]: Tuning for the 6.6 MHZ AUXHFRCO band.

0x0FE081D6 AUXHFRCO_CALIB_BAND_11 [7:0]: Tuning for the 11 MHZ AUXHFRCO band.

0x0FE081D7 AUXHFRCO_CALIB_BAND_14 [7:0]: Tuning for the 14 MHZ AUXHFRCO band.

0x0FE081D8 AUXHFRCO_CALIB_BAND_21 [7:0]: Tuning for the 21 MHZ AUXHFRCO band.

0x0FE081D9 AUXHFRCO_CALIB_BAND_28 [7:0]: Tuning for the 28 MHZ AUXHFRCO band.

0x0FE081DC HFRCO_CALIB_BAND_1 [7:0]: Tuning for the 1.2 MHZ HFRCO band.

0x0FE081DD HFRCO_CALIB_BAND_7 [7:0]: Tuning for the 6.6 MHZ HFRCO band.

0x0FE081DE HFRCO_CALIB_BAND_11 [7:0]: Tuning for the 11 MHZ HFRCO band.

0x0FE081DF HFRCO_CALIB_BAND_14 [7:0]: Tuning for the 14 MHZ HFRCO band.

0x0FE081E0 HFRCO_CALIB_BAND_21 [7:0]: Tuning for the 21 MHZ HFRCO band.

0x0FE081E1 HFRCO_CALIB_BAND_28 [7:0]: Tuning for the 28 MHZ HFRCO band.

0x0FE081E7 MEM_INFO_PAGE_SIZE [7:0] Flash page size in bytes coded as 2 ^

((MEM_INFO_PAGE_SIZE + 10) & 0xFF). Ie. the value

0xFF = 512 bytes.

0x0FE081F0 UNIQUE_0 [31:0] Unique number.

0x0FE081F4 UNIQUE_1 [63:32] Unique number.

0x0FE081F8 MEM_INFO_FLASH [15:0]: Flash size, kbyte count as unsigned integer (eg.

128).

0x0FE081FA MEM_INFO_RAM [15:0]: Ram size, kbyte count as unsigned integer (eg. 16).

0x0FE081FC PART_NUMBER [15:0]: EFM32 part number as unsigned integer (eg. 230).

0x0FE081FE PART_FAMILY [7:0]: EFM32 part family number (Gecko = 71, Giant Gecko

= 72, Tiny Gecko = 73, Leopard Gecko=74, Wonder

Gecko=75).

0x0FE081FF PROD_REV [7:0]: EFM32 Production ID.

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6 DBG - Debug Interface

01 2 3 4

ARM Cortex-M3

DBG Debug Data

Quick Facts

What?

The DBG (Debug Interface) is used to

program and debug EFM32LG devices.

Why?

The Debug Interface makes it easy to re-

program and update the system in the field,

and allows debugging with minimal I/O pin

usage.

How?

The Cortex-M3 supports advanced

debugging features. EFM32LG devices

only use two port pins for debugging or

programming. The internal and external state

of the system can be examined with debug

extensions supporting instruction or data

access break- and watch points.

6.1 Introduction

The EFM32LG devices include hardware debug support through a 2-pin serial-wire debug (SWD)

interface and an Embedded Trace Module (ETM) for data/instruction tracing. In addition, there is also

a Serial Wire Viewer pin which can be used to output profiling information, data trace and software-

generated messages.

For more technical information about the debug interface the reader is referred to:

• ARM Cortex-M3 Technical Reference Manual

• ARM CoreSight Components Technical Reference Manual

• ARM Debug Interface v5 Architecture Specification

6.2 Features

• Flash Patch and Breakpoint (FPB) unit

• Implement breakpoints and code patches

• Data Watch point and Trace (DWT) unit

• Implement watch points, trigger resources and system profiling

• Instrumentation Trace Macrocell (ITM)

• Application-driven trace source that supports printf style debugging

• Embedded Trace Macrocell v3.5 (ETM)

• Real time instruction and data trace information of the processor

6.3 Functional Description

There are three debug pins and four trace pins available on the device. Operation of these pins are

described in the following section.

6.3.1 Debug Pins

The following pins are the debug connections for the device:

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• Serial Wire Clock input (SWCLK): This pin is enabled after reset and has a built-in pull down.

• Serial Wire Data Input/Output (SWDIO): This pin is enabled after reset and has a built-in pull-up.

• Serial Wire Viewer (SWV): This pin is disabled after reset.

The debug pins can be enabled and disabled through GPIO_ROUTE, see Section 32.3.4.1 (p. 761)

. Please remeberer that upon disabling, debug contact with the device is lost. Also note that, because

the debug pins have pull-down and pull-up enabled by default, leaving them enabled might increase the

current consumption with up to 200 µA if left connected to supply or ground.

6.3.2 Embedded Trace Macrocell v3.5 (ETM)

The ETM makes it possible to trace both instruction and data from the processor in real time. The

trace can be controlled through a set of triggering and filtering resources. The resources include 4

address comparators, 2 data value comparators, 2 counters, a context ID comparator and a sequencer.

Before enabling the ETM, the AUXHFRCO clock needs to be enabled by setting AUXHFRCOEN in

CMU_OSCENCMD. The trace can be exported through a set of trace pins, which include:

• Trace Clock (TCLK): Functions as a sample clock for the trace. This pin is disabled after reset.

• Trace Data 0 - Trace Data 3 (TD0-TD3): The data pins provide the compressed trace stream. These

pins are disabled after reset.

For information on how to configure the ETM, see the ARM Embedded Trace Macrocell Architecture

Specification. The Trace Clock and Trace Data pins can be enabled through the GPIO. For more

information on how to enable the ETM Trace pins, the reader is referred to Section 32.3.4.2 (p. 761) .

6.3.3 Debug and EM2/EM3

Leaving the debugger connected when issuing a WFI or WFE to enter EM2 or EM3 will make the system

enter a special EM2. This mode differs from regular EM2 and EM3 in that the high frequency clocks

are still enabled, and certain core functionality is still powered in order to maintain debug-functionality.

Because of this, the current consumption in this mode is closer to EM1 and it is therefore important to

disconnect the debugger before doing current consumption measurements.

6.4 Debug Lock and Device Erase

The debug access to the Cortex-M3 is locked by clearing the Debug Lock Word (DLW) and resetting

the device, see Section 7.3.2 (p. 32) .

When debug access is locked, the debug interface remains accessible but the connection to the Cortex-

M3 core and the whole bus-system is blocked as shown in Figure 6.2 (p. 27) . This mechanism is

controlled by the Authentication Access Port (AAP) as illustrated by Figure 6.1 (p. 26) . The AAP is

only accessible from a debugger and not from the core.

Figure 6.1. AAP - Authentication Access Port

SW-DP AHB-AP

Cortex

SerialWire

debug

interface

DEVICEERASE

Authentication

Access Port

(AAP)

ERASEBUSY

DLW[3:0] == 0xF

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The debugger can access the AAP-registers, and only these registers just after reset, for the time of the

AAP-window outlined in Figure 6.2 (p. 27) . If the device is locked, access to the core and bus-system

is blocked even after code execution starts, and the debugger can only access the AAP-registers. If the

device is not locked, the AAP is no longer accessible after code execution starts, and the debugger can

access the core and bus-system normally. The AAP window can be extended by issuing the bit pattern

on SWDIO/SWCLK as shown in Figure 6.3 (p. 27) . This pattern should be applied just before reset

is deasserted, and will give the debugger more time to access the AAP.

Figure 6.2. Device Unlock

Unlocked Cortex

Extended

unlocked Extended AAP

Locked No access AAP

Program

execution

Reset

150 us

47 us

No access AAP

Cortex

255 x 47 us

No access

Program

execution

Program

execution

Figure 6.3. AAP Expansion

SWDIO

SWCLK

AAP expand

If the device is locked, it can be unlocked by writing a valid key to the AAP_CMDKEY register and then

setting the DEVICEERASE bit of the AAP_CMD register via the debug interface. The commands are not

executed before AAP_CMDKEY is invalidated, so this register should be cleared to to start the erase

operation. This operation erases the main block of flash, all lock bits are reset and debug access through

the AHB-AP is enabled. The operation takes 125 ms to complete. Note that the SRAM contents will also

be deleted during a device erase, while the UD-page is not erased.

Even if the device is not locked, the can device can be erased through the AAP, using the above

procedure during the AAP window. This can be useful if the device has been programmed with code that,

e.g., disables the debug interface pins on start-up, or does something else that prevents communication

with a debugger.

If the device is locked, the debugger may read the status from the AAP_STATUS register. When the

ERASEBUSY bit is set low after DEVICEERASE of the AAP_CMD register is set, the debugger may

set the SYSRESETREQ bit in the AAP_CMD register. After reset, the debugger may resume a normal

debug session through the AHB-AP. If the device is not locked, the device erase starts when the AAP

window closes, so it is not possible to poll the status.

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6.5 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 AAP_CMD W1 Command Register

0x004 AAP_CMDKEY W1 Command Key Register

0x008 AAP_STATUS R Status Register

0x0FC AAP_IDR R AAP Identification Register

6.6 Register Description

6.6.1 AAP_CMD - Command Register

Offset Bit Position

0x000

Reset

Access

Name

SYSRESETREQ

DEVICEERASE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SYSRESETREQ 0 W1 System Reset Request

A system reset request is generated when set to 1. This register is write enabled from the AAP_CMDKEY register.

0 DEVICEERASE 0 W1 Erase the Flash Main Block, SRAM and Lock Bits

When set, all data and program code in the main block is erased, the SRAM is cleared and then the Lock Bit (LB) page is erased.

This also includes the Debug Lock Word (DLW), causing debug access to be enabled after the next reset. The information block

User Data page (UD) is left unchanged, but the User data page Lock Word (ULW) is erased. This register is write enabled from

the AAP_CMDKEY register.

6.6.2 AAP_CMDKEY - Command Key Register

Offset Bit Position

0x004

Reset

0x00000000

Access

Name

WRITEKEY

Bit Name Reset Access Description

31:0 WRITEKEY 0x00000000 W1 CMD Key Register

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Bit Name Reset Access Description

The key value must be written to this register to write enable the AAP_CMD register. After AAP_CMD is written, this register should

be cleared to excecute the command.

Value Mode Description

0xCFACC118 WRITEEN Enable write to AAP_CMD

6.6.3 AAP_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

ERASEBUSY

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 ERASEBUSY 0 R Device Erase Command Status

This bit is set when a device erase is executing.

6.6.4 AAP_IDR - AAP Identification Register

Offset Bit Position

0x0FC

Reset

0x16E60001

Access

Name

Bit Name Reset Access Description

31:0 ID 0x16E60001 R AAP Identification Register

Access port identification register in compliance with the ARM ADI v5 specification (JEDEC Manufacturer ID) .

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7 MSC - Memory System Controller

01 2 3 4

01000101011011100110010101110010

01100111011110010010000001001101

01101001011000110111001001101111

00100000011100100111010101101100

01100101011100110010000001110100

01101000011001010010000001110111

01101111011100100110110001100100

00100000011011110110011000100000

01101100011011110111011100101101

01100101011011100110010101110010

01100111011110010010000001101101

01101001011000110111001001101111

01100011011011110110111001110100

01110010011011110110110001101100

01100101011100100010000001100100

01100101011100110110100101100111

01101110001000010100010101101110

Quick Facts

What?

The user can perform Flash memory read,

read configuration and write operations

through the Memory System Controller

(MSC) .

Why?

The MSC allows the application code, user

data and flash lock bits to be stored in non-

volatile Flash memory. Certain memory

system functions, such as program memory

wait-states and bus faults are also configured

from the MSC peripheral register interface,

giving the developer the ability to dynamically

customize the memory system performance,

security level, energy consumption and error

handling capabilities to the requirements at

hand.

How?

The MSC integrates a low-energy Flash

IP with a charge pump, enabling minimum

energy consumption while eliminating the

need for external programming voltage to

erase the memory. An easy to use write and

erase interface is supported by an internal,

fixed-frequency oscillator and autonomous

flash timing and control reduces software

complexity while not using other timer

resources.

Application code may dynamically scale

between high energy optimization and

high code execution performance through

advanced read modes.

A highly efficient low energy instruction

cache reduces the number of flash

reads significantly, thus saving energy.

Performance is also improved when wait-

states are used, since many of the wait-states

are eliminated. Built-in performance counters

can be used to measure the efficiency of the

instruction cache.

7.1 Introduction

The Memory System Controller (MSC) is the program memory unit of the EFM32LG microcontroller. The

flash memory is readable and writable from both the Cortex-M3 and DMA. The flash memory is divided

into two blocks; the main block and the information block. Program code is normally written to the main

block. Additionally, the information block is available for special user data and flash lock bits. There is

also a read-only page in the information block containing system and device calibration data. Read and

write operations are supported in the energy modes EM0 and EM1.

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7.2 Features

• AHB read interface

• Scalable access performance to optimize the Cortex-M3 code interface

• Zero wait-state access up to 16 MHz and one wait-state for up to 32 MHz and two wait-states

for up to 48 MHz

• Advanced energy optimization functionality

• Conditional branch target prefetch suppression

• Cortex-M3 disfolding of if-then (IT) blocks

• Instruction Cache

• DMA read support in EM0 and EM1

• Command and status interface

• Flash write and erase

• Accessible from Cortex-M3 in EM0

• DMA write support in EM0 and EM1

• Core clock independent Flash timing

• Internal oscillator and internal timers for precise and autonomous Flash timing

• General purpose timers are not occupied during Flash erase and write operations

• Configurable interrupt erase abort

• Improved interrupt predictability

• Memory and bus fault control

• Security features

• Lockable debug access

• Page lock bits

• SW Mass erase Lock bits

• User data lock bits

• End-of-write and end-of-erase interrupts

7.3 Functional Description

The size of the main block is device dependent. The largest size available is 256 kB (128 pages).

The information block has 2048 bytes available for user data. The information block also contains chip

configuration data located in a reserved area. The main block is mapped to address 0x00000000 and

the information block is mapped to address 0x0FE00000. Table 7.1 (p. 32) outlines how the Flash

is mapped in the memory space. All Flash memory is organized into 2048 byte pages.

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Table 7.1. MSC Flash Memory Mapping

Block Page Base address Write/Erase by Software

readable Purpose/Name Size

0 0x00000000 Software, debug Yes

. Software, debug Yes

Main1

127 0x0003F800 Software, debug Yes

User code and data 64 kB - 256 kB

Reserved - 0x00040000 - - Reserved for flash

expansion ~24 MB

0 0x0FE00000 Software, debug Yes User Data (UD) 2 kB

- 0x0FE00800 - - Reserved -

1 0x0FE04000 Write: Software,

debug

Erase: Debug

only

Yes Lock Bits (LB) 2 kB

- 0x0FE04800 - - Reserved -

2 0x0FE08000 - Yes Device Information

(DI) 2 kB

Information

- 0x0FE08800 - - Reserved -

Reserved - 0x0FE10000 - - Reserved for flash

expansion Rest of code

space

1Block/page erased by a device erase

7.3.1 User Data (UD) Page Description

This is the user data page in the information block. The page can be erased and written by software. The

page is erased by the ERASEPAGE command of the MSC_WRITECMD register. Note that the page is

not erased by a device erase operation. The device erase operation is described in Section 6.4 (p. 26) .

7.3.2 Lock Bits (LB) Page Description

This page contains the following information:

• Debug Lock Word (DLW)

• User data page Lock Word (ULW)

• Mass erase Lock Word (MLW)

• Main block Page Lock Words (PLWs)

The words in this page are organized as shown in Table 7.2 (p. 32) :

Table 7.2. Lock Bits Page Structure

127 DLW

126 ULW

125 MLW

N PLW[N]

… …

1 PLW[1]

0 PLW[0]

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Word 127 is the debug lock word (DLW). The four LSBs of this word are the debug lock bits. If these bits

are 0xF, then debug access is enabled. If the bits are not 0xF, then debug access to the core is locked.

See Section 6.4 (p. 26) for details on how to unlock the debug access.

Word 126 is the user page lock word (ULW). Bit 0 of this word is the User Data Page lock bit. Bit 1 in

this word locks the Lock Bits Page.

Word 125 is the mass erase lock word (MLW). Bit 0 locks the entire flash. The mass erase lock bits will

not have any effect on device erases initiated from the Authentication Access Port (AAP) registers. The

AAP is described in more detail in Section 6.4 (p. 26) .

There are 32 page lock bits per page lock word (PLW). Bit 0 refers to the first page and bit 31 refers to

the last page within a PLW. Thus, PLW[0] contains lock bits for page 0-31 in the main block. Similarly,

PLW[1] contains lock bits for page 32-63 and so on. A page is locked when the bit is 0. A locked page

cannot be erased or written.

The lock bits can be reset by a device erase operation initiated from the Authentication Access Port

(AAP) registers. The AAP is described in more detail in Section 6.4 (p. 26) . Note that the AAP is only

accessible from the debug interface, and cannot be accessed from the Cortex-M3 core.

7.3.3 Device Information (DI) Page

This read-only page holds the calibration data for the oscillator and other analog peripherals from the

production test as well as a unique device ID. The page is further described in Section 5.6 (p. 23) .

7.3.4 Post-reset Behavior

Calibration values are automatically written to registers by the MSC before application code startup. The

values are also available to read from the DI page for later reference by software. Other information

such as the device ID and production date is also stored in the DI page and is readable from software.

7.3.4.1 One Wait-state Access

After reset, the HFCORECLK is normally 14 MHz from the HFRCO and the MODE field of the

MSC_READCTRL register is set to WS1 (one wait-state). The reset value must be WS1 as an

uncalibrated HFRCO may produce a frequency higher than 16 MHz. Software must not select a zero

wait-state mode unless the clock is guaranteed to be 16 MHz or below, otherwise the resulting behavior

is undefined. If a HFCORECLK frequency above 16 MHz is to be set by software, the MODE field of

the MSC_READCTRL register must be set to WS1 or WS1SCBTP before the core clock is switched to

the higher frequency clock source.

When changing to a lower frequency, the MODE field of the MSC_READCTRL register can be set to

WS0 or WS0SCBTP, but only after the frequency transition is completed. If the HFRCO is used, wait

until the oscillator is stable on the new frequency. Otherwise, the behavior is unpredictable.

To run at a frequency higher than 32 MHz, WS2 or WS2SCBTP must be selected to insert two wait-

states for every flash access.

7.3.4.2 Zero Wait-state Access

At 16 MHz and below, read operations from flash may be performed without any wait-states. Zero wait-

state access greatly improves code execution performance at frequencies from 16 MHz and below.

By default, the Cortex-M3 uses speculative prefetching and If-Then block folding to maximize code

execution performance at the cost of additional flash accesses and energy consumption.

7.3.4.3 Operation Above 32 MHz

To run at frequencies higher than 32 MHz, MODE in MSC_READCTRL must be set to WS2 or

WS2SCBTP.

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7.3.4.4 Suppressed Conditional Branch Target Prefetch (SCBTP)

MSC offers a special instruction fetch mode which optimizes energy consumption by cancelling Cortex-

M3 conditional branch target prefetches. Normally, the Cortex-M3 core prefetches both the next

sequential instruction and the instruction at the branch target address when a conditional branch

instruction reaches the pipeline decode stage. This prefetch scheme improves performance while one

extra instruction is fetched from memory at each conditional branch, regardless of whether the branch is

taken or not. To optimize for low energy, the MSC can be configured to cancel these speculative branch

target prefetches. With this configuration, energy consumption is more optimal, as the branch target

instruction fetch is delayed until the branch condition is evaluated.

The performance penalty with this mode enabled is source code dependent, but is normally less than

1% for core frequencies from 16 MHz and below. To enable the mode at frequencies from 16 MHz and

below write WS0SCBTP to the MODE field of the MSC_READCTRL register. For frequencies above 16

MHz, use the WS1SCBTP mode, and for frequencies above 32 MHz, use the WS2SCBTP mode. An

increased performance penalty per clock cycle must be expected compared to WS0SCBTP mode. The

performance penalty in WS1SCBTP/WS2SCBTP mode depends greatly on the density and organization

of conditional branch instructions in the code.

7.3.4.5 Cortex-M3 If-Then Block Folding

The Cortex-M3 offers a mechanism known as if-then block folding. This is a form of speculative

prefetching where small if-then blocks are collapsed in the prefetch buffer if the condition evaluates to

false. The instructions in the block then appear to execute in zero cycles. With this scheme, performance

is optimized at the cost of higher energy consumption as the processor fetches more instructions from

memory than it actually executes. To disable the mode, write a 1 to the DISFOLD bit in the NVIC Auxiliary

Control Register; see the Cortex-M3 Technical Reference Manual for details. Normally, it is expected

that this feature is most efficient at core frequencies above 16 MHz. Folding is enabled by default.

7.3.4.6 Instruction Cache

The MSC includes an instruction cache. The instruction cache for the internal flash memory is enabled

by default, but can be disabled by setting IFCDIS in MSC_READCTRL. When enabled, the instruction

cache typically reduces the number of flash reads significantly, thus saving energy. In most cases a

cache hit-rate of more than 70 % is achievable. When a 32-bit instruction fetch hits in the cache the data

is returned to the processor in one clock cycle. Thus, performance is also improved when wait-states

are used (i.e. running at frequencies above 16 MHz).

The instruction cache is connected directly to the Cortex-M3 and functions as a memory access filter

between the processor and the memory system, as illustrated in Figure 7.1 (p. 35) . The cache

consists of an access filter, lookup logic, a 128x32 SRAM (512 bytes) and two performance counters.

The access filter checks that the address for the access is of an instruction in the code space (instructions

in RAM outside the code space are not cached). If the address matches, the cache lookup logic and

SRAM is enabled. Otherwise, the cache is bypassed and the access is forwarded to the memory system.

The cache is then updated when the memory access completes. The access filter also disables cache

updates for interrupt context accesses if caching in interrupt context is disabled. The performance

counters, when enabled, keep track of the number of cache hits and misses. The cache consists of 16

8-word cachelines organized as 4 sets with 4 ways. The cachelines are filled up continuously one word

at a time as the individual words are requested by the processor. Thus, not all words of a cacheline

might be valid at a given time.

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Figure 7.1. Instruction Cache

Cortex

128x32

SRAM

Access

Filter

Cache

Look-up Logic

ICODE

AHB-Lite Bus ICODE

AHB-Lite Bus

CODE

Memory Space

Instruction Cache

Performance Counters

DCODE

AHB-Lite Bus

IDCODE

AHB-Lite Bus

IDCODE

MUX

By default, the instruction cache is automatically invalidated when the contents of the flash is changed

(i.e. written or erased). In many cases, however, the application only makes changes to data in the

flash, not code. In this case, the automatic invalidate feature can be disabled by setting AIDIS in

MSC_READCTRL. The cache can (independent of the AIDIS setting) be manually invalidated by writing

1 to INVCACHE in MSC_CMD.

In general it is highly recommended to keep the cache enabled all the time. However, for some sections

of code with very low cache hit-rate more energy-efficient execution can be achieved by disabling the

cache temporarily. To measure the hit-rate of a code-section, the built-in performance counters can

be used. Before the section, start the performance counters by writing 1 to STARTPC in MSC_CMD.

This starts the performance counters, counting from 0. At the end of the section, stop the performance

counters by writing 1 to STOPPC in MSC_CMD. The number of cache hits and cache misses for

that section can then be read from MSC_CACHEHITS and MSC_CACHEMISSES respectively. The

total number of 32-bit instruction fetches will be MSC_CACHEHITS + MSC_CACHEMISSES. Thus, the

cache hit-ratio can be calculated as MSC_CACHEHITS / (MSC_CACHEHITS + MSC_CACHEMISSES).

When MSC_CACHEHITS overflows the CHOF interrupt flag is set. When MSC_CACHEMISSES

overflows the CMOF interrupt flag is set. These flags must be cleared explicitly by software. The

range of the performance counters can thus be extended by increasing a counter in the MSC interrupt

routine. The performance counters only count when a cache lookup is performed. If the lookup fails,

MSC_CACHEMISSES is increased. If the lookup is successful, MSC_CACHEHITS is increased. For

example, a cache lookup is not performed if the cache is disabled or the code is executed from RAM

outside the code space. When caching of vector fetches and instructions in interrupt routines is disabled

(ICCDIS in MSC_READCTRL is set), the performance counters do not count when these types of fetches

occur (i.e. while in interrupt context).

By default, interrupt vector fetches and instructions in interrupt routines are also cached. Some

applications may get better cache utilization by not caching instructions in interrupt context. This is done

by setting ICCDIS in MSC_READCTRL. You should only set this bit based on the results from a cache

hit ratio measurement. In general, it is recommended to keep the ICCDIS bit cleared. Note that lookups

in the cache are still performed, regardless of the ICCDIS setting - but instructions are not cached when

cache misses occur inside the interrupt routine. So, for example, if a cached function is called from the

interrupt routine, the instructions for that function will be taken from the cache.

The cache content is not retained in EM2, EM3 and EM4. The cache is therefore invalidated regardless

of the setting of AIDIS in MSC_READCTRL when entering these energy modes. Applications that switch

frequently between EM0 and EM2/3 and execute the very same non-looping code almost every time

will most likely benefit from putting this code in RAM. The interrupt vectors can also be put in RAM to

reduce current consumption even further.

The cache also supports caching of instruction fetches from the external bus interface (EBI) when

accessing the EBI through code space. By default, this is enabled, but it can be disabled by setting

EBICDIS in MSC_READCTRL.

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7.3.5 Erase and Write Operations

The AUXHFRCO is used for timing during flash write and erase operations. To achieve correct timing,

the MSC_TIMEBASE register has to be configured according to the settings in CMU_AUXHFRCOCTRL.

BASE in MSC_TIMEBASE defines how many AUXCLK cycles - 1 there is in 1 us or 5 us, depending

on the configuration of PERIOD. To ensure that timing of flash write and erase operations is within the

specification of the flash, the value written to BASE should give at least a 10% margin with respect to

the period, i.e. for the 1 us PERIOD, the number of cycles should at least span 1.1 us, and for the 5 us

period they should span at least 5.5 us. For the 1 MHz band, PERIOD in MSC_TIMEBASE should be

set to 5US, while it should be set to 1US for all other AUXHFRCO bands.

Both page erase and write operations require that the address is written into the MSC_ADDRB register.

For erase operations, the address may be any within the page to be erased. Load the address by

writing 1 to the LADDRIM bit in the MSC_WRITECMD register. The LADDRIM bit only has to be written

once when loading the first address. After each word is written the internal address register ADDR

will be incremented automatically by 4. The INVADDR bit of the MSC_STATUS register is set if the

loaded address is outside the flash and the LOCKED bit of the MSC_STATUS register is set if the

page addressed is locked. Any attempts to command erase of or write to the page are ignored if

INVADDR or the LOCKED bits of the MSC_STATUS register are set. To abort an ongoing erase, set

the ERASEABORT bit in the MSC_WRITECMD register.

When a word is written to the MSC_WDATA register, the WDATAREADY bit of the MSC_STATUS

A single word write is commanded by setting the WRITEONCE bit of the MSC_WRITECMD register.

The operation is complete when the BUSY bit of the MSC_STATUS register is cleared and control of

the flash is handed back to the AHB interface, allowing application code to resume execution.

For a DMA write the software must write the first word to the MSC_WDATA register and then set the

WRITETRIG bit of the MSC_WRITECMD register. DMA triggers when the WDATAREADY bit of the

MSC_STATUS register is set.

It is possible to write words twice between each erase by keeping at 1 the bits that are not to be changed.

Let us take as an example writing two 16 bit values, 0xAAAA and 0x5555. To safely write them in the

same flash word this method can be used:

• Write 0xFFFFAAAA (word in flash becomes 0xFFFFAAAA)

• Write 0x5555FFFF (word in flash becomes 0x5555AAAA)

Note that there is a maximum of two writes to the same word between each erase due to a physical

limitation of the flash.

Note During a write or erase, flash read accesses will be stalled, effectively halting code

execution from flash. Code execution continues upon write/erase completion. Code residing

in RAM may be executed during a write/erase operation.

Note The MSC_WDATA and MSC_ADDRB registers are not retained when entering EM2 or

lower energy modes.

7.3.5.1 Mass erase

A mass erase can be initiated from software using ERASEMAIN0 in MSC_WRITECMD. This command

will start a mass erase of the entire flash. Prior to initiating a mass erase, MSC_MASSLOCK must be

unlocked by writing 0x631A to it. After a mass erase has been started, this register can be locked again

to prevent runaway code from accidentally triggering a mass erase.

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The regular flash page lock bits will not prevent a mass erase. To prevent software from initiating mass

erases, use the mass erase lock bits in the mass erase lock word (MLW).

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7.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 MSC_CTRL RW Memory System Control Register

0x004 MSC_READCTRL RW Read Control Register

0x008 MSC_WRITECTRL RW Write Control Register

0x00C MSC_WRITECMD W1 Write Command Register

0x010 MSC_ADDRB RW Page Erase/Write Address Buffer

0x018 MSC_WDATA RW Write Data Register

0x01C MSC_STATUS R Status Register

0x02C MSC_IF R Interrupt Flag Register

0x030 MSC_IFS W1 Interrupt Flag Set Register

0x034 MSC_IFC W1 Interrupt Flag Clear Register

0x038 MSC_IEN RW Interrupt Enable Register

0x03C MSC_LOCK RW Configuration Lock Register

0x040 MSC_CMD W1 Command Register

0x044 MSC_CACHEHITS R Cache Hits Performance Counter

0x048 MSC_CACHEMISSES R Cache Misses Performance Counter

0x050 MSC_TIMEBASE RW Flash Write and Erase Timebase

0x054 MSC_MASSLOCK RW Mass Erase Lock Register

7.5 Register Description

7.5.1 MSC_CTRL - Memory System Control Register

Offset Bit Position

0x000

Reset

Access

Name

BUSFAULT

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BUSFAULT 1 RW Bus Fault Response Enable

When this bit is set, the memory system generates bus error response.

Value Mode Description

0 GENERATE A bus fault is generated on access to unmapped code and system space.

1 IGNORE Accesses to unmapped address space is ignored.

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7.5.2 MSC_READCTRL - Read Control Register

Offset Bit Position

0x004

Reset

0x0

0x1

Access

Name

BUSSTRATEGY

RAMCEN

EBICDIS

ICCDIS

AIDIS

IFCDIS

MODE

Bit Name Reset Access Description

31:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 BUSSTRATEGY 0x0 RW Strategy for bus matrix

Specify which master has low latency to bus matrix.

Value Mode Description

0 CPU

1 DMA

2 DMAEM1

3 NONE

15:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 RAMCEN 0 RW RAM Cache Enable

Enable instruction caching for RAM in code-space.

6 EBICDIS 0 RW External Bus Interface Cache Disable

Disable instruction cache for external bus interface.

5 ICCDIS 0 RW Interrupt Context Cache Disable

Set this bit to automatically disable caching of vector fetches and instruction fetches in interrupt context. Cache lookup will still be

performed in interrupt context. When set, the performance counters will not count when these types of fetches occur.

4 AIDIS 0 RW Automatic Invalidate Disable

When this bit is set the cache is not automatically invalidated when a write or page erase is performed.

3 IFCDIS 0 RW Internal Flash Cache Disable

Disable instruction cache for internal flash memory.

2:0 MODE 0x1 RW Read Mode

If software wants to set a core clock frequency above 16 MHz, this register must be set to WS1 or WS1SCBTP before the core

clock is switched to the higher frequency. When changing to a lower frequency, this register can be set to WS0 or WS0SCBTP

after the frequency transition has been completed. After reset, the core clock is 14 MHz from the HFRCO but the MODE field of

MSC_READCTRL register is set to WS1. This is because the HFRCO may produce a frequency above 16 MHz before it is calibrated.

If the HFRCO is used as clock source, wait until the oscillator is stable on the new frequency to avoid unpredictable behavior.

Value Mode Description

0 WS0 Zero wait-states inserted in fetch or read transfers.

1 WS1 One wait-state inserted for each fetch or read transfer. This mode is required for a core

frequency above 16 MHz.

2 WS0SCBTP Zero wait-states inserted with the Suppressed Conditional Branch Target Prefetch

(SCBTP) function enabled. SCBTP saves energy by delaying the Cortex' conditional

branch target prefetches until the conditional branch instruction is in the execute stage.

When the instruction reaches this stage, the evaluation of the branch condition is

completed and the core does not perform a speculative prefetch of both the branch

target address and the next sequential address. With the SCBTP function enabled,

one instruction fetch is saved for each branch not taken, with a negligible performance

penalty.

3 WS1SCBTP One wait-state access with SCBTP enabled.

4 WS2 Two wait-states inserted for each fetch or read transfer. This mode is required for a

core frequency above 32 MHz.

5 WS2SCBTP Two wait-state access with SCBTP enabled.

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7.5.3 MSC_WRITECTRL - Write Control Register

Offset Bit Position

0x008

Reset

Access

Name

IRQERASEABORT

WREN

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 IRQERASEABORT 0 RW Abort Page Erase on Interrupt

When this bit is set to 1, any Cortex interrupt aborts any current page erase operation.

0 WREN 0 RW Enable Write/Erase Controller

When this bit is set, the MSC write and erase functionality is enabled.

7.5.4 MSC_WRITECMD - Write Command Register

Offset Bit Position

0x00C

Reset

Access

Name

CLEARWDATA

ERASEMAIN0

ERASEABORT

WRITETRIG

WRITEONCE

WRITEEND

ERASEPAGE

LADDRIM

Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 CLEARWDATA 0 W1 Clear WDATA state

Will set WDATAREADY and DMA request. Should only be used when no write is active.

11:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 ERASEMAIN0 0 W1 Mass erase region 0

Initiate mass erase of region 0. For devices supporting read-while-write, this is the lower half of the flash. For other devices it is

the entire flash. Before use MSC_MASSLOCK must be unlocked. To completely prevent access from software, clear bit 0 in the

mass erase lock-word (MLW).

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 ERASEABORT 0 W1 Abort erase sequence

Writing to this bit will abort an ongoing erase sequence.

4 WRITETRIG 0 W1 Word Write Sequence Trigger

Functions like MSC_CMD_WRITEONCE, but will set MSC_STATUS_WORDTIMEOUT if no new data is written to MSC_WDATA

within the 30 µs timeout.

3 WRITEONCE 0 W1 Word Write-Once Trigger

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Bit Name Reset Access Description

Start write of the first word written to MSC_WDATA, then add 4 to ADDR and write the next word if available within a 30 µs timeout.

When ADDR is incremented past the page boundary, ADDR is set to the base of the page.

2 WRITEEND 0 W1 End Write Mode

Write 1 to end write mode when using the WRITETRIG command.

1 ERASEPAGE 0 W1 Erase Page

Erase any user defined page selected by the MSC_ADDRB register. The WREN bit in the MSC_WRITECTRL register must be set

in order to use this command.

0 LADDRIM 0 W1 Load MSC_ADDRB into ADDR

Load the internal write address register ADDR from the MSC_ADDRB register. The internal address register ADDR is incremented

automatically by 4 after each word is written. When ADDR is incremented past the page boundary, ADDR is set to the base of the page.

7.5.5 MSC_ADDRB - Page Erase/Write Address Buffer

Offset Bit Position

0x010

Reset

0x00000000

Access

Name

ADDRB

Bit Name Reset Access Description

31:0 ADDRB 0x00000000 RW Page Erase or Write Address Buffer

This register holds the page address for the erase or write operation. This register is loaded into the internal MSC_ADDR register

when the LADDRIM field in MSC_WRITECMD is set. The MSC_ADDR register is not readable. This register is not retained when

entering EM2 or lower energy modes.

7.5.6 MSC_WDATA - Write Data Register

Offset Bit Position

0x018

Reset

0x00000000

Access

Name

WDATA

Bit Name Reset Access Description

31:0 WDATA 0x00000000 RW Write Data

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Bit Name Reset Access Description

The data to be written to the address in MSC_ADDR. This register must be written when the WDATAREADY bit of MSC_STATUS

is set. This register is not retained when entering EM2 or lower energy modes.

7.5.7 MSC_STATUS - Status Register

Offset Bit Position

0x01C

Reset

Access

Name

PCRUNNING

ERASEABORTED

WORDTIMEOUT

WDATAREADY

INVADDR

LOCKED

BUSY

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 PCRUNNING 0 R Performance Counters Running

This bit is set while the performance counters are running. When one performance counter reaches the maximum value, this bit

is cleared.

5 ERASEABORTED 0 R The Current Flash Erase Operation Aborted

When set, the current erase operation was aborted by interrupt.

4 WORDTIMEOUT 0 R Flash Write Word Timeout

When this bit is set, MSC_WDATA was not written within the timeout. The flash write operation timed out and access to the

flash is returned to the AHB interface. This bit is cleared when the ERASEPAGE, WRITETRIG or WRITEONCE commands in

MSC_WRITECMD are triggered.

3 WDATAREADY 1 R WDATA Write Ready

When this bit is set, the content of MSC_WDATA is read by MSC Flash Write Controller and the register may be updated with the

next 32-bit word to be written to flash. This bit is cleared when writing to MSC_WDATA.

2 INVADDR 0 R Invalid Write Address or Erase Page

Set when software attempts to load an invalid (unmapped) address into ADDR.

1 LOCKED 0 R Access Locked

When set, the last erase or write is aborted due to erase/write access constraints.

0 BUSY 0 R Erase/Write Busy

When set, an erase or write operation is in progress and new commands are ignored.

7.5.8 MSC_IF - Interrupt Flag Register

Offset Bit Position

0x02C

Reset

Access

Name

CMOF

CHOF

WRITE

ERASE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

3 CMOF 0 R Cache Misses Overflow Interrupt Flag

Set when MSC_CACHEMISSES overflows.

2 CHOF 0 R Cache Hits Overflow Interrupt Flag

Set when MSC_CACHEHITS overflows.

1 WRITE 0 R Write Done Interrupt Read Flag

Set when a write is done.

0 ERASE 0 R Erase Done Interrupt Read Flag

Set when erase is done.

7.5.9 MSC_IFS - Interrupt Flag Set Register

Offset Bit Position

0x030

Reset

Access

Name

CMOF

CHOF

WRITE

ERASE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 CMOF 0 W1 Cache Misses Overflow Interrupt Set

Set the CMOF flag and generate interrupt.

2 CHOF 0 W1 Cache Hits Overflow Interrupt Set

Set the CHOF flag and generate interrupt.

1 WRITE 0 W1 Write Done Interrupt Set

Set the write done bit and generate interrupt.

0 ERASE 0 W1 Erase Done Interrupt Set

Set the erase done bit and generate interrupt.

7.5.10 MSC_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x034

Reset

Access

Name

CMOF

CHOF

WRITE

ERASE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 CMOF 0 W1 Cache Misses Overflow Interrupt Clear

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Bit Name Reset Access Description

Clear the CMOF interrupt flag.

2 CHOF 0 W1 Cache Hits Overflow Interrupt Clear

Clear the CHOF interrupt flag.

1 WRITE 0 W1 Write Done Interrupt Clear

Clear the write done bit.

0 ERASE 0 W1 Erase Done Interrupt Clear

Clear the erase done bit.

7.5.11 MSC_IEN - Interrupt Enable Register

Offset Bit Position

0x038

Reset

Access

Name

CMOF

CHOF

WRITE

ERASE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 CMOF 0 RW Cache Misses Overflow Interrupt Enable

Enable the cache misses performance counter overflow interrupt.

2 CHOF 0 RW Cache Hits Overflow Interrupt Enable

Enable the cache hits performance counter overflow interrupt.

1 WRITE 0 RW Write Done Interrupt Enable

Enable the write done interrupt.

0 ERASE 0 RW Erase Done Interrupt Enable

Enable the erase done interrupt.

7.5.12 MSC_LOCK - Configuration Lock Register

Offset Bit Position

0x03C

Reset

0x0000

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 LOCKKEY 0x0000 RW Configuration Lock

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Bit Name Reset Access Description

Write any other value than the unlock code to lock access to MSC_CTRL, MSC_READCTRL, MSC_WRITECTRL and

MSC_TIMEBASE. Write the unlock code to enable access. When reading the register, bit 0 is set when the lock is enabled.

Mode Value Description

Read Operation

UNLOCKED 0 MSC registers are unlocked.

LOCKED 1 MSC registers are locked.

Write Operation

LOCK 0 Lock MSC registers.

UNLOCK 0x1B71 Unlock MSC registers.

7.5.13 MSC_CMD - Command Register

Offset Bit Position

0x040

Reset

Access

Name

STOPPC

STARTPC

INVCACHE

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 STOPPC 0 W1 Stop Performance Counters

Use this command bit to stop the performance counters.

1 STARTPC 0 W1 Start Performance Counters

Use this command bit to start the performance counters. The performance counters always start counting from 0.

0 INVCACHE 0 W1 Invalidate Instruction Cache

Use this register to invalidate the instruction cache.

7.5.14 MSC_CACHEHITS - Cache Hits Performance Counter

Offset Bit Position

0x044

Reset

0x00000

Access

Name

CACHEHITS

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:0 CACHEHITS 0x00000 R Cache hits since last performance counter start command.

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Bit Name Reset Access Description

Use to measure cache performance for a particular code section.

7.5.15 MSC_CACHEMISSES - Cache Misses Performance Counter

Offset Bit Position

0x048

Reset

0x00000

Access

Name

CACHEMISSES

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:0 CACHEMISSES 0x00000 R Cache misses since last performance counter start command.

Use to measure cache performance for a particular code section.

7.5.16 MSC_TIMEBASE - Flash Write and Erase Timebase

Offset Bit Position

0x050

Reset

0x10

Access

Name

PERIOD

BASE

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 PERIOD 0 RW Sets the timebase period

Decides whether TIMEBASE specifies the number of AUX cycles in 1 us or 5 us. 5 us should only be used with 1 MHz AUXHFRCO

band.

Value Mode Description

0 1US TIMEBASE period is 1 us.

1 5US TIMEBASE period is 5 us.

15:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 BASE 0x10 RW Timebase used by MSC to time flash writes and erases

Should be set to the number of full AUX clock cycles in the period given by MSC_TIMEBASE_PERIOD. I.e. 1.1 us or 5.5. us with

PERIOD cleared or set, respectively. The resetvalue of the timebase matches a 14 MHz AUXHFRCO, which is the default frequency

of the AUXHFRCO.

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7.5.17 MSC_MASSLOCK - Mass Erase Lock Register

Offset Bit Position

0x054

Reset

0x0001

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 LOCKKEY 0x0001 RW Mass Erase Lock

Write any other value than the unlock code to lock access the the ERASEMAIN0 and ERASEMAIN1 commands. Write the unlock

code 631A to enable access. When reading the register, bit 0 is set when the lock is enabled. Locked by default.

Mode Value Description

Read Operation

UNLOCKED 0 Mass erase unlocked.

LOCKED 1 Mass erase locked.

Write Operation

LOCK 0 Lock mass erase.

UNLOCK 0x631A Unlock mass erase.

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8 DMA - DMA Controller

01 2 3 4

DMA

controller

Flash

RAM

External Bus

Interface

Peripherals

Quick Facts

What?

The DMA controller can move data without

CPU intervention, effectively reducing the

energy consumption for a data transfer.

Why?

The DMA can perform data transfers more

energy efficiently than the CPU and allows

autonomous operation in low energy modes.

The LEUART can for instance provide full

UART communication in EM2, consuming

only a few µA by using the DMA to move data

between the LEUART and RAM.

How?

The DMA controller has multiple highly

configurable, prioritized DMA channels.

Advanced transfer modes such as ping-pong

and scatter-gather make it possible to tailor

the controller to the specific needs of an

application.

8.1 Introduction

The Direct Memory Access (DMA) controller performs memory operations independently of the CPU.

This has the benefit of reducing the energy consumption and the workload of the CPU, and enables

the system to stay in low energy modes for example when moving data from the USART to RAM or

from the External Bus Interface (EBI) to the DAC. The DMA controller uses the PL230 µDMA controller

licensed from ARM1. Each of the PL230s channels on the EFM32 can be connected to any of the EFM32

peripherals.

8.2 Features

• The DMA controller is accessible as a memory mapped peripheral

• Possible data transfers include

• RAM/EBI/Flash to peripheral

• RAM/EBI to Flash

• Peripheral to RAM/EBI

• RAM/EBI/Flash to RAM/EBI

• The DMA controller has 12 independent channels

• Each channel has one (primary) or two (primary and alternate) descriptors

• The configuration for each channel includes

• Transfer mode

• Priority

• Word-count

• Word-size (8, 16, 32 bit)

• The transfer modes include

• Basic (using the primary or alternate DMA descriptor)

1ARM PL230 homepage [http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0417a/index.html]

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• Ping-pong (switching between the primary or alternate DMA descriptors, for continuous data flow

to/from peripherals)

• Scatter-gather (using the primary descriptor to configure the alternate descriptor)

• Each channel has a programmable transfer length

• Channels 0 and 1 support looped transfers

• Channel 0 supports 2D copy

• A DMA channel can be triggered by any of several sources:

• Communication modules (USART, UART, LEUART)

• Timers (TIMER)

• Analog modules (DAC, ACMP, ADC)

• External Bus Interface (EBI)

• Software

• Programmable mapping between channel number and peripherals - any DMA channel can be

triggered by any of the available sources

• Interrupts upon transfer completion

• Data transfer to/from LEUART in EM2 is supported by the DMA, providing extremely low energy

consumption while performing UART communications

8.3 Block Diagram

An overview of the DMA and the modules it interacts with is shown in Figure 8.1 (p. 49) .

Figure 8.1. DMA Block Diagram

Interrupts

APB block

APB

memory

mapped

registers

AHB block

AHB-Lite

master

interface

DMA control block

DMA Core

Cortex

AHB to

APB

bridge

AHB

Configuration

control DMA data

transfer

Error

Channel

done

Peripheral

Channel

select REQ/

ACK

Configuration

The DMA Controller consists of four main parts:

• An APB block allowing software to configure the DMA controller

• An AHB block allowing the DMA to read and write the DMA descriptors and the source and destination

data for the DMA transfers

• A DMA control block controlling the operation of the DMA, including request/acknowledge signals for

the connected peripherals

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• A channel select block routing the right peripheral request to each DMA channel

8.4 Functional Description

The DMA Controller is highly flexible. It is capable of transferring data between peripherals and memory

without involvement from the processor core. This can be used to increase system performance by

off-loading the processor from copying large amounts of data or avoiding frequent interrupts to service

peripherals needing more data or having available data. It can also be used to reduce the system energy

consumption by making the DMA work autonomously with the LEUART for data transfer in EM2 without

having to wake up the processor core from sleep.

The DMA Controller contains 12 independent channels. Each of these channels can be connected to any

of the available peripheral trigger sources by writing to the configuration registers, see Section 8.4.1 (p.

50) . In addition, each channel can be triggered by software (for large memory transfers or for

debugging purposes).

What the DMA Controller should do (when one of its channels is triggered) is configured through channel

descriptors residing in system memory. Before enabling a channel, the software must therefore take

care to write this configuration to memory. When a channel is triggered, the DMA Controller will first read

the channel descriptor from system memory, and then it will proceed to perform the memory transfers

as specified by the descriptor. The descriptor contains the memory address to read from, the memory

address to write to, the number of bytes to be transferred, etc. The channel descriptor is described in

detail in Section 8.4.3 (p. 61) .

In addition to the basic transfer mode, the DMA Controller also supports two advanced transfer modes;

ping-pong and scatter-gather. Ping-pong transfers are ideally suited for streaming data for high-speed

peripheral communication as the DMA will be ready to retrieve the next incoming data bytes immediately

while the processor core is still processing the previous ones (and similarly for outgoing communication).

Scatter-gather involves executing a series of tasks from memory and allows sophisticated schemes to

be implemented by software.

Using different priority levels for the channels and setting the number of bytes after which the DMA

Controller re-arbitrates, it is possible to ensure that timing-critical transfers are serviced on time.

8.4.1 Channel Select Configuration

The channel select block allows selecting which peripheral's request lines (dma_req, dma_sreq) to

connect to each DMA channel.

This configuration is done by software through the control registers DMA_CH0_CTRL-

DMA_CH11_CTRL, with SOURCESEL and SIGSEL components. SOURCESEL selects which

peripheral to listen to and SIGSEL picks which output signals to use from the selected peripheral.

All peripherals are connected to dma_req. When this signal is triggered, the DMA performs a number

of transfers as specified by the channel descriptor (2R). The USARTs are additionally connected to the

dma_sreq line. When only dma_sreq is asserted but not dma_req, then the DMA will perform exactly

one transfer only (given that dma_sreq is enabled by software).

Note A DMA channel should not be active when the clock to the selected peripheral is off.

8.4.2 DMA control

8.4.2.1 DMA arbitration rate

You can configure when the controller arbitrates during a DMA transfer. This enables you to reduce the

latency to service a higher priority channel.

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The controller provides four bits that configure how many AHB bus transfers occur before it re-arbitrates.

These bits are known as the R_power bits because the value you enter, R, is raised to the power of two

and this determines the arbitration rate. For example, if R=4 then the arbitration rate is 24, that is, the

controller arbitrates every 16 DMA transfers.

Table 8.1 (p. 51) lists the arbitration rates.

Table 8.1. AHB bus transfer arbitration interval

R_power Arbitrate after x DMA transfers

b0000 x=1

b0001 x=2

b0010 x=4

b0011 x=8

b0100 x=16

b0101 x=32

b0110 x=64

b0111 x=128

b1000 x=256

b1001 x=512

b1010-b1111 x = 1024

Note You must take care not to assign a low-priority channel with a large R_power because this

prevents the controller from servicing high-priority requests, until it re-arbitrates.

The number of dma transfers N that need to be done is specified by the user. When N > 2R and is not an

integer multiple of 2R then the controller always performs sequences of 2R transfers until N < 2R remain

to be transferred. The controller performs the remaining N transfers at the end of the DMA cycle.

You store the value of the R_power bits in the channel control data structure. See Section 8.4.3.3 (p.

64) for more information about the location of the R_power bits in the data structure.

8.4.2.2 Priority

When the controller arbitrates, it determines the next channel to service by using the following

information:

• the channel number

• the priority level, default or high, that is assigned to the channel.

You can configure each channel to use either the default priority level or a high priority level by setting

the DMA_CHPRIS register.

Channel number zero has the highest priority and as the channel number increases, the priority of a

channel decreases. Table 8.2 (p. 51) lists the DMA channel priority levels in descending order of

priority.

Table 8.2. DMA channel priority

Channel

number

Priority level

setting

Descending order of

channel priority

0 High Highest-priority DMA channel

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Channel

number

Priority level

setting

Descending order of

channel priority

1 High -

2 High -

3 High -

4 High -

5 High -

6 High -

7 High -

8 High -

9 High -

10 High -

11 High -

0 Default -

1 Default -

2 Default -

3 Default -

4 Default -

5 Default -

6 Default -

7 Default -

8 Default -

9 Default -

10 Default -

11 Default Lowest-priority DMA channel

After a DMA transfer completes, the controller polls all the DMA channels that are available. Figure 8.2 (p.

53) shows the process it uses to determine which DMA transfer to perform next.

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Figure 8.2. Polling flowchart

Start polling

Is there

a channel

request ?

Are any

channel requests

using a high priority-

level ?

Start DMA transfer

Yes

Select channel that has

the lowest channel

number and is set to

high priority-level

Select channel that has

the lowest channel

number

8.4.2.3 DMA cycle types

The cycle_ctrl bits control how the controller performs a DMA cycle. You can set the cycle_ctrl bits as

Table 8.3 (p. 53) lists.

Table 8.3. DMA cycle types

cycle_ctrl Description

b000 Channel control data structure is invalid

b001 Basic DMA transfer

b010 Auto-request

b011 Ping-pong

b100 Memory scatter-gather using the primary data structure

b101 Memory scatter-gather using the alternate data structure

b110 Peripheral scatter-gather using the primary data structure

b111 Peripheral scatter-gather using the alternate data structure

Note The cycle_ctrl bits are located in the channel_cfg memory location that Section 8.4.3.3 (p.

64) describes.

For all cycle types, the controller arbitrates after 2R DMA transfers. If you set a low-priority channel with

a large 2R value then it prevents all other channels from performing a DMA transfer, until the low-priority

DMA transfer completes. Therefore, you must take care when setting the R_power, that you do not

significantly increase the latency for high-priority channels.

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8.4.2.3.1 Invalid

After the controller completes a DMA cycle it sets the cycle type to invalid, to prevent it from repeating

the same DMA cycle.

8.4.2.3.2 Basic

In this mode, you configure the controller to use either the primary or the alternate data structure. After

you enable the channel C and the controller receives a request for this channel, then the flow for this

DMA cycle is as follows:

1. The controller performs 2R transfers. If the number of transfers remaining becomes zero, then the

flow continues at step 3 (p. 54) .

2. The controller arbitrates:

• if a higher-priority channel is requesting service then the controller services that channel

• if the peripheral or software signals a request to the controller then it continues at step 1 (p. 54) .

3. The controller sets dma_done[C] HIGH for one HFCORECLK cycle. This indicates to the host

processor that the DMA cycle is complete.

8.4.2.3.3 Auto-request

When the controller operates in this mode, it is only necessary for it to receive a single request to enable

it to complete the entire DMA cycle. This enables a large data transfer to occur, without significantly

increasing the latency for servicing higher priority requests, or requiring multiple requests from the

processor or peripheral.

You can configure the controller to use either the primary or the alternate data structure. After you enable

the channel C and the controller receives a request for this channel, then the flow for this DMA cycle

is as follows:

1. The controller performs 2R transfers for channel C. If the number of transfers remaining is zero the

flow continues at step 3 (p. 54) .

2. The controller arbitrates. When channel C has the highest priority then the DMA cycle continues at

step 1 (p. 54) .

3. The controller sets dma_done[C] HIGH for one HFCORECLK cycle. This indicates to the host

processor that the DMA cycle is complete.

8.4.2.3.4 Ping-pong

In ping-pong mode, the controller performs a DMA cycle using one of the data structures (primary or

alternate) and it then performs a DMA cycle using the other data structure. The controller continues to

switch from primary to alternate to primary… until it reads a data structure that is invalid, or until the

host processor disables the channel.

Figure 8.3 (p. 55) shows an example of a ping-pong DMA transaction.

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Figure 8.3. Ping-pong example

Task A

Request

Task A: Primary, cycle_ctrl = b011, 2R = 4, N = 6

dma_done[C]

Task B

Request

Task B: Alternate, cycle_ctrl = b011, 2R = 4, N = 12

dma_done[C]

Request

Task C

Request

Task C: Primary, cycle_ctrl = b011, 2R = 2, N = 2

dma_done[C]

Task D

Request

Task D: Alternate, cycle_ctrl = b011, 2R = 4, N = 5

dma_done[C]

Task E

Request

Task E: Primary, cycle_ctrl = b011, 2R = 4, N = 7

dma_done[C]

End: Alternate, cycle_ctrl = b000 Invalid

Request

In Figure 8.3 (p. 55) :

Task A 1. The host processor configures the primary data structure for task A.

2. The host processor configures the alternate data structure for task B. This enables the

controller to immediately switch to task B after task A completes, provided that a higher

priority channel does not require servicing.

3. The controller receives a request and performs four DMA transfers.

4. The controller arbitrates. After the controller receives a request for this channel, the flow

continues if the channel has the highest priority.

5. The controller performs the remaining two DMA transfers.

6. The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters the

arbitration process.

After task A completes, the host processor can configure the primary data structure for task C. This

enables the controller to immediately switch to task C after task B completes, provided that a higher

priority channel does not require servicing.

After the controller receives a new request for the channel and it has the highest priority then task B

commences:

Task B 7. The controller performs four DMA transfers.

8. The controller arbitrates. After the controller receives a request for this channel, the flow

continues if the channel has the highest priority.

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9. The controller performs four DMA transfers.

10.The controller arbitrates. After the controller receives a request for this channel, the flow

continues if the channel has the highest priority.

11.The controller performs the remaining four DMA transfers.

12.The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters the

arbitration process.

After task B completes, the host processor can configure the alternate data structure for task D.

After the controller receives a new request for the channel and it has the highest priority then task C

commences:

Task C 13.The controller performs two DMA transfers.

14.The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters the

arbitration process.

After task C completes, the host processor can configure the primary data structure for task E.

After the controller receives a new request for the channel and it has the highest priority then task D

commences:

Task D 15.The controller performs four DMA transfers.

16.The controller arbitrates. After the controller receives a request for this channel, the flow

continues if the channel has the highest priority.

17.The controller performs the remaining DMA transfer.

18.The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters the

arbitration process.

After the controller receives a new request for the channel and it has the highest priority then task E

commences:

Task E 19.The controller performs four DMA transfers.

20.The controller arbitrates. After the controller receives a request for this channel, the flow

continues if the channel has the highest priority.

21.The controller performs the remaining three DMA transfers.

22.The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters the

arbitration process.

If the controller receives a new request for the channel and it has the highest priority then it attempts to

start the next task. However, because the host processor has not configured the alternate data structure,

and on completion of task D the controller set the cycle_ctrl bits to b000, then the ping-pong DMA

transaction completes.

Note You can also terminate the ping-pong DMA cycle in Figure 8.3 (p. 55) , if you configure

task E to be a basic DMA cycle by setting the cycle_ctrl field to 3’b001.

8.4.2.3.5 Memory scatter-gather

In memory scatter-gather mode the controller receives an initial request and then performs four DMA

transfers using the primary data structure. After this transfer completes, it starts a DMA cycle using the

alternate data structure. After this cycle completes, the controller performs another four DMA transfers

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using the primary data structure. The controller continues to switch from primary to alternate to primary…

until either:

• the host processor configures the alternate data structure for a basic cycle

• it reads an invalid data structure.

Note After the controller completes the N primary transfers it invalidates the primary data

structure by setting the cycle_ctrl field to b000.

The controller only asserts dma_done[C] when the scatter-gather transaction completes using an auto-

request cycle.

In scatter-gather mode, the controller uses the primary data structure to program the alternate data

structure. Table 8.4 (p. 57) lists the fields of the channel_cfg memory location for the primary data

structure, that you must program with constant values and those that can be user defined.

Table 8.4. channel_cfg for a primary data structure, in memory scatter-gather mode

Bit Field Value Description

Constant-value fields:

[31:30} dst_inc b10 Configures the controller to use word increments for the address

[29:28] dst_size b10 Configures the controller to use word transfers

[27:26] src_inc b10 Configures the controller to use word increments for the address

[25:24] src_size b10 Configures the controller to use word transfers

[17:14] R_power b0010 Configures the controller to perform four DMA transfers

[3] next_useburst 0 For a memory scatter-gather DMA cycle, this bit must be set to zero

[2:0] cycle_ctrl b100 Configures the controller to perform a memory scatter-gather DMA cycle

User defined values:

[23:21] dst_prot_ctrl - Configures the state of HPROT1 when the controller writes the destination data

[20:18] src_prot_ctrl - Configures the state of HPROT when the controller reads the source data

[13:4] n_minus_1 N2Configures the controller to perform N DMA transfers, where N is a multiple of four

1ARM PL230 homepage [http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0417a/index.html]

2Because the R_power field is set to four, you must set N to be a multiple of four. The value given by N/4 is the number of times

that you must configure the alternate data structure.

See Section 8.4.3.3 (p. 64) for more information.

Figure 8.4 (p. 58) shows a memory scatter-gather example.

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Figure 8.4. Memory scatter-gather example

Copy from A in

memory, to Alternate

Request

1. Configure primary to enable the copy A, B, C, and D operations: cycle_ctrl = b100, 2R = 4, N = 16.

Task A

Task B

Auto request

dma_done[C]

Copy from B in

memory, to Alternate

Auto request

Auto

request

Auto

request

Auto

request

Copy from C in

memory, to Alternate

Task C

Copy from D in

memory, to Alternate

Task D

Data for Task A cycle_ctrl = b101, 2R = 4, N = 3

cycle_ctrl = b101, 2R = 2, N = 8

cycle_ctrl = b101, 2R = 8, N = 5

cycle_ctrl = b010, 2R = 4, N = 4

src_data_end_ptr dst_data_end_ptr channel_cfg Unused

0x0A000000 0x0AE00000

0x0B000000 0x0BE00000

0x0C000000 0x0CE00000

0x0D000000 0x0DE00000

0xXXXXXXXX

Data for Task B

Data for Task C

Data for Task D

Memory scatter-gather transaction:

Initialization:

Auto

request

Auto

request

Auto

request

Auto

request

Primary Alternate

N = 3, 2R = 4

N = 8, 2R = 2

N = 5, 2R = 8

N = 4, 2R = 4

2. Write the primary source data to memory, using the structure shown in the following table.

0xXXXXXXXX

In Figure 8.4 (p. 58) :

Initialization 1. The host processor configures the primary data structure to operate in memory

scatter-gather mode by setting cycle_ctrl to b100. Because a data structure for a

single channel consists of four words then you must set 2R to 4. In this example,

there are four tasks and therefore N is set to 16.

2. The host processor writes the data structure for tasks A, B, C, and D to the

memory locations that the primary src_data_end_ptr specifies.

3. The host processor enables the channel.

The memory scatter-gather transaction commences when the controller receives a request on

dma_req[ ] or a manual request from the host processor. The transaction continues as follows:

Primary, copy A 1. After receiving a request, the controller performs four DMA transfers. These

transfers write the alternate data structure for task A.

2. The controller generates an auto-request for the channel and then arbitrates.

Task A 3. The controller performs task A. After it completes the task, it generates an

auto-request for the channel and then arbitrates.

Primary, copy B 4. The controller performs four DMA transfers. These transfers write the alternate

data structure for task B.

5. The controller generates an auto-request for the channel and then arbitrates.

Task B 6. The controller performs task B. After it completes the task, it generates an

auto-request for the channel and then arbitrates.

Primary, copy C 7. The controller performs four DMA transfers. These transfers write the alternate

data structure for task C.

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8. The controller generates an auto-request for the channel and then arbitrates.

Task C 9. The controller performs task C. After it completes the task, it generates an

auto-request for the channel and then arbitrates.

Primary, copy D 10.The controller performs four DMA transfers. These transfers write the alternate

data structure for task D.

11.The controller sets the cycle_ctrl bits of the primary data structure to b000, to

indicate that this data structure is now invalid.

12.The controller generates an auto-request for the channel and then arbitrates.

Task D 13.The controller performs task D using an auto-request cycle.

14.The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters

the arbitration process.

8.4.2.3.6 Peripheral scatter-gather

In peripheral scatter-gather mode the controller receives an initial request from a peripheral and then it

performs four DMA transfers using the primary data structure. It then immediately starts a DMA cycle

using the alternate data structure, without re-arbitrating.

Note These are the only circumstances, where the controller does not enter the arbitration

process after completing a transfer using the primary data structure.

After this cycle completes, the controller re-arbitrates and if the controller receives a request from the

peripheral that has the highest priority then it performs another four DMA transfers using the primary

data structure. It then immediately starts a DMA cycle using the alternate data structure, without re-

arbitrating. The controller continues to switch from primary to alternate to primary… until either:

• the host processor configures the alternate data structure for a basic cycle

• it reads an invalid data structure.

Note After the controller completes the N primary transfers it invalidates the primary data

structure by setting the cycle_ctrl field to b000.

The controller asserts dma_done[C] when the scatter-gather transaction completes using a basic cycle.

In scatter-gather mode, the controller uses the primary data structure to program the alternate data

structure. Table 8.5 (p. 59) lists the fields of the channel_cfg memory location for the primary data

structure, that you must program with constant values and those that can be user defined.

Table 8.5. channel_cfg for a primary data structure, in peripheral scatter-gather mode

Bit Field Value Description

Constant-value fields:

[31:30] dst_inc b10 Configures the controller to use word increments for the address

[29:28] dst_size b10 Configures the controller to use word transfers

[27:26] src_inc b10 Configures the controller to use word increments for the address

[25:24] src_size b10 Configures the controller to use word transfers

[17:14] R_power b0010 Configures the controller to perform four DMA transfers

[2:0] cycle_ctrl b110 Configures the controller to perform a peripheral scatter-gather DMA cycle

User defined values:

[23:21] dst_prot_ctrl - Configures the state of HPROT when the controller writes the destination data

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Bit Field Value Description

[20:18] src_prot_ctrl - Configures the state of HPROT when the controller reads the source data

[13:4] n_minus_1 N1Configures the controller to perform N DMA transfers, where N is a multiple of four

[3] next_useburst - When set to 1, the controller sets the chnl_useburst_set [C] bit to 1 after the

alternate transfer completes

1Because the R_power field is set to four, you must set N to be a multiple of four. The value given by N/4 is the number of times

that you must configure the alternate data structure.

See Section 8.4.3.3 (p. 64) for more information.

Figure 8.5 (p. 60) shows a peripheral scatter-gather example.

Figure 8.5. Peripheral scatter-gather example

Copy from A in

memory, to Alternate

Request

Task A

Task B

Request

Copy from B in

memory, to Alternate

Request

Copy from C in

memory, to Alternate

Task C

Copy from D in

memory, to Alternate

Task D

Peripheral scatter-gather transaction:

For all primary to alternate transitions,

the controller does not enter the

arbitration process and immediately

performs the DMA transfer that the

alternate channel control data structure

specifies.

1. Configure primary to enable the copy A, B, C, and D operations: cycle_ctrl = b110, 2R = 4, N = 16.

Initialization: 2. Write the primary source data in memory, using the structure shown in the following table.

cycle_ctrl = b111, 2R = 4, N = 3

cycle_ctrl = b111, 2R = 2, N = 8

cycle_ctrl = b111, 2R = 8, N = 5

cycle_ctrl = b001, 2R = 4, N = 4

src_data_end_ptr dst_data_end_ptr channel_cfg Unused

0x0A000000 0x0AE00000

0x0B000000 0x0BE00000

0x0C000000 0x0CE00000

0x0D000000 0x0DE00000

0xXXXXXXXX

0xXXXXXXXXData for Task A

Data for Task B

Data for Task C

Data for Task D

Request

Primary Alternate

dma_done[C]

N = 3, 2R = 4

N = 8, 2R = 2

N = 5, 2R = 8

N = 4, 2R = 4

In Figure 8.5 (p. 60) :

Initialization 1. The host processor configures the primary data structure to operate in peripheral

scatter-gather mode by setting cycle_ctrl to b110. Because a data structure for a

single channel consists of four words then you must set 2R to 4. In this example,

there are four tasks and therefore N is set to 16.

2. The host processor writes the data structure for tasks A, B, C, and D to the

memory locations that the primary src_data_end_ptr specifies.

3. The host processor enables the channel.

The peripheral scatter-gather transaction commences when the controller receives a request on

dma_req[ ]. The transaction continues as follows:

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Primary, copy A 1. After receiving a request, the controller performs four DMA transfers. These

transfers write the alternate data structure for task A.

Task A 2. The controller performs task A.

3. After the controller completes the task it enters the arbitration process.

After the peripheral issues a new request and it has the highest priority then the process continues with:

Primary, copy B 4. The controller performs four DMA transfers. These transfers write the alternate

data structure for task B.

Task B 5. The controller performs task B. To enable the controller to complete the task,

the peripheral must issue a further three requests.

6. After the controller completes the task it enters the arbitration process.

After the peripheral issues a new request and it has the highest priority then the process continues with:

Primary, copy C 7. The controller performs four DMA transfers. These transfers write the alternate

data structure for task C.

Task C 8. The controller performs task C.

9. After the controller completes the task it enters the arbitration process.

After the peripheral issues a new request and it has the highest priority then the process continues with:

Primary, copy D 10.The controller performs four DMA transfers. These transfers write the alternate

data structure for task D.

11.The controller sets the cycle_ctrl bits of the primary data structure to b000, to

indicate that this data structure is now invalid.

Task D 12.The controller performs task D using a basic cycle.

13.The controller sets dma_done[C] HIGH for one HFCORECLK cycle and enters

the arbitration process.

8.4.2.4 Error signaling

If the controller detects an ERROR response on the AHB-Lite master interface, it:

• disables the channel that corresponds to the ERROR

• sets dma_err HIGH.

After the host processor detects that dma_err is HIGH, it must check which channel was active when

the ERROR occurred. It can do this by:

1. Reading the DMA_CHENS register to create a list of disabled channels.

When a channel asserts dma_done[ ] then the controller disables the channel. The program running

on the host processor must always keep a record of which channels have recently asserted their

dma_done[ ] outputs.

2. It must compare the disabled channels list from step 1 (p. 61) , with the record of the channels that

have recently set their dma_done[ ] outputs. The channel with no record of dma_done[C] being

set is the channel that the ERROR occurred on.

8.4.3 Channel control data structure

You must provide an area of system memory to contain the channel control data structure. This system

memory must:

• provide a contiguous area of system memory that the controller and host processor can access

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• have a base address that is an integer multiple of the total size of the channel control data structure.

Figure 8.6 (p. 62) shows the memory that the controller requires for the channel control data structure,

when all 12 channels and the optional alternate data structure are in use.

Figure 8.6. Memory map for 12 channels, including the alternate data structure

Primary_Ch_0

Primary_Ch_1

Primary_Ch_2

Primary_Ch_3

Primary_Ch_4

Primary_Ch_5

Primary_Ch_6

Primary_Ch_7

0x000

0x010

0x050

0x080

0x070

0x060

0x040

0x030

0x020

Alternate_Ch_0

Alternate_Ch_1

Alternate_Ch_2

Alternate_Ch_3

Alternate_Ch_4

Alternate_Ch_5

Alternate_Ch_6

Alternate_Ch_7

0x100

0x110

0x150

0x180

0x170

0x160

0x140

0x130

0x120 Destination End Pointer

Source End Pointer

Control

User

0x000

0x004

0x008

0x00C

Alternate data structure Primary data structure

Primary_Ch_8

Primary_Ch_9

Primary_Ch_10

Primary_Ch_11

0x090

0x0C0

0x0B0

0x0A0

Alternate_Ch_8

Alternate_Ch_9

Alternate_Ch_10

Alternate_Ch_11

0x190

0x1C0

0x1B0

0x1A0

This structure in Figure 8.6 (p. 62) uses 384 bytes of system memory. The controller uses the lower

8 address bits to enable it to access all of the elements in the structure and therefore the base address

must be at 0xXXXXXX00.

You can configure the base address for the primary data structure by writing the appropriate value in

the DMA_CTRLBASE register.

You do not need to set aside the full 384 bytes if all dma channels are not used or if all alternate

descriptors are not used. If, for example, only 4 channels are used and they only need the primary

descriptors, then only 64 bytes need to be set aside.

Table 8.6 (p. 62) lists the address bits that the controller uses when it accesses the elements of the

channel control data structure.

Table 8.6. Address bit settings for the channel control data structure

Address bits

[8] [7] [6] [5] [4] [3:0]

A C[3] C[2] C[1] C[0] 0x0, 0x4, or 0x8

Where:

A Selects one of the channel control data structures:

A = 0 Selects the primary data structure.

A = 1 Selects the alternate data structure.

C[3:0] Selects the DMA channel.

Address[3:0] Selects one of the control elements:

0x0 Selects the source data end pointer.

0x4 Selects the destination data end pointer.

0x8 Selects the control data configuration.

0xC The controller does not access this address location. If required, you can

enable the host processor to use this memory location as system memory.

Note It is not necessary for you to calculate the base address of the alternate data structure

because the DMA_ALTCTRLBASE register provides this information.

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Figure 8.7 (p. 63) shows a detailed memory map of the descriptor structure.

Figure 8.7. Detailed memory map for the 12 channels, including the alternate data structure

0x000

Source End Pointer

Destination End Pointer

Control

Unused

Source End Pointer

Destination End Pointer

Control

Unused

Source End Pointer

Destination End Pointer

Control

Unused

0x004

0x008

0x010

0x014

0x018

0x0B0

0x0B4

0x0B8

Source End Pointer

Destination End Pointer

Control

Unused

0x100

0x104

0x108

Source End Pointer

Destination End Pointer

Control

Unused

0x110

0x114

0x118

Source End Pointer

Destination End Pointer

Control

Unused

0x1B0

0x1B4

0x1B8

0x00C

0x01C

0x0BC

0x10C

0x11C

0x1BC

Primary

data

structure

Alternate

data

structure

Alternate for

channel 11

Alternate for

channel 1

Alternate for

channel 0

Primary for

channel 11

Primary for

channel 1

Primary for

channel 0

The controller uses the system memory to enable it to access two pointers and the control information

that it requires for each channel. The following subsections will describe these 32-bit memory locations

and how the controller calculates the DMA transfer address.

8.4.3.1 Source data end pointer

The src_data_end_ptr memory location contains a pointer to the end address of the source data.

Figure 8.7 (p. 63) lists the bit assignments for this memory location.

Table 8.7. src_data_end_ptr bit assignments

Bit Name Description

[31:0] src_data_end_ptr Pointer to the end address of the source data

Before the controller can perform a DMA transfer, you must program this memory location with the end

address of the source data. The controller reads this memory location when it starts a 2R DMA transfer.

Note The controller does not write to this memory location.

8.4.3.2 Destination data end pointer

The dst_data_end_ptr memory location contains a pointer to the end address of the destination data.

Table 8.8 (p. 64) lists the bit assignments for this memory location.

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Table 8.8. dst_data_end_ptr bit assignments

Bit Name Description

[31:0] dst_data_end_ptr Pointer to the end address of the destination data

Before the controller can perform a DMA transfer, you must program this memory location with the end

address of the destination data. The controller reads this memory location when it starts a 2R DMA

transfer.

Note The controller does not write to this memory location.

8.4.3.3 Control data configuration

For each DMA transfer, the channel_cfg memory location provides the control information for the

controller. Figure 8.8 (p. 64) shows the bit assignments for this memory location.

Figure 8.8. channel_cfg bit assignments

31 21 20 13 40

dst_inc src_prot_ctrl

R_power n_minus_1

next_useburst

30 29 28 27 26 25 24 23

dst_size src_size

src_inc dst_prot_ctrl

18 17

cycle_ctrl

314 2

Table 8.9 (p. 64) lists the bit assignments for this memory location.

Table 8.9. channel_cfg bit assignments

Bit Name Description

[31:30] dst_inc Destination address increment.

The address increment depends on the source data width as follows:

Source data width = byte b00 = byte.

b01 = halfword.

b10 = word.

b11 = no increment. Address remains set to the value that

the dst_data_end_ptr memory location contains.

Source data width = halfword b00 = reserved.

b01 = halfword.

b10 = word.

b11 = no increment. Address remains set to the value that

the dst_data_end_ptr memory location contains.

Source data width = word b00 = reserved.

b01 = reserved.

b10 = word.

b11 = no increment. Address remains set to the value that

the dst_data_end_ptr memory location contains.

[29:28] dst_size Destination data size.

Note

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Bit Name Description

You must set dst_size to contain the same value that src_size contains.

[27:26] src_inc Set the bits to control the source address increment. The address increment depends on the

source data width as follows:

Source data width = byte b00 = byte.

b01 = halfword.

b10 = word.

b11 = no increment. Address remains set to the value that

the src_data_end_ptr memory location contains.

Source data width = halfword b00 = reserved.

b01 = halfword.

b10 = word.

b11 = no increment. Address remains set to the value that

the src_data_end_ptr memory location contains.

Source data width = word b00 = reserved.

b01 = reserved.

b10 = word.

b11 = no increment. Address remains set to the value that

the src_data_end_ptr memory location contains.

[25:24] src_size Set the bits to match the size of the source data:

b00 = byte

b01 = halfword

b10 = word

b11 = reserved.

[23:21] dst_prot_ctrl Set the bits to control the state of HPROT when the controller writes the destination data.

Bit [23] This bit has no effect on the DMA.

Bit [22] This bit has no effect on the DMA.

Bit [21] Controls the state of HPROT as follows:

0 = HPROT is LOW and the access is non-privileged.

1 = HPROT is HIGH and the access is privileged.

[20:18] src_prot_ctrl Set the bits to control the state of HPROT when the controller reads the source data.

Bit [20] This bit has no effect on the DMA.

Bit [19] This bit has no effect on the DMA.

Bit [18] Controls the state of HPROT as follows:

0 = HPROT is LOW and the access is non-privileged.

1 = HPROT is HIGH and the access is privileged.

[17:14] R_power Set these bits to control how many DMA transfers can occur before the controller re-arbitrates.

The possible arbitration rate settings are:

b0000 Arbitrates after each DMA transfer.

b0001 Arbitrates after 2 DMA transfers.

b0010 Arbitrates after 4 DMA transfers.

b0011 Arbitrates after 8 DMA transfers.

b0100 Arbitrates after 16 DMA transfers.

b0101 Arbitrates after 32 DMA transfers.

b0110 Arbitrates after 64 DMA transfers.

b0111 Arbitrates after 128 DMA transfers.

b1000 Arbitrates after 256 DMA transfers.

b1001 Arbitrates after 512 DMA transfers.

b1010-b1111 Arbitrates after 1024 DMA transfers. This means that no arbitration occurs

during the DMA transfer because the maximum transfer size is 1024.

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Bit Name Description

[13:4] n_minus_1 Prior to the DMA cycle commencing, these bits represent the total number of DMA transfers

that the DMA cycle contains. You must set these bits according to the size of DMA cycle that

you require.

The 10-bit value indicates the number of DMA transfers, minus one. The possible values are:

b000000000 = 1 DMA transfer

b000000001 = 2 DMA transfers

b000000010 = 3 DMA transfers

b000000011 = 4 DMA transfers

b000000100 = 5 DMA transfers

b111111111 = 1024 DMA transfers.

The controller updates this field immediately prior to it entering the arbitration process. This

enables the controller to store the number of outstanding DMA transfers that are necessary to

complete the DMA cycle.

[3] next_useburst Controls if the chnl_useburst_set [C] bit is set to a 1, when the controller is performing a

peripheral scatter-gather and is completing a DMA cycle that uses the alternate data structure.

Note Immediately prior to completion of the DMA cycle that the alternate data structure

specifies, the controller sets the chnl_useburst_set [C] bit to 0 if the number of

remaining transfers is less than 2R. The setting of the next_useburst bit controls if the

controller performs an additional modification of the chnl_useburst_set [C] bit.

In peripheral scatter-gather DMA cycle then after the DMA cycle that uses the alternate data

structure completes, either:

0 = the controller does not change the value of the chnl_useburst_set [C] bit. If the

chnl_useburst_set [C] bit is 0 then for all the remaining DMA cycles in the peripheral scatter-

gather transaction, the controller responds to requests on dma_req[ ] and dma_sreq[ ],

when it performs a DMA cycle that uses an alternate data structure.

1 = the controller sets the chnl_useburst_set [C] bit to a 1. Therefore, for the remaining DMA

cycles in the peripheral scatter-gather transaction, the controller only responds to requests on

dma_req[ ], when it performs a DMA cycle that uses an alternate data structure.

[2:0] cycle_ctrl The operating mode of the DMA cycle. The modes are:

b000 Stop. Indicates that the data structure is invalid.

b001 Basic. The controller must receive a new request, prior to it entering the arbitration

process, to enable the DMA cycle to complete.

b010 Auto-request. The controller automatically inserts a request for the appropriate channel

during the arbitration process. This means that the initial request is sufficient to enable

the DMA cycle to complete.

b011 Ping-pong. The controller performs a DMA cycle using one of the data structures. After

the DMA cycle completes, it performs a DMA cycle using the other data structure. After

the DMA cycle completes and provided that the host processor has updated the original

data structure, it performs a DMA cycle using the original data structure. The controller

continues to perform DMA cycles until it either reads an invalid data structure or the

host processor changes the cycle_ctrl bits to b001 or b010. See Section 8.4.2.3.4 (p.

54) .

b100 Memory scatter/gather. See Section 8.4.2.3.5 (p. 56) .

When the controller operates in memory scatter-gather mode, you must only use this

value in the primary data structure.

b101 Memory scatter/gather. See Section 8.4.2.3.5 (p. 56) .

When the controller operates in memory scatter-gather mode, you must only use this

value in the alternate data structure.

b110 Peripheral scatter/gather. See Section 8.4.2.3.6 (p. 59) .

When the controller operates in peripheral scatter-gather mode, you must only use this

value in the primary data structure.

b111 Peripheral scatter/gather. See Section 8.4.2.3.6 (p. 59) .

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Bit Name Description

When the controller operates in peripheral scatter-gather mode, you must only use this

value in the alternate data structure.

At the start of a DMA cycle, or 2R DMA transfer, the controller fetches the channel_cfg from system

memory. After it performs 2R, or N, transfers it stores the updated channel_cfg in system memory.

The controller does not support a dst_size value that is different to the src_size value. If it detects a

mismatch in these values, it uses the src_size value for source and destination and when it next updates

the n_minus_1 field, it also sets the dst_size field to the same as the src_size field.

After the controller completes the N transfers it sets the cycle_ctrl field to b000, to indicate that the

channel_cfg data is invalid. This prevents it from repeating the same DMA transfer.

8.4.3.4 Address calculation

To calculate the source address of a DMA transfer, the controller performs a left shift operation on the

n_minus_1 value by a shift amount that src_inc specifies, and then subtracts the resulting value from the

source data end pointer. Similarly, to calculate the destination address of a DMA transfer, it performs a

left shift operation on the n_minus_1 value by a shift amount that dst_inc specifies, and then subtracts

the resulting value from the destination end pointer.

Depending on the value of src_inc and dst_inc, the source address and destination address can be

calculated using the equations:

src_inc=b00 and dst_inc= b00 • source address = src_data_end_ptr - n_minus_1

• destination address = dst_data_end_ptr - n_minus_1.

src_inc=b01 and dst_inc= b01 • source address = src_data_end_ptr - (n_minus_1 << 1)

• destination address = dst_data_end_ptr - (n_minus_1 << 1).

src_inc=b10 and dst_inc= b10 • source address = src_data_end_ptr - (n_minus_1 << 2)

• destination address = dst_data_end_ptr - (n_minus_1 << 2).

src_inc=b11 and dst_inc= b11 • source address = src_data_end_ptr

• destination address = dst_data_end_ptr.

Table 8.10 (p. 67) lists the destination addresses for a DMA cycle of six words.

Table 8.10. DMA cycle of six words using a word increment

Initial values of channel_cfg, prior to the DMA cycle

src_size=b10, dst_inc = b10, n_minus_1 =b101, cycle_ctrl=1

End Pointer Count Difference1Address

0x2AC 50x14 0x298

0x2AC 40x10 0x29C

0x2AC 30xC 0x2A0

0x2AC 20x8 0x2A4

0x2AC 10x4 0x2A8

DMA transfers

0x2AC 00x0 0x2AC

Final values of channel_cfg, after the DMA cycle

src_size=b10, dst_inc = b10, n_minus_1 =0, cycle_ctrl=0

1This value is the result of count being shifted left by the value of dst_inc.

Table 8.11 (p. 68) lists the destination addresses for a DMA transfer of 12 bytes using a halfword

increment.

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Table 8.11. DMA cycle of 12 bytes using a halfword increment

Initial values of channel_cfg, prior to the DMA cycle

src_size=b00, dst_inc = b01, n_minus_1 =b1011, cycle_ctrl=1, R_power = b11

End Pointer Count Difference1Address

0x5E7 11 0x16 0x5D1

0x5E7 10 0x14 0x5D3

0x5E7 90x12 0x5D5

0x5E7 80x10 0x5D7

0x5E7 70xE 0x5D9

0x5E7 60xC 0x5DB

0x5E7 50xA 0x5DD

DMA transfers

0x5E7 40x8 0x5DF

Values of channel_cfg after 2R DMA transfers

src_size=b00, dst_inc = b01, n_minus_1 =b011, cycle_ctrl=1, R_power = b11

End Pointer Count Difference Address

0x5E7 30x6 0x5E1

0x5E7 20x4 0x5E3

0x5E7 10x2 0x5E5

DMA transfers 0x5E7 00x0 0x5E7

Final values of channel_cfg, after the DMA cycle

src_size=b00, dst_inc = b01, n_minus_1 =0, cycle_ctrl=0 2, R_power =b11

1This value is the result of count being shifted left by the value of dst_inc.

2After the controller completes the DMA cycle it invalidates the channel_cfg memory location by clearing the cycle_ctrl field.

8.4.4 Looped Transfers

A regular DMA channel is done when it has performed the number of transfers given by the channel

descriptor. If an application wants a continuous flow of data, one option is to use ping-pong mode,

alternating between two descriptors and having software update one descriptor while the other is being

used. Another way is to use looped transfers.

For DMA channels 0 and 1, looping can be enabled by setting EN in DMA_LOOP0 and DMA_LOOP1

respectively. A looping DMA channel will on completion set the respective DONE interrupt flag, but then

reload n_minus_1 in the channel descriptor with the loop width defined by WIDTH in DMA_LOOPx and

continue transmitting data.

The total length of the transfer is given by the original value of n_minus_1 in the channel descriptor and

WIDTH in DMA_LOOPx times the number of loops taken. The loop feature can for instance be used to

implement a ring buffer, contiguously overwriting old data when new data is available. To end the loop

clear EN in DMA_LOOPx. The channel will then complete the last loop before stopping.

8.4.5 2D Copy

In addition to looped transfers, DMA channel 0 has the ability to do rectangle transfers, or 2D copy. For

an application working with graphics, this would mean the ability to copy a rectangle of a given width and

height from one picture to another. The DMA also has the ability to copy from linear data to a rectangle,

and from a rectangle to linear data.

To set up rectangle copy for DMA channel 0, configure WIDTH in DMA_LOOP0 to one less than

the rectangle width, and HEIGHT in DMA_RECT0 to one less than the rectangle height. Then

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set SRCSTRIDE in DMA_RECT0 to the outer rectangle width of the source, and DSTSTRIDE in

DMA_RECT0 to the outer rectangle width of the destination rectangle. Finally, the channel descriptor for

channel 0 has to be configured. The source and destination end pointers should be set to the last element

of the first line of the source data and destination data respectively. The number of elements to be

transferred, n_minus_1 should be set equal to WIDTH in DMA_LOOP0. The parameters are visualized

in Figure 8.9 (p. 69) .

Figure 8.9. 2D copy

Source buffer Destination buffer

SRCSTRIDE DSTSTRIDE

WIDTH

HEIGHT

WIDTH

HEIGHT

Source

end

pointer

Destination

end pointer

When doing a rectangle copy, the source and destination address of the channel descriptor will be

incremented line for line as the DMA works its way through the rectangle. The operation is done when

the number of lines specified by HEIGHT in DMA_RECT0 has been copied. The source and destination

addresses in the channel descriptor will then point at the last element of the source and destination

rectangles.

On completion, the DONE interrupt flag of channel 0 is set. Looping is not supported for rectangle copy.

In some cases, e.g. when performing graphics operations, it is desirable to create a list of copy operations

and have them executed automatically. This can be done using 2D copy together with the scatter gather

mode of the DMA controller. Set DESCRECT in DMA_CTRL to override SCRSTRIDE and HEIGHT

in DMA_RECT0 and WIDTH in DMA_LOOP0 by the values in the user part of the DMA descriptor as

shown in Table 8.12 (p. 69) . In this way every copy command in the list can specify these parameters

individually.

Table 8.12. User data assignments when DESCRECT is set

Bit Field Description

[30:20] SRCSTRIDE Stride in source buffer

[19:10] HEIGHT Height - 1 of data to be copied

[9:0] WIDTH Width - 1 of data to be copied

With regular 2D copy, the DMA descriptor will be updated as the copy operation proceeds. To be able to

reuse the 2D copy scatter gather list without rewriting source and destination end addresses, set PRDU

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in DMA_CTRL. This will prevent the address in the descriptor from being updated. In this case RDSCH0

in DMA_RDS must be set and all other bits in DMA_RDS must be cleared. The bits in DMA_RDS make

individual DMA channels remember the source and destination end pointers while active, speeding up

their transfers.

8.4.6 Interaction with the EMU

The DMA interacts with the Energy Management Unit (EMU) to allow transfers from , e.g., the LEUART

to occur in EM2. The EMU can wake up the DMA sufficiently long to allow data transfers to occur. See

section "DMA Support" in the LEUART documentation.

8.4.7 Interrupts

The PL230 dma_done[n:0] signals (one for each channel) as well as the dma_err signal, are available as

interrupts to the Cortex-M3 core. They are combined into one interrupt vector, DMA_INT. If the interrupt

for the DMA is enabled in the ARM Cortex-M3 core, an interrupt will be made if one or more of the

interrupt flags in DMA_IF and their corresponding bits in DMA_IEN are set.

8.5 Examples

A basic example of how to program the DMA for transferring 42 bytes from the USART1 to

memory location 0x20003420. Assumes that the channel 0 is currently disabled, and that the

DMA_ALTCTRLBASE register has already been configured.

Example 8.1. DMA Transfer

1. Configure the channel select for using USART1 with DMA channel 0

a. Write SOURCESEL=0b001101 and SIGSEL=XX to DMA_CHCTRL0

2. Configure the primary channel descriptor for DMA channel 0

a. Write XX (read address of USART1) to src_data_end_ptr

b. Write 0x20003420 + 40 to dst_data_end_ptr c

c. Write these values to channel_cfg for channel 0:

i. dst_inc=b01 (destination halfword address increment)

ii. dst_size=b01 (halfword transfer size)

iii. src_inc=b11 (no address increment for source)

iv.src_size=01 (halfword transfer size)

v. dst_prot_ctrl=000 (no cache/buffer/privilege)

vi.src_prot_ctrl=000 (no cache/buffer/privilege)

vii.R_power=b0000 (arbitrate after each DMA transfer)

viii.n_minus_1=d20 (transfer 21 halfwords)

ix.next_useburst=b0 (not applicable)

x. cycle_ctrl=b001 (basic operating mode)

3. Enable the DMA

a. Write EN=1 to DMA_CONFIG

4. Disable the single requests for channel 0 (i.e., do not react to data available, wait for buffer full)

a. Write DMA_CHUSEBURSTS[0]=1

5. Enable buffer-full requests for channel 0

a. Write DMA_CHREQMASKC[0]=1

6. Use the primary data structure for channel 0

a. Write DMA_CHALTC[0]=1

7. Enable channel 0

a. Write DMA_CHENS[0]=1

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8.6 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 DMA_STATUS R DMA Status Registers

0x004 DMA_CONFIG W DMA Configuration Register

0x008 DMA_CTRLBASE RW Channel Control Data Base Pointer Register

0x00C DMA_ALTCTRLBASE R Channel Alternate Control Data Base Pointer Register

0x010 DMA_CHWAITSTATUS R Channel Wait on Request Status Register

0x014 DMA_CHSWREQ W1 Channel Software Request Register

0x018 DMA_CHUSEBURSTS RW1H Channel Useburst Set Register

0x01C DMA_CHUSEBURSTC W1 Channel Useburst Clear Register

0x020 DMA_CHREQMASKS RW1 Channel Request Mask Set Register

0x024 DMA_CHREQMASKC W1 Channel Request Mask Clear Register

0x028 DMA_CHENS RW1 Channel Enable Set Register

0x02C DMA_CHENC W1 Channel Enable Clear Register

0x030 DMA_CHALTS RW1 Channel Alternate Set Register

0x034 DMA_CHALTC W1 Channel Alternate Clear Register

0x038 DMA_CHPRIS RW1 Channel Priority Set Register

0x03C DMA_CHPRIC W1 Channel Priority Clear Register

0x04C DMA_ERRORC RW Bus Error Clear Register

0xE10 DMA_CHREQSTATUS R Channel Request Status

0xE18 DMA_CHSREQSTATUS R Channel Single Request Status

0x1000 DMA_IF R Interrupt Flag Register

0x1004 DMA_IFS W1 Interrupt Flag Set Register

0x1008 DMA_IFC W1 Interrupt Flag Clear Register

0x100C DMA_IEN RW Interrupt Enable register

0x1010 DMA_CTRL RW DMA Control Register

0x1014 DMA_RDS RW DMA Retain Descriptor State

0x1020 DMA_LOOP0 RWH Channel 0 Loop Register

0x1024 DMA_LOOP1 RW Channel 1 Loop Register

0x1060 DMA_RECT0 RWH Channel 0 Rectangle Register

0x1100 DMA_CH0_CTRL RW Channel Control Register

... DMA_CHx_CTRL RW Channel Control Register

0x112C DMA_CH11_CTRL RW Channel Control Register

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8.7 Register Description

8.7.1 DMA_STATUS - DMA Status Registers

Offset Bit Position

0x000

Reset

0x0B

0x0

Access

Name

CHNUM

STATE

Bit Name Reset Access Description

31:21 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

20:16 CHNUM 0x0B R Channel Number

Number of available DMA channels minus one.

15:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:4 STATE 0x0 R Control Current State

State can be one of the following. Higher values (11-15) are undefined.

Value Mode Description

0 IDLE Idle

1 RDCHCTRLDATA Reading channel controller data

2 RDSRCENDPTR Reading source data end pointer

3 RDDSTENDPTR Reading destination data end pointer

4 RDSRCDATA Reading source data

5 WRDSTDATA Writing destination data

6 WAITREQCLR Waiting for DMA request to clear

7 WRCHCTRLDATA Writing channel controller data

8 STALLED Stalled

9 DONE Done

10 PERSCATTRANS Peripheral scatter-gather transition

3:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 EN 0 R DMA Enable Status

When this bit is 1, the DMA is enabled.

8.7.2 DMA_CONFIG - DMA Configuration Register

Offset Bit Position

0x004

Reset

Access

Name

CHPROT

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

5 CHPROT 0 W Channel Protection Control

Control whether accesses done by the DMA controller are privileged or not. When CHPROT = 1 then HPROT is HIGH and the access

is privileged. When CHPROT = 0 then HPROT is LOW and the access is non-privileged.

4:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 EN 0 W Enable DMA

Set this bit to enable the DMA controller.

8.7.3 DMA_CTRLBASE - Channel Control Data Base Pointer Register

Offset Bit Position

0x008

Reset

0x00000000

Access

Name

CTRLBASE

Bit Name Reset Access Description

31:0 CTRLBASE 0x00000000 RW Channel Control Data Base Pointer

The base pointer for a location in system memory that holds the channel control data structure. This register must be written to point

to a location in system memory with the channel control data structure before the DMA can be used. Note that ctrl_base_ptr[8:0]

must be 0.

8.7.4 DMA_ALTCTRLBASE - Channel Alternate Control Data Base Pointer

Offset Bit Position

0x00C

Reset

0x00000100

Access

Name

ALTCTRLBASE

Bit Name Reset Access Description

31:0 ALTCTRLBASE 0x00000100 R Channel Alternate Control Data Base Pointer

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Bit Name Reset Access Description

The base address of the alternate data structure. This register will read as DMA_CTRLBASE + 0x100.

8.7.5 DMA_CHWAITSTATUS - Channel Wait on Request Status Register

Offset Bit Position

0x010

Reset

Access

Name

CH11WAITSTATUS

CH10WAITSTATUS

CH9WAITSTATUS

CH8WAITSTATUS

CH7WAITSTATUS

CH6WAITSTATUS

CH5WAITSTATUS

CH4WAITSTATUS

CH3WAITSTATUS

CH2WAITSTATUS

CH1WAITSTATUS

CH0WAITSTATUS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11WAITSTATUS 1 R Channel 11 Wait on Request Status

Status for wait on request for channel 11.

10 CH10WAITSTATUS 1 R Channel 10 Wait on Request Status

Status for wait on request for channel 10.

9 CH9WAITSTATUS 1 R Channel 9 Wait on Request Status

Status for wait on request for channel 9.

8 CH8WAITSTATUS 1 R Channel 8 Wait on Request Status

Status for wait on request for channel 8.

7 CH7WAITSTATUS 1 R Channel 7 Wait on Request Status

Status for wait on request for channel 7.

6 CH6WAITSTATUS 1 R Channel 6 Wait on Request Status

Status for wait on request for channel 6.

5 CH5WAITSTATUS 1 R Channel 5 Wait on Request Status

Status for wait on request for channel 5.

4 CH4WAITSTATUS 1 R Channel 4 Wait on Request Status

Status for wait on request for channel 4.

3 CH3WAITSTATUS 1 R Channel 3 Wait on Request Status

Status for wait on request for channel 3.

2 CH2WAITSTATUS 1 R Channel 2 Wait on Request Status

Status for wait on request for channel 2.

1 CH1WAITSTATUS 1 R Channel 1 Wait on Request Status

Status for wait on request for channel 1.

0 CH0WAITSTATUS 1 R Channel 0 Wait on Request Status

Status for wait on request for channel 0.

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8.7.6 DMA_CHSWREQ - Channel Software Request Register

Offset Bit Position

0x014

Reset

Access

Name

CH11SWREQ

CH10SWREQ

CH9SWREQ

CH8SWREQ

CH7SWREQ

CH6SWREQ

CH5SWREQ

CH4SWREQ

CH3SWREQ

CH2SWREQ

CH1SWREQ

CH0SWREQ

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11SWREQ 0 W1 Channel 11 Software Request

Write 1 to this bit to generate a DMA request for this channel.

10 CH10SWREQ 0 W1 Channel 10 Software Request

Write 1 to this bit to generate a DMA request for this channel.

9 CH9SWREQ 0 W1 Channel 9 Software Request

Write 1 to this bit to generate a DMA request for this channel.

8 CH8SWREQ 0 W1 Channel 8 Software Request

Write 1 to this bit to generate a DMA request for this channel.

7 CH7SWREQ 0 W1 Channel 7 Software Request

Write 1 to this bit to generate a DMA request for this channel.

6 CH6SWREQ 0 W1 Channel 6 Software Request

Write 1 to this bit to generate a DMA request for this channel.

5 CH5SWREQ 0 W1 Channel 5 Software Request

Write 1 to this bit to generate a DMA request for this channel.

4 CH4SWREQ 0 W1 Channel 4 Software Request

Write 1 to this bit to generate a DMA request for this channel.

3 CH3SWREQ 0 W1 Channel 3 Software Request

Write 1 to this bit to generate a DMA request for this channel.

2 CH2SWREQ 0 W1 Channel 2 Software Request

Write 1 to this bit to generate a DMA request for this channel.

1 CH1SWREQ 0 W1 Channel 1 Software Request

Write 1 to this bit to generate a DMA request for this channel.

0 CH0SWREQ 0 W1 Channel 0 Software Request

Write 1 to this bit to generate a DMA request for this channel.

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8.7.7 DMA_CHUSEBURSTS - Channel Useburst Set Register

Offset Bit Position

0x018

Reset

Access

RW1H

Name

CH11USEBURSTS

CH10USEBURSTS

CH9USEBURSTS

CH8USEBURSTS

CH7USEBURSTS

CH6USEBURSTS

CH5USEBURSTS

CH4USEBURSTS

CH3USEBURSTS

CH2USEBURSTS

CH1USEBURSTS

CH0USEBURSTS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11USEBURSTS 0 RW1H Channel 11 Useburst Set

See description for channel 0.

10 CH10USEBURSTS 0 RW1H Channel 10 Useburst Set

See description for channel 0.

9 CH9USEBURSTS 0 RW1H Channel 9 Useburst Set

See description for channel 0.

8 CH8USEBURSTS 0 RW1H Channel 8 Useburst Set

See description for channel 0.

7 CH7USEBURSTS 0 RW1H Channel 7 Useburst Set

See description for channel 0.

6 CH6USEBURSTS 0 RW1H Channel 6 Useburst Set

See description for channel 0.

5 CH5USEBURSTS 0 RW1H Channel 5 Useburst Set

See description for channel 0.

4 CH4USEBURSTS 0 RW1H Channel 4 Useburst Set

See description for channel 0.

3 CH3USEBURSTS 0 RW1H Channel 3 Useburst Set

See description for channel 0.

2 CH2USEBURSTS 0 RW1H Channel 2 Useburst Set

See description for channel 0.

1 CH1USEBURSTS 0 RW1H Channel 1 Useburst Set

See description for channel 0.

0 CH0USEBURSTS 0 RW1H Channel 0 Useburst Set

Write to 1 to enable the useburst setting for this channel. Reading returns the useburst status. After the penultimate 2^R transfer

completes, if the number of remaining transfers, N, is less than 2^R then the controller resets the chnl_useburst_set bit to 0.

This enables you to complete the remaining transfers using dma_req[] or dma_sreq[]. In peripheral scatter-gather mode, if the

next_useburst bit is set in channel_cfg then the controller sets the chnl_useburst_set[C] bit to a 1, when it completes the DMA cycle

that uses the alternate data structure.

Value Mode Description

0 SINGLEANDBURST Channel responds to both single and burst requests

1 BURSTONLY Channel responds to burst requests only

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8.7.8 DMA_CHUSEBURSTC - Channel Useburst Clear Register

Offset Bit Position

0x01C

Reset

Access

Name

CH11USEBURSTC

CH10USEBURSTC

CH9USEBURSTC

CH08USEBURSTC

CH7USEBURSTC

CH6USEBURSTC

CH5USEBURSTC

CH4USEBURSTC

CH3USEBURSTC

CH2USEBURSTC

CH1USEBURSTC

CH0USEBURSTC

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11USEBURSTC 0 W1 Channel 11 Useburst Clear

Write to 1 to disable useburst setting for this channel.

10 CH10USEBURSTC 0 W1 Channel 10 Useburst Clear

Write to 1 to disable useburst setting for this channel.

9 CH9USEBURSTC 0 W1 Channel 9 Useburst Clear

Write to 1 to disable useburst setting for this channel.

8 CH08USEBURSTC 0 W1 Channel 8 Useburst Clear

Write to 1 to disable useburst setting for this channel.

7 CH7USEBURSTC 0 W1 Channel 7 Useburst Clear

Write to 1 to disable useburst setting for this channel.

6 CH6USEBURSTC 0 W1 Channel 6 Useburst Clear

Write to 1 to disable useburst setting for this channel.

5 CH5USEBURSTC 0 W1 Channel 5 Useburst Clear

Write to 1 to disable useburst setting for this channel.

4 CH4USEBURSTC 0 W1 Channel 4 Useburst Clear

Write to 1 to disable useburst setting for this channel.

3 CH3USEBURSTC 0 W1 Channel 3 Useburst Clear

Write to 1 to disable useburst setting for this channel.

2 CH2USEBURSTC 0 W1 Channel 2 Useburst Clear

Write to 1 to disable useburst setting for this channel.

1 CH1USEBURSTC 0 W1 Channel 1 Useburst Clear

Write to 1 to disable useburst setting for this channel.

0 CH0USEBURSTC 0 W1 Channel 0 Useburst Clear

Write to 1 to disable useburst setting for this channel.

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8.7.9 DMA_CHREQMASKS - Channel Request Mask Set Register

Offset Bit Position

0x020

Reset

Access

RW1

Name

CH11REQMASKS

CH10REQMASKS

CH9REQMASKS

CH8REQMASKS

CH7REQMASKS

CH6REQMASKS

CH5REQMASKS

CH4REQMASKS

CH3REQMASKS

CH2REQMASKS

CH1REQMASKS

CH0REQMASKS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11REQMASKS 0 RW1 Channel 11 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

10 CH10REQMASKS 0 RW1 Channel 10 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

9 CH9REQMASKS 0 RW1 Channel 9 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

8 CH8REQMASKS 0 RW1 Channel 8 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

7 CH7REQMASKS 0 RW1 Channel 7 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

6 CH6REQMASKS 0 RW1 Channel 6 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

5 CH5REQMASKS 0 RW1 Channel 5 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

4 CH4REQMASKS 0 RW1 Channel 4 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

3 CH3REQMASKS 0 RW1 Channel 3 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

2 CH2REQMASKS 0 RW1 Channel 2 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

1 CH1REQMASKS 0 RW1 Channel 1 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

0 CH0REQMASKS 0 RW1 Channel 0 Request Mask Set

Write to 1 to disable peripheral requests for this channel.

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8.7.10 DMA_CHREQMASKC - Channel Request Mask Clear Register

Offset Bit Position

0x024

Reset

Access

Name

CH11REQMASKC

CH10REQMASKC

CH9REQMASKC

CH8REQMASKC

CH7REQMASKC

CH6REQMASKC

CH5REQMASKC

CH4REQMASKC

CH3REQMASKC

CH2REQMASKC

CH1REQMASKC

CH0REQMASKC

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11REQMASKC 0 W1 Channel 11 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

10 CH10REQMASKC 0 W1 Channel 10 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

9 CH9REQMASKC 0 W1 Channel 9 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

8 CH8REQMASKC 0 W1 Channel 8 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

7 CH7REQMASKC 0 W1 Channel 7 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

6 CH6REQMASKC 0 W1 Channel 6 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

5 CH5REQMASKC 0 W1 Channel 5 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

4 CH4REQMASKC 0 W1 Channel 4 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

3 CH3REQMASKC 0 W1 Channel 3 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

2 CH2REQMASKC 0 W1 Channel 2 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

1 CH1REQMASKC 0 W1 Channel 1 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

0 CH0REQMASKC 0 W1 Channel 0 Request Mask Clear

Write to 1 to enable peripheral requests for this channel.

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8.7.11 DMA_CHENS - Channel Enable Set Register

Offset Bit Position

0x028

Reset

Access

RW1

Name

CH11ENS

CH10ENS

CH9ENS

CH8ENS

CH7ENS

CH6ENS

CH5ENS

CH4ENS

CH3ENS

CH2ENS

CH1ENS

CH0ENS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11ENS 0 RW1 Channel 11 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

10 CH10ENS 0 RW1 Channel 10 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

9 CH9ENS 0 RW1 Channel 9 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

8 CH8ENS 0 RW1 Channel 8 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

7 CH7ENS 0 RW1 Channel 7 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

6 CH6ENS 0 RW1 Channel 6 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

5 CH5ENS 0 RW1 Channel 5 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

4 CH4ENS 0 RW1 Channel 4 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

3 CH3ENS 0 RW1 Channel 3 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

2 CH2ENS 0 RW1 Channel 2 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

1 CH1ENS 0 RW1 Channel 1 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

0 CH0ENS 0 RW1 Channel 0 Enable Set

Write to 1 to enable this channel. Reading returns the enable status of the channel.

8.7.12 DMA_CHENC - Channel Enable Clear Register

Offset Bit Position

0x02C

Reset

Access

Name

CH11ENC

CH10ENC

CH9ENC

CH8ENC

CH7ENC

CH6ENC

CH5ENC

CH4ENC

CH3ENC

CH2ENC

CH1ENC

CH0ENC

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Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11ENC 0 W1 Channel 11 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

10 CH10ENC 0 W1 Channel 10 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

9 CH9ENC 0 W1 Channel 9 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

8 CH8ENC 0 W1 Channel 8 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

7 CH7ENC 0 W1 Channel 7 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

6 CH6ENC 0 W1 Channel 6 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

5 CH5ENC 0 W1 Channel 5 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

4 CH4ENC 0 W1 Channel 4 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

3 CH3ENC 0 W1 Channel 3 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

2 CH2ENC 0 W1 Channel 2 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

1 CH1ENC 0 W1 Channel 1 Enable Clear

Write to 1 to disable this channel. See also description for channel 0.

0 CH0ENC 0 W1 Channel 0 Enable Clear

Write to 1 to disable this channel. Note that the controller disables a channel, by setting the appropriate bit, when either it completes

the DMA cycle, or it reads a channel_cfg memory location which has cycle_ctrl = b000, or an ERROR occurs on the AHB-Lite bus.

A read from this field returns the value of CH0ENS from the DMA_CHENS register.

8.7.13 DMA_CHALTS - Channel Alternate Set Register

Offset Bit Position

0x030

Reset

Access

RW1

Name

CH11ALTS

CH10ALTS

CH9ALTS

CH8ALTS

CH7ALTS

CH6ALTS

CH5ALTS

CH4ALTS

CH3ALTS

CH2ALTS

CH1ALTS

CH0ALTS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11ALTS 0 RW1 Channel 11 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

10 CH10ALTS 0 RW1 Channel 10 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

9 CH9ALTS 0 RW1 Channel 9 Alternate Structure Set

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Bit Name Reset Access Description

Write to 1 to select the alternate structure for this channel.

8 CH8ALTS 0 RW1 Channel 8 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

7 CH7ALTS 0 RW1 Channel 7 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

6 CH6ALTS 0 RW1 Channel 6 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

5 CH5ALTS 0 RW1 Channel 5 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

4 CH4ALTS 0 RW1 Channel 4 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

3 CH3ALTS 0 RW1 Channel 3 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

2 CH2ALTS 0 RW1 Channel 2 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

1 CH1ALTS 0 RW1 Channel 1 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

0 CH0ALTS 0 RW1 Channel 0 Alternate Structure Set

Write to 1 to select the alternate structure for this channel.

8.7.14 DMA_CHALTC - Channel Alternate Clear Register

Offset Bit Position

0x034

Reset

Access

Name

CH11ALTC

CH10ALTC

CH9ALTC

CH8ALTC

CH7ALTC

CH6ALTC

CH5ALTC

CH4ALTC

CH3ALTC

CH2ALTC

CH1ALTC

CH0ALTC

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11ALTC 0 W1 Channel 11 Alternate Clear

Write to 1 to select the primary structure for this channel.

10 CH10ALTC 0 W1 Channel 10 Alternate Clear

Write to 1 to select the primary structure for this channel.

9 CH9ALTC 0 W1 Channel 9 Alternate Clear

Write to 1 to select the primary structure for this channel.

8 CH8ALTC 0 W1 Channel 8 Alternate Clear

Write to 1 to select the primary structure for this channel.

7 CH7ALTC 0 W1 Channel 7 Alternate Clear

Write to 1 to select the primary structure for this channel.

6 CH6ALTC 0 W1 Channel 6 Alternate Clear

Write to 1 to select the primary structure for this channel.

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Bit Name Reset Access Description

5 CH5ALTC 0 W1 Channel 5 Alternate Clear

Write to 1 to select the primary structure for this channel.

4 CH4ALTC 0 W1 Channel 4 Alternate Clear

Write to 1 to select the primary structure for this channel.

3 CH3ALTC 0 W1 Channel 3 Alternate Clear

Write to 1 to select the primary structure for this channel.

2 CH2ALTC 0 W1 Channel 2 Alternate Clear

Write to 1 to select the primary structure for this channel.

1 CH1ALTC 0 W1 Channel 1 Alternate Clear

Write to 1 to select the primary structure for this channel.

0 CH0ALTC 0 W1 Channel 0 Alternate Clear

Write to 1 to select the primary structure for this channel.

8.7.15 DMA_CHPRIS - Channel Priority Set Register

Offset Bit Position

0x038

Reset

Access

RW1

Name

CH11PRIS

CH10PRIS

CH9PRIS

CH8PRIS

CH7PRIS

CH6PRIS

CH5PRIS

CH4PRIS

CH3PRIS

CH2PRIS

CH1PRIS

CH0PRIS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11PRIS 0 RW1 Channel 11 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

10 CH10PRIS 0 RW1 Channel 10 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

9 CH9PRIS 0 RW1 Channel 9 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

8 CH8PRIS 0 RW1 Channel 8 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

7 CH7PRIS 0 RW1 Channel 7 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

6 CH6PRIS 0 RW1 Channel 6 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

5 CH5PRIS 0 RW1 Channel 5 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

4 CH4PRIS 0 RW1 Channel 4 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

3 CH3PRIS 0 RW1 Channel 3 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

2 CH2PRIS 0 RW1 Channel 2 High Priority Set

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Bit Name Reset Access Description

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

1 CH1PRIS 0 RW1 Channel 1 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

0 CH0PRIS 0 RW1 Channel 0 High Priority Set

Write to 1 to obtain high priority for this channel. Reading returns the channel priority status.

8.7.16 DMA_CHPRIC - Channel Priority Clear Register

Offset Bit Position

0x03C

Reset

Access

Name

CH11PRIC

CH10PRIC

CH9PRIC

CH8PRIC

CH7PRIC

CH6PRIC

CH5PRIC

CH4PRIC

CH3PRIC

CH2PRIC

CH1PRIC

CH0PRIC

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11PRIC 0 W1 Channel 11 High Priority Clear

Write to 1 to clear high priority for this channel.

10 CH10PRIC 0 W1 Channel 10 High Priority Clear

Write to 1 to clear high priority for this channel.

9 CH9PRIC 0 W1 Channel 9 High Priority Clear

Write to 1 to clear high priority for this channel.

8 CH8PRIC 0 W1 Channel 8 High Priority Clear

Write to 1 to clear high priority for this channel.

7 CH7PRIC 0 W1 Channel 7 High Priority Clear

Write to 1 to clear high priority for this channel.

6 CH6PRIC 0 W1 Channel 6 High Priority Clear

Write to 1 to clear high priority for this channel.

5 CH5PRIC 0 W1 Channel 5 High Priority Clear

Write to 1 to clear high priority for this channel.

4 CH4PRIC 0 W1 Channel 4 High Priority Clear

Write to 1 to clear high priority for this channel.

3 CH3PRIC 0 W1 Channel 3 High Priority Clear

Write to 1 to clear high priority for this channel.

2 CH2PRIC 0 W1 Channel 2 High Priority Clear

Write to 1 to clear high priority for this channel.

1 CH1PRIC 0 W1 Channel 1 High Priority Clear

Write to 1 to clear high priority for this channel.

0 CH0PRIC 0 W1 Channel 0 High Priority Clear

Write to 1 to clear high priority for this channel.

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8.7.17 DMA_ERRORC - Bus Error Clear Register

Offset Bit Position

0x04C

Reset

Access

Name

ERRORC

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 ERRORC 0 RW Bus Error Clear

This bit is set high if an AHB bus error has occurred. Writing a 1 to this bit will clear the bit. If the error is deasserted at the same time

as an error occurs on the bus, the error condition takes precedence and ERRORC remains asserted.

8.7.18 DMA_CHREQSTATUS - Channel Request Status

Offset Bit Position

0xE10

Reset

Access

Name

CH11REQSTATUS

CH10REQSTATUS

CH9REQSTATUS

CH8REQSTATUS

CH7REQSTATUS

CH6REQSTATUS

CH5REQSTATUS

CH4REQSTATUS

CH3REQSTATUS

CH2REQSTATUS

CH1REQSTATUS

CH0REQSTATUS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11REQSTATUS 0 R Channel 11 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

10 CH10REQSTATUS 0 R Channel 10 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

9 CH9REQSTATUS 0 R Channel 9 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

8 CH8REQSTATUS 0 R Channel 8 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

7 CH7REQSTATUS 0 R Channel 7 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

6 CH6REQSTATUS 0 R Channel 6 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

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Bit Name Reset Access Description

5 CH5REQSTATUS 0 R Channel 5 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

4 CH4REQSTATUS 0 R Channel 4 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

3 CH3REQSTATUS 0 R Channel 3 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

2 CH2REQSTATUS 0 R Channel 2 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

1 CH1REQSTATUS 0 R Channel 1 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

0 CH0REQSTATUS 0 R Channel 0 Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using 2R DMA transfers.

8.7.19 DMA_CHSREQSTATUS - Channel Single Request Status

Offset Bit Position

0xE18

Reset

Access

Name

CH11SREQSTATUS

CH10SREQSTATUS

CH9SREQSTATUS

CH8SREQSTATUS

CH7SREQSTATUS

CH6SREQSTATUS

CH5SREQSTATUS

CH4SREQSTATUS

CH3SREQSTATUS

CH2SREQSTATUS

CH1SREQSTATUS

CH0SREQSTATUS

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11SREQSTATUS 0 R Channel 11 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

10 CH10SREQSTATUS 0 R Channel 10 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

9 CH9SREQSTATUS 0 R Channel 9 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

8 CH8SREQSTATUS 0 R Channel 8 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

7 CH7SREQSTATUS 0 R Channel 7 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

6 CH6SREQSTATUS 0 R Channel 6 Single Request Status

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Bit Name Reset Access Description

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

5 CH5SREQSTATUS 0 R Channel 5 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

4 CH4SREQSTATUS 0 R Channel 4 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

3 CH3SREQSTATUS 0 R Channel 3 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

2 CH2SREQSTATUS 0 R Channel 2 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

1 CH1SREQSTATUS 0 R Channel 1 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

0 CH0SREQSTATUS 0 R Channel 0 Single Request Status

When this bit is 1, it indicates that the peripheral connected as the input to this DMA channel is requesting the controller to service

the DMA channel. The controller services the request by performing the DMA cycle using single DMA transfers.

8.7.20 DMA_IF - Interrupt Flag Register

Offset Bit Position

0x1000

Reset

Access

Name

ERR

CH11DONE

CH10DONE

CH9DONE

CH8DONE

CH7DONE

CH6DONE

CH5DONE

CH4DONE

CH3DONE

CH2DONE

CH1DONE

CH0DONE

Bit Name Reset Access Description

31 ERR 0 R DMA Error Interrupt Flag

This flag is set when an error has occurred on the AHB bus.

30:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11DONE 0 R DMA Channel 11 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

10 CH10DONE 0 R DMA Channel 10 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

9 CH9DONE 0 R DMA Channel 9 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

8 CH8DONE 0 R DMA Channel 8 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

7 CH7DONE 0 R DMA Channel 7 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

6 CH6DONE 0 R DMA Channel 6 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

5 CH5DONE 0 R DMA Channel 5 Complete Interrupt Flag

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Bit Name Reset Access Description

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

4 CH4DONE 0 R DMA Channel 4 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

3 CH3DONE 0 R DMA Channel 3 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

2 CH2DONE 0 R DMA Channel 2 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

1 CH1DONE 0 R DMA Channel 1 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

0 CH0DONE 0 R DMA Channel 0 Complete Interrupt Flag

Set when the DMA channel has completed its transfer. If the channel is disabled, the flag is set when there is a request for the channel.

8.7.21 DMA_IFS - Interrupt Flag Set Register

Offset Bit Position

0x1004

Reset

Access

Name

ERR

CH11DONE

CH10DONE

CH9DONE

CH8DONE

CH7DONE

CH6DONE

CH5DONE

CH4DONE

CH3DONE

CH2DONE

CH1DONE

CH0DONE

Bit Name Reset Access Description

31 ERR 0 W1 DMA Error Interrupt Flag Set

Set to 1 to set DMA error interrupt flag.

30:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11DONE 0 W1 DMA Channel 11 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

10 CH10DONE 0 W1 DMA Channel 10 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

9 CH9DONE 0 W1 DMA Channel 9 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

8 CH8DONE 0 W1 DMA Channel 8 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

7 CH7DONE 0 W1 DMA Channel 7 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

6 CH6DONE 0 W1 DMA Channel 6 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

5 CH5DONE 0 W1 DMA Channel 5 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

4 CH4DONE 0 W1 DMA Channel 4 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

3 CH3DONE 0 W1 DMA Channel 3 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

2 CH2DONE 0 W1 DMA Channel 2 Complete Interrupt Flag Set

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Bit Name Reset Access Description

Write to 1 to set the corresponding DMA channel complete interrupt flag.

1 CH1DONE 0 W1 DMA Channel 1 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

0 CH0DONE 0 W1 DMA Channel 0 Complete Interrupt Flag Set

Write to 1 to set the corresponding DMA channel complete interrupt flag.

8.7.22 DMA_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x1008

Reset

Access

Name

ERR

CH11DONE

CH10DONE

CH9DONE

CH8DONE

CH7DONE

CH6DONE

CH5DONE

CH4DONE

CH3DONE

CH2DONE

CH1DONE

CH0DONE

Bit Name Reset Access Description

31 ERR 0 W1 DMA Error Interrupt Flag Clear

Set to 1 to clear DMA error interrupt flag. Note that if an error happened, the Bus Error Clear Register must be used to clear the DMA.

30:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11DONE 0 W1 DMA Channel 11 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

10 CH10DONE 0 W1 DMA Channel 10 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

9 CH9DONE 0 W1 DMA Channel 9 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

8 CH8DONE 0 W1 DMA Channel 8 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

7 CH7DONE 0 W1 DMA Channel 7 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

6 CH6DONE 0 W1 DMA Channel 6 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

5 CH5DONE 0 W1 DMA Channel 5 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

4 CH4DONE 0 W1 DMA Channel 4 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

3 CH3DONE 0 W1 DMA Channel 3 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

2 CH2DONE 0 W1 DMA Channel 2 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

1 CH1DONE 0 W1 DMA Channel 1 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

0 CH0DONE 0 W1 DMA Channel 0 Complete Interrupt Flag Clear

Write to 1 to clear the corresponding DMA channel complete interrupt flag.

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8.7.23 DMA_IEN - Interrupt Enable register

Offset Bit Position

0x100C

Reset

Access

Name

ERR

CH11DONE

CH10DONE

CH9DONE

CH8DONE

CH7DONE

CH6DONE

CH5DONE

CH4DONE

CH3DONE

CH2DONE

CH1DONE

CH0DONE

Bit Name Reset Access Description

31 ERR 0 RW DMA Error Interrupt Flag Enable

Set this bit to enable interrupt on AHB bus error.

30:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11DONE 0 RW DMA Channel 11 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

10 CH10DONE 0 RW DMA Channel 10 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

9 CH9DONE 0 RW DMA Channel 9 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

8 CH8DONE 0 RW DMA Channel 8 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

7 CH7DONE 0 RW DMA Channel 7 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

6 CH6DONE 0 RW DMA Channel 6 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

5 CH5DONE 0 RW DMA Channel 5 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

4 CH4DONE 0 RW DMA Channel 4 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

3 CH3DONE 0 RW DMA Channel 3 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

2 CH2DONE 0 RW DMA Channel 2 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

1 CH1DONE 0 RW DMA Channel 1 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

0 CH0DONE 0 RW DMA Channel 0 Complete Interrupt Enable

Write to 1 to enable complete interrupt on this DMA channel. Clear to disable the interrupt.

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8.7.24 DMA_CTRL - DMA Control Register

Offset Bit Position

0x1010

Reset

Access

Name

PRDU

DESCRECT

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 PRDU 0 RW Prevent Rect Descriptor Update

Allows the reuse of a rect descriptor. When active CH0 and no others can have RDS set

0 DESCRECT 0 RW Descriptor Specifies Rectangle

Word 4 (user data) in dma descriptor specifies WIDTH, HEIGHT and SRCSTRIDE for rectangle copies. WIDTH is given by bits 9:0,

HEIGHT is given by bits 19:10, and SRCSTRIDE is given by bits 30:20

8.7.25 DMA_RDS - DMA Retain Descriptor State

Offset Bit Position

0x1014

Reset

Access

Name

RDSCH11

RDSCH10

RDSCH9

RDSCH8

RDSCH7

RDSCH6

RDSCH5

RDSCH4

RDSCH3

RDSCH2

RDSCH1

RDSCH0

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 RDSCH11 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

10 RDSCH10 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

9 RDSCH9 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

8 RDSCH8 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

7 RDSCH7 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

6 RDSCH6 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

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Bit Name Reset Access Description

5 RDSCH5 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

4 RDSCH4 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

3 RDSCH3 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

2 RDSCH2 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

1 RDSCH1 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

0 RDSCH0 0 RW Retain Descriptor State

Speed up execution of consecutive DMA requests from the same channel by not reading descriptor at the start of every arbitration

cycle if the next channel is the same as the previous

8.7.26 DMA_LOOP0 - Channel 0 Loop Register

Offset Bit Position

0x1020

Reset

0x000

Access

RWH

Name

WIDTH

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 EN 0 RW DMA Channel 0 Loop Enable

Loop enable for channel 0

15:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:0 WIDTH 0x000 RWH Loop Width

Reload value for N_MINUS_1 when loop is enabled

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8.7.27 DMA_LOOP1 - Channel 1 Loop Register

Offset Bit Position

0x1024

Reset

0x000

Access

Name

WIDTH

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 EN 0 RW DMA Channel 1 Loop Enable

Loop enable for channel 1

15:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:0 WIDTH 0x000 RW DMA Channel 1 Loop Width

Reload value for N_MINUS_1 when loop is enabled

8.7.28 DMA_RECT0 - Channel 0 Rectangle Register

Offset Bit Position

0x1060

Reset

0x000

Access

RWH

Name

DSTSTRIDE

SRCSTRIDE

HEIGHT

Bit Name Reset Access Description

31:21 DSTSTRIDE 0x000 RW DMA Channel 0 Destination Stride

Space between start of lines in destination rectangle

20:10 SRCSTRIDE 0x000 RWH DMA Channel 0 Source Stride

Space between start of lines in source rectangle

9:0 HEIGHT 0x000 RWH DMA Channel 0 Rectangle Height

Number of lines when doing rectangle copy. Set to the number of lines - 1.

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8.7.29 DMA_CHx_CTRL - Channel Control Register

Offset Bit Position

0x1100

Reset

0x00

0x0

Access

Name

SOURCESEL

SIGSEL

Bit Name Reset Access Description

31:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:16 SOURCESEL 0x00 RW Source Select

Select input source to DMA channel.

Value Mode Description

0b000000 NONE No source selected

0b001000 ADC0 Analog to Digital Converter 0

0b001010 DAC0 Digital to Analog Converter 0

0b001100 USART0 Universal Synchronous/Asynchronous Receiver/Transmitter 0

0b001101 USART1 Universal Synchronous/Asynchronous Receiver/Transmitter 1

0b001110 USART2 Universal Synchronous/Asynchronous Receiver/Transmitter 2

0b010000 LEUART0 Low Energy UART 0

0b010001 LEUART1 Low Energy UART 1

0b010100 I2C0 I2C 0

0b010101 I2C1 I2C 1

0b011000 TIMER0 Timer 0

0b011001 TIMER1 Timer 1

0b011010 TIMER2 Timer 2

0b011011 TIMER3 Timer 3

0b101100 UART0 Universal Asynchronous Receiver/Transmitter 0

0b101101 UART1 Universal Asynchronous Receiver/Transmitter 1

0b110000 MSC

0b110001 AES Advanced Encryption Standard Accelerator

0b110010 LESENSE Low Energy Sensor Interface

0b110011 EBI External Bus Interface

15:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 SIGSEL 0x0 RW Signal Select

Select input signal to DMA channel.

Value Mode Description

SOURCESEL = 0b000000 (NONE)

0bxxxx OFF Channel input selection is turned off

SOURCESEL = 0b001000 (ADC0)

0b0000 ADC0SINGLE ADC0SINGLE

0b0001 ADC0SCAN ADC0SCAN

SOURCESEL = 0b001010 (DAC0)

0b0000 DAC0CH0 DAC0CH0

0b0001 DAC0CH1 DAC0CH1

SOURCESEL = 0b001100

(USART0)

0b0000 USART0RXDATAV USART0RXDATAV REQ/SREQ

0b0001 USART0TXBL USART0TXBL REQ/SREQ

0b0010 USART0TXEMPTY USART0TXEMPTY

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Bit Name Reset Access Description

Value Mode Description

SOURCESEL = 0b001101

(USART1)

0b0000 USART1RXDATAV USART1RXDATAV REQ/SREQ

0b0001 USART1TXBL USART1TXBL REQ/SREQ

0b0010 USART1TXEMPTY USART1TXEMPTY

0b0011 USART1RXDATAVRIGHT USART1RXDATAVRIGHT REQ/SREQ

0b0100 USART1TXBLRIGHT USART1TXBLRIGHT REQ/SREQ

SOURCESEL = 0b001110

(USART2)

0b0000 USART2RXDATAV USART2RXDATAV REQ/SREQ

0b0001 USART2TXBL USART2TXBL REQ/SREQ

0b0010 USART2TXEMPTY USART2TXEMPTY

0b0011 USART2RXDATAVRIGHT USART2RXDATAVRIGHT REQ/SREQ

0b0100 USART2TXBLRIGHT USART2TXBLRIGHT REQ/SREQ

SOURCESEL = 0b010000

(LEUART0)

0b0000 LEUART0RXDATAV LEUART0RXDATAV

0b0001 LEUART0TXBL LEUART0TXBL

0b0010 LEUART0TXEMPTY LEUART0TXEMPTY

SOURCESEL = 0b010001

(LEUART1)

0b0000 LEUART1RXDATAV LEUART1RXDATAV

0b0001 LEUART1TXBL LEUART1TXBL

0b0010 LEUART1TXEMPTY LEUART1TXEMPTY

SOURCESEL = 0b010100 (I2C0)

0b0000 I2C0RXDATAV I2C0RXDATAV

0b0001 I2C0TXBL I2C0TXBL

SOURCESEL = 0b010101 (I2C1)

0b0000 I2C1RXDATAV I2C1RXDATAV

0b0001 I2C1TXBL I2C1TXBL

SOURCESEL = 0b011000

(TIMER0)

0b0000 TIMER0UFOF TIMER0UFOF

0b0001 TIMER0CC0 TIMER0CC0

0b0010 TIMER0CC1 TIMER0CC1

0b0011 TIMER0CC2 TIMER0CC2

SOURCESEL = 0b011001

(TIMER1)

0b0000 TIMER1UFOF TIMER1UFOF

0b0001 TIMER1CC0 TIMER1CC0

0b0010 TIMER1CC1 TIMER1CC1

0b0011 TIMER1CC2 TIMER1CC2

SOURCESEL = 0b011010

(TIMER2)

0b0000 TIMER2UFOF TIMER2UFOF

0b0001 TIMER2CC0 TIMER2CC0

0b0010 TIMER2CC1 TIMER2CC1

0b0011 TIMER2CC2 TIMER2CC2

SOURCESEL = 0b011011

(TIMER3)

0b0000 TIMER3UFOF TIMER3UFOF

0b0001 TIMER3CC0 TIMER3CC0

0b0010 TIMER3CC1 TIMER3CC1

0b0011 TIMER3CC2 TIMER3CC2

SOURCESEL = 0b101100 (UART0)

0b0000 UART0RXDATAV UART0RXDATAV REQ/SREQ

0b0001 UART0TXBL UART0TXBL REQ/SREQ

0b0010 UART0TXEMPTY UART0TXEMPTY

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Bit Name Reset Access Description

Value Mode Description

SOURCESEL = 0b101101 (UART1)

0b0000 UART1RXDATAV UART1RXDATAV REQ/SREQ

0b0001 UART1TXBL UART1TXBL REQ/SREQ

0b0010 UART1TXEMPTY UART1TXEMPTY

SOURCESEL = 0b110000 (MSC)

0b0000 MSCWDATA MSCWDATA

SOURCESEL = 0b110001 (AES)

0b0000 AESDATAWR AESDATAWR

0b0001 AESXORDATAWR AESXORDATAWR

0b0010 AESDATARD AESDATARD

0b0011 AESKEYWR AESKEYWR

SOURCESEL = 0b110010

(LESENSE)

0b0000 LESENSEBUFDATAV LESENSEBUFDATAV REQ/SREQ

SOURCESEL = 0b110011 (EBI)

0b0000 EBIPXL0EMPTY EBIPXL0EMPTY

0b0001 EBIPXL1EMPTY EBIPXL1EMPTY

0b0010 EBIPXLFULL EBIPXLFULL

0b0011 EBIDDEMPTY EBIDDEMPTY

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9 RMU - Reset Management Unit

01 2 3 4

SYSRESETREQ

WATCHDOG

BROWNOUT

POWERON

Reset Management Unit RESET

LOCKUP

RESETn

Quick Facts

What?

The RMU ensures correct reset operation.

It is responsible for connecting the different

reset sources to the reset lines of the

EFM32LG.

Why?

A correct reset sequence is needed to

ensure safe and synchronous startup of the

EFM32LG. In the case of error situations

such as power supply glitches or software

crash, the RMU provides proper reset and

startup of the EFM32LG.

How?

The Power-on Reset and Brown-out Detector

of the EFM32LG provides power line

monitoring with exceptionally low power

consumption. The cause of the reset may be

read from a register, thus providing software

with information about the cause of the reset.

9.1 Introduction

The RMU is responsible for handling the reset functionality of the EFM32LG.

9.2 Features

• Reset sources

• Power-on Reset (POR)

• Brown-out Detection (BOD) on the following power domains:

• Regulated domain

• Unregulated domain

• Analog Power Domain 0 (AVDD0)

• Analog Power Domain 1 (AVDD1)

• RESETn pin reset

• Watchdog reset

• EM4 wakeup reset from pin

• EM4 wakeup reset from Backup RTC interrupt

• Wakeup from Backup Mode

• Software triggered reset (SYSRESETREQ)

• Core LOCKUP condition

• EM4 Detection

• A software readable register indicates the cause of the last reset

9.3 Functional Description

The RMU monitors each of the reset sources of the EFM32LG. If one or more reset sources go active,

the RMU applies reset to the EFM32LG. When the reset sources go inactive the EFM32LG starts up.

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At startup the EFM32LG loads the stack pointer and program entry point from memory, and starts

execution.

As seen in Figure 9.1 (p. 98) the Power-on Reset, Brown-out Detectors, Watchdog timeout and

RESETn pin all reset the whole system including the Debug Interface. A Core Lockup condition or a

System reset request from software resets the whole system except the Debug Interface.

Whenever a reset source is active, the corresponding bit in the RMU_RSTCAUSE register is set. At

startup the program code may investigate this register in order to determine the cause of the reset. The

Figure 9.1. RMU Reset Input Sources and Connections.

SYSREQRST

WDOG

Reset Management Unit

PORESETn

SYSRESETn

LOCKUP

POWERONn

BROWNOUT_UNREGn

RESETn Filter

LOCKUPRDIS

VDD

POR

BOD

Core

Debug

Interface

Cortex

Peripherals

VDD_REGULATED

RMU_RSTCAUSE

BROWNOUT_REGn

RCCLR

Edge-to-pulse

filter

BOD

AVDD0 BROWNOUT_AVDD0

BOD

AVDD1 BROWNOUT_AVDD1

BOD

EM4 wakeup

em4

Backup mode

Backup mode exit

9.3.1 RMU_RSTCAUSE Register

The RMU_RSTCAUSE register indicates the reason for the last reset. The register should be cleared

after the value has been read at startup. Otherwise the register may indicate multiple causes for the

reset at next startup.

The following procedure must be done to clear RMU_RSTCAUSE:

1. Write a 1 to RCCLR in RMU_CMD

2. Write a 1 to bit 0 in EMU_AUXCTRL

3. Write a 0 to bit 0 in EMU_AUXCTRL

RMU_RSTCAUSE should be interpreted according to Table 9.1 (p. 99) . X bits are don't care. Notice

that it is possible to have multiple reset causes. For example, an external reset and a watchdog reset

may happen simultaneously.

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Table 9.1. RMU Reset Cause Register Interpretation

0bXXXX XXXX XXXX XXX1 A Power-on Reset has been performed. X bits are don't care.

0bXXXX XXXX 0XXX XX10 A Brown-out has been detected on the unregulated power.

0bXXXX XXXX XXX0 0100 A Brown-out has been detected on the regulated power.

0bXXXX XXXX XXXX 1X00 An external reset has been applied.

0bXXXX XXXX XXX1 XX00 A watchdog reset has occurred.

0bXXXX X000 0010 0000 A lockup reset has occurred.

0bXXXX X000 01X0 0000 A system request reset has occurred.

0bXXXX X000 1XX0 0XX0 The system has woken up from EM4.

0bXXXX X001 1XX0 0XX0 The system has woken up from EM4 on an EM4 wakeup reset request from pin.

0bXXXX X01X XXX0 0000 A Brown-out has been detected on Analog Power Domain 0 (AVDD0).

0bXXXX X10X XXX0 0000 A Brown-out has been detected on Analog Power Domain 1 (AVDD1).

0bXXXX 1XXX XXXX 0XX0 A Brown-out has been detected by the Backup BOD on VDD_DREG.

0bXXX1 XXXX XXXX 0XX0 A Brown-out has been detected by the Backup BOD on BU_VIN.

0bXX1X XXXX XXXX 0XX0 A Brown-out has been detected by the Backup BOD on unregulated power

0bX1XX XXXX XXXX 0XX0 A Brown-out has been detected by the Backup BOD on regulated power.

0b1XXX XXXX XXXX XXX0 The system has been in Backup mode.

Note When exiting EM4 with external reset, both the BODREGRST and BODUNREGRST in

RSTCAUSE might be set (i.e. are invalid)

9.3.2 Power-On Reset (POR)

The POR ensures that the EFM32LG does not start up before the supply voltage VDD has reached

the threshold voltage VPORthr (see Device Datasheet Electrical Characteristics for details). Before the

threshold voltage is reached, the EFM32LG is kept in reset state. The operation of the POR is illustrated

in Figure 9.2 (p. 99) , with the active low POWERONn reset signal. The reason for the “unknown”

region is that the corresponding supply voltage is too low for any reliable operation.

Figure 9.2. RMU Power-on Reset Operation

POWERONn

VDD

time

Unknown

VPORthr

9.3.3 Brown-Out Detector Reset (BOD)

The EFM32LG has 4 brownout detectors, one for the unregulated 3.0 V power, one for the regulated

internal power, one for Analog Power Domain 0 (AVDD0), and one for Analog Power Domain 1 (AVDD1).

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The BODs are constantly monitoring the voltages. Whenever the unregulated or regulated power drops

below the VBODthr value (see Electrical Characteristics for details), or if the AVDD0 or AVDD1 drops

below the voltage at the decouple pin (DEC), the corresponding active low BROWNOUTn line is held

low. The BODs also include hysteresis, which prevents instability in the corresponding BROWNOUTn

line when the supply is crossing the VBODthr limit or the AVDD bods drops below decouple pin (DEC).

The operation of the BOD is illustrated in Figure 9.3 (p. 100) . The “unknown” regions are handled

by the POR module.

Figure 9.3. RMU Brown-out Detector Operation

Unknown

BROWNOUTn

VDD

time

Unknown

VBODthr VBODhyst VBODhyst

9.3.4 RESETn pin Reset

Forcing the RESETn pin low generates a reset of the EFM32LG. The RESETn pin includes an on-

chip pull-up resistor, and can therefore be left unconnected if no external reset source is needed. Also

connected to the RESETn line is a filter which prevents glitches from resetting the EFM32LG.

9.3.5 Watchdog Reset

The Watchdog circuit is a timer which (when enabled) must be cleared by software regularly. If software

does not clear it, a Watchdog reset is activated. This functionality provides recovery from a software

stalemate. Refer to the Watchdog section for specifications and description.

9.3.6 Lockup Reset

A Cortex-M3 lockup is the result of the core being locked up because of an unrecoverable exception

following the activation of the processor’s built-in system state protection hardware.

For more information about the Cortex-M3 lockup conditions see the ARMv7-M Architecture Reference

Manual. The Lockup reset does not reset the Debug Interface. Set the LOCKUPRDIS bit in the

RMU_CTRL register in order to disable this reset source.

9.3.7 System Reset Request

Software may initiate a reset (e.g. if it finds itself in a non-recoverable state). By writing to the

SYSRESETREQ bit in the Application Interrupt and Reset Control Register (see the Cortex-M3 reference

manual), a reset is issued. The SYSRESETREQ does not reset the Debug Interface.

9.3.8 EM4 Reset

Whenever EM4 is entered, the EM4RST bit is set. This bit enables the user to identify that the device

has been in EM4. Upon wake-up this bit should be cleared by software.

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9.3.9 EM4 Wakeup Reset

Whenever the system is woken up from EM4 on a pin wake-up request, the EM4WURST bit is set. This

bit enables the user to identify that the device was woken up from EM4 using a pin wake-up request.

Upon wake-up this bit should be cleared by software.

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9.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 RMU_CTRL RW Control Register

0x004 RMU_RSTCAUSE R Reset Cause Register

0x008 RMU_CMD W1 Command Register

9.5 Register Description

9.5.1 RMU_CTRL - Control Register

Offset Bit Position

0x000

Reset

Access

Name

BURSTEN

LOCKUPRDIS

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 BURSTEN 1 RW Backup domain reset enable

This bit has to be cleared before accessing the registers in the BURTC.

0 LOCKUPRDIS 0 RW Lockup Reset Disable

Set this bit to disable the LOCKUP signal (from the Cortex) from resetting the device.

9.5.2 RMU_RSTCAUSE - Reset Cause Register

Offset Bit Position

0x004

Reset

Access

Name

BUMODERST

BUBODREG

BUBODUNREG

BUBODBUVIN

BUBODVDDDREG

BODAVDD1

BODAVDD0

EM4WURST

EM4RST

SYSREQRST

LOCKUPRST

WDOGRST

EXTRST

BODREGRST

BODUNREGRST

PORST

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 BUMODERST 0 R Backup mode reset

Set if the system has been in Backup mode. Must be cleared by software. Please see Section 10.3.4 (p. 111) for details on how

to interpret this bit.

14 BUBODREG 0 R Backup Brown Out Detector Regulated Domain

Set if the Backup BOD sensing on regulated power triggers. Must be cleared by software. Please see Section 10.3.4.2 (p. 112)

for details on how to interpret this bit.

13 BUBODUNREG 0 R Backup Brown Out Detector Unregulated Domain

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Bit Name Reset Access Description

Set if the Backup BOD sensing on unregulated power triggers. Must be cleared by software. Please see Section 10.3.4.2 (p. 112)

for details on how to interpret this bit.

12 BUBODBUVIN 0 R Backup Brown Out Detector, BU_VIN

Set if the Backup BOD sensing on BU_VIN triggers. Must be cleared by software. Please see Section 10.3.4.2 (p. 112) for details

on how to interpret this bit.

11 BUBODVDDDREG 0 R Backup Brown Out Detector, VDD_DREG

Set if the Backup BOD sensing on VDDD_REG triggers. Must be cleared by software. Please see Section 10.3.4.2 (p. 112) for

details on how to interpret this bit.

10 BODAVDD1 0 R AVDD1 Bod Reset

Set if analog power domain 1 brown out detector reset has been performed. Must be cleared by software. Please see Table 9.1 (p.

99) for details on how to interpret this bit.

9 BODAVDD0 0 R AVDD0 Bod Reset

Set if analog power domain 0 brown out detector reset has been performed. Must be cleared by software. Please see Table 9.1 (p.

99) for details on how to interpret this bit.

8 EM4WURST 0 R EM4 Wake-up Reset

Set if the system has been woken up from EM4 from a reset request from pin. Must be cleared by software. Please see Table 9.1 (p.

99) for details on how to interpret this bit.

7 EM4RST 0 R EM4 Reset

Set if the system has been in EM4. Must be cleared by software. Please see Table 9.1 (p. 99) for details on how to interpret this bit.

6 SYSREQRST 0 R System Request Reset

Set if a system request reset has been performed. Must be cleared by software. Please see Table 9.1 (p. 99) for details on how

to interpret this bit.

5 LOCKUPRST 0 R LOCKUP Reset

Set if a LOCKUP reset has been requested. Must be cleared by software. Please see Table 9.1 (p. 99) for details on how to interpret

this bit.

4 WDOGRST 0 R Watchdog Reset

Set if a watchdog reset has been performed. Must be cleared by software. Please see Table 9.1 (p. 99) for details on how to interpret

this bit.

3 EXTRST 0 R External Pin Reset

Set if an external pin reset has been performed. Must be cleared by software. Please see Table 9.1 (p. 99) for details on how to

interpret this bit.

2 BODREGRST 0 R Brown Out Detector Regulated Domain Reset

Set if a regulated domain brown out detector reset has been performed. Must be cleared by software. Please see Table 9.1 (p. 99)

for details on how to interpret this bit.

1 BODUNREGRST 0 R Brown Out Detector Unregulated Domain Reset

Set if a unregulated domain brown out detector reset has been performed. Must be cleared by software. Please see Table 9.1 (p.

99) for details on how to interpret this bit.

0 PORST 0 R Power On Reset

Set if a power on reset has been performed. Must be cleared by software. Please see Table 9.1 (p. 99) for details on how to interpret

this bit.

9.5.3 RMU_CMD - Command Register

Offset Bit Position

0x008

Reset

Access

Name

RCCLR

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Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 RCCLR 0 W1 Reset Cause Clear

Set this bit to clear the LOCKUPRST and SYSREQRST bits in the RMU_RSTCAUSE register. Use the HRCCLR bit in the

EMU_AUXCTRL register to clear the remaining bits.

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10 EMU - Energy Management Unit

01 2 3 4

Quick Facts

What?

The EMU (Energy Management Unit)

handles the different low energy modes in the

EFM32LG microcontrollers.

Why?

The need for performance and peripheral

functions varies over time in most

applications. By efficiently scaling the

available resources in real-time to match

the demands of the application, the energy

consumption can be kept at a minimum.

How?

With a broad selection of energy modes,

a high number of low-energy peripherals

available even in EM2, and short wake-

up time (2 µs from EM2 and EM3),

applications can dynamically minimize energy

consumption during program execution.

10.1 Introduction

The Energy Management Unit (EMU) manages all the low energy modes (EM) in EFM32LG

microcontrollers. Each energy mode manages if the CPU and the various peripherals are available. The

energy modes range from EM0 to EM4, where EM0, also called run mode, enables the CPU and all

peripherals. The lowest recoverable energy mode, EM3, disables the CPU and most peripherals while

maintaining wake-up and RAM functionality. EM4 disables everything except the POR, pin reset and

optionally Backup RTC, 512 byte data retention, GPIO state retention, and EM4 reset wakeup request.

The various energy modes differ in:

• Energy consumption

• CPU activity

• Reaction time

• Wake-up triggers

• Active peripherals

• Available clock sources

Low energy modes EM1 to EM4 are enabled through the application software. In EM1-EM3, a range

of wake-up triggers return the microcontroller back to EM0. EM4 can only return to EM0 by power on

reset, external pin reset, EM4 GPIO wakeup request, or Backup RTC interrupt.

10.2 Features

• Energy Mode control from software

• Flexible wakeup from low energy modes

• Low wakeup time

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10.3 Functional Description

The Energy Management Unit (EMU) is responsible for managing the wide range of energy modes

available in EFM32LG. An overview of the EMU module is shown in Figure 10.1 (p. 106) .

Figure 10.1. EMU Overview

Peripheral bus

Control and

status registers Energy Management

State Machine

Cortex Voltage

regulator

system

Oscillator

system Reset

system Memory

system Interrupt

controller

The EMU is available as a peripheral on the peripheral bus. The energy management state machine

is triggered from the Cortex-M3 and controls the internal voltage regulators, oscillators, memories and

interrupt systems in the low energy modes. Events from the interrupt or reset systems can in turn cause

the energy management state machine to return to its active state. This is further described in the

following sections.

10.3.1 Energy Modes

There are five main energy modes available in EFM32LG, called Energy Mode 0 (EM0) through Energy

Mode 4 (EM4). EM0, also called the active mode, is the energy mode in which any peripheral function

can be enabled and the Cortex-M3 core is executing instructions. EM1 through EM4, also called low

energy modes, provide a selection of reduced peripheral functionality that also lead to reduced energy

consumption, as described below.

Figure 10.2 (p. 107) shows the transitions between different energy modes. After reset the EMU will

always start in EM0. A transition from EM0 to another energy mode is always initiated by software. EM0

is the highest activity mode, in which all functionality is available. EM0 is therefore also the mode with

highest energy consumption.

The low energy modes EM1 through EM4 result in less functionality being available, and therefore also

reduced energy consumption. The Cortex-M3 is not executing instructions in any low energy mode.

Each low energy mode provides different energy consumptions associated with it, for example because

a different set of peripherals are enabled or because these peripherals are configured differently.

A transition from EM0 to a low energy mode can only be triggered by software.

A transition from EM1 – EM3 to EM0 can be triggered by an enabled interrupt or event. In addition, a

chip reset will return the device to EM0. A transition from EM4 can be triggered by a pin reset, power-

on reset, EM4 GPIO wakeup, or Backup RTC interrupt.

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Figure 10.2. EMU Energy Mode Transitions

EM0

EM1

EM2

Software triggered sleep

Interrupt triggered wakeup

Reduced energy consumption

EM3

Low energy

modes

Active

mode

EM4

pin reset,

power-on reset,

EM4 wakeup,

BURTC interrupt

No direct transitions between EM1, EM2 or EM3 are available, as can also be seen from Figure 10.2 (p.

107) . Instead, a wakeup will transition back to EM0, in which software can enter any other low energy

mode. An overview of the supported energy modes and the functionality available in each mode is shown

in Table 10.1 (p. 108) . Most peripheral functionality indicated as "On" in a particular energy mode can

also be turned off from software in order to save further energy.

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Table 10.1. EMU Energy Mode Overview

EM01EM12EM22EM32EM42

Wakeup time to EM0 - - 2 µs 2 µs 160 µs

MCU clock tree On - - - -

High frequency peripheral clock trees On On - - -

Core voltage regulator On On - - -

High frequency oscillator On On - - -

I2C full functionality On On - - -

Low frequency peripheral clock trees On On On - -

Low frequency oscillator On On On - -

Real Time Counter On On On On3-

LCD On On On - -

LEUART On On On - -

LETIMER On On On On3-

LESENSE On On On On3-

PCNT On On On On -

ACMP On On On On -

I2C receive address recognition On On On On -

Watchdog On On On On3-

Pin interrupts On On On On -

RAM voltage regulator/RAM retention On On On On -

Brown Out Reset On On On On -

Power On Reset On On On On On

Pin Reset On On On On On

GPIO state retention On On On On On4

EM4 Reset Wakeup Request - - - - On4

Backup RTC On On On On On

Backup retention registers On On On On On

1Energy Mode 0/Active Mode

2Energy Mode 1/2/3/4

3When the 1 kHz ULFRCO is selected

4Not available in Backup mode

The different Energy Modes are summarized in the following sections.

10.3.1.1 EM0

• The high frequency oscillator is active

• High frequency clock trees are active

• All peripheral functionality is available

10.3.1.2 EM1

• The high frequency oscillator is active

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• MCU clock tree is inactive

• High frequency peripheral clock trees are active

• All peripheral functionality is available

10.3.1.3 EM2

• The high frequency oscillator is inactive

• The high frequency peripheral and MCU clock trees are inactive

• The low frequency oscillator and clock trees are active

• Low frequency peripheral functionality is available

• Wakeup through peripheral interrupt or asynchronous pin interrupt

• RAM and register values are preserved

• DAC and OPAMPs are available

10.3.1.4 EM3

• Both high and low frequency oscillators and clock trees are inactive

• Wakeup through asynchronous pin interrupts, I2C address recognition or ACMP edge interrupt

• Watchdog and some low frequency peripherals available when ULFRCO (1 kHz clock) has been

selected

• BURTC is available.

• All other peripheral functionality is disabled

• RAM and register values are preserved

• DAC and OPAMPs are available

10.3.1.5 EM4

• All oscillators and regulators are inactive, if Backup RTC is not enabled.

• RAM and register values are not preserved, except for the ones located in the Backup RTC.

• Optional GPIO state retention

• Wakeup from Backup RTC interrupt, external pin reset or pins that support EM4 wakeup

10.3.2 Entering a Low Energy Mode

A low energy mode is entered by first configuring the desired Energy Mode through the EMU_CTRL

A Wait For Interrupt (WFI) or Wait For Event (WFE) instruction from the Cortex-M3 triggers the transition

into a low energy mode.

The transition into a low energy mode can optionally be delayed until the lowest priority Interrupt Service

Routine (ISR) is exited, if the SLEEPONEXIT bit in the Cortex-M3 System Control Register is set.

Entering the lowest energy mode, EM4, is done by writing a sequence to the EM4CTRL bitfield in

the EMU_CTRL register. Writing a zero to the EM4CTRL bitfield will restart the power sequence.

EM2BLOCK prevents the EMU to enter EM2 or lower, and it will instead enter EM1.

EM3 is equal to EM2, except that the LFACLK/LFBCLK are disabled in EM3. The LFACLK/LFBCLK

must be disabled by the user before entering low energy mode.

The EMVREG bit in EMU_CTRL can be used to prevent the voltage regulator from being turned off

in low energy modes. The device will then essentially stay in EM1 (with HF oscillators disabled) when

entering a low energy mode. Note that if a DMA transfer is initiated in this mode, the HF-oscillators will

start and remain enabled until the device is woken up from an EM2 interrupt.

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Table 10.2. EMU Entering a Low Energy Mode

Low Energy Mode EM4CTRL EMVREG EM2BLOCK SLEEPDEEP Cortex-M3

Instruction

EM1 0 x x 0 WFI or WFE

EM2 0 0 0 1 WFI or WFE

EM4 Write sequence:

2, 3, 2, 3, 2, 3, 2,

3, 2

xxxx

(‘x’ means don’t care)

10.3.3 Leaving a Low Energy Mode

In each low energy mode a selection of peripheral units are available, and software can either enable or

disable the functionality. Enabled interrupts that can cause wakeup from a low energy mode are shown

in Table 10.3 (p. 111) . The wakeup triggers always return the EFM32 to EM0. Additionally, any reset

source will return to EM0.

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Table 10.3. EMU Wakeup Triggers from Low Energy Modes

Peripheral Wakeup Trigger EM01EM12EM22EM32EM42

RTC Any enabled interrupt - Yes Yes Yes3-

USART Receive / transmit - Yes - - -

UART Receive / transmit - Yes - - -

LEUART Receive / transmit - Yes Yes - -

LESENSE Any enabled interrupt - Yes Yes Yes3-

I2C Any enabled interrupt - Yes - - -

I2C Receive address recognition - Yes Yes Yes -

TIMER Any enabled interrupt - Yes - - -

LETIMER Any enabled interrupt - Yes Yes Yes3-

CMU Any enabled interrupt - Yes - - -

DMA Any enabled interrupt - Yes - - -

MSC Any enabled interrupt - Yes - - -

DAC Any enabled interrupt - Yes - - -

ADC Any enabled interrupt - Yes - - -

AES Any enabled interrupt - Yes - - -

PCNT Any enabled interrupt - Yes Yes Yes4-

LCD Any enabled interrupt - Yes Yes - -

ACMP Any enabled edge interrupt - Yes Yes Yes -

VCMP Any enabled edge interrupt - Yes Yes Yes -

Pin interrupts Asynchronous - Yes Yes Yes -

Pin Reset - Yes Yes Yes Yes

EM4 wakeup on supported

pins Asynchronous - - - - Yes

Backup RTC Any enabled interrupt Yes Yes Yes Yes Yes

Power Cycle Off/On Yes Yes Yes Yes

1Energy Mode 0/Active Mode

2Energy mode 1/2/3/4

3When the 1 kHz ULFRCO is selected

4When using an external clock

10.3.4 Backup power domain

10.3.4.1 Introduction

The EFM32LG has the possibility to be partly powered by a backup battery. The backup power input,

BU_VIN, is connected to a power domain in the EFM32LG containing the Backup RTC and 512 bytes of

data retention, available in all energy modes. Figure 10.3 (p. 112) shows an overview of the backup

powering scheme. During normal operation, the entire chip is powered by the main power supply. If the

main power supply drains out and the Backup mode functionality is enabled, the system enters a low

energy mode, equivalent to EM4, and automatically switches over to the backup power supply.

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Figure 10.3. Backup power domain overview

EFM32

Main domain

Backup domain

BURTC

BOD WDOG

POR EXT EM4 pin Wake-Up

BURTC

Wake-Up

reset

Wake-up

controller

SW reset

512 byte

retention

Main power OK

BU_VIN

Main power

Backup power

Main power BOD

RESETn

BU_STAT

BU_VOUT

BUCTRL_EN

PWRCONF_VOUTxxx

BUCTRL_STATEN

VDD_DREG

PWRCONF_PWRRES

BUINACT_PWRCON /

BUACT_PWRCON

Main

power

supply

Backup

power

supply

STRONG

MEDIUM

WEAK

BUBODVDDDREG

BUBODBUVIN

Backup regulator

BUBODUNREG

BUBODREG

When in backup mode, available functionality is the same as the functionality available in EM4. Refer

to Section 10.3.4.10 (p. 115) for further details.

10.3.4.2 Brown out detectors

The backup power domain functionality utilizes four brown-out detectors, BODs. One senses the main

power supply, one senses the backup power supply, one senses the unregulated selected power supply

(main or backup, depending on mode), and one BOD senses the regulated power supply. The bits

BUBODVDDDREG ,BUBODBUVIN, BUBODUNREG, and BUBODREG in the RSTCAUSE register in

the RMU are set when the associated BOD triggers. The locations of the Backup BODs are indicated in

Figure 10.3 (p. 112) . A brown out on the main power supply will trigger a switch to the backup power

supply if the backup functionality is enabled and the BOD sensing on the backup power supply has not

triggered. The two other BODs are used for error indication and will only set the bits in RMU_RSTCAUSE

if they are triggered.

A reset from backup mode on BUBODUNREG brown-out can also be triggered if BUMODEBODEN in

EMU_BUCTRL is set. This will cause the device to switch back to the main power supply regardless

of whether this is valid or not. Set this bit to make sure the device always asssume a known condition

when the backup voltage drops below the operating limits.

10.3.4.3 Entering backup mode

To be able to enter backup mode, the EN bit in EMU_BUCTRL has to be set. The BURDY interrupt

flag will be set as soon as the backup sensing module is operational. Status of the backup functionality

is also available in the BURDY flag in the EMU_STATUS register. The BU_VIN pin also needs to be

enabled. This is done by setting the BUVINPEN bit in EMU_ROUTE. To enter backup mode, the voltage

on VDD_DREG has to drop below the programmable threshold of the BOD sensing on this power. This

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threshold is programmed using BUENRANGE and BUENTHRES in EMU_BUINACT. BUENRANGE

decides the voltage range for the BOD, while BUENTHRES is used for tuning of the BOD threshold.

Refer to Section 10.3.4.5 (p. 113) for details regarding BOD calibration.

Note BUVINPEN in EMU_ROUTE is by default set. If Backup mode is not to be used, this bit

should be cleared.

Note The voltage on BU_VIN has to be above the threshold for the BOD sensing on BU_VIN to

enter backup mode.

The BU_STAT pin can be used to indicate whether or not the system is in backup mode. To enable

exporting of the backup mode status, set STATEN in EMU_BUCTRL and enable the GPIO clock. The

BU_STAT pin is driven to BU_VIN when backup mode is active and to ground otherwise.

10.3.4.4 Leaving backup mode

To exit backup mode, the voltage on VDD_DREG has to be above the threshold programmed in

EMU_BUACT. BUEXRANGE decides the voltage range for backup mode exit, while BUEXTHRES is

used for tuning. When leaving backup mode, a system reset is triggered, resetting everything except the

backup domain. When backup mode has been active, the BURST bit in RMU_RSTCAUSE is set.

Figure 10.4. Entering and leaving backup mode

EMU_BUACT_BUEXRANGE /

EMU_BUACT_BUEXTHRES

VDDREG

Time

Backup mode active

EMU_BUINACT_BUENRANGE /

EMU_BUINACT_BUENTHRES

Figure 10.4 (p. 113) illustrates how the BOD sensing on VDD_DREG can be programmed to

implement hysteresis on entering and exiting backup mode.

10.3.4.5 Threshold calibration

The thresholds for entering and exiting backup mode are configured in the EMU_BUINACT and

EMU_BUACT registers, respectively. Calibration of these thresholds is performed during production

test, but may also be performed using the DAC. The calibration values for the BODs sensing on

unregulated power and BU_VIN, BUBODUNREG and BUBODBUVIN respectively, are available in

EMU_BUBODVINCAL and EMU_BUBODUNREGCAL. These registers are written during production

test and should not be modified except for calibrating the Backup BOD sensing on VDD_DREG, as

described in the following section.

Setting BODCAL in EMU_BUCTRL will enable a mode where the BOD is sensing the DAC output, as

depicted in Figure 10.5 (p. 114) . For the BODCAL bit to take effect, the backup power enable bit, EN

in EMU_BUCTRL, has to be cleared. The procedure for BOD calibration is as follows:

• Clear EN and set BODCAL in EMU_BUCTRL.

• Store the values in EMU_BUBODVINCAL and EMU_BUBODUNREGCAL before clearing these

registers.

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• Configure the DAC to output to the maximum level and wait for 500 us before configuring the DAC

output to the wanted BOD trigger voltage level.

• Step through the BOD calibration values (RANGE and THRES in EMU_BUINACT) with 500 us delay in

between steps until the BUBODVDDDREG flag in RMU_RSTCAUSE is set. The RANGE and THRES

values in EMU_BUINACT can now be written to EMU_BUINACT for configuration of threshold for

entering backup mode, or EMU_BUACT for configuration of the threshold for leaving backup mode.

• Restore the values in EMU_BUBODVINCAL and EMU_BUBODUNREGCAL.

Figure 10.5. BOD calibration using DAC

1.8V

BUCTRL_BODCAL

DAC alternative output

VDD_DREG

BOD trigger

EMU_BUINACT_BUENRANGE /

EMU_BUINACT_BUENTHRES

10.3.4.6 Backup battery charging

The EFM32LG includes functionality for charging of the backup battery. This is done by connecting

the main power and the backup power through a resistor, and optionally a diode. The connection is

configured individually for when in backup mode and when in normal mode. When in normal mode, the

connection is configured in PWRCON in EMU_BUINACT. PWRCON in EMU_BUACT configures the

connection when in backup mode. The series resistance between the two power domains is configured

in PWRRES in EMU_PWRCONF, this configuration applies both to backup mode and normal mode.

10.3.4.7 Supply voltage output

To be able to power external devices, the supply voltage for the backup domain is available as an output.

Three switches connect the backup supply voltage to the BU_VOUT pin. To be able to control the series

resistance, the switches have different strengths: weak, medium, and strong. The switches are controlled

using the VOUTWEAK, VOUTMED, and VOUTSTRONG bits in EMU_PWRCONF. For resistor values,

refer to Device Datasheet Electrical Characteristics.

10.3.4.8 Voltage probing

It is possible to probe the voltage levels at VDD_DREG, BU_VIN, and BU_VOUT. This is done by

configuring the ADC to measure a tristated channel, for instance a disabled DAC channel. The PROBE

bitfield in EMU_BUCTRL configures which voltage to be probed. The voltage measured by the ADC will

be 1/8 of the actual probed voltage, meaning that the result needs to be multiplied by 8 for the correct

result. Voltage probing does not work when BODCAL in the EMU_BUCTRL register is set.

10.3.4.9 Configuration lock

Configurations used in Backup mode and EM4, like BOD calibration, and Backup RTC settings need

to be locked before entering EM4, this is done by setting the LOCKCONF bit in EMU_EM4CONF. This

bit should also be set before a potential entry to backup mode. Setting this bit will lock following the

configuration:

• LFXOMODE, LFXOBUFCUR, and LFXOBOOST in CMU_CTRL

• TUNING in CMU_LFRCOCTRL

• BURSTEN in RMU_CTRL

• BURTCWU and VREGEN in EMU_EM4CONF

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• EMU_BUCTRL

• EMU_PWRCONF

• EMU_BUINACT

• EMU_BUACT

• EMU_ROUTE

Note For registers residing in the CMU and EMU_AUXCTRL, the reset value will be read after

exit from EM4 or Backup mode, but if LOCKCONF in EMU_EM4CONF has been set, the

locked configuration will be used until LOCKCONF is cleared. This also applies for the

LOCKCONF bit itself.

The LOCKCONF bit does not lock the PROBE bitfield in EMU_BUCTRL.

10.3.4.10 EM4 with RTC and data retention

The backup power domain can also be powered by the main power. This provides possibility for

Backup RTC operation and data retention in EM4. Available functionality in EM4 is configured in

EMU_EM4CONF. Setting the VREGEN bit will keep the voltage regulator for the Backup domain enabled

when in EM4. This allows the Backup RTC to keep running. To enable the Backup RTC to wake up

the system from EM4, BURTCWU in EMU_EM4CONF needs to be set. When BURTCWU is set, any

enabled Backup RTC interrupt will wake up the system. For further details regarding the Backup RTC

and EM4 data retention, refer to Chapter 22 (p. 569) .

The voltage regulator can also be used to power the Backup RTC during a watchdog reset from any

energy mode. Set EMU_EM4CONF_VREGEN to enable the Backup RTC to be powered from the

regulator, making sure it survives a watchdog reset.

10.3.4.10.1 Oscillators in EM4

When the system is in EM4 or backup mode with the voltage regulator enabled, the ULFRCO is by

default enabled. If the LFXO or LFRCO is used by the Backup RTC, the ULFRCO can be shut down to

reduce power consumption. To do this, configure the OSC bitfield in EMU_EM4CONF.

Note If OSC in EMU_EM4CONF is not set to ULFRCO, PRESC and LPCOMP in BURTC_CTRL

has to be configured in the following manner:

• 4 < (PRESC + LPCOMP) < 8, PRESC = 0,5,6,7

Refer to Chapter 22 (p. 569) for details on how to configure the Backup RTC.

10.3.4.10.2 Brown-out detector in EM4

To enable Brown-out detection in EM4, the Backup BODs have to be enabled, by setting EN in

EMU_BUCTRL. When BURDY in EMU_STATUS is set, the Brown-out detectors are ready and able to

issue a reset from EM4 if a Brown-out is detected on either regulated or unregulated power. The Backup

BOD' ability to issue reset from EM4 can be disabled by setting BUBODRSTDIS in EMU_EM4CONF.

Note The Backup BODs can be enabled without allowing entrance to backup mode. This is done

by setting EN in EMU_BUCTRL, and clearing BUVINPEN in EMU_ROUTE.

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10.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 EMU_CTRL RW Control Register

0x008 EMU_LOCK RW Configuration Lock Register

0x024 EMU_AUXCTRL RW Auxiliary Control Register

0x02C EMU_EM4CONF RW Energy mode 4 configuration register

0x030 EMU_BUCTRL RW Backup Power configuration register

0x034 EMU_PWRCONF RW Power connection configuration register

0x038 EMU_BUINACT RW Backup mode inactive configuration register

0x03C EMU_BUACT RW Backup mode active configuration register

0x040 EMU_STATUS R Status register

0x044 EMU_ROUTE RW I/O Routing Register

0x048 EMU_IF R Interrupt Flag Register

0x04C EMU_IFS W1 Interrupt Flag Set Register

0x050 EMU_IFC W1 Interrupt Flag Clear Register

0x054 EMU_IEN RW Interrupt Enable Register

0x058 EMU_BUBODBUVINCAL RW BU_VIN Backup BOD calibration

0x05C EMU_BUBODUNREGCAL RW Unregulated power Backup BOD calibration

10.5 Register Description

10.5.1 EMU_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

EM4CTRL

EM2BLOCK

EMVREG

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:2 EM4CTRL 0x0 RW Energy Mode 4 Control

This register is used to enter Energy Mode 4, in which the device only wakes up from an external pin reset, from a power cycle,

Backup RTC interrupt, or EM4 wakeup reset request. Energy Mode 4 is entered when the EM4 sequence is written to this bitfield.

1 EM2BLOCK 0 RW Energy Mode 2 Block

This bit is used to prevent the MCU to enter Energy Mode 2 or lower.

0 EMVREG 0 RW Energy Mode Voltage Regulator Control

Control the voltage regulator in low energy modes 2 and 3.

Value Mode Description

0 REDUCED Reduced voltage regulator drive strength in EM2 and EM3.

1 FULL Full voltage regulator drive strength in EM2 and EM3.

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10.5.2 EMU_LOCK - Configuration Lock Register

Offset Bit Position

0x008

Reset

0x0000

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 LOCKKEY 0x0000 RW Configuration Lock Key

Write any other value than the unlock code to lock all EMU registers, except the interrupt registers, from editing. Write the unlock

code to unlock. When reading the register, bit 0 is set when the lock is enabled.

Mode Value Description

Read Operation

UNLOCKED 0 EMU registers are unlocked.

LOCKED 1 EMU registers are locked.

Write Operation

LOCK 0 Lock EMU registers.

UNLOCK 0xADE8 Unlock EMU registers.

10.5.3 EMU_AUXCTRL - Auxiliary Control Register

Offset Bit Position

0x024

Reset

Access

Name

HRCCLR

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 HRCCLR 0 RW Hard Reset Cause Clear

Write to 1 and then 0 to clear the POR, BOD and WDOG reset cause register bits. See also the Reset Management Unit (RMU).

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10.5.4 EMU_EM4CONF - Energy mode 4 configuration register

Offset Bit Position

0x02C

Reset

0x0

Access

Name

LOCKCONF

BUBODRSTDIS

OSC

BURTCWU

VREGEN

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 LOCKCONF 0 RW EM4 configuration lock enable

Lock regulator, BOD and oscillator configuration. This is necessary before going to EM4 if the regulator is to be used in EM4, and

must also be done before a potential entry to backup mode.

15:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 BUBODRSTDIS 0 RW Disable reset from Backup BOD in EM4

When set, no reset will be asserted due to Brownout when in EM4.

3:2 OSC 0x0 RW Select EM4 duty oscillator

Value Mode Description

0 ULFRCO ULFRCO is available.

1 LFRCO LFRCO is available. Can only be set if LFRCO is running before EM4/backup entry.

2 LFXO LFXO is available. Can only be set if LFXO is available before EM4/backup entry.

1 BURTCWU 0 RW Backup RTC EM4 wakeup enable

Exit EM4 on Backup RTC interrupt.

0 VREGEN 0 RW EM4 voltage regulator enable

When set, the voltage regulator is enabled in EM4, enabling operation of the Backup RTC and retention registers.

10.5.5 EMU_BUCTRL - Backup Power configuration register

Offset Bit Position

0x030

Reset

0x0

Access

Name

PROBE

BUMODEBODEN

BODCAL

STATEN

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:5 PROBE 0x0 RW Voltage probe select

Configure which voltage to export to ADC.

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Bit Name Reset Access Description

Value Mode Description

0 DISABLE Disable voltage probe.

1 VDDDREG Connect probe to VDD_DREG.

2 BUIN Connect probe to BU_IN.

3 BUOUT Connect probe to BU_OUT.

4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 BUMODEBODEN 0 RW Enable brown out detection on BU_VIN when in backup mode

When set, a reset (and switch back to main power) will be performed when in backup mode and the BUBODUNREG-bod senses

a brown-out on BU_VIN.

2 BODCAL 0 RW Enable BOD calibration mode

When set, the Backup BOD sensing on VDD_DREG will be sensing the DAC output.

1 STATEN 0 RW Enable backup mode status export

When enabled, BU_STAT will indicate when backup mode is active.

0 EN 0 RW Enable backup mode

Backup mode will be entered when main power browns out and backup battery is present.

10.5.6 EMU_PWRCONF - Power connection configuration register

Offset Bit Position

0x034

Reset

0x0

Access

Name

PWRRES

VOUTSTRONG

VOUTMED

VOUTWEAK

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4:3 PWRRES 0x0 RW Power domain resistor select

Select value of series resistor between main power domain and backup power domain.

Value Mode Description

0 RES0 Main power and backup power connected with RES0 series resistance.

1 RES1 Main power and backup power connected with RES1 series resistance.

2 RES2 Main power and backup power connected with RES2 series resistance.

3 RES3 Main power and backup power connected with RES3 series resistance.

2 VOUTSTRONG 0 RW BU_VOUT strong enable

Enable strong switch between backup domain power supply and BU_VOUT.

1 VOUTMED 0 RW BU_VOUT medium enable

Enable medium switch between backup domain power supply and BU_VOUT.

0 VOUTWEAK 0 RW BU_VOUT weak enable

Enable weak switch between backup domain power supply and BU_VOUT.

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10.5.7 EMU_BUINACT - Backup mode inactive configuration register

Offset Bit Position

0x038

Reset

0x0

0x1

0x3

Access

Name

PWRCON

BUENRANGE

BUENTHRES

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:5 PWRCON 0x0 RW Power connection configuration when not in Backup mode

Value Mode Description

0 NONE No connection.

1 BUMAIN Main power and backup power are connected through a diode, allowing current to flow

from backup power source to main power source, but not the other way.

2 MAINBU Main power and backup power are connected through a diode, allowing current to flow

from main power source to backup power source, but not the other way.

3 NODIODE Main power and backup power are connected without diode.

4:3 BUENRANGE 0x1 RW

Threshold range for Backup BOD sensing on VDD_DREG when not in backup mode. This field is set to the threshold range calibrated

during production, hence the reset value might differ from device to device.

2:0 BUENTHRES 0x3 RW

Threshold for Backup BOD sensing on VDD_DREG when not in backup mode. This field is set to the threshold value calibrated

during production, hence the reset value might differ from device to device.

10.5.8 EMU_BUACT - Backup mode active configuration register

Offset Bit Position

0x03C

Reset

0x0

0x1

0x3

Access

Name

PWRCON

BUEXRANGE

BUEXTHRES

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:5 PWRCON 0x0 RW Power connection configuration when in Backup mode

Value Mode Description

0 NONE No connection.

1 BUMAIN Main power and backup power are connected through a diode, allowing current to flow

from backup power source to main power source, but not the other way.

2 MAINBU Main power and backup power are connected through a diode, allowing current to flow

from main power source to backup power source, but not the other way.

3 NODIODE Main power and backup power are connected without diode.

4:3 BUEXRANGE 0x1 RW

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Bit Name Reset Access Description

Threshold range for Backup BOD sensing on VDD_DREG when in backup mode. This field is set to the threshold range calibrated

during production, hence the reset value might differ from device to device.

2:0 BUEXTHRES 0x3 RW

Threshold for Backup BOD sensing on VDD_DREG when in backup mode. This field is set to the threshold value calibrated during

production, hence the reset value might differ from device to device.

10.5.9 EMU_STATUS - Status register

Offset Bit Position

0x040

Reset

Access

Name

BURDY

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BURDY 0 R Backup mode ready

Set when the Backup power functionality is ready.

10.5.10 EMU_ROUTE - I/O Routing Register

Offset Bit Position

0x044

Reset

Access

Name

BUVINPEN

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BUVINPEN 1 RW BU_VIN Pin Enable

When set, the BU_VIN pin is enabled.

10.5.11 EMU_IF - Interrupt Flag Register

Offset Bit Position

0x048

Reset

Access

Name

BURDY

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Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BURDY 0 R Backup functionality ready Interrupt Flag

Set when the Backup functionality is ready for use.

10.5.12 EMU_IFS - Interrupt Flag Set Register

Offset Bit Position

0x04C

Reset

Access

Name

BURDY

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BURDY 0 W1 Set Backup functionality ready Interrupt Flag

Write to 1 to set the BURDY interrupt flag.

10.5.13 EMU_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x050

Reset

Access

Name

BURDY

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BURDY 0 W1 Clear Backup functionality ready Interrupt Flag

Write to 1 to clear the BURDY interrupt flag.

10.5.14 EMU_IEN - Interrupt Enable Register

Offset Bit Position

0x054

Reset

Access

Name

BURDY

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Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 BURDY 0 RW Backup functionality ready Interrupt Enable

Enable interrupt when Backup functionality is ready.

10.5.15 EMU_BUBODBUVINCAL - BU_VIN Backup BOD calibration

Offset Bit Position

0x058

Reset

0x1

0x3

Access

Name

RANGE

THRES

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4:3 RANGE 0x1 RW

Threshold range for Backup BOD sensing on BU_VIN. This field is set to the threshold range calibrated during production, hence

the reset value might differ from device to device.

2:0 THRES 0x3 RW

Threshold for Backup BOD sensing on BU_VIN. This field is set to the threshold value calibrated during production, hence the reset

value might differ from device to device.

10.5.16 EMU_BUBODUNREGCAL - Unregulated power Backup BOD

calibration

Offset Bit Position

0x05C

Reset

0x1

0x3

Access

Name

RANGE

THRES

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4:3 RANGE 0x1 RW

Threshold range for Backup BOD sensing on unregulated power. This field is set to the threshold range calibrated during production,

hence the reset value might differ from device to device.

2:0 THRES 0x3 RW

Threshold for Backup BOD sensing on unregulated power. This field is set to the threshold value calibrated during production, hence

the reset value might differ from device to device.

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11 CMU - Clock Management Unit

01 2 3 4

Oscillators CMU

WDOG clock

LETIMER clock

LCD clock

Peripheral A clock

Peripheral B clock

Peripheral C clock

Peripheral D clock

CPU clock

Quick Facts

What?

The CMU controls oscillators and clocks.

EFM32LG supports several different

oscillators with minimized power consumption

and short start-up time. An additional

separate RC oscillator is used for flash

programming and debug trace. The CMU

also has HW support for calibration of RC

oscillators.

Why?

Oscillators and clocks contribute significantly

to the power consumption of the MCU. With

the low power oscillators combined with the

flexible clock control scheme, it is possible

to minimize the energy consumption in any

given application.

How?

The CMU can configure different clock

sources, enable/disable clocks to peripherals

on an individual basis and set the prescaler

for the different clocks. The short oscillator

start-up times makes duty-cycling between

active mode and the different low energy

modes (EM2-EM4) very efficient. The

calibration feature ensures high accuracy RC

oscillators. Several interrupts are available to

avoid CPU polling of flags.

11.1 Introduction

The Clock Management Unit (CMU) is responsible for controlling the oscillators and clocks on-board

the EFM32LG. The CMU provides the capability to turn on and off the clock on an individual basis to all

peripheral modules in addition to enable/disable and configure the available oscillators. The high degree

of flexibility enables software to minimize energy consumption in any specific application by not wasting

power on peripherals and oscillators that are inactive.

11.2 Features

• Multiple clock sources available:

• 1-28 MHz High Frequency RC Oscillator (HFRCO)

• 4-48 MHz High Frequency Crystal Oscillator (HFXO)

• 32768 Hz Low Frequency RC Oscillator (LFRCO)

• 32768 Hz Low Frequency Crystal Oscillator (LFXO)

• 1000 Hz Ultra Low Frequency RC Oscillator (ULFRCO)

•

• Low power oscillators

• Low start-up times

• Separate prescaler for High Frequency Core Clocks (HFCORECLK) and Peripheral Clocks

(HFPERCLK)

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• Individual clock prescaler selection for each Low Energy Peripheral

• Clock Gating on an individual basis to core modules and all peripherals

• Selectable clocks can be output on two pins for use externally.

• Auxiliary 1-28 MHz RC oscillator (AUXHFRCO) for flash programming, and debug trace, and

LESENSE timing.

11.3 Functional Description

An overview of the CMU is shown in Figure 11.1 (p. 126) . The number of peripheral modules that are

connected to the different clocks varies from device to device.

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Figure 11.1. CMU Overview

HFXO

HFRCO

LFXO

LFRCO

prescaler

CMU_HFPERCLKEN0.I2C0

HFPERCLKTIMER1

Timeout

CMU_LFACLKEN0.RTC

HFPERCLKI2C0

CMU_HFPERCLKEN0.TIMER0 HFPERCLKTIMER0

HFCORECLKCM3

CMU_HFPERCLKDIV.HFPERCLKEN

CMU_HFPERCLKEN0.TIMER1

HFCLK

Clock

Gate

Clock

Gate

prescaler

EM0

HFCORECLKDMA

CMU_HFCORECLKEN0.DMA

Clock

Gate LFACLKRTC

CMU_LFACLKEN0.LETIMER0 Clock

Gate LFACLKLETIMER0

CMU_LFACLKEN0.LCD Clock

Gate LFACLKLCD

LFACLK

CMU_LFBCLKEN0.LEUART0 Clock

Gate LFBCLKLEUART0

Clock

Gate LFBCLKLEUART1

LFBCLK

Clock

Gate

Clock

Gate

Clock

Gate

clock

switch

clock

switch

clock

switch

prescaler

HFCORECLKLE

CMU_HFCORECLKEN0.LE Clock

Gate

/2 or /4

HFCORECLK

HFPERCLK

Frame Rate Control

ULFRCO

PCNTnCLK

PCNTn_S0

WDOG

WDOG_CTRL.CLKSEL

CMU_LFCLKSEL.LFB / LFBE

CMU_LFCLKSEL.LFA / LFAE

CMU_LFBCLKEN0.LEUART1

CMU_LCDCTRL.FDIV

CMU_HFPERCLKDIV.HFPERCLKDIV

CMU_HFCORECLKDIV

CMU_LFBPRESC0.LEUART1

CMU_LFBPRESC0.LEUART0

CMU_LFAPRES C0.LCD

CMU_LFAPRES C0.LETIMER0

CMU_LFAPRES C0.RTC

CMU_PCNTCTRL.PCNTnCLKSEL

LFACLKLCDpre

AUXHFRCO

Debug Trace

MSC

(Flash Programming)

Timeout AUXCLK

WDOGCLK

CMU_CMD.HFCLKSEL

clock

switch

CMU_CTRL_DBGCLK

CMU_LFACLKEN0.LESENSE Clock

Gate LFACLKLESENSE

prescaler

CMU_LFAPRES C0.LESENSE

LESENSE

(High frequency timing)

HFCLK

DIV

CMU_CTRL.HFCLKDIV

clock

switch

CMU_CMD.USBCCLKSEL

HFCORECLKUSBC

CMU_HFCORECLKEN0.USBC

BURTC

11.3.1 System Clocks

11.3.1.1 HFCLK - High Frequency Clock

HFCLK is the selected High Frequency Clock. This clock is used by the CMU and drives the two

prescalers that generate HFCORECLK and HFPERCLK. The HFCLK can be driven by a high-frequency

oscillator (HFRCO or HFXO) or one of the low-frequency oscillators (LFRCO or LFXO). By default the

HFRCO is selected. In most applications, one of the high frequency oscillators will be the preferred

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choice. To change the selected HFCLK write to HFCLKSEL in CMU_CMD. The HFCLK is running in

EM0 and EM1.

HFCLK can optionally be divided down by setting HFCLKDIV in CMU_CTRL to a nonzero value. This

divides down HFCLK to all high frequency components except the USB Core and is typically used to

save energy in USB applications where the system is not required to run at 48 MHz. Combined with the

HFCORECLK and HFPERCLK prescalers the HFCLK divider also allows for more flexible clock division.

11.3.1.2 HFCORECLK - High Frequency Core Clock

HFCORECLK is a prescaled version of HFCLK. This clock drives the Core Modules, which consists of

the CPU and modules that are tightly coupled to the CPU, e.g. MSC, DMA etc. This also includes the

interface to the Low Energy Peripherals. Some of the modules that are driven by this clock can be clock

gated completely when not in use. This is done by clearing the clock enable bit for the specific module

in CMU_HFCORECLKEN0. The frequency of HFCORECLK is set using the CMU_HFCORECLKDIV

The USB Core runs on HFCORECLKUSBC. Selectable clock sources are LFXO, LFRCO , HFCLK . If

HFCLK is selected, it will always be undivided, regardless of the HFCLKDIV setting. When the USB

Core is active this clock must be switched to a 32 kHz clock (LFRCO or LFXO) when entering EM2.

The USB Core uses this clock for monitoring the USB bus. The switch is done by writing USBCCLKSEL

in CMU_CMD. The currently active clock can be checked by reading CMU_STATUS. The clock switch

can take up to 1.5 32 kHz cycle (45 us). To avoid polling the clock selection status when switching from

32 kHz to HFCLK when coming up from EM2 the USBCHFCLKSEL interrupt can be used. EM3 is not

supported when the USB is active.

Note Note that if HFPERCLK runs faster than HFCORECLK, the number of clock cycles for each

bus-access to peripheral modules will increase with the ratio between the clocks. Please

refer to Section 5.2.3.2 (p. 19) for more details.

11.3.1.3 HFPERCLK - High Frequency Peripheral Clock

Like HFCORECLK, HFPERCLK can also be a prescaled version of HFCLK. This clock drives the

High-Frequency Peripherals. All the peripherals that are driven by this clock can be clock gated

completely when not in use. This is done by clearing the clock enable bit for the specific peripheral in

CMU_HFPERCLKEN0. The frequency of HFPERCLK is set using the CMU_HFPERCLKDIV register.

The setting can be changed dynamically and the new setting takes effect immediately.

Note Note that if HFPERCLK runs faster than HFCORECLK, the number of clock cycles for each

bus-access to peripheral modules will increase with the ratio between the clocks. E.g. if a

bus-access normally takes three cycles, it will take 9 cycles if HFPERCLK runs three times

as fast as the HFCORECLK.

11.3.1.4 LFACLK - Low Frequency A Clock

LFACLK is the selected clock for the Low Energy A Peripherals. There are four selectable sources for

LFACLK: LFRCO, LFXO, HFCORECLK/2 and ULFRCO. In addition, the LFACLK can be disabled. From

reset, the LFACLK source is set to LFRCO. However, note that the LFRCO is disabled from reset. The

selection is configured using the LFA field in CMU_LFCLKSEL. The HFCORECLK/2 setting allows the

Low Energy A Peripherals to be used as high-frequency peripherals.

Note If HFCORECLK/2 is selected as LFACLK, the clock will stop in EM2/3.

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Each Low Energy Peripheral that is clocked by LFACLK has its own prescaler setting and enable bit.

The prescaler settings are configured using CMU_LFAPRESC0 and the clock enable bits can be found

in CMU_LFACLKEN0. Notice that the LCD has an additional high resolution prescaler for Frame Rate

Control, configured by FDIV in CMU_LCDCTRL. When operating in oversampling mode, the pulse

counters are clocked by LFACLK. This is configured for each pulse counter (n) individually by setting

PCNTnCLKSEL in CMU_PCNTCTRL.

11.3.1.5 LFBCLK - Low Frequency B Clock

LFBCLK is the selected clock for the Low Energy B Peripherals. There are four selectable sources for

LFBCLK: LFRCO, LFXO, HFCORECLK/2 and ULFRCO. In addition, the LFBCLK can be disabled. From

reset, the LFBCLK source is set to LFRCO. However, note that the LFRCO is disabled from reset. The

selection is configured using the LFB field in CMU_LFCLKSEL. The HFCORECLK/2 setting allows the

Low Energy B Peripherals to be used as high-frequency peripherals.

Note If HFCORECLK/2 is selected as LFBCLK, the clock will stop in EM2/3.

Each Low Energy Peripheral that is clocked by LFBCLK has its own prescaler setting and enable bit.

The prescaler settings are configured using CMU_LFBPRESC0 and the clock enable bits can be found

in CMU_LFBCLKEN0.

11.3.1.6 PCNTnCLK - Pulse Counter n Clock

Each available pulse counter is driven by its own clock, PCNTnCLK where n is the pulse counter instance

number. Each pulse counter can be configured to use an external pin (PCNTn_S0) or LFACLK as

PCNTnCLK.

11.3.1.7 WDOGCLK - Watchdog Timer Clock

The Watchdog Timer (WDOG) can be configured to use one of three different clock sources: LFRCO,

LFXO or ULFRCO. ULFRCO (Ultra Low Frequency RC Oscillator) is a separate 1 kHz RC oscillator

that also runs in EM3.

11.3.1.8 AUXCLK - Auxiliary Clock

AUXCLK is a 1-28 MHz clock driven by a separate RC oscillator, AUXHFRCO. This clock is used for flash

programming, and Serial Wire Output (SWO), and LESENSE operation. During flash programming, or

if needed by LESENSE, this clock will be active. If the AUXHFRCO has not been enabled explicitly by

software, the MSC or LESENSE module will automatically start and stop it. The AUXHFRCO is enabled

by writing a 1 to AUXHFRCOEN in CMU_OSCENCMD. This explicit enabling is required when SWO

is used.

11.3.2 Oscillator Selection

11.3.2.1 Start-up Time

The different oscillators have different start-up times. For the RC oscillators, the start-up time is fixed,

but both the LFXO and the HFXO have configurable start-up time. At the end of the start-up time a ready

flag is set to indicated that the start-up time has exceeded and that the clock is available. The low start-

up time values can be used for an external clock source of already high quality, while the higher start-up

times should be used when the clock signal is coming directly from a crystal. The startup time for HFXO

and LFXO can be set by configuring the HFXOTIMEOUT and LFXOTIMEOUT bitfields, respectively.

Both bitfields are located in CMU_CTRL. For HFXO it is also possible to enable a glitch detection filter

by setting HFXOGLITCHDETEN in CMU_CTRL. The glitch detector will reset the start-up counter if a

glitch is detected, making the start-up process start over again.

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There are individual bits for each oscillator indicating the status of the oscillator:

• ENABLED - Indicates that the oscillator is enabled

• READY - Start-up time is exceeded

• SELECTED - Start-up time is exceeded and oscillator is chosen as clock source

These status bits are located in the CMU_STATUS register.

11.3.2.2 Switching Clock Source

The HFRCO oscillator is a low energy oscillator with extremely short wake-up time. Therefore, this

oscillator is always chosen by hardware as the clock source for HFCLK when the device starts up (e.g.

after reset and after waking up from EM2 and EM3). After reset, the HFRCO frequency is 14 MHz.

Software can switch between the different clock sources at run-time. E.g., when the HFRCO is the

clock source, software can switch to HFXO by writing the field HFCLKSEL in the CMU_CMD command

Note It is important first to enable the HFXO since switching to a disabled oscillator will effectively

stop HFCLK and only a reset can recover the system.

During the start-up period HFCLK will stop since the oscillator driving it is not ready. This effectively

stalls the Core Modules and the High-Frequency Peripherals. It is possible to avoid this by first enabling

the HFXO and then wait for the oscillator to become ready before switching the clock source. This way,

the system continues to run on the HFRCO until the HFXO has timed out and provides a reliable clock.

This sequence of events is shown in Figure 11.3 (p. 130) .

A separate flag is set when the oscillator is ready. This flag can also be configured to generate an

interrupt.

Figure 11.2. CMU Switching from HFRCO to HFXO before HFXO is ready

HFXO

CMU_STATUS..HFXORDY

CMU_STATUS.HFXOENS

CMU_STATUS.HFXOSEL

HFRCO

HFCLK

HFXO time-out period

CMU_STATUS.HFRCORDY

CMU_STATUS.HFRCOENS

CMU_STATUS.HFRCOSEL

CMU_OSCENCMD.HFXOEN

CMU_OSCENCMD.HFXODIS

clocks

CMU_CMD.HFCLKSEL

CMU_OSCENCMD.HFRCOEN

CMU_OSCENCMD.HFRCODIS

command

status

00 02 00

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Figure 11.3. CMU Switching from HFRCO to HFXO after HFXO is ready

00 02 00

HFXO

CMU_STATUS.HFXORDY

CMU_STATUS.HFXOENS

CMU_STATUS.HFXOSEL

HFRCO

HFCLK

HFXO time-out period

CMU_STATUS.HFRCORDY

CMU_STATUS.HFRCOENS

CMU_STATUS.HFRCOSEL

CMU_OSCENCMD.HFXOEN

CMU_OSCENCMD.HFXODIS

clocks

CMU_CMD.HFCLKSEL

CMU_OSCENCMD.HFRCOEN

CMU_OSCENCMD.HFRCODIS

command

status

Switching clock source for LFACLK and LFBCLK is done by setting the LFA and LFB fields in

CMU_LFCLKSEL. To ensure no stalls in the Low Energy Peripherals, the clock source should be ready

before switching to it.

Note To save energy, remember to turn off all oscillators not in use.

11.3.3 Oscillator Configuration

11.3.3.1 HFXO and LFXO

The crystal oscillators are by default configured to ensure safe startup and operation of the most common

crystals. In order to optimize startup margin, startup time and power consumption for a given crystal, it is

possible to adjust the gain in the oscillator. HFXO gain can be increased by setting HFXOBOOST field in

CMU_CTRL, LFXO gain can be increased by setting LFXOBOOST field in CMU_CTRL. It is important

that the boost settings, along with the crystal load capacitors are matched to the crystals in use. Correct

values for these parameters can be found using the energyAware Designer.

The HFXO crystal is connected to the HFXTAL_N/HFXTAL_P pins as shown in Figure 11.4 (p. 130)

Figure 11.4. HFXO Pin Connection

Similarly, the LFXO crystal is connected to the LFXTAL_N/LFXTAL_P pins as shown in Figure 11.5 (p.

131)

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Figure 11.5. LFXO Pin Connection

MCU

LFXTAL_N

LFXTAL_P

32.768kHz

CL1 CL2

It is possible to connect an external clock source to HFXTAL_N/LFXTAL_N pin of the HFXO or LFXO

oscillator. By configuring the HFXOMODE/LFXOMODE fields in CMU_CTRL, the HFXO/LFXO can be

bypassed.

11.3.3.2 HFRCO, LFRCO and AUXHFRCO

The HFRCO and AUXHFRCO can be set to one of several different frequency bands from 1 MHz to 28

MHz by setting the BAND field in CMU_HFRCOCTRL and CMU_AUXHFRCOCTRL.The HFRCO and

AUXHFRCO frequency bands are calibrated during production test, and the production tested calibration

values can be read from the Device Information (DI) page. The DI page contains a separate tuning value

for each frequency band. During reset, HFRCO and AUXHFRCO tuning values are set to the production

calibrated values for the 14 MHz band, which is the default frequency band. When changing to a different

HFRCO or AUXHFRCO band, make sure to also update the tuning value.

The LFRCO and is also calibrated in production and its TUNING value is set to the correct value during

reset.

11.3.3.3 RC oscillator calibration

It is possible to calibrate the HFRCO, AUXHFRCO and LFRCO to achieve higher accuracy (see the

device datasheets for details on accuracy). The frequency is adjusted by changing the TUNING fields

in CMU_HFRCOCTRL/CMU_AUXHFRCOCTRL/CMU_LFRCOCTRL. Changing to a higher value will

result in a higher frequency. Please refer to the datasheet for stepsize details.

The CMU has built-in HW support to efficiently calibrate the RC oscillators at run-time, see Figure 11.6 (p.

132) The concept is to select a reference and compare the RC frequency with the reference frequency.

When the calibration circuit is started, one down-counter running on a selectable clock (DOWNSEL in

CMU_CALCTRL) and one up-counter running on a selectable clock (UPSEL in CMU_CALCTRL) are

started simultaneously. The top value for the down-counter must be written to CMU_CALCNT before

calibration is started. The smallest value that can be written to the CMU_CALCNT is 1. The down-counter

counts for CMU_CALCNT+1 cycles. When the down-counter has reached 0, the up-counter is sampled

and the CALRDY interrupt flag is set. If CONT in CMU_CALCTRL is cleared, the counters are stopped

at this point. If continuous mode is selected by setting CONT in CMU_CALCTRL the down-counter

reloads the top value and continues counting and the up-counter restarts from 0. Software can then

read out the sampled up-counter value from CMU_CALCNT. Then it is easy to find the ratio between

the reference and the oscillator subject to the calibration. Overflows of the up-counter will not occur. If

the up-counter reaches its top value before the down counter reaches 0, the top counter stays at its top

value. Calibration can be stopped by writing CALSTOP in CMU_CMD. With this HW support, it is simple

to write efficient calibration algorithms in software.

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Figure 11.6. HW-support for RC Oscillator Calibration

CMU_CALCTRL.REFSEL

AUXHFRCO

HFRCO

LFRCO

HFXO

LFXO

20-bit up-counter

CMU_CALCTRL.DOWNSEL

AUXHFRCO

HFRCO

LFRCO

HFXO

LFXO

TOP Write top-value using

CMU_CALCNT before

starting calibration.

DOWNCLK Domain

UPCLK Domain

HFCLK Domain

= 0 ?

SYNC

(Default) HFCLK

SYNC

20-bit up-counter

buffer

SYNC

20-bit down-counter

Set CMU_IF.CALRDY

CMU_CALCNT

DOWNCLK

UPCLK

Reload down-counter with

top value in continouous

mode.

Take snapshot of up-counter

in up-counter bufffer. If in

continouous mode, restart

up-counter from 0.

The counter operation for single and continuous mode are shown in Figure 11.7 (p. 132) and

Figure 11.8 (p. 132) respectively.

Figure 11.7. Single Calibration (CONT=0)

TOP

Calibration Started Calibration Stopped

(counters stopped)

Down-counter

Up-counter

Up-counter sampled and CALRDY

interrupt flag set.

Sampled value available in

CMU_CALCNT.

Figure 11.8. Continuous Calibration (CONT=1)

TOP

Calibration Started

Down-counter

Up-counter

Up-counter sampled and CALRDY

interrupt flag set.

Sampled value available in

CMU_CALCNT.

Up-counter sampled and CALRDY

interrupt flag set.

Sampled value available in

CMU_CALCNT.

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11.3.4 Configuration For Operating Frequencies

The HFXO is capable of driving crystals up to 48 MHz, which allows the EFM32 to run at up to this

frequency. Different frequencies have different requirements as shown in Table 11.1 (p. 133) . Before

going to a high frequency, make sure the registers in the table have the correct values. When going

down in frequency, make sure to keep the registers at the values required by the higher frequency until

after the switch has been done.

Table 11.1. Configuration For Operating Frequencies

Maximum Frequency MODE in MSC_READCTRL HFLE in CMU_CTRL HFXOBUFCUR in

CMU_CTRL

16 MHz WS0 / WS0SCBTP / WS1 /

WS1SCBTP / WS2 /

WS2SCBTP

- BOOSTUPTO32MHZ

(default value)

24 MHz WS1 / WS1SCBTP / WS2 /

WS2SCBTP - BOOSTUPTO32MHZ

(default value)

32 MHz WS1 / WS1SCBTP / WS2 /

WS2SCBTP 1 BOOSTUPTO32MHZ

(default value)

48 MHz WS2 / WS2SCBTP 1 BOOSTABOVE32MHZ

MODE in MSC_READCTRL makes sure the flash is able to operate at the given frequencies

by inserting waitstates for flash accesses. HFXOBUFCUR in CMU_CTRL should be set to

BOOSTABOVE32MHZ when operating above 32 MHz. When operating at 32 MHz or below, the default

value (BOOSTUPTO32MHZ) should be used. HFLE in CMU_CTRL is only required for frequencies

above 24 MHz, and ensures correct operation of LE peripherals. The CMU_CTRL_HFLE is or'ed with

HFCORECLKLEDIV in CMU_HFCORECLKDIV, so setting either of this bits will reduce the the frequency

of CMU_HFCORECLKLEDIV2.

11.3.5 Output Clock on a Pin

It is possible to configure the CMU to output clocks on two pins. This clock selection is done using

CLKOUTSEL0 and CLKOUTSEL1 fields in CMU_CTRL. The output pins must be configured in the

CMU_ROUTE register.

• LFRCO, LFXO, HFCLK or the qualified clock from any of the oscillators can be output on one pin

(CMU_OUT1). A qualified clock will not have any glitches or skewed duty-cycle during startup. For

LFXO and HFXO you need to configure LFXOTIMEOUT and HFXOTIMEOUT in CMU_CTRL correctly

to guarantee a qualified clock.

• HFRCO, HFXO, HFCLK/2, HFCLK/4, HFCLK/8, HFCLK/16, ULFRCO or AUXHFRCO can be output

on another pin (CMU_OUT0)

Note that HFXO and HFRCO clock outputs to pin can be unstable after startup and should not be output

on a pin before HFXORDY/HFRCORDY is set high in CMU_STATUS.

11.3.6 Protection

It is possible to lock the control- and command registers to prevent unintended software writes to critical

clock settings. This is controlled by the CMU_LOCK register.

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11.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 CMU_CTRL RW CMU Control Register

0x004 CMU_HFCORECLKDIV RW High Frequency Core Clock Division Register

0x008 CMU_HFPERCLKDIV RW High Frequency Peripheral Clock Division Register

0x00C CMU_HFRCOCTRL RW HFRCO Control Register

0x010 CMU_LFRCOCTRL RW LFRCO Control Register

0x014 CMU_AUXHFRCOCTRL RW AUXHFRCO Control Register

0x018 CMU_CALCTRL RW Calibration Control Register

0x01C CMU_CALCNT RWH Calibration Counter Register

0x020 CMU_OSCENCMD W1 Oscillator Enable/Disable Command Register

0x024 CMU_CMD W1 Command Register

0x028 CMU_LFCLKSEL RW Low Frequency Clock Select Register

0x02C CMU_STATUS R Status Register

0x030 CMU_IF R Interrupt Flag Register

0x034 CMU_IFS W1 Interrupt Flag Set Register

0x038 CMU_IFC W1 Interrupt Flag Clear Register

0x03C CMU_IEN RW Interrupt Enable Register

0x040 CMU_HFCORECLKEN0 RW High Frequency Core Clock Enable Register 0

0x044 CMU_HFPERCLKEN0 RW High Frequency Peripheral Clock Enable Register 0

0x050 CMU_SYNCBUSY R Synchronization Busy Register

0x054 CMU_FREEZE RW Freeze Register

0x058 CMU_LFACLKEN0 RW Low Frequency A Clock Enable Register 0 (Async Reg)

0x060 CMU_LFBCLKEN0 RW Low Frequency B Clock Enable Register 0 (Async Reg)

0x068 CMU_LFAPRESC0 RW Low Frequency A Prescaler Register 0 (Async Reg)

0x070 CMU_LFBPRESC0 RW Low Frequency B Prescaler Register 0 (Async Reg)

0x078 CMU_PCNTCTRL RW PCNT Control Register

0x07C CMU_LCDCTRL RW LCD Control Register

0x080 CMU_ROUTE RW I/O Routing Register

0x084 CMU_LOCK RW Configuration Lock Register

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11.5 Register Description

11.5.1 CMU_CTRL - CMU Control Register

Offset Bit Position

0x000

Reset

0x0

0x3

0x0

0x3

0x1

0x3

0x0

Access

Name

HFLE

DBGCLK

CLKOUTSEL1

CLKOUTSEL0

LFXOTIMEOUT

LFXOBUFCUR

HFCLKDIV

LFXOBOOST

LFXOMODE

HFXOTIMEOUT

HFXOGLITCHDETEN

HFXOBUFCUR

HFXOBOOST

HFXOMODE

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30 HFLE 0 RW High-Frequency LE Interface

Set to allow access to LE peripherals when running at frequencies higher than 24 MHz. Or'ed with

CMU_HFCORECLKDIV_HFCORECLKLEDIV to reduce the frequency of CMU_HFCORECLKLEDIV2.

29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 DBGCLK 0 RW Debug Clock

Select clock used for the debug system.

Value Mode Description

0 AUXHFRCO AUXHFRCO is the debug clock.

1 HFCLK The system clock is the debug clock.

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26:23 CLKOUTSEL1 0x0 RW Clock Output Select 1

Controls the clock output multiplexer. To actually output on the pin, set CLKOUT1PEN in CMU_ROUTE.

Value Mode Description

0 LFRCO LFRCO (directly from oscillator).

1 LFXO LFXO (directly from oscillator).

2 HFCLK HFCLK (undivided).

3 LFXOQ LFXO (qualified).

4 HFXOQ HFXO (qualified).

5 LFRCOQ LFRCO (qualified).

6 HFRCOQ HFRCO (qualified).

7 AUXHFRCOQ AUXHFRCO (qualified).

22:20 CLKOUTSEL0 0x0 RW Clock Output Select 0

Controls the clock output multiplexer. To actually output on the pin, set CLKOUT0PEN in CMU_ROUTE.

Value Mode Description

0 HFRCO HFRCO (directly from oscillator).

1 HFXO HFXO (directly from oscillator).

2 HFCLK2 HFCLK/2.

3 HFCLK4 HFCLK/4.

4 HFCLK8 HFCLK/8.

5 HFCLK16 HFCLK/16.

6 ULFRCO ULFRCO (directly from oscillator).

7 AUXHFRCO AUXHFRCO (directly from oscillator).

19:18 LFXOTIMEOUT 0x3 RW LFXO Timeout

Configures the start-up delay for LFXO.

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Bit Name Reset Access Description

Value Mode Description

0 8CYCLES Timeout period of 8 cycles.

1 1KCYCLES Timeout period of 1024 cycles.

2 16KCYCLES Timeout period of 16384 cycles.

3 32KCYCLES Timeout period of 32768 cycles.

17 LFXOBUFCUR 0 RW LFXO Boost Buffer Current

This value has been updated to the correct level during calibration and should not be changed.

16:14 HFCLKDIV 0x0 RW HFCLK Division

Use to divide HFCLK frequency by (HFCLKDIV + 1).

13 LFXOBOOST 1 RW LFXO Start-up Boost Current

Adjusts start-up boost current for LFXO.

Value Mode Description

0 70PCENT 70 %.

1 100PCENT 100 %.

12:11 LFXOMODE 0x0 RW LFXO Mode

Set this to configure the external source for the LFXO. The oscillator setting takes effect when 1 is written to LFXOEN in

CMU_OSCENCMD. The oscillator setting is reset to default when 1 is written to LFXODIS in CMU_OSCENCMD.

Value Mode Description

0 XTAL 32.768 kHz crystal oscillator.

1 BUFEXTCLK An AC coupled buffer is coupled in series with LFXTAL_N pin, suitable for external

sinus wave (32.768 kHz).

2 DIGEXTCLK Digital external clock on LFXTAL_N pin. Oscillator is effectively bypassed.

10:9 HFXOTIMEOUT 0x3 RW HFXO Timeout

Configures the start-up delay for HFXO.

Value Mode Description

0 8CYCLES Timeout period of 8 cycles.

1 256CYCLES Timeout period of 256 cycles.

2 1KCYCLES Timeout period of 1024 cycles.

3 16KCYCLES Timeout period of 16384 cycles.

8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 HFXOGLITCHDETEN 0 RW HFXO Glitch Detector Enable

This bit enables the glitch detector which is active as long as the start-up ripple-counter is counting. A detected glitch will reset the

ripple-counter effectively increasing the start-up time. Once the ripple-counter has timed-out, glitches will not be detected.

6:5 HFXOBUFCUR 0x1 RW HFXO Boost Buffer Current

The current level in the HFXO buffer should be set to default value when operating on 32 MHz or below. When operating on

frequencies above 32 MHz, the buffer current level should be set to 3.

Value Mode Description

1 BOOSTUPTO32MHZ Boost Buffer Current level when HFXO is below or equal to 32 MHz.

3 BOOSTABOVE32MHZ Boost Buffer Current Level when HFXO is above 32 MHz.

4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:2 HFXOBOOST 0x3 RW HFXO Start-up Boost Current

Used to adjust start-up boost current for HFXO.

Value Mode Description

0 50PCENT 50 %.

1 70PCENT 70 %.

2 80PCENT 80 %.

3 100PCENT 100 % (default).

1:0 HFXOMODE 0x0 RW HFXO Mode

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Bit Name Reset Access Description

Set this to configure the external source for the HFXO. The oscillator setting takes effect when 1 is written to HFXOEN in

CMU_OSCENCMD. The oscillator setting is reset to default when 1 is written to HFXODIS in CMU_OSCENCMD.

Value Mode Description

0 XTAL 4-48 MHz crystal oscillator.

1 BUFEXTCLK An AC coupled buffer is coupled in series with HFXTAL_N, suitable for external sine

wave (4-48 MHz). The sine wave should have a minimum of 200 mV peak to peak.

2 DIGEXTCLK Digital external clock on HFXTAL_N pin. Oscillator is effectively bypassed.

11.5.2 CMU_HFCORECLKDIV - High Frequency Core Clock Division

Offset Bit Position

0x004

Reset

0x0

Access

Name

HFCORECLKLEDIV

HFCORECLKDIV

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 HFCORECLKLEDIV 0 RW Additional Division Factor For HFCORECLKLE

Additional division factor for HFCORECLKLE. When running at frequencies higher than 24 MHz, this must be set to DIV4.

Value Mode Description

0 DIV2 Valid for frequencies 24 MHz and lower.

1 DIV4 Must be used when HFCORECLK may go above 24 MHz.

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 HFCORECLKDIV 0x0 RW HFCORECLK Divider

Specifies the clock divider for HFCORECLK.

Value Mode Description

0 HFCLK HFCORECLK = HFCLK.

1 HFCLK2 HFCORECLK = HFCLK/2.

2 HFCLK4 HFCORECLK = HFCLK/4.

3 HFCLK8 HFCORECLK = HFCLK/8.

4 HFCLK16 HFCORECLK = HFCLK/16.

5 HFCLK32 HFCORECLK = HFCLK/32.

6 HFCLK64 HFCORECLK = HFCLK/64.

7 HFCLK128 HFCORECLK = HFCLK/128.

8 HFCLK256 HFCORECLK = HFCLK/256.

9 HFCLK512 HFCORECLK = HFCLK/512.

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11.5.3 CMU_HFPERCLKDIV - High Frequency Peripheral Clock Division

Offset Bit Position

0x008

Reset

0x0

Access

Name

HFPERCLKEN

HFPERCLKDIV

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 HFPERCLKEN 1 RW HFPERCLK Enable

Set to enable the HFPERCLK.

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 HFPERCLKDIV 0x0 RW HFPERCLK Divider

Specifies the clock divider for the HFPERCLK.

Value Mode Description

0 HFCLK HFPERCLK = HFCLK.

1 HFCLK2 HFPERCLK = HFCLK/2.

2 HFCLK4 HFPERCLK = HFCLK/4.

3 HFCLK8 HFPERCLK = HFCLK/8.

4 HFCLK16 HFPERCLK = HFCLK/16.

5 HFCLK32 HFPERCLK = HFCLK/32.

6 HFCLK64 HFPERCLK = HFCLK/64.

7 HFCLK128 HFPERCLK = HFCLK/128.

8 HFCLK256 HFPERCLK = HFCLK/256.

9 HFCLK512 HFPERCLK = HFCLK/512.

11.5.4 CMU_HFRCOCTRL - HFRCO Control Register

Offset Bit Position

0x00C

Reset

0x00

0x3

0x80

Access

Name

SUDELAY

BAND

TUNING

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16:12 SUDELAY 0x00 RW HFRCO Start-up Delay

Always write this field to 0.

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

10:8 BAND 0x3 RW HFRCO Band Select

Write this field to set the frequency band in which the HFRCO is to operate. When changing this setting there will be no glitches on

the HFRCO output, hence it is safe to change this setting even while the system is running on the HFRCO. To ensure an accurate

frequency, the HFTUNING value should also be written when changing the frequency band. The calibrated tuning value for the

different bands can be read from the Device Information page.

Value Mode Description

0 1MHZ 1 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

1 7MHZ 7 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

2 11MHZ 11 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

3 14MHZ 14 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

4 21MHZ 21 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

5 28MHZ 28 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

7:0 TUNING 0x80 RW HFRCO Tuning Value

Writing this field adjusts the HFRCO frequency (the higher value, the higher frequency). This field is updated with the production

calibrated value for the 14 MHz band during reset, and the reset value might therefore vary between devices.

11.5.5 CMU_LFRCOCTRL - LFRCO Control Register

Offset Bit Position

0x010

Reset

0x40

Access

Name

TUNING

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:0 TUNING 0x40 RW LFRCO Tuning Value

Writing this field adjusts the LFRCO frequency (the higher value, the higher frequency). This field is updated with the production

calibrated value during reset, and the reset value might therefore vary between devices.

11.5.6 CMU_AUXHFRCOCTRL - AUXHFRCO Control Register

Offset Bit Position

0x014

Reset

0x0

0x80

Access

Name

BAND

TUNING

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

10:8 BAND 0x0 RW AUXHFRCO Band Select

Write this field to set the frequency band in which the AUXHFRCO is to operate. When changing this setting there will be no glitches

on the AUXHFRCO output, hence it is safe to change this setting even while the system is using the AUXHFRCO. To ensure an

accurate frequency, the AUXTUNING value should also be written when changing the frequency band. The calibrated tuning value

for the different bands can be read from the Device Information page. Flash erase and write use this clock. If it is changed to another

value than the default, MSC_TIMEBASE must also be configured to ensure correct flash erase and write operation.

Value Mode Description

0 14MHZ 14 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

1 11MHZ 11 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

2 7MHZ 7 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

3 1MHZ 1 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

6 28MHZ 28 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

7 21MHZ 21 MHz band. NOTE: Also set the TUNING value (bits 7:0) when changing band.

7:0 TUNING 0x80 RW AUXHFRCO Tuning Value

Writing this field adjusts the AUXHFRCO frequency (the higher value, the higher frequency).This field is updated with the production

calibrated value during reset, and the reset value might therefore vary between devices.

11.5.7 CMU_CALCTRL - Calibration Control Register

Offset Bit Position

0x018

Reset

0x0

Access

Name

CONT

DOWNSEL

UPSEL

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 CONT 0 RW Continuous Calibration

Set this bit to enable continuous calibration.

5:3 DOWNSEL 0x0 RW Calibration Down-counter Select

Selects clock source for the calibration down-counter.

Value Mode Description

0 HFCLK Select HFCLK for down-counter.

1 HFXO Select HFXO for down-counter.

2 LFXO Select LFXO for down-counter.

3 HFRCO Select HFRCO for down-counter.

4 LFRCO Select LFRCO for down-counter.

5 AUXHFRCO Select AUXHFRCO for down-counter.

2:0 UPSEL 0x0 RW Calibration Up-counter Select

Selects clock source for the calibration up-counter.

Value Mode Description

0 HFXO Select HFXO as up-counter.

1 LFXO Select LFXO as up-counter.

2 HFRCO Select HFRCO as up-counter.

3 LFRCO Select LFRCO as up-counter.

4 AUXHFRCO Select AUXHFRCO as up-counter.

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11.5.8 CMU_CALCNT - Calibration Counter Register

Offset Bit Position

0x01C

Reset

0x00000

Access

RWH

Name

CALCNT

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:0 CALCNT 0x00000 RWH Calibration Counter

Write top value before calibration. Read calibration result from this register when Calibration Ready flag has been set.

11.5.9 CMU_OSCENCMD - Oscillator Enable/Disable Command Register

Offset Bit Position

0x020

Reset

Access

Name

LFXODIS

LFXOEN

LFRCODIS

LFRCOEN

AUXHFRCODIS

AUXHFRCOEN

HFXODIS

HFXOEN

HFRCODIS

HFRCOEN

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 LFXODIS 0 W1 LFXO Disable

Disables the LFXO. LFXOEN has higher priority if written simultaneously.

8 LFXOEN 0 W1 LFXO Enable

Enables the LFXO.

7 LFRCODIS 0 W1 LFRCO Disable

Disables the LFRCO. LFRCOEN has higher priority if written simultaneously.

6 LFRCOEN 0 W1 LFRCO Enable

Enables the LFRCO.

5 AUXHFRCODIS 0 W1 AUXHFRCO Disable

Disables the AUXHFRCO. AUXHFRCOEN has higher priority if written simultaneously. WARNING: Do not disable this clock during

a flash erase/write operation.

4 AUXHFRCOEN 0 W1 AUXHFRCO Enable

Enables the AUXHFRCO.

3 HFXODIS 0 W1 HFXO Disable

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Bit Name Reset Access Description

Disables the HFXO. HFXOEN has higher priority if written simultaneously. WARNING: Do not disable the HFRXO if this oscillator

is selected as the source for HFCLK.

2 HFXOEN 0 W1 HFXO Enable

Enables the HFXO.

1 HFRCODIS 0 W1 HFRCO Disable

Disables the HFRCO. HFRCOEN has higher priority if written simultaneously. WARNING: Do not disable the HFRCO if this oscillator

is selected as the source for HFCLK.

0 HFRCOEN 0 W1 HFRCO Enable

Enables the HFRCO.

11.5.10 CMU_CMD - Command Register

Offset Bit Position

0x024

Reset

0x0

Access

Name

USBCCLKSEL

CALSTOP

CALSTART

HFCLKSEL

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:5 USBCCLKSEL 0x0 W1 USB Core Clock Select

Selects the clock for HFCORECLKUSBC. The status register is updated when the clock switch has taken effect.

Value Mode Description

1 HFCLKNODIV Select HFCLK (undivided) as HFCORECLKUSBC.

2 LFXO Select LFXO as HFCORECLKUSBC.

3 LFRCO Select LFRCO as HFCORECLKUSBC.

4 CALSTOP 0 W1 Calibration Stop

Stops the calibration counters.

3 CALSTART 0 W1 Calibration Start

Starts the calibration, effectively loading the CMU_CALCNT into the down-counter and start decrementing.

2:0 HFCLKSEL 0x0 W1 HFCLK Select

Selects the clock source for HFCLK. Note that selecting an oscillator that is disabled will cause the system clock to stop. Check the

status register and confirm that oscillator is ready before switching.

Value Mode Description

1 HFRCO Select HFRCO as HFCLK.

2 HFXO Select HFXO as HFCLK.

3 LFRCO Select LFRCO as HFCLK.

4 LFXO Select LFXO as HFCLK.

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11.5.11 CMU_LFCLKSEL - Low Frequency Clock Select Register

Offset Bit Position

0x028

Reset

0x1

Access

Name

LFBE

LFAE

LFB

LFA

Bit Name Reset Access Description

31:21 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

20 LFBE 0 RW Clock Select for LFB Extended

This bit redefines the meaning of the LFB field.

Value Mode Description

0 DISABLED LFBCLK is disabled (when LFB = DISABLED).

1 ULFRCO ULFRCO selected as LFBCLK (when LFB = DISABLED).

19:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 LFAE 0 RW Clock Select for LFA Extended

This bit redefines the meaning of the LFA field.

Value Mode Description

0 DISABLED LFACLK is disabled (when LFA = DISABLED).

1 ULFRCO ULFRCO selected as LFACLK (when LFA = DISABLED).

15:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:2 LFB 0x1 RW Clock Select for LFB

Selects the clock source for LFBCLK.

LFB LFBE Mode Description

0 0 Disabled LFBCLK is disabled

1 0 LFRCO LFRCO selected as LFBCLK

2 0 LFXO LFXO selected as LFBCLK

3 0 HFCORECLKLEDIV2 HFCORECLKLE divided by two is selected as

LFBCLK

0 1 ULFRCO ULFRCO selected as LFBCLK

1:0 LFA 0x1 RW Clock Select for LFA

Selects the clock source for LFACLK.

LFA LFAE Mode Description

0 0 Disabled LFACLK is disabled

1 0 LFRCO LFRCO selected as LFACLK

2 0 LFXO LFXO selected as LFACLK

3 0 HFCORECLKLEDIV2 HFCORECLKLE divided by two is selected as

LFACLK

0 1 ULFRCO ULFRCO selected as LFACLK

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11.5.12 CMU_STATUS - Status Register

Offset Bit Position

0x02C

Reset

Access

Name

USBCLFRCOSEL

USBCLFXOSEL

USBCHFCLKSEL

CALBSY

LFXOSEL

LFRCOSEL

HFXOSEL

HFRCOSEL

LFXORDY

LFXOENS

LFRCORDY

LFRCOENS

AUXHFRCORDY

AUXHFRCOENS

HFXORDY

HFXOENS

HFRCORDY

HFRCOENS

Bit Name Reset Access Description

31:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 USBCLFRCOSEL 0 R USBC LFRCO Selected

LFRCO is selected (and active) as HFCORECLKUSBC.

16 USBCLFXOSEL 0 R USBC LFXO Selected

LFXO is selected (and active) as HFCORECLKUSBC.

15 USBCHFCLKSEL 0 R USBC HFCLK Selected

HFCLK is selected (and active) as HFCORECLKUSBC.

14 CALBSY 0 R Calibration Busy

Calibration is on-going.

13 LFXOSEL 0 R LFXO Selected

LFXO is selected as HFCLK clock source.

12 LFRCOSEL 0 R LFRCO Selected

LFRCO is selected as HFCLK clock source.

11 HFXOSEL 0 R HFXO Selected

HFXO is selected as HFCLK clock source.

10 HFRCOSEL 1 R HFRCO Selected

HFRCO is selected as HFCLK clock source.

9 LFXORDY 0 R LFXO Ready

LFXO is enabled and start-up time has exceeded.

8 LFXOENS 0 R LFXO Enable Status

LFXO is enabled.

7 LFRCORDY 0 R LFRCO Ready

LFRCO is enabled and start-up time has exceeded.

6 LFRCOENS 0 R LFRCO Enable Status

LFRCO is enabled.

5 AUXHFRCORDY 0 R AUXHFRCO Ready

AUXHFRCO is enabled and start-up time has exceeded.

4 AUXHFRCOENS 0 R AUXHFRCO Enable Status

AUXHFRCO is enabled.

3 HFXORDY 0 R HFXO Ready

HFXO is enabled and start-up time has exceeded.

2 HFXOENS 0 R HFXO Enable Status

HFXO is enabled.

1 HFRCORDY 1 R HFRCO Ready

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Bit Name Reset Access Description

HFRCO is enabled and start-up time has exceeded.

0 HFRCOENS 1 R HFRCO Enable Status

HFRCO is enabled.

11.5.13 CMU_IF - Interrupt Flag Register

Offset Bit Position

0x030

Reset

Access

Name

USBCHFCLKSEL

CALOF

CALRDY

AUXHFRCORDY

LFXORDY

LFRCORDY

HFXORDY

HFRCORDY

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 USBCHFCLKSEL 0 R USBC HFCLK Selected Interrupt Flag

Set when HFCLK is selected as HFCORECLKUSBC.

6 CALOF 0 R Calibration Overflow Interrupt Flag

Set when calibration overflow has occurred

5 CALRDY 0 R Calibration Ready Interrupt Flag

Set when calibration is completed.

4 AUXHFRCORDY 0 R AUXHFRCO Ready Interrupt Flag

Set when AUXHFRCO is ready (start-up time exceeded).

3 LFXORDY 0 R LFXO Ready Interrupt Flag

Set when LFXO is ready (start-up time exceeded).

2 LFRCORDY 0 R LFRCO Ready Interrupt Flag

Set when LFRCO is ready (start-up time exceeded).

1 HFXORDY 0 R HFXO Ready Interrupt Flag

Set when HFXO is ready (start-up time exceeded).

0 HFRCORDY 1 R HFRCO Ready Interrupt Flag

Set when HFRCO is ready (start-up time exceeded).

11.5.14 CMU_IFS - Interrupt Flag Set Register

Offset Bit Position

0x034

Reset

Access

Name

USBCHFCLKSEL

CALOF

CALRDY

AUXHFRCORDY

LFXORDY

LFRCORDY

HFXORDY

HFRCORDY

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Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 USBCHFCLKSEL 0 W1 USBC HFCLK Selected Interrupt Flag Set

Write to 1 to set the USBC HFCLK Selected Interrupt Flag.

6 CALOF 0 W1 Calibration Overflow Interrupt Flag Set

Write to 1 to set the Calibration Overflow Interrupt Flag.

5 CALRDY 0 W1 Calibration Ready Interrupt Flag Set

Write to 1 to set the Calibration Ready(completed) Interrupt Flag.

4 AUXHFRCORDY 0 W1 AUXHFRCO Ready Interrupt Flag Set

Write to 1 to set the AUXHFRCO Ready Interrupt Flag.

3 LFXORDY 0 W1 LFXO Ready Interrupt Flag Set

Write to 1 to set the LFXO Ready Interrupt Flag.

2 LFRCORDY 0 W1 LFRCO Ready Interrupt Flag Set

Write to 1 to set the LFRCO Ready Interrupt Flag.

1 HFXORDY 0 W1 HFXO Ready Interrupt Flag Set

Write to 1 to set the HFXO Ready Interrupt Flag.

0 HFRCORDY 0 W1 HFRCO Ready Interrupt Flag Set

Write to 1 to set the HFRCO Ready Interrupt Flag.

11.5.15 CMU_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x038

Reset

Access

Name

USBCHFCLKSEL

CALOF

CALRDY

AUXHFRCORDY

LFXORDY

LFRCORDY

HFXORDY

HFRCORDY

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 USBCHFCLKSEL 0 W1 USBC HFCLK Selected Interrupt Flag Clear

Write to 1 to clear the USBC HFCLK Selected Interrupt Flag.

6 CALOF 0 W1 Calibration Overflow Interrupt Flag Clear

Write to 1 to clear the Calibration Overflow Interrupt Flag.

5 CALRDY 0 W1 Calibration Ready Interrupt Flag Clear

Write to 1 to clear the Calibration Ready Interrupt Flag.

4 AUXHFRCORDY 0 W1 AUXHFRCO Ready Interrupt Flag Clear

Write to 1 to clear the AUXHFRCO Ready Interrupt Flag.

3 LFXORDY 0 W1 LFXO Ready Interrupt Flag Clear

Write to 1 to clear the LFXO Ready Interrupt Flag.

2 LFRCORDY 0 W1 LFRCO Ready Interrupt Flag Clear

Write to 1 to clear the LFRCO Ready Interrupt Flag.

1 HFXORDY 0 W1 HFXO Ready Interrupt Flag Clear

Write to 1 to clear the HFXO Ready Interrupt Flag.

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Bit Name Reset Access Description

0 HFRCORDY 0 W1 HFRCO Ready Interrupt Flag Clear

Write to 1 to clear the HFRCO Ready Interrupt Flag.

11.5.16 CMU_IEN - Interrupt Enable Register

Offset Bit Position

0x03C

Reset

Access

Name

USBCHFCLKSEL

CALOF

CALRDY

AUXHFRCORDY

LFXORDY

LFRCORDY

HFXORDY

HFRCORDY

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 USBCHFCLKSEL 0 RW USBC HFCLK Selected Interrupt Enable

Set to enable the USBC HFCLK Selected Interrupt.

6 CALOF 0 RW Calibration Overflow Interrupt Enable

Set to enable the Calibration Overflow Interrupt.

5 CALRDY 0 RW Calibration Ready Interrupt Enable

Set to enable the Calibration Ready Interrupt.

4 AUXHFRCORDY 0 RW AUXHFRCO Ready Interrupt Enable

Set to enable the AUXHFRCO Ready Interrupt.

3 LFXORDY 0 RW LFXO Ready Interrupt Enable

Set to enable the LFXO Ready Interrupt.

2 LFRCORDY 0 RW LFRCO Ready Interrupt Enable

Set to enable the LFRCO Ready Interrupt.

1 HFXORDY 0 RW HFXO Ready Interrupt Enable

Set to enable the HFXO Ready Interrupt.

0 HFRCORDY 0 RW HFRCO Ready Interrupt Enable

Set to enable the HFRCO Ready Interrupt.

11.5.17 CMU_HFCORECLKEN0 - High Frequency Core Clock Enable

Offset Bit Position

0x040

Reset

Access

Name

EBI

USB

USBC

AES

DMA

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Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 EBI 0 RW External Bus Interface Clock Enable

Set to enable the clock for EBI.

4 LE 0 RW Low Energy Peripheral Interface Clock Enable

Set to enable the clock for LE. Interface used for bus access to Low Energy peripherals.

3 USB 0 RW Universal Serial Bus Interface Clock Enable

Set to enable the clock for USB.

2 USBC 0 RW Universal Serial Bus Interface Core Clock Enable

Set to enable the clock for USBC.

1 AES 0 RW Advanced Encryption Standard Accelerator Clock Enable

Set to enable the clock for AES.

0 DMA 0 RW Direct Memory Access Controller Clock Enable

Set to enable the clock for DMA.

11.5.18 CMU_HFPERCLKEN0 - High Frequency Peripheral Clock Enable

Offset Bit Position

0x044

Reset

Access

Name

DAC0

ADC0

PRS

VCMP

GPIO

I2C1

I2C0

ACMP1

ACMP0

TIMER3

TIMER2

TIMER1

TIMER0

UART1

UART0

USART2

USART1

USART0

Bit Name Reset Access Description

31:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 DAC0 0 RW Digital to Analog Converter 0 Clock Enable

Set to enable the clock for DAC0.

16 ADC0 0 RW Analog to Digital Converter 0 Clock Enable

Set to enable the clock for ADC0.

15 PRS 0 RW Peripheral Reflex System Clock Enable

Set to enable the clock for PRS.

14 VCMP 0 RW Voltage Comparator Clock Enable

Set to enable the clock for VCMP.

13 GPIO 0 RW General purpose Input/Output Clock Enable

Set to enable the clock for GPIO.

12 I2C1 0 RW I2C 1 Clock Enable

Set to enable the clock for I2C1.

11 I2C0 0 RW I2C 0 Clock Enable

Set to enable the clock for I2C0.

10 ACMP1 0 RW Analog Comparator 1 Clock Enable

Set to enable the clock for ACMP1.

9 ACMP0 0 RW Analog Comparator 0 Clock Enable

Set to enable the clock for ACMP0.

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Bit Name Reset Access Description

8 TIMER3 0 RW Timer 3 Clock Enable

Set to enable the clock for TIMER3.

7 TIMER2 0 RW Timer 2 Clock Enable

Set to enable the clock for TIMER2.

6 TIMER1 0 RW Timer 1 Clock Enable

Set to enable the clock for TIMER1.

5 TIMER0 0 RW Timer 0 Clock Enable

Set to enable the clock for TIMER0.

4 UART1 0 RW Universal Asynchronous Receiver/Transmitter 1 Clock Enable

Set to enable the clock for UART1.

3 UART0 0 RW Universal Asynchronous Receiver/Transmitter 0 Clock Enable

Set to enable the clock for UART0.

2 USART2 0 RW Universal Synchronous/Asynchronous Receiver/Transmitter 2

Clock Enable

Set to enable the clock for USART2.

1 USART1 0 RW Universal Synchronous/Asynchronous Receiver/Transmitter 1

Clock Enable

Set to enable the clock for USART1.

0 USART0 0 RW Universal Synchronous/Asynchronous Receiver/Transmitter 0

Clock Enable

Set to enable the clock for USART0.

11.5.19 CMU_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x050

Reset

Access

Name

LFBPRESC0

LFBCLKEN0

LFAPRESC0

LFACLKEN0

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 LFBPRESC0 0 R Low Frequency B Prescaler 0 Busy

Used to check the synchronization status of CMU_LFBPRESC0.

Value Description

1 CMU_LFBPRESC0 is busy synchronizing new value.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 LFBCLKEN0 0 R Low Frequency B Clock Enable 0 Busy

Used to check the synchronization status of CMU_LFBCLKEN0.

Value Description

0 CMU_LFBCLKEN0 is ready for update.

1 CMU_LFBCLKEN0 is busy synchronizing new value.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 LFAPRESC0 0 R Low Frequency A Prescaler 0 Busy

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Bit Name Reset Access Description

Used to check the synchronization status of CMU_LFAPRESC0.

Value Description

0 CMU_LFAPRESC0 is ready for update.

1 CMU_LFAPRESC0 is busy synchronizing new value.

1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 LFACLKEN0 0 R Low Frequency A Clock Enable 0 Busy

Used to check the synchronization status of CMU_LFACLKEN0.

Value Description

0 CMU_LFACLKEN0 is ready for update.

1 CMU_LFACLKEN0 is busy synchronizing new value.

11.5.20 CMU_FREEZE - Freeze Register

Offset Bit Position

0x054

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

When set, the update of the Low Frequency clock control registers is postponed until this bit is cleared. Use this bit to update several

registers simultaneously.

Value Mode Description

0 UPDATE Each write access to a Low Frequency clock control register is updated into the Low

Frequency domain as soon as possible.

1 FREEZE The LE Clock Control registers are not updated with the new written value.

11.5.21 CMU_LFACLKEN0 - Low Frequency A Clock Enable Register 0

(Async Reg)

Offset Bit Position

0x058

Reset

Access

Name

LCD

LETIMER0

RTC

LESENSE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

3 LCD 0 RW Liquid Crystal Display Controller Clock Enable

Set to enable the clock for LCD.

2 LETIMER0 0 RW Low Energy Timer 0 Clock Enable

Set to enable the clock for LETIMER0.

1 RTC 0 RW Real-Time Counter Clock Enable

Set to enable the clock for RTC.

0 LESENSE 0 RW Low Energy Sensor Interface Clock Enable

Set to enable the clock for LESENSE.

11.5.22 CMU_LFBCLKEN0 - Low Frequency B Clock Enable Register 0

(Async Reg)

Offset Bit Position

0x060

Reset

Access

Name

LEUART1

LEUART0

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 LEUART1 0 RW Low Energy UART 1 Clock Enable

Set to enable the clock for LEUART1.

0 LEUART0 0 RW Low Energy UART 0 Clock Enable

Set to enable the clock for LEUART0.

11.5.23 CMU_LFAPRESC0 - Low Frequency A Prescaler Register 0 (Async

Reg)

Offset Bit Position

0x068

Reset

0x0

Access

Name

LCD

LETIMER0

RTC

LESENSE

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:12 LCD 0x0 RW Liquid Crystal Display Controller Prescaler

Configure Liquid Crystal Display Controller prescaler

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Bit Name Reset Access Description

Value Mode Description

0 DIV16 LFACLKLCD = LFACLK/16

1 DIV32 LFACLKLCD = LFACLK/32

2 DIV64 LFACLKLCD = LFACLK/64

3 DIV128 LFACLKLCD = LFACLK/128

11:8 LETIMER0 0x0 RW Low Energy Timer 0 Prescaler

Configure Low Energy Timer 0 prescaler

Value Mode Description

0 DIV1 LFACLKLETIMER0 = LFACLK

1 DIV2 LFACLKLETIMER0 = LFACLK/2

2 DIV4 LFACLKLETIMER0 = LFACLK/4

3 DIV8 LFACLKLETIMER0 = LFACLK/8

4 DIV16 LFACLKLETIMER0 = LFACLK/16

5 DIV32 LFACLKLETIMER0 = LFACLK/32

6 DIV64 LFACLKLETIMER0 = LFACLK/64

7 DIV128 LFACLKLETIMER0 = LFACLK/128

8 DIV256 LFACLKLETIMER0 = LFACLK/256

9 DIV512 LFACLKLETIMER0 = LFACLK/512

10 DIV1024 LFACLKLETIMER0 = LFACLK/1024

11 DIV2048 LFACLKLETIMER0 = LFACLK/2048

12 DIV4096 LFACLKLETIMER0 = LFACLK/4096

13 DIV8192 LFACLKLETIMER0 = LFACLK/8192

14 DIV16384 LFACLKLETIMER0 = LFACLK/16384

15 DIV32768 LFACLKLETIMER0 = LFACLK/32768

7:4 RTC 0x0 RW Real-Time Counter Prescaler

Configure Real-Time Counter prescaler

Value Mode Description

0 DIV1 LFACLKRTC = LFACLK

1 DIV2 LFACLKRTC = LFACLK/2

2 DIV4 LFACLKRTC = LFACLK/4

3 DIV8 LFACLKRTC = LFACLK/8

4 DIV16 LFACLKRTC = LFACLK/16

5 DIV32 LFACLKRTC = LFACLK/32

6 DIV64 LFACLKRTC = LFACLK/64

7 DIV128 LFACLKRTC = LFACLK/128

8 DIV256 LFACLKRTC = LFACLK/256

9 DIV512 LFACLKRTC = LFACLK/512

10 DIV1024 LFACLKRTC = LFACLK/1024

11 DIV2048 LFACLKRTC = LFACLK/2048

12 DIV4096 LFACLKRTC = LFACLK/4096

13 DIV8192 LFACLKRTC = LFACLK/8192

14 DIV16384 LFACLKRTC = LFACLK/16384

15 DIV32768 LFACLKRTC = LFACLK/32768

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 LESENSE 0x0 RW Low Energy Sensor Interface Prescaler

Configure Low Energy Sensor Interface prescaler

Value Mode Description

0 DIV1 LFACLKLESENSE = LFACLK

1 DIV2 LFACLKLESENSE = LFACLK/2

2 DIV4 LFACLKLESENSE = LFACLK/4

3 DIV8 LFACLKLESENSE = LFACLK/8

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11.5.24 CMU_LFBPRESC0 - Low Frequency B Prescaler Register 0 (Async

Reg)

Offset Bit Position

0x070

Reset

0x0

Access

Name

LEUART1

LEUART0

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 LEUART1 0x0 RW Low Energy UART 1 Prescaler

Configure Low Energy UART 1 prescaler

Value Mode Description

0 DIV1 LFBCLKLEUART1 = LFBCLK

1 DIV2 LFBCLKLEUART1 = LFBCLK/2

2 DIV4 LFBCLKLEUART1 = LFBCLK/4

3 DIV8 LFBCLKLEUART1 = LFBCLK/8

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 LEUART0 0x0 RW Low Energy UART 0 Prescaler

Configure Low Energy UART 0 prescaler

Value Mode Description

0 DIV1 LFBCLKLEUART0 = LFBCLK

1 DIV2 LFBCLKLEUART0 = LFBCLK/2

2 DIV4 LFBCLKLEUART0 = LFBCLK/4

3 DIV8 LFBCLKLEUART0 = LFBCLK/8

11.5.25 CMU_PCNTCTRL - PCNT Control Register

Offset Bit Position

0x078

Reset

Access

Name

PCNT2CLKSEL

PCNT2CLKEN

PCNT1CLKSEL

PCNT1CLKEN

PCNT0CLKSEL

PCNT0CLKEN

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 PCNT2CLKSEL 0 RW PCNT2 Clock Select

This bit controls which clock that is used for the PCNT.

Value Mode Description

0 LFACLK LFACLK is clocking PCNT2.

1 PCNT2S0 External pin PCNT2_S0 is clocking PCNT0.

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Bit Name Reset Access Description

4 PCNT2CLKEN 0 RW PCNT2 Clock Enable

This bit enables/disables the clock to the PCNT.

Value Description

0 PCNT2 is disabled.

1 PCNT2 is enabled.

3 PCNT1CLKSEL 0 RW PCNT1 Clock Select

This bit controls which clock that is used for the PCNT.

Value Mode Description

0 LFACLK LFACLK is clocking PCNT0.

1 PCNT1S0 External pin PCNT1_S0 is clocking PCNT0.

2 PCNT1CLKEN 0 RW PCNT1 Clock Enable

This bit enables/disables the clock to the PCNT.

Value Description

0 PCNT1 is disabled.

1 PCNT1 is enabled.

1 PCNT0CLKSEL 0 RW PCNT0 Clock Select

This bit controls which clock that is used for the PCNT.

Value Mode Description

0 LFACLK LFACLK is clocking PCNT0.

1 PCNT0S0 External pin PCNT0_S0 is clocking PCNT0.

0 PCNT0CLKEN 0 RW PCNT0 Clock Enable

This bit enables/disables the clock to the PCNT.

Value Description

0 PCNT0 is disabled.

1 PCNT0 is enabled.

11.5.26 CMU_LCDCTRL - LCD Control Register

Offset Bit Position

0x07C

Reset

0x2

0x0

Access

Name

VBFDIV

VBOOSTEN

FDIV

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:4 VBFDIV 0x2 RW Voltage Boost Frequency Division

These bits control the voltage boost update frequency division.

Value Mode Description

0 DIV1 Voltage Boost update Frequency = LFACLK.

1 DIV2 Voltage Boost update Frequency = LFACLK/2.

2 DIV4 Voltage Boost update Frequency = LFACLK/4.

3 DIV8 Voltage Boost update Frequency = LFACLK/8.

4 DIV16 Voltage Boost update Frequency = LFACLK/16.

5 DIV32 Voltage Boost update Frequency = LFACLK/32.

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Bit Name Reset Access Description

Value Mode Description

6 DIV64 Voltage Boost update Frequency = LFACLK/64.

7 DIV128 Voltage Boost update Frequency = LFACLK/128.

3 VBOOSTEN 0 RW Voltage Boost Enable

This bit enables/disables the VBOOST function.

2:0 FDIV 0x0 RW Frame Rate Control

These bits controls the framerate according to this formula: LFACLKLCD = LFACLKLCDpre / (1 + FDIV). Do not change this value while

the LCD bit in CMU_LFACLKEN0 is set to 1.

11.5.27 CMU_ROUTE - I/O Routing Register

Offset Bit Position

0x080

Reset

0x0

Access

Name

LOCATION

CLKOUT1PEN

CLKOUT0PEN

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4:2 LOCATION 0x0 RW I/O Location

Decides the location of the CMU I/O pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

1 CLKOUT1PEN 0 RW CLKOUT1 Pin Enable

When set, the CLKOUT1 pin is enabled.

0 CLKOUT0PEN 0 RW CLKOUT0 Pin Enable

When set, the CLKOUT0 pin is enabled.

11.5.28 CMU_LOCK - Configuration Lock Register

Offset Bit Position

0x084

Reset

0x0000

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

15:0 LOCKKEY 0x0000 RW Configuration Lock Key

Write any other value than the unlock code to lock CMU_CTRL, CMU_HFCORECLKDIV,

CMU_HFPERCLKDIV, CMU_HFRCOCTRL, CMU_LFRCOCTRL, CMU_AUXHFRCOCTRL, CMU_OSCENCMD, CMU_CMD,

CMU_LFCLKSEL, CMU_HFCORECLKEN0, CMU_HFPERCLKEN0, CMU_LFACLKEN0, CMU_LFBCLKEN0, CMU_LFAPRESC0,

CMU_LFBPRESC0, and CMU_PCNTCTRL from editing. Write the unlock code to unlock. When reading the register, bit 0 is set

when the lock is enabled.

Mode Value Description

Read Operation

UNLOCKED 0 CMU registers are unlocked.

LOCKED 1 CMU registers are locked.

Write Operation

LOCK 0 Lock CMU registers.

UNLOCK 0x580E Unlock CMU registers.

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12 WDOG - Watchdog Timer

01 2 3 4

Timeout period

Counter value

Time

Watchdog clear System reset

Quick Facts

What?

The WDOG (Watchdog Timer) resets the

system in case of a fault condition, and can

be enabled in all energy modes as long as

the low frequency clock source is available.

Why?

If a software failure or external event renders

the MCU unresponsive, a Watchdog timeout

will reset the system to a known, safe state.

How?

An enabled Watchdog Timer implements a

configurable timeout period. If the CPU fails

to re-start the Watchdog Timer before it times

out, a full system reset will be triggered. The

Watchdog consumes insignificant power,

and allows the device to remain safely in low

energy modes for up to 256 seconds at a

time.

12.1 Introduction

The purpose of the watchdog timer is to generate a reset in case of a system failure, to increase

application reliability. The failure may e.g. be caused by an external event, such as an ESD pulse, or

by a software failure.

12.2 Features

• Clock input from selectable oscillators

• Internal 32.768 Hz RC oscillator

• Internal 1 kHz RC oscillator

• External 32.768 Hz XTAL oscillator

• Configurable timeout period from 9 to 256k watchdog clock cycles

• Individual selection to keep running or freeze when entering EM2 or EM3

• Selection to keep running or freeze when entering debug mode

• Selection to block the CPU from entering Energy Mode 4

• Selection to block the CMU from disabling the selected watchdog clock

12.3 Functional Description

The watchdog is enabled by setting the EN bit in WDOG_CTRL. When enabled, the watchdog counts

up to the period value configured through the PERSEL field in WDOG_CTRL. If the watchdog timer is

not cleared to 0 (by writing a 1 to the CLEAR bit in WDOG_CMD) before the period is reached, the chip

is reset. If a timely clear command is issued, the timer starts counting up from 0 again. The watchdog

can optionally be locked by writing the LOCK bit in WDOG_CTRL. Once locked, it cannot be disabled

or reconfigured by software.

The watchdog counter is reset when EN is reset.

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12.3.1 Clock Source

Three clock sources are available for use with the watchdog, through the CLKSEL field in WDOG_CTRL.

The corresponding clocks must be enabled in the CMU. The SWOSCBLOCK bit in WDOG_CTRL can be

written to prevent accidental disabling of the selected clocks. Also, setting this bit will automatically start

the selected oscillator source when the watchdog is enabled. The PERSEL field in WDOG_CTRL is used

to divide the selected watchdog clock, and the timeout for the watchdog timer can be calculated like this:

WDOG Timeout Equation

TTIMEOUT = (23+PERSEL + 1)/f, (12.1)

where f is the frequency of the selected clock.

It is recommended to clear the watchdog first, if PERSEL is changed while the watchdog is enabled.

To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0, in addition to

the module clock.

Note Before changing the clock source for WDOG, the EN bit in WDOG_CTRL should be

cleared. In addition to this, the WDOG_SYNCBUSY value should be zero.

12.3.2 Debug Functionality

The watchdog timer can either keep running or be frozen when the device is halted by a debugger. This

configuration is done through the DEBUGRUN bit in WDOG_CTRL. When code execution is resumed,

the watchdog will continue counting where it left off.

12.3.3 Energy Mode Handling

The watchdog timer can be configured to either keep on running or freeze when entering EM2 or EM3.

The configuration is done individually for each energy mode in the EM2RUN and EM3RUN bits in

WDOG_CTRL. When the watchdog has been frozen and is re-entering an energy mode where it is

running, the watchdog timer will continue counting where it left off. For the watchdog there is no difference

between EM0 and EM1. The watchdog does not run in EM4, and if EM4BLOCK in WDOG_CTRL is set,

the CPU is prevented from entering EM4.

Note If the WDOG is clocked by the LFXO or LFRCO, writing the SWOSCBLOCK bit will

effectively prevent the CPU from entering EM3. When running from the ULFRCO, writing

the SWOSCBLOCK bit will prevent the CPU from entering EM4.

12.3.4 Register access

Since this module is a Low Energy Peripheral, and runs off a clock which is asynchronous to

the HFCORECLK, special considerations must be taken when accessing registers. Please refer to

Section 5.3 (p. 20) for a description on how to perform register accesses to Low Energy Peripherals.

note that clearing the EN bit in WDOG_CTRL will reset the WDOG module, which will halt any ongoing

Note Never write to the WDOG registers when it is disabled, except to enable it by setting

WDOG_CTRL_EN or when changing the clock source using WDOG_CTRL_CLKSEL.

Make sure that the enable is registered (i.e. WDOG_SYNCBUSY_CTRL goes low), before

writing other registers.

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12.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 WDOG_CTRL RW Control Register

0x004 WDOG_CMD W1 Command Register

0x008 WDOG_SYNCBUSY R Synchronization Busy Register

12.5 Register Description

12.5.1 WDOG_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x000

Reset

0x0

0xF

Access

Name

CLKSEL

PERSEL

SWOSCBLOCK

EM4BLOCK

LOCK

EM3RUN

EM2RUN

DEBUGRUN

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:12 CLKSEL 0x0 RW Watchdog Clock Select

Selects the WDOG oscillator, i.e. the clock on which the watchdog will run.

Value Mode Description

0 ULFRCO ULFRCO

1 LFRCO LFRCO

2 LFXO LFXO

11:8 PERSEL 0xF RW Watchdog Timeout Period Select

Select watchdog timeout period.

Value Description

0 Timeout period of 9 watchdog clock cycles.

1 Timeout period of 17 watchdog clock cycles.

2 Timeout period of 33 watchdog clock cycles.

3 Timeout period of 65 watchdog clock cycles.

4 Timeout period of 129 watchdog clock cycles.

5 Timeout period of 257 watchdog clock cycles.

6 Timeout period of 513 watchdog clock cycles.

7 Timeout period of 1k watchdog clock cycles.

8 Timeout period of 2k watchdog clock cycles.

9 Timeout period of 4k watchdog clock cycles.

10 Timeout period of 8k watchdog clock cycles.

11 Timeout period of 16k watchdog clock cycles.

12 Timeout period of 32k watchdog clock cycles.

13 Timeout period of 64k watchdog clock cycles.

14 Timeout period of 128k watchdog clock cycles.

15 Timeout period of 256k watchdog clock cycles.

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Bit Name Reset Access Description

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 SWOSCBLOCK 0 RW Software Oscillator Disable Block

Set to disallow disabling of the selected WDOG oscillator. Writing this bit to 1 will turn on the selected WDOG oscillator if it is not

already running.

Value Description

0 Software is allowed to disable the selected WDOG oscillator. See CMU for detailed description. Note that also CMU

registers are lockable.

1 Software is not allowed to disable the selected WDOG oscillator.

5 EM4BLOCK 0 RW Energy Mode 4 Block

Set to prevent the EMU from entering EM4.

Value Description

0 EM4 can be entered. See EMU for detailed description.

1 EM4 cannot be entered.

4 LOCK 0 RW Configuration lock

Set to lock the watchdog configuration. This bit can only be cleared by reset.

Value Description

0 Watchdog configuration can be changed.

1 Watchdog configuration cannot be changed.

3 EM3RUN 0 RW Energy Mode 3 Run Enable

Set to keep watchdog running in EM3.

Value Description

0 Watchdog timer is frozen in EM3.

1 Watchdog timer is running in EM3.

2 EM2RUN 0 RW Energy Mode 2 Run Enable

Set to keep watchdog running in EM2.

Value Description

0 Watchdog timer is frozen in EM2.

1 Watchdog timer is running in EM2.

1 DEBUGRUN 0 RW Debug Mode Run Enable

Set to keep watchdog running in debug mode.

Value Description

0 Watchdog timer is frozen in debug mode.

1 Watchdog timer is running in debug mode.

0 EN 0 RW Watchdog Timer Enable

Set to enabled watchdog timer.

12.5.2 WDOG_CMD - Command Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x004

Reset

Access

Name

CLEAR

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Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 CLEAR 0 W1 Watchdog Timer Clear

Clear watchdog timer. The bit must be written 4 watchdog cycles before the timeout.

Value Mode Description

0 UNCHANGED Watchdog timer is unchanged.

1 CLEARED Watchdog timer is cleared to 0.

12.5.3 WDOG_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x008

Reset

Access

Name

CMD

CTRL

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 CMD 0 R CMD Register Busy

Set when the value written to CMD is being synchronized.

0 CTRL 0 R CTRL Register Busy

Set when the value written to CTRL is being synchronized.

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13 PRS - Peripheral Reflex System

01 2 3 4

Timer

ADC

DMA

PRS

Quick Facts

What?

The PRS (Peripheral Reflex System)

allows configurable, fast and autonomous

communication between the peripherals.

Why?

Events and signals from one peripheral

can be used as input signals or triggers by

other peripherals and ensure timing-critical

operation and reduced software overhead.

How?

Without CPU intervention the peripherals can

send reflex signals (both pulses and level) to

each other in single- or chained steps. The

peripherals can be set up to perform actions

based on the incoming reflex signals. This

results in improved system performance and

reduced energy consumption.

13.1 Introduction

The Peripheral Reflex System (PRS) system is a network which allows the different peripheral modules

to communicate directly with each other without involving the CPU. Peripheral modules which send out

reflex signals are called producers. The PRS routes these reflex signals to consumer peripherals which

apply actions depending on the reflex signals received. The format for the reflex signals is not given, but

edge triggers and other functionality can be applied by the PRS.

13.2 Features

• 12 configurable interconnect channels

• Each channel can be connected to any producing peripheral

• Consumers can choose which channel to listen to

• Selectable edge detector (rising, falling and both edges)

• Software controlled channel output

• Configurable level

• Triggered pulses

13.3 Functional Description

An overview of the PRS module is shown in Figure 13.1 (p. 163) . The PRS contains 12 interconnect

channels, and each of these can select between all the output reflex signals offered by the producers.

The consumers can then choose which PRS channel to listen to and perform actions based on the

reflex signals routed through that channel. The reflex signals can be both pulse signals and level signals.

Synchronous PRS pulses are one HFPERCLK cycle long, and can either be sent out by a producer (e.g.,

ADC conversion complete) or be generated from the edge detector in the PRS channel. Level signals

can have an arbitrary waveform (e.g., Timer PWM output).

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13.3.1 Asynchronous Mode

Many reflex signals can operate in two modes, synchronous or asynchronous. A synchronous reflex is

clocked on HFPERCLK, and can be used as an input to all reflex consumers, but since they require

HFPERCLK, they will not work in EM2/EM3.

Asynchronous reflexes are not clocked on HFPERCLK, and can be used even in EM2/EM3. There is

a limitation to reflexes operating in asynchronous mode though: they can only be used by a subset of

the reflex consumers, the ones marked with async support in Table 13.2 (p. 165) . Peripherals that

can produce asynchronous reflexes are marked with async support in Table 13.1 (p. 164) . To use

these reflexes asynchronously, set ASYNC in the CHCTRL register for the PRS channel selecting the

reflex signal.

Note If a peripheral channel with ASYNC set is used in a consumer not supporting asynchronous

reflexes, the behaviour is undefined.

13.3.2 Channel Functions

Different functions can be applied to a reflex signal within the PRS. Each channel includes an edge

detector to enable generation of pulse signals from level signals. It is also possible to generate output

reflex signals by configuring the SWPULSE and SWLEVEL bits. SWLEVEL is a programmable level

for each channel and holds the value it is programmed to. The SWPULSE will give out a one-cycle

high pulse if it is written to 1, otherwise a 0 is asserted. The SWLEVEL and SWPULSE signals are

then XOR'ed with the selected input from the producers to form the output signal sent to the consumers

listening to the channel.

Note The edge detector controlled by EDSEL should only be used when working with

synchronous reflexes, i.e., ASYNC in CHCTRL is cleared.

Figure 13.1. PRS Overview

APB Interface

Reg

SIGSEL[2:0]

ASYNC[n]

APB bus

Signals from

producer

peripherals

Signals to

consumer

peripherals

EDSEL[1:0]

SWPULSE[n]

SOURCESEL[5:0]

SWLEVEL[n]

13.3.3 Producers

Each PRS channel can choose between signals from several producers, which is configured in

SOURCESEL in PRS_CHx_CTRL. Each of these producers outputs one or more signals which can

be selected by setting the SIGSEL field in PRS_CHx_CTRL. Setting the SOURCESEL bits to 0 (Off)

leads to a constant 0 output from the input mux. An overview of the available producers is given in

Table 13.1 (p. 164) .

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Table 13.1. Reflex Producers

Module Reflex Output Output Format Async Support

ACMP Comparator Output Level Yes

Single Conversion Done Pulse ADC

Scan Conversion Done Pulse

Channel 0 Conversion

Done Pulse DAC

Channel 1 Conversion

Done Pulse

Pin 0 Input Level Yes

Pin 1 Input Level Yes

Pin 2 Input Level Yes

Pin 3 Input Level Yes

Pin 4 Input Level Yes

Pin 5 Input Level Yes

Pin 6 Input Level Yes

Pin 7 Input Level Yes

Pin 8 Input Level Yes

Pin 9 Input Level Yes

Pin 10 Input Level Yes

Pin 11 Input Level Yes

Pin 12 Input Level Yes

Pin 13 Input Level Yes

Pin 14 Input Level Yes

GPIO

Pin 15 Input Level Yes

Overflow Pulse Yes

Compare Match 0 Pulse Yes

RTC

Compare Match 1 Pulse Yes

Underflow Pulse

Overflow Pulse

CC0 Output Level

CC1 Output Level

TIMER

CC2 Output Level

CH0 Level YesLETIMER

CH1 Level Yes

TX Complete Pulse UART

RX Data Received Pulse

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Module Reflex Output Output Format Async Support

TX Complete Pulse

RX Data Received Pulse

USART

IrDA Decoder Output Level

VCMP Comparator Output Level Yes

SCANRES register Level YesLESENSE

Decoder Output Level/Pulse Yes

Overflow Pulse YesBURTC

Compare match 0 Pulse Yes

Start of Frame YesUSB

Start of Fram Sent/

Received Yes

13.3.4 Consumers

Consumer peripherals (listed in Table 13.2 (p. 165) ) can be set to listen to a PRS channel and perform

an action based on the signal received on that channel. Most consumers expect pulse input, while some

can handle level inputs as well.

Table 13.2. Reflex Consumers

Module Reflex Input Input Format Async Support

Single Mode Trigger Pulse ADC

Scan Mode Trigger Pulse

Channel 0 Trigger Pulse DAC

Channel 1 Trigger Pulse

CC0 Input Pulse/Level

CC1 Input Pulse/Level

CC2 Input Pulse/Level

DTI Fault Source 0

(TIMER0 only) Pulse

DTI Fault Source 1

(TIMER0 only) Pulse

TIMER

DTI Input (TIMER0 only) Pulse/Level

TX/RX Enable Pulse UART

RX Input Pulse/Level Yes

TX/RX Enable Pulse

IrDA Encoder Input

(USART0 only) Pulse

USART

RX Input Pulse/Level Yes

LEUART RX Input Pulse/Level Yes

PCNT S0 input Level Yes

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Module Reflex Input Input Format Async Support

S1 input Level Yes

Start scan Pulse/Level Yes

Decoder Bit 0 Level Yes

Decoder Bit 1 Level Yes

Decoder Bit 2 Level Yes

LESENSE

Decoder Bit 3 Level Yes

Note It is possible to output prs channel 0 - channel 3 onto the GPIO by setting CH0PEN,

CH1PEN, CH2PEN, or CH3PEN in the PRS_ROUTE register.

13.3.5 Example

The example below (illustrated in Figure 13.2 (p. 166) ) shows how to set up ADC0 to start single

conversions every time TIMER0 overflows (one HFPERCLK cycle high pulse), using PRS channel 5:

• Set SOURCESEL in PRS_CH5_CTRL to 0b011100 to select TIMER0 as input to PRS channel 5.

• Set SIGSEL in PRS_CH5_CTRL to 0b001 to select the overflow signal (from TIMER0).

• Configure ADC0 with the desired conversion set-up.

• Set SINGLEPRSEN in ADC0_SINGLECTRL to 1 to enable single conversions to be started by a high

PRS input signal.

• Set SINGLEPRSSEL in ADC0_SINGLECTRL to 0x5 to select PRS channel 5 as input to start the

single conversion.

• Start TIMER0 with the desired TOP value, an overflow PRS signal is output automatically on overflow.

Note that the ADC results needs to be fetched either by the CPU or DMA.

Figure 13.2. TIMER0 overflow starting ADC0 single conversions through PRS channel 5.

PRS

TIMER0 ADC0

ch0

ch1

ch2

ch3

ch4

ch5

ch6

ch7

Start single conv.Overflow

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13.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 PRS_SWPULSE W1 Software Pulse Register

0x004 PRS_SWLEVEL RW Software Level Register

0x008 PRS_ROUTE RW I/O Routing Register

0x010 PRS_CH0_CTRL RW Channel Control Register

... PRS_CHx_CTRL RW Channel Control Register

0x03C PRS_CH11_CTRL RW Channel Control Register

13.5 Register Description

13.5.1 PRS_SWPULSE - Software Pulse Register

Offset Bit Position

0x000

Reset

Access

Name

CH11PULSE

CH10PULSE

CH9PULSE

CH8PULSE

CH7PULSE

CH6PULSE

CH5PULSE

CH4PULSE

CH3PULSE

CH2PULSE

CH1PULSE

CH0PULSE

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11PULSE 0 W1 Channel 11 Pulse Generation

See bit 0.

10 CH10PULSE 0 W1 Channel 10 Pulse Generation

See bit 0.

9 CH9PULSE 0 W1 Channel 9 Pulse Generation

See bit 0.

8 CH8PULSE 0 W1 Channel 8 Pulse Generation

See bit 0.

7 CH7PULSE 0 W1 Channel 7 Pulse Generation

See bit 0.

6 CH6PULSE 0 W1 Channel 6 Pulse Generation

See bit 0.

5 CH5PULSE 0 W1 Channel 5 Pulse Generation

See bit 0.

4 CH4PULSE 0 W1 Channel 4 Pulse Generation

See bit 0.

3 CH3PULSE 0 W1 Channel 3 Pulse Generation

See bit 0.

2 CH2PULSE 0 W1 Channel 2 Pulse Generation

See bit 0.

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Bit Name Reset Access Description

1 CH1PULSE 0 W1 Channel 1 Pulse Generation

See bit 0.

0 CH0PULSE 0 W1 Channel 0 Pulse Generation

Write to 1 to generate one HFPERCLK cycle high pulse. This pulse is XOR'ed with the corresponding bit in the SWLEVEL register

and the selected PRS input signal to generate the channel output.

13.5.2 PRS_SWLEVEL - Software Level Register

Offset Bit Position

0x004

Reset

Access

Name

CH11LEVEL

CH10LEVEL

CH9LEVEL

CH8LEVEL

CH7LEVEL

CH6LEVEL

CH5LEVEL

CH4LEVEL

CH3LEVEL

CH2LEVEL

CH1LEVEL

CH0LEVEL

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CH11LEVEL 0 RW Channel 11 Software Level

See bit 0.

10 CH10LEVEL 0 RW Channel 10 Software Level

See bit 0.

9 CH9LEVEL 0 RW Channel 9 Software Level

See bit 0.

8 CH8LEVEL 0 RW Channel 8 Software Level

See bit 0.

7 CH7LEVEL 0 RW Channel 7 Software Level

See bit 0.

6 CH6LEVEL 0 RW Channel 6 Software Level

See bit 0.

5 CH5LEVEL 0 RW Channel 5 Software Level

See bit 0.

4 CH4LEVEL 0 RW Channel 4 Software Level

See bit 0.

3 CH3LEVEL 0 RW Channel 3 Software Level

See bit 0.

2 CH2LEVEL 0 RW Channel 2 Software Level

See bit 0.

1 CH1LEVEL 0 RW Channel 1 Software Level

See bit 0.

0 CH0LEVEL 0 RW Channel 0 Software Level

The value in this register is XOR'ed with the corresponding bit in the SWPULSE register and the selected PRS input signal to generate

the channel output.

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13.5.3 PRS_ROUTE - I/O Routing Register

Offset Bit Position

0x008

Reset

0x0

Access

Name

LOCATION

CH3PEN

CH2PEN

CH1PEN

CH0PEN

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 LOCATION 0x0 RW I/O Location

Decides the location of the PRS I/O pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 CH3PEN 0 RW CH3 Pin Enable

When set, GPIO output from PRS channel 3 is enabled

2 CH2PEN 0 RW CH2 Pin Enable

When set, GPIO output from PRS channel 2 is enabled

1 CH1PEN 0 RW CH1 Pin Enable

When set, GPIO output from PRS channel 1 is enabled

0 CH0PEN 0 RW CH0 Pin Enable

When set, GPIO output from PRS channel 0 is enabled

13.5.4 PRS_CHx_CTRL - Channel Control Register

Offset Bit Position

0x010

Reset

0x0

0x00

0x0

Access

Name

ASYNC

EDSEL

SOURCESEL

SIGSEL

Bit Name Reset Access Description

31:29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 ASYNC 0 RW Asynchronous reflex

Set to disable synchronization of this reflex signal

27:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:24 EDSEL 0x0 RW Edge Detect Select

Select edge detection.

Value Mode Description

0 OFF Signal is left as it is

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Bit Name Reset Access Description

Value Mode Description

1 POSEDGE A one HFPERCLK cycle pulse is generated for every positive edge of the incoming

signal

2 NEGEDGE A one HFPERCLK clock cycle pulse is generated for every negative edge of the

incoming signal

3 BOTHEDGES A one HFPERCLK clock cycle pulse is generated for every edge of the incoming signal

23:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:16 SOURCESEL 0x00 RW Source Select

Select input source to PRS channel.

Value Mode Description

0b000000 NONE No source selected

0b000001 VCMP Voltage Comparator

0b000010 ACMP0 Analog Comparator 0

0b000011 ACMP1 Analog Comparator 1

0b000110 DAC0 Digital to Analog Converter 0

0b001000 ADC0 Analog to Digital Converter 0

0b010000 USART0 Universal Synchronous/Asynchronous Receiver/Transmitter 0

0b010001 USART1 Universal Synchronous/Asynchronous Receiver/Transmitter 1

0b010010 USART2 Universal Synchronous/Asynchronous Receiver/Transmitter 2

0b011100 TIMER0 Timer 0

0b011101 TIMER1 Timer 1

0b011110 TIMER2 Timer 2

0b011111 TIMER3 Timer 3

0b100100 USB Universal Serial Bus Interface

0b101000 RTC Real-Time Counter

0b101001 UART0 Universal Asynchronous Receiver/Transmitter 0

0b101010 UART1 Universal Asynchronous Receiver/Transmitter 1

0b110000 GPIOL General purpose Input/Output

0b110001 GPIOH General purpose Input/Output

0b110100 LETIMER0 Low Energy Timer 0

0b110111 BURTC Backup RTC

0b111001 LESENSEL Low Energy Sensor Interface

0b111010 LESENSEH Low Energy Sensor Interface

0b111011 LESENSED Low Energy Sensor Interface

15:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 SIGSEL 0x0 RW Signal Select

Select signal input to PRS channel.

Value Mode Description

SOURCESEL = 0b000000

(NONE)

0bxxx OFF Channel input selection is turned off

SOURCESEL = 0b000001

(VCMP)

0b000 VCMPOUT Voltage comparator output VCMPOUT

SOURCESEL = 0b000010

(ACMP0)

0b000 ACMP0OUT Analog comparator output ACMP0OUT

SOURCESEL = 0b000011

(ACMP1)

0b000 ACMP1OUT Analog comparator output ACMP1OUT

SOURCESEL = 0b000110 (DAC0)

0b000 DAC0CH0 DAC ch0 conversion done DAC0CH0

0b001 DAC0CH1 DAC ch1 conversion done DAC0CH1

SOURCESEL = 0b001000 (ADC0)

0b000 ADC0SINGLE ADC single conversion done ADC0SINGLE

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Bit Name Reset Access Description

Value Mode Description

0b001 ADC0SCAN ADC scan conversion done ADC0SCAN

SOURCESEL = 0b010000

(USART0)

0b000 USART0IRTX USART 0 IRDA out USART0IRTX

0b001 USART0TXC USART 0 TX complete USART0TXC

0b010 USART0RXDATAV USART 0 RX Data Valid USART0RXDATAV

SOURCESEL = 0b010001

(USART1)

0b001 USART1TXC USART 1 TX complete USART1TXC

0b010 USART1RXDATAV USART 1 RX Data Valid USART1RXDATAV

SOURCESEL = 0b010010

(USART2)

0b001 USART2TXC USART 2 TX complete USART2TXC

0b010 USART2RXDATAV USART 2 RX Data Valid USART2RXDATAV

SOURCESEL = 0b011100

(TIMER0)

0b000 TIMER0UF Timer 0 Underflow TIMER0UF

0b001 TIMER0OF Timer 0 Overflow TIMER0OF

0b010 TIMER0CC0 Timer 0 Compare/Capture 0 TIMER0CC0

0b011 TIMER0CC1 Timer 0 Compare/Capture 1 TIMER0CC1

0b100 TIMER0CC2 Timer 0 Compare/Capture 2 TIMER0CC2

SOURCESEL = 0b011101

(TIMER1)

0b000 TIMER1UF Timer 1 Underflow TIMER1UF

0b001 TIMER1OF Timer 1 Overflow TIMER1OF

0b010 TIMER1CC0 Timer 1 Compare/Capture 0 TIMER1CC0

0b011 TIMER1CC1 Timer 1 Compare/Capture 1 TIMER1CC1

0b100 TIMER1CC2 Timer 1 Compare/Capture 2 TIMER1CC2

SOURCESEL = 0b011110

(TIMER2)

0b000 TIMER2UF Timer 2 Underflow TIMER2UF

0b001 TIMER2OF Timer 2 Overflow TIMER2OF

0b010 TIMER2CC0 Timer 2 Compare/Capture 0 TIMER2CC0

0b011 TIMER2CC1 Timer 2 Compare/Capture 1 TIMER2CC1

0b100 TIMER2CC2 Timer 2 Compare/Capture 2 TIMER2CC2

SOURCESEL = 0b011111

(TIMER3)

0b000 TIMER3UF Timer 3 Underflow TIMER3UF

0b001 TIMER3OF Timer 3 Overflow TIMER3OF

0b010 TIMER3CC0 Timer 3 Compare/Capture 0 TIMER3CC0

0b011 TIMER3CC1 Timer 3 Compare/Capture 1 TIMER3CC1

0b100 TIMER3CC2 Timer 3 Compare/Capture 2 TIMER3CC2

SOURCESEL = 0b100100 (USB)

0b000 USBSOF USB Start of Frame USBSOF

0b001 USBSOFSR USB Start of Frame Sent/Received USBSOFSR

SOURCESEL = 0b101000 (RTC)

0b000 RTCOF RTC Overflow RTCOF

0b001 RTCCOMP0 RTC Compare 0 RTCCOMP0

0b010 RTCCOMP1 RTC Compare 1 RTCCOMP1

SOURCESEL = 0b101001

(UART0)

0b001 UART0TXC USART 0 TX complete UART0TXC

0b010 UART0RXDATAV USART 0 RX Data Valid UART0RXDATAV

SOURCESEL = 0b101010

(UART1)

0b001 UART1TXC USART 0 TX complete UART1TXC

0b010 UART1RXDATAV USART 0 RX Data Valid UART1RXDATAV

SOURCESEL = 0b110000 (GPIO)

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Bit Name Reset Access Description

Value Mode Description

0b000 GPIOPIN0 GPIO pin 0 GPIOPIN0

0b001 GPIOPIN1 GPIO pin 1 GPIOPIN1

0b010 GPIOPIN2 GPIO pin 2 GPIOPIN2

0b011 GPIOPIN3 GPIO pin 3 GPIOPIN3

0b100 GPIOPIN4 GPIO pin 4 GPIOPIN4

0b101 GPIOPIN5 GPIO pin 5 GPIOPIN5

0b110 GPIOPIN6 GPIO pin 6 GPIOPIN6

0b111 GPIOPIN7 GPIO pin 7 GPIOPIN7

SOURCESEL = 0b110001 (GPIO)

0b000 GPIOPIN8 GPIO pin 8 GPIOPIN8

0b001 GPIOPIN9 GPIO pin 9 GPIOPIN9

0b010 GPIOPIN10 GPIO pin 10 GPIOPIN10

0b011 GPIOPIN11 GPIO pin 11 GPIOPIN11

0b100 GPIOPIN12 GPIO pin 12 GPIOPIN12

0b101 GPIOPIN13 GPIO pin 13 GPIOPIN13

0b110 GPIOPIN14 GPIO pin 14 GPIOPIN14

0b111 GPIOPIN15 GPIO pin 15 GPIOPIN15

SOURCESEL = 0b110100

(LETIMER0)

0b000 LETIMER0CH0 LETIMER CH0 Out LETIMER0CH0

0b001 LETIMER0CH1 LETIMER CH1 Out LETIMER0CH1

SOURCESEL = 0b110111

(BURTC)

0b000 BURTCOF BURTC Overflow BURTCOF

0b001 BURTCCOMP0 BURTC Compare 0 BURTCCOMP0

SOURCESEL = 0b111001

(LESENSE)

0b000 LESENSESCANRES0 LESENSE SCANRES register, bit 0 LESENSESCANRES0

0b001 LESENSESCANRES1 LESENSE SCANRES register, bit 1 LESENSESCANRES1

0b010 LESENSESCANRES2 LESENSE SCANRES register, bit 2 LESENSESCANRES2

0b011 LESENSESCANRES3 LESENSE SCANRES register, bit 3 LESENSESCANRES3

0b100 LESENSESCANRES4 LESENSE SCANRES register, bit 4 LESENSESCANRES4

0b101 LESENSESCANRES5 LESENSE SCANRES register, bit 5 LESENSESCANRES5

0b110 LESENSESCANRES6 LESENSE SCANRES register, bit 6 LESENSESCANRES6

0b111 LESENSESCANRES7 LESENSE SCANRES register, bit 7 LESENSESCANRES7

SOURCESEL = 0b111010

(LESENSE)

0b000 LESENSESCANRES8 LESENSE SCANRES register, bit 8 LESENSESCANRES8

0b001 LESENSESCANRES9 LESENSE SCANRES register, bit 9 LESENSESCANRES9

0b010 LESENSESCANRES10 LESENSE SCANRES register, bit 10

LESENSESCANRES10

0b011 LESENSESCANRES11 LESENSE SCANRES register, bit 11

LESENSESCANRES11

0b100 LESENSESCANRES12 LESENSE SCANRES register, bit 12

LESENSESCANRES12

0b101 LESENSESCANRES13 LESENSE SCANRES register, bit 13

LESENSESCANRES13

0b110 LESENSESCANRES14 LESENSE SCANRES register, bit 14

LESENSESCANRES14

0b111 LESENSESCANRES15 LESENSE SCANRES register, bit 15

LESENSESCANRES15

SOURCESEL = 0b111011

(LESENSE)

0b000 LESENSEDEC0 LESENSE Decoder PRS out 0 LESENSEDEC0

0b001 LESENSEDEC1 LESENSE Decoder PRS out 1 LESENSEDEC1

0b010 LESENSEDEC2 LESENSE Decoder PRS out 2 LESENSEDEC2

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14 EBI - External Bus Interface

01 2 3 4

EBI

(MCU)

External

Async.

Device

Parallel Interface

Quick Facts

What?

The EBI is used for accessing external

parallel devices. The devices appear as a

part of the EFM32LG's internal memory map

and are therefore extremely simple to use.

Why?

Even though the EFM32LG is versatile, there

might be a need for specific external devices

such as extra RAM, FLASH, LCD, TFT. The

EBI simplifies the access to such devices.

How?

Through memory mapping the devices

appear as a part of the internal memory map.

When the processor performs read or writes

to the address range of the EBI, the EBI

handles the data transfers to and from the

external devices. The EBI may be interfaced

by the DMA, thus enabling operation in EM1.

14.1 Introduction

The External Bus Interface provides access to external parallel interface devices such as SRAM, FLASH,

ADCs and LCDs. The interface is memory mapped into the address bus of the Cortex-M3. This enables

seamless access from software without manually manipulating the IO settings each time a read or write

is performed. The data and address lines can be multiplexed in order to reduce the number of pins

required to interface the external devices. The bus timing is adjustable to meet specifications of the

external devices. The interface is limited to asynchronous devices and TFT.

14.2 Features

• Programmable interface for various memory types

• 4 memory bank regions

• Individual chip select line (EBI_CSn) per memory bank

• Accurate control of setup, strobe, hold and turn-around timing per memory bank

• Individual active high / active low setting of interface control signals per memory bank

• Slave read/write cycle extension per memory bank

• Page mode read

• NAND Flash support

• Both multiplexed and non-multiplexed address and data line configurations

• Up to 28 address lines

• Up to 16-bit data bus width

• Automatic translation when AHB transaction width and memory width differ

• Configurable prefetch from external device

• Write buffer to limit stalling of the Cortex-M3 or DMA

• TFT Direct Drive

• Programmable display and porch sizes

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• Programmable bus timing (frequency, setup and hold timing)

• Individual active high / active low setting of interface control signals

• Frame buffer can be either on-chip or off-chip

• Alpha-blending and masking

14.3 Functional Description

An overview of the EBI module is shown in Figure 14.1 (p. 175) . The EBI module consists of two

submodules. The first submodule implements a generic external device interface to for example SRAM

or Flash devices. The second submodule implements a TFT RGB interface which can be used together

with the generic external device interface to perform TFT Direct Drive from an external framebuffer to

a TFT display.

The EBI has multiplexed and non-multiplexed addressing modes. Fastest operation is achieved when

using a non-multiplexed addressing mode. The multiplexed addressing modes are somewhat slower

and require an external latch, but they use a significantly lower number of pins. The use of the 16 EBI_AD

pin connections depends on the addressing mode. They are used for both address and data in the

multiplexed modes. Also for the non-multiplexed 8-bit address mode both the address and data fit into

these 16 EBI_AD pins. If more address bits or data bits are needed, external latches can be used to

support up to 24-bit addresses or 16-bit data in the multiplexed addressing modes using only the 16

EBI_AD pins. Furthermore, independent of the addressing mode, up to 28 non-multiplexed address lines

can be enabled on the EBI_A pin connections.

When a read operation is requested by the Cortex-M3 or DMA via the EBI's AHB interface, the address

is transferred onto the EBI_AD and/or EBI_A bus. After a specific number of cycles, the EBI_REn pin

is activated and data is read from the EBI_AD bus. When a write operation is requested, the address

is transferred onto the EBI_AD and/or EBI_A bus and subsequently the write data is transferred onto

the EBI_AD bus as the EBI_WEn pin is activated. The detailed operation in the supported modes is

presented in the following sections.

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Figure 14.1. EBI Overview

Timing

AHB

EBI_AD[15:0]

APB

CONTROL

Data/Address EBI_REn

EBI_BLn[1:0]

EBI_CSn[3:0]

EBI_ARDY

EBI_ALE

Polarity

MODE

TFT Timing

AHB

APB

TFT CONTROL

EBI_DCLK

EBI_DATAEN

EBI_VSYNC

EBI_HSYNC

EBI_CSTFTn

TFT Polarity

TFT Size

EBI_A[27:0]

EBI_WEn

EBI_NANDWEn

EBI_NANDREn

Memory Interface

EBI

TFT Interface

14.3.1 Non-multiplexed 8-bit Data, 8-bit Address Mode

In this mode, 8-bit address and 8-bit data is supported. The address is put on the higher 8 bits of the

EBI_AD lines while the data uses the lower 8 bits. This mode is set by programming the MODE field in

the EBI_CTRL register to D8A8. The address space can be extended to 256 MB by using the EBI_A

lines as described in Section 14.3.6 (p. 181) . Read and write signals in 8-bit mode are shown in

Figure 14.2 (p. 176) and Figure 14.3 (p. 176) respectively.

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Figure 14.2. EBI Non-multiplexed 8-bit Data, 8-bit Address Read Operation

ADDR[7:0]

EBI_AD[15:8]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA[7:0] Z

EBI_AD[7:0]

Figure 14.3. EBI Non-multiplexed 8-bit Data, 8-bit Address Write Operation

ADDR[7:0]

EBI_AD[15:8]

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_WEn

DATA[7:0] Z

EBI_AD[7:0]

WRHOLD

(0, 1, 2, ...)

14.3.2 Multiplexed 16-bit Data, 16-bit Address Mode

In this mode, 16-bit address and 16-bit data is supported, but the utilization of an external latch is

required. The 16-bit address and 16-bit data bits are multiplexed on the EBI_AD lines. An illustration of

such a setup is shown in Figure 14.4 (p. 177) . This mode is set by programming the MODE field in

the EBI_CTRL register to D16A16ALE.

Note In this mode the 16-bit address is organized in 2-byte chunks at memory addresses aligned

to 2-byte offsets. Consequently, the LSB of the 16-bit address will always be 0. In order to

double the address space, the 16-bit address is internally shifted one bit to the right so that

the LSB of the address driven into the EBI_AD bus, i.e. the EBI_AD[0]-bit, corresponds to

the second least significant bit of the address, i.e. ADDR[1]. At the external device, the LSB

of the address must be tied either low or high in order to create a full address.

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Figure 14.4. EBI Address Latch Setup

EBI

(MCU)

External

Async.

Device

Latch

EBI_AD ADDR

DATA

Control

ALE

At the start of the transaction the address is output on the EBI_AD lines. The Latch is controlled by the

ALE (Address Latch Enable) signal and stores the address. Then the data is read or written according

to operation. Read and write signals are shown in Figure 14.5 (p. 177) and Figure 14.6 (p. 177)

respectively.

Figure 14.5. EBI Multiplexed 16-bit Data, 16-bit Address Read Operation

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

Z DATA[15:0]

EBI_CSn

EBI_REn

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

Figure 14.6. EBI Multiplexed 16-bit Data, 16-bit Address Write Operation

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

DATA[15:0]

EBI_CSn

EBI_WEn

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

WRHOLD

(0, 1, 2, ...)

ADDRHOLD

(0, 1, 2, ...)

14.3.3 Multiplexed 8-bit Data, 24-bit Address Mode

This mode allows 24-bit address with 8-bit data multiplexed on the EBI_AD lines. The upper 8 bits of

the EBI_AD lines are consecutively used for the highest 8 bits and the lowest 8 bits of the address. The

lower 8 bits of the EBI_AD lines are used for the middle 8 address bits and for data. This mode is set

by programming the MODE field in the EBI_CTRL register to D8A24ALE. Read and write signals are

shown in Figure 14.7 (p. 178) and Figure 14.8 (p. 178) respectively.

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Figure 14.7. EBI Multiplexed 8-bit Data, 24-bit Address Read Operation

ADDR[23:16]

EBI_AD[15:8]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

ADDR[15:8] Z DATA[7:0] Z

EBI_AD[7:0]

ADDR[7:0]

Figure 14.8. EBI Multiplexed 8-bit Data, 24-bit Address Write Operation

ADDR[23:16]

EBI_AD[15:8]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

ADDRHOLD

(0, 1, 2, ...)

WRSETUP

(0, 1, 2, ...)

EBI_CSn

EBI_WEn

WRSTRB

(1, 2, 3, ...)

ADDR[15:8] DATA[7:0] Z

EBI_AD[7:0]

ADDR[7:0]

WRHOLD

(0, 1, 2, ...)

14.3.4 Non-multiplexed 16-bit Data, N-bit Address Mode

In this non-multiplexed mode 16-bit data is driven on the 16 EBI_AD lines. The addresses are driven

on the EBI_A lines. The address space can be up to 256 MB as described in Section 14.3.6 (p. 181)

. This mode is set by programming the MODE field in the EBI_CTRL register to D16. Read and write

signals are shown in Figure 14.9 (p. 179) and Figure 14.10 (p. 179) respectively for the case in

which N address lines on EBI_A have been enabled.

Note In this mode the 16-bit address is organized in 2-byte chunks at memory addresses aligned

to 2-byte offsets. Consequently, the LSB of the 16-bit address will always be 0. In order to

double the address space, the 16-bit address is internally shifted one bit to the right so that

the LSB of the address driven into the EBI_A bus, i.e. the EBI_A[0]-bit, corresponds to the

second least significant bit of the address, i.e. ADDR[1]. At the external device, the LSB of

the address must be tied either low or high in order to create a full address.

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Figure 14.9. EBI Non-multiplexed 16-bit Data Read Operation with Extended Address

ADDR[N:1]

EBI_A[N-1:0]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA[15:0] Z

EBI_AD[15:0]

Figure 14.10. EBI Non-multiplexed 16-bit Data Write Operation with Extended Address

ADDR[N:1]

EBI_A[N-1:0]

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_WEn

DATA[15:0] Z

EBI_AD[15:0]

WRHOLD

(0, 1, 2, ...)

14.3.5 Page Mode Read Operation

Page mode read operation can enhance the performance of a sequence of consecutive asynchronous

read transactions by allowing data at subsequent intrapage addresses to be read faster. Page mode

operation is enabled by setting the PAGEMODE bitfield in the EBI_RDTIMING (or EBI_RDTIMINGn)

intrapage access and the PAGELEN bitfield in the EBI_PAGECTRL register defines the number of

members in a page. Page mode reads can for example be triggered by consecutive reads resulting from

wide AHB reads which are automatically translated into multiple narrow external device reads. Page

mode reads can also be triggered by sequential reads resulting from the EBI prefetch unit.

The number of members in a page together with the width of the external device and the INCHIT bit of

the EBI_PAGECTRL register define whether an address change results in an interpage access or in an

intrapage access as shown in Table 14.1 (p. 180) .

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Table 14.1. EBI Intrapage hit condition for read on address Addr (non-mentioned Addr bits are

unchanged)

PAGELEN, INCHIT 8-bit External Device 16-bit External Device

PAGELEN=MEMBER4, INCHIT=0 Addr[1:0] changed Addr[2:0] changed

PAGELEN=MEMBER8, INCHIT=0 Addr[2:0] changed Addr[3:0] changed

PAGELEN=MEMBER16, INCHIT=0 Addr[3:0] changed Addr[4:0] changed

PAGELEN=MEMBER32, INCHIT=0 Addr[4:0] changed Addr[5:0] changed

PAGELEN=MEMBER4, INCHIT=1 Addr[1:0] incremented by 1 Addr[2:0] incremented by 2

PAGELEN=MEMBER8, INCHIT=1 Addr[2:0] incremented by 1 Addr[3:0] incremented by 2

PAGELEN=MEMBER16, INCHIT=1 Addr[3:0] incremented by 1 Addr[4:0] incremented by 2

PAGELEN=MEMBER32, INCHIT=1 Addr[4:0] incremented by 1 Addr[5:0] incremented by 2

The initial page mode transaction uses the read setup and read strobe timing as shown in Figure 14.2 (p.

176) , Figure 14.5 (p. 177) , Figure 14.7 (p. 178) or Figure 14.9 (p. 179) depending on the

used addressing mode. Subsequent transactions are started by changing the low-order address bits

and use the page access time defined in the RDPA bitfield of the EBI_PAGECTRL register. The read

hold state RDHOLD is only performed at the end of a page mode read sequence or when bus turn-

around occurs. Note that bus turn-around can occur even if only read transactions are performed as

the D16A16ALE addressing mode will drive the EBI_AD lines when programming the external address

latch. In this case one bus turn-around RDHOLDX cycle is automatically inserted in between the read

and the write action on the EBI_AD lines. Note that for the D16A16ALE addressing mode the RDPA

state immediately follows the ADDRSETUP state, so the HALFALE feature will typically be required to

satisfy the external address latch hold requirement. In the D8A24ALE addressing mode there is no need

to reprogram the external address latch for intrapage addresses as the external latch then only latches

the most significant, non-changed address lines. The following figures show typical page mode read

sequences for all addressing modes.

Figure 14.11. EBI Page Mode Read Operation for D8A8 addressing mode

ADDR0

EBI_AD[15:8]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA0

EBI_AD[7:0] DATA1 DATA2 DATA3

ADDR1 ADDR2 ADDR3 Z

RDPA

(1, 2, 3, ...)

RDPA

(1, 2, 3, ...)

RDPA

(1, 2, 3, ...)

Figure 14.12. EBI Page Mode Read Operation for D16A16ALE addressing mode

ADDR0

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

Z DATA0

EBI_CSn

EBI_REn

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

ADDR1 Z DATA1

RDSETUP

(0, 1, 2, ...)

RDPA

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

ADDRSETUP

(1, 2, 3, ...)

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Figure 14.13. EBI Page Mode Read Operation for D8A24ALE addressing mode

ADDR0[23:16]

EBI_AD[15:8]

ADDRSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

RDHOLD

(0, 1, 2, ...)

DATA0

EBI_AD[7:0] DATA1 DATA2 DATA3

ADDR1[7:0] ADDR2[7:0] ADDR3[7:0] Z

RDPA

(1, 2, 3, ...)

RDPA

(1, 2, 3, ...)

RDPA

(1, 2, 3, ...)

EBI_ALE

EBI_REn

RDSETUP

(0, 1, 2, ...)

ADDR0[15:8]

ADDR0[7:0]

Figure 14.14. EBI Page Mode Read Operation for D16 addressing mode

ADDR0

EBI_A[N-1:0]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA0

EBI_AD[15:0] DATA1 DATA2 DATA3

ADDR1 ADDR2 ADDR3 Z

RDPA

(1, 2, 3, ...)

RDPA

(1, 2, 3, ...)

RDPA

(1, 2, 3, ...)

The maximum duration that a page is kept open is defined in the KEEPOPEN bitfield of the

EBI_PAGECTRL register. New read transactions which hit in an open page are started with RDPA

intrapage timing if the KEEPOPEN time has not been exceeded at the start of such a transaction. The

default setting of KEEPOPEN, which is equal to 0, will therefore never allow for intrapage timing to occur.

Transactions are allowed to finish if the KEEPOPEN time is exceeded during the transaction. Otherwise

the RDSTRB interpage timing is used for the read transaction. Next to exceeding the KEEPOPEN time

there are other reasons for closing an open page. In particular EBI transactions which result in a write or a

non-intrapage read always cause the page to be closed. Also the lack of a new EBI transaction will cause

an open page to be closed. In order to prevent this last scenario as much as possible read transactions

can often be made back to back. This is achieved by enabling prefetching by setting PREFETCH to 1

in the EBI_RDTIMING (or EBI_RDTIMINGn) register and by disallowing idle state insertion in between

transfers by setting the NOIDLE (or NOIDLEn) bit to 1 in EBI_CTRL register. Figure 14.15 (p. 181)

shows an example in which only ADDR1 benefits from intrapage timing because an unrelated AHB

transfer not directed at the EBI causes late arrival of ADDR2. ADDR2 arrives too late to be inserted as

a back to back read transfer. The page is considered closed and ADDR2 can therefore not benefit from

intrapage timing and it results in an interpage access instead.

Figure 14.15. EBI Page Closing

ADDR0

EBI_A[N-1:0]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA0

EBI_AD[15:0] DATA1

ADDR1 Z ADDR2

RDPA

(1, 2, 3, ...)

ADDR0

AHB ADDRESS NON-EBI ADDR2

ADDR1

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

IDLE

14.3.6 Extended addressing

Extended addressing is used to extend the address range for any of the addressing modes described in

Section 14.3.4 (p. 178) , Section 14.3.1 (p. 175) , Section 14.3.2 (p. 176) and Section 14.3.3 (p.

177) . Up to 28 address bits can be individually enabled on the EBI_A address lines providing up to 256

MB of address space per memory bank. The operation on the EBI_AD lines is not affected by this. See

Section 14.3.12 (p. 187) for the memory map definitions related to the EBI. An example of address

extension for the D16 mode is shown in Figure 14.9 (p. 179) and Figure 14.10 (p. 179) . A further

example for address extension in the multiplexed 16-bit data, 16-bit address mode of Section 14.3.2 (p.

176) is shown in Figure 14.16 (p. 182) . This is achieved by programming the MODE field in the

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EBI_CTRL register to D16A16ALE and by enabling the required address lines via the ALB and APEN

bitfields of the EBI_ROUTE register.

Figure 14.16. EBI Extended Address Latch Setup

EBI

(MCU)

External

Async.

Device

Latch

EBI_AD ADDR LSBs

DATA

Control

ALE

ADDR MSBs

EBI_A

Read and write signals for using extended addressing in the D16A16ALE mode are shown in

Figure 14.17 (p. 182) and Figure 14.18 (p. 182) respectively for the case in which N extra address

lines have been enabled. At the start of the transaction the lower address bits are output on the EBI_AD

lines. The Latch is controlled by the ALE (Address Latch Enable) signal and stores the address. Then

the data is read or written according to operation. The higher address bits are output on the EBI_A lines

throughout the transfer.

Figure 14.17. EBI 16-bit Data Multiplexed Read Operation using Extended Addressing

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

Z DATA[15:0]

EBI_CSn

EBI_REn

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

ADDR[16+N:17]

EBI_A[16+N-1:16]

Figure 14.18. EBI 16-bit Data Multiplexed Write Operation using Extended Addressing

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

DATA[15:0]

EBI_CSn

EBI_WEn

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

WRHOLD

(0, 1, 2, ...)

ADDRHOLD

(0, 1, 2, ...)

ADDR[16+N:17]

EBI_A[16+N-1:16]

In order to minimize the pin requirements both the lower bound and the upper bound of the enabled

EBI_A lines can be set. This is done in the ALB and APEN bitfields of the EBI_ROUTE register

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respectively. For example, in case all memory banks use the 8-bit addressing mode D8A8, then the

lower 8 address bits are always output on EBI_AD. Therefore, if address extension is required, only

address bits 8 and upwards need to be enabled on EBI_A. This is done by setting the EBI_A lower

bound to 8 by setting ALB to A8 in EBI_ROUTE and by enabling the required higher address lines via the

APEN bitfield in EBI_ROUTE. The operation of the APEN and ALB bitfields is shown in Table 14.2 (p.

183) for some typical configurations.

Table 14.2. EBI Enabling EBI_ADDR lines for transaction with address Addr and data Data

Configuration Addresses on EBI_A Addresses/data on EBI_AD

MODE = D8A8, ALB = A8, APEN =

A28 EBI_A[27:8] = Addr[27:8] EBI_AD[15:0] = {Addr[7:0], Data[7:0]}

MODE = D16A16ALE, ALB = A16,

APEN = A27 EBI_A[26:16] = Addr[27:17] EBI_AD[15:0] = Addr[16:1]; Data[15:0]

MODE = D8A24ALE, ALB = A24,

APEN = A28 EBI_A[27:24] = Addr[27:24] EBI_AD[15:0] = Addr[23:8]; {Addr[7:0],

Data[7:0]}

MODE = D16, ALB = A0, APEN = A27 EBI_A[26:0] = Addr[27:1] EBI_AD[15:0] = Data[15:0]

14.3.7 Prefetch Unit and Write Buffer

Prefetching from external memory can enhance the performance of a sequence of consecutive transfers.

In particular sequential code execution from external memory can benefit from prefetch. Also prefetch will

typically lead to better utilization of intrapage accesses in case page mode is used. If prefetch is enabled,

the prefetch unit will sequentially prefetch one data item of the same width as the last Cortex-M3 or DMA

read transaction handled by the EBI. Note that one prefetch transaction might lead to multiple external

device transactions as described in Table 14.3 (p. 186) . Prefetch is not performed in reaction to write

transactions, nor will prefetch cross bank boundaries. The prefetch unit is enabled via the PREFETCH

bitfield in the EBI_RDTIMING and EBI_RDTIMINGn registers. When the ITS bitfield in the EBI_CTRL

ITS is set to 1 the prefetch unit can be individually enabled per bank. In this case register EBI_RDTIMING

only applies to bank 0. Prefetch enabling for bank n is then defined in the EBI_RDTIMINGn register.

The EBI has a 1 entry 32-bit wide write buffer. The write buffer can be used to limit stalling by partially

decoupling the Cortex-M3 or DMA from a potentially slow external device. Only writes which are

guaranteed to not cause an error (e.g. timeout) in the EBI will be buffered when the write buffer is

enabled, such that precise error generation is guaranteed. The write buffer is disabled via the WBUFDIS

bitfield in the EBI_WRTIMING and EBI_WRTIMINGn registers. When the ITS bitfield in the EBI_CTRL

is set to 1 the write buffer can be individually disabled per bank. In this case register EBI_WRTIMING

only applies to bank 0. Write buffer disabling for bank n is then defined in the EBI_WRTIMINGn register.

The AHBACT status bit in the EBI_STATUS register indicates whether an AHB transaction is still active

in the EBI or not. When performing an AHB write, the AHBACT bit stays 1 until the required transaction(s)

with the external device have finished, independent of whether the AHB write gets buffered or not. On

an AHB read with prefetching enabled, AHBACT stays high until the potential external device prefetch

transaction(s) have finished.

14.3.8 Strobe length

For external devices with low, but non-zero, setup requirements the performance overhead for EBI

transactions can be relatively large if a full cycle setup time needs to be used. It is possible to borrow

half of the cycle time from a neighboring strobe phase in order to define setup times with a granularity

of half the internal clock period.

The durations of the EBI_ALE, EBI_REn, EBI_WEn, EBI_NANDREn and EBI_NANDWEn strobes can

be individually decreased by half the internal clock period via the HALFALE, HALFRE and HALFWE

bitfields in the address timing, read timing and write timing registers respectively. In case of EBI_ALE

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the trailing edge of the strobe can be moved half a clock period earlier. In case of EBI_REn, EBI_WEn,

EBI_NANDREn and EBI_NANDWEn the leading edge of the strobe can be moved half a clock period

later. Decreasing the length of the EBI_ALE strobe can be thought of as increasing the length of the

RDSETUP phase by the same amount. Similarly, decreasing the length of the EBI_REn, EBI_WEn,

EBI_NANDREn, EBI_NANDWEn strobes can be thought of as increasing the length of the RDSETUP

and WRSETUP phases. Note that the length of the ADDRSETUP, RDSTRB, and WRSTRB phases is still

1 or more internal clock cycles. For example, when HALFRE is set to 1 and RDSTRB is programmed to

2, the length of the RDSTRB phase is 2 cycles. The duration of the EBI_REn pulse is however decreased

by half a cycle to 1 1/2 cycles.

Figure 14.5 (p. 177) and Figure 14.6 (p. 177) respectively show read and write transactions in the

multiplexed 16-bit address, 16-bit data mode in which half strobes are enabled for EBI_ALE, EBI_REn

and EBI_WEn.

Figure 14.19. EBI Multiplexed Read Operation with Reduced Length Strobes

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

Z DATA[15:0]

EBI_CSn

EBI_REn

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

(½ , 1 ½ , 2 ½ , ...) (½) (½ , 1 ½ , 2 ½ , ...)(½)

Figure 14.20. EBI Multiplexed Write Operation with Reduced Length Strobes

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

DATA[15:0]

EBI_CSn

EBI_WEn

ADDRHOLD

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

WRHOLD

(0, 1, 2, ...)

(½ , 1 ½ , 2 ½ , ...) (½) (½ , 1 ½ , 2 ½ , ...)(½)

WRSETUP

(0, 1, 2, ...)

14.3.9 Bus turn-around and Idle cycles

The EBI_AD lines can be driven by either the EFM32LG or by the external device. Depending on the

characteristics of an external device, the RDHOLD should be programmed to ensure adequate bus turn-

around time. Default the EBI inserts an initial IDLE cycle, during which the EBI does not drive the EBI_AD

lines, after each external transaction. Furthermore, the EBI deasserts the EBI_CSn, EBI_REn, and

EBI_WEn lines during IDLE cycles. In case of subsequent IDLE cycles, after the initial one, the EBI will

drive the EBI_AD lines while keeping the EBI_CSn, EBI_REn, and EBI_WEn lines deasserted. The IDLE

state insertion is shown for two back-to-back read transactions in Figure 14.21 (p. 185) . In case that

the IDLE state provides the required bus turn-around time, the RDHOLD parameter can be programmed

to 0. For increased performance, the automatic IDLE state insertion can be prevented by setting the

NOIDLE/NOIDLEn bits in the EBI_CTRL register to 1. This scenario is shown in Figure 14.22 (p. 185)

for two back-to-back reads in a non-multiplexed addressing mode. Note that in case RDSETUP and

RDHOLD are both programmed to 0, then the EBI_REn line will not be deasserted between back-to-

back read transfers. The same will happen for non-multiplexed back-to-back write transactions with

WRSETUP and WRHOLD both programmed to 0. In case that NOIDLE/NOIDLEn is 1 and a read is

immediately followed by a write on the EBI_AD lines, one bus turn-around cycle called RDHOLDX is

automatically inserted in between the read and the write action. During a RDHOLDX cycle the external

EBI signals are driven in the same way as during regular RDHOLD cycles, i.e. the EBI_REn line will get

deasserted while the EBI_CSn line will stay asserted.

An IDLE cycle will automatically get inserted for the following cases:

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• Between two external device transactions in case the NOIDLE/NOIDLEn bit is 0.

• Between two external device transactions to different banks.

• When no request for an external transaction is available in the EBI.

A RDHOLDX cycle will automatically get inserted for the following case:

• Between a read and a subsequent write on the EBI_AD lines. Note that this is only possible if NOIDLE/

NOIDLEn is set to 1. Also note that a read in a multiplexed addressing mode (e.g. D16A16ALE) starts

with a write on the EBI_AD lines when it is in the ADDRSETUP state.

Figure 14.21. EBI Enforced IDLE cycles between Transactions

ADDR0[7:0]

EBI_AD[15:8]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA0[7:0]

EBI_AD[7:0]

ADDR1[7:0]

Z DATA1[7:0]

IDLE

(1, 2, ...) RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

IDLE

(1, 2, ...)

Figure 14.22. EBI No Enforced IDLE cycles between Transactions

ADDR0[7:0]

EBI_AD[15:8]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

EBI_CSn

EBI_REn

RDHOLD

(0, 1, 2, ...)

Z DATA0[7:0]

EBI_AD[7:0]

ADDR1[7:0]

Z DATA1[7:0]

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

Note In case NOIDLE/NOIDLEn bits are set in EBI_CTRL the read or write strobes can remain

asserted for back-to-back transfers if no further separation is guaranteed via for example

RDSETUP, RDHOLD, WRSETUP, or WRHOLD bitfields.

14.3.10 Timing

The duration of the states in the transaction is defined by the corresponding uppercase name above

the state, e.g. the address setup state in Figure 14.8 (p. 178) is active for a number of internal clock

cycles defined by ADDRSET bitfield in the EBI_ADDRTIMING register. Similar timing can be defined

by the RDSTRB bitfield in the EBI_RDTIMING register and WRSTRB in the EBI_WRTIMING register.

These parameters all have a minimum duration of 1 cycle, which is set by HW in case the bitfield is

programmed to 0.

The setup and hold timing parameters are ADDRHOLD in the EBI_ADDRTIMING register, RDHOLD

and RDSETUP in the EBI_RDTIMING register and WRHOLD and WR SETUP in the EBI_WRTIMING

cycles. If these parameters are set to 0, it effectively means that the state is skipped.

Page mode access time is defined in the RDPA bitfield of the EBI_PAGECTRL register. This parameters

has a minimum duration of 1 cycle, which is set by HW in case the bitfield is programmed to 0.

When the ITS bitfield in the EBI_CTRL register is set to 0, the timing set defined in the

EBI_ADDRTIMING, EBI_RDTIMING and EBI_WRTIMING registers applies to all 4 memory banks.

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When ITS is set to 1 each memory bank uses an individual timing set. In this case registers

EBI_ADDRTIMING, EBI_RDTIMING and EBI_WRTIMING only apply to bank 0. Timing for bank n is

then defined in the EBI_ADDRTIMINGn, EBI_RDTIMINGn and EBI_WRTIMINGn registers.

Note All timing related bitfields have a default value which is equal to the highest possible value

for these bitfields, which makes the default values a better fit for slow memory devices.

This differs from the EFM32G devices in which the default values correspond to the lowest

possible values, which would only be appropriate for fast memory devices.

14.3.11 Data Access Width

The mapping of AHB transactions to external device accesses depends on the data width of the external

device and on whether or not it supports byte lanes. The data width of external devices is specified in

the MODE and MODEn bitfields of the EBI_CTRL register. An external device is specified to be either

8-bit or 16-bit wide. Availability of byte lane support by the external device is specified via the BL and

BLn bitfields of the EBI_CTRL register. When the ITS bitfield in the EBI_CTRL register is set to 0, the

MODE and BL bitfields apply to all 4 memory banks. When ITS is set to 1 each memory bank uses an

individual mode and byte lane enable definition. In this case bitfields MODE and BL only apply to bank

0. The mode and byte lane availability for bank n is then defined in the MODEn and BLn bitfields.

In case the AHB transaction width does not match the width of the selected device, the EBI automatically

translates the AHB transaction into 1 or more external device transactions matching the capabilities

of that device. If one AHB transaction is translated into multiple external transactions, then the

external transactions have incrementing addresses and start with the lowest data byte(s) from the AHB

transaction. The translation, and possibly bus fault generation, is explained below and in Table 14.3 (p.

186) :

• If the AHB transaction width is larger than the external device width, then multiple consecutive external

transactions are performed starting with the least significant data.

• If the AHB transaction width is smaller than the external device width, then EBI behavior depends on

whether or not byte lanes are available for the selected device. Reads either use byte lane support

when available, or read according to the full external device width and disregard the superfluous data.

Writes normally either use byte lane support when available, or perform a read-modify-write sequence

to only change the required data. However, NAND Flash does not support byte lanes or random

access read-modify-write and therefore a hard fault is generated in case of an 8-bit write to a bank

designated as 16-bit NAND bank.

Table 14.3. EBI Mapping of AHB Transactions to External Device Transactions

Data Access

by Cortex-

M3, DMA, or

prefetch

8-bit External

Device (non-

NAND)

transaction(s)

16-bit External

Device (non-

NAND)

transaction(s)

(with byte lanes)

16-bit External

Device (non-

NAND)

transaction(s)

(without byte

lanes)

8-bit NAND Flash

transaction(s) 16-bit

NAND Flash

transaction(s)

8-bit read 1 x 8-bit read 1 x 8-bit read

(using byte lane) 1 x 16-bit read 1 x 8-bit read 1 x 16-bit read

16-bit read 2 x 8-bit read 1 x 16-bit read 1 x 16-bit read 2 x 8-bit read 1 x 16-bit read

32-bit read 4 x 8-bit read 2 x 16-bit read 2 x 16-bit read 4 x 8-bit read 2 x 16-bit read

8-bit write 1 x 8-bit write 1 x 8-bit write

(using byte lane) 1 x 16-bit read;

1 x 16-bit write

(read-modify-

write)

1 x 8-bit write - (Hard fault)

16-bit write 2 x 8-bit write 1 x 16-bit write 1 x 16-bit write 2 x 8-bit write 1 x 16-bit write

32-bit write 4 x 8-bit write 2 x 16-bit write 2 x 16-bit write 4 x 8-bit write 2 x 16-bit write

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14.3.12 Bank Access

The EBI is split in 4 different address regions, each connected to an individual EBI_CSn line. When

accessing one of the memory regions, the corresponding CSn line is asserted. This way up to 4 separate

devices can share the EBI lines and be identified by the EBI_CSn line. Each bank can individually be

enabled or disabled in the EBI_CTRL register.

The bank separation depends on whether the access originates from code space or not and on the

setting of the ALTMAP bit in the EBI_CTRL register. From code space three 32 MB banks and one 128

MB bank can be accessed. From data space either four 64 MB banks (when ALTMAP bit is 0) or four

256 MB banks (when the ALTMAP bit is 1) can be accessed as shown in Figure 14.23 (p. 188) and

Figure 14.24 (p. 189) respectively.

The EBI regions starting at address 0x80000000 in the memory map of the EFM32LG can also be used

for code execution. When running code via EBI regions starting at this address, the Cortex-M3 uses

the System bus interface to fetch instructions. This results in reduced performance as the Cortex-M3

accesses stack, other data in SRAM and peripherals using the System bus interface. Code accesses

via the System bus interface will not be cached. Furthermore, it should be noted that the address area

from 0xA0000000 to 0xC0000000 is marked NX (no-execute) by default. To be able to run code via

the EBI efficiently, the EBI is also mapped in the code space at address 0x12000000. When running

code from this space, the Cortex-M3 fetches instructions through the I/D-Code bus interface, leaving

the System bus interface for data access. Instructions fetched via the I/D-Code bus interface can be

cached to increase performance. The EBI regions mapped into the code space can however only be

accessed by the CPU, i.e. not the DMA.

Depending on the setting of the ITS bitfield in the EBI_CTRL register. The external device behavior,

including for example data width, timing definitions, page mode operation, and pin polarities, is either

defined for all banks at once or individually per bank.

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Figure 14.23. EBI Default Memory Map (ALTMAP = 0)

EBI Region 0 (32 MB)

Code

0x00000000

0x1fffffff

0x20000000

0x7fffffff

0x12000000

EBI Region 1 (32 MB)

EBI Region 2 (32 MB)

0x13ffffff

0x14000000

0x15ffffff

0x16000000

0x17ffffff

0x18000000

0x1fffffff

EBI Region 3 (128 MB)

EBI Region 0 (64 MB)

0x80000000

EBI Region 2 (64 MB)

EBI Region 1 (64 MB)

0x83ffffff

0x84000000

0x87ffffff

0x88000000

0x8bffffff

0x8c000000

0x8fffffff

EBI Region 3 (64 MB)

EBI Regions

0x80000000

0xbfffffff

0xc0000000

0xffffffff

0x12000000

0x8fffffff

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Figure 14.24. EBI Alternative Memory Map (ALTMAP = 1)

EBI Region 0 (32 MB)

Code

0x00000000

0x1fffffff

EBI Regions

0x80000000

0xbfffffff

0xc0000000

0xffffffff

0x20000000

0x7fffffff

0x12000000

EBI Region 1 (32 MB)

EBI Region 2 (32 MB)

0x13ffffff

0x14000000

0x15ffffff

0x16000000

0x17ffffff

0x18000000

0x1fffffff

EBI Region 3 (128 MB)

EBI Region 0 (256 MB)

0x80000000

EBI Region 2 (256 MB)

EBI Region 1 (256 MB)

0x8fffffff

0x90000000

0x9fffffff

0xa0000000

0xafffffff

0xb0000000

0xbfffffff

EBI Region 3 (256 MB)

0x12000000

14.3.13 WAIT/ARDY.

Some external devices are able to indicate that they are not finished with either write or read operation

by asserting the WAIT / ARDY line. This input signal is used to extend the REn/WEn cycles for slow

devices. The interpretation of the polarity of this signal can be configured with the ARDYPOL bit in

EBI_POLARITY. E.g. if the ARDYPOL is set to ACTIVELOW, then the REn/WEn cycle is extended

while the ARDY line is kept low. The ARDY functionality is enabled by setting the ARDYEN bit in the

EBI_CTRL register. It is also possible to enable a timeout check, which generates a bus error if the ARDY

is not deasserted within the timeout period. This prevents a system lock up condition in the case that the

external device does not deassert ARDY. The timeout functionality is disabled by setting ARDYTODIS

in the EBI_CTRL register.

When the ITS bitfield in the EBI_CTRL register is set to 0, the wait behavior defined in the ARDYEN and

ARDYTODIS bitfields applies to all 4 memory banks. When ITS is set to 1 each memory bank uses an

individual wait behavior definition. In this case bitfields ARDYEN and ARDYTODIS only apply to bank

0. Wait behavior for bank n is then defined in the ARDYnEN and ARDYTOnDIS bitfields.

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14.3.14 NAND Flash Support

NAND Flash devices offer high density at relatively low cost when compared to NOR Flash devices.

Unlike NOR Flash, which offers random read access, NAND Flash devices are based on page access

and use an indirect interface. Furthermore, a NAND Flash can contain invalid bits leading to invalid

blocks, which leads to requirements such as bit error detection/correction and bad block management.

The EBI offers support for glueless connection of a NAND Flash by implementing dedicated

EBI_NANDREn and EBI_NANDWEn pins and by providing hardware for single error correction

double error detection (SEC-DED) Error Correction Code (ECC) generation. NAND Flash support is

enabled by setting the EN bitfield in the EBI_NANDCTRL register to 1. The BANKSEL bitfield in

EBI_NANDCTRL defines which memory bank has a NAND Flash devices attached to it. NAND Flash

data width, read timing, and write timing are programmed via the standard EBI registers as described in

Section 14.3.14.2 (p. 191) . ECC support is described in Section 14.3.15 (p. 195) .

Both standard and Chip Enable Don't Care (CEDC) NAND Flash devices are supported and they can

be attached as shown in Figure 14.25 (p. 190) and Figure 14.26 (p. 191) respectively. For standard

NAND Flash devices, the Chip Enable (CEn) pin needs to remain asserted low during the entire read

cycle busy period, in which data is transferred from the memory array into the NAND Flash internal

data registers in order to prevent an early return to standby mode. CEDC NAND Flash devices do not

have this restriction, but they do not support the automatic sequential read function. For CEDC NAND

Flash the shared EBI_REn and EBI_WEn pins can be used instead of the dedicated EBI_NANDREn

and EBI_NANDWEn pins.

Figure 14.25. EBI Connection with Standard NAND Flash

EBI

(MCU) NAND

Flash

GPIO

CLE

ALE

R/B

CEn

WPn

IO[]

WEn

REn

EBI_NANDREn

GPIO (0)

EBI_A[25] (1)

EBI_A[24] (1)

EBI_NANDWEn

EBI_AD[] (3)

GPIO (4)

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Figure 14.26. EBI Connection with Chip Enable Don't Care NAND Flash

EBI

(MCU) CE don’t care

NAND

Flash

GPIO

CLE

ALE

R/B

CEn

WPn

IO[]

WEn

REn

EBI_NANDREn(2)

GPIO (4)

EBI_CSn

EBI_A[25] (1)

EBI_A[24] (1)

EBI_NANDWEn(2)

EBI_AD[] (3)

Note • (0) For a standard NAND Flash the EBI_CSn should be left unconnected.

• (1) The address lines mapping to the NAND Flash ALE and CLE signals can be chosen

as explained in Section 14.3.14.1 (p. 191)

• (2) For a CEDC NAND Flash the shared EBI_REn and EBI_WEn pins can be used

instead of the dedicated EBI_NANDREn and EBI_NANDWEn pins

• (3) Both 8-bit and 16-bit NAND Flash are supported.

• (4) The NAND Flash ready/busy (R/B) signal should be observed via GPIO (not via

EBI_ARDY)

14.3.14.1 Register Selection

NAND Flash uses an indirect I/O interface in which the NAND Flash is controlled by programming the

NAND Flash internal Command, Address, and Data registers. NAND Flash does not use dedicated

address lines. Because of this indirect I/O interface the NAND Flash memory size is not restricted by the

memory map of the EFM32LG. The NAND Command, Address, and Data registers can be accessed

via memory mapped IO in which two address lines are chosen for connection with the ALE and CLE

signals. The memory mapping and the two used address lines should be chosen such that they adhere

to the ALE/CLE encoding shown in Table 14.4 (p. 191) . Either EBI_A or EBI_AD address lines can

be used as long as the chosen addressing mode does not multiplex data signals onto the chosen lines.

The EBI_A[25:24] address lines used in Figure 14.25 (p. 190) and Figure 14.26 (p. 191) are just

an example.

Table 14.4. EBI NAND Flash Register Select

ALE CLE Selected NAND Flash Register

0 0 Data Register

0 1 Command Register

1 0 Address Register

1 1 Undefined

14.3.14.2 Width and Timing Configuration

The regular EBI registers are used for defining transfer width, read timing, and write timing for the

transactions on the NAND Flash interface. NAND Flash specific parameters as for example block size or

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the number of address cycles are not configured in the EBI and need to be dealt with via driver software.

Also higher level tasks as for example wear-leveling, bad block management, and logical-to-physical

block mapping should be addressed via driver software.

External transaction width is defined via the address mode as defined in MODE field of EBI_CTRL. As

only 3 NAND Flash registers are memory mapped it suffices to use either the D8A8 or D16 address

mode. The D16A16ALE and D8A24ALE address modes can also be used, but they require unnecessary

external address latch cycles and/or circuitry. For a 8-bit wide NAND Flash device, the D8A8 address

mode is therefore recommended, whereas for a 16-bit wide NAND Flash device the D16 address mode

is recommended. If the AHB transaction width does not match the external NAND device transaction

width, then automatic transaction translation is performed as described in Section 14.3.11 (p. 186) .

Note that a bus fault is generated in case of an 8-bit write to a 16-bit NAND device as neither byte lanes

nor read-modify-write is supported for NAND Flash.

NAND Flash write timing is defined in the EBI_WRTIMING(n) register. Figure 14.27 (p. 192) ,

Figure 14.28 (p. 192) , and Figure 14.29 (p. 193) show the command latch, address latch and data

input timing respectively assuming the D8A8 address mode with EBI_AD[x] used as ALE and EBI_AD[y]

used as CLE.

Figure 14.27. EBI NAND Flash Command Latch Timing

EBI_AD[y] = NAND CLE

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

GPIO or EBI_CSn = NAND CEn

EBI_NANDWEn = NAND WEn

COMMAND

EBI_AD[7:0] = NAND IO

WRHOLD

(0, 1, 2, ...)

EBI_AD[x] = NAND ALE

tDS tDH

tCS tCH

tCLS

tALS

tCLH

tALH

tWP

GPIO = NAND R/B

tWB

Figure 14.28. EBI NAND Flash Address Latch Timing

EBI_AD[y] = NAND CLE

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

GPIO or EBI_CSn = NAND CEn

EBI_NANDWEn = NAND WEn

ADDRESS

EBI_AD[7:0] = NAND IO

WRHOLD

(0, 1, 2, ...)

EBI_AD[x] = NAND ALE

tDS tDH

tCS tCH

tCLS

tALS

tCLH

tALH

tWP tWH

tWC

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Figure 14.29. EBI NAND Flash Data Input Timing

EBI_AD[y] = NAND CLE

WRSETUP

(0, 1, 2, ...)

WRSTRB

(1, 2, 3, ...)

GPIO or EBI_CSn = NAND CEn

EBI_NANDWEn = NAND WEn

DATA IN

EBI_AD[7:0] = NAND IO

WRHOLD

(0, 1, 2, ...)

EBI_AD[x] = NAND ALE

tDS tDH

tCS tCH

tCLS

tALS

tCLH

tALH

tWP tWH

tWC

The EBI_WRTIMING(n) setting requirements for satisfying the NAND Flash timing parameters for

command latching, address latching and data input timing are shown in Table 14.5 (p. 193) .

Table 14.5. EBI NAND Flash Write Timing

NAND Flash Write Timing Parameter EBI Write Timing Parameter Requirements

tADL <= t(WRHOLD) + t(WRSETUP) + t(WRSTRB)

tALS <= t(WRSETUP) + t(WRSTRB)

tCS <= t(WRSETUP) + t(WRSTRB)

tCLS <= t(WRSETUP) + t(WRSTRB)

tDS <= t(WRSETUP) + t(WRSTRB)

tALH <= t(WRHOLD)

tCH <= t(WRHOLD)

tCLH <= t(WRHOLD)

tDH <= t(WRHOLD)

tWC <= t(WRHOLD) + t(WRSETUP) + t(WRSTRB)

tWH <= t(WRHOLD) + t(WRSETUP)

tWP <= t(WRSTRB)

tWB (R/B edges can be detected by edge triggered GPIO

interrupts)

NAND Flash read timing is defined in the EBI_RDTIMING(n) register. Figure 14.30 (p. 194) shows

the NAND Flash data output timing assuming the D8A8 address mode.

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Figure 14.30. EBI NAND Flash Data Output Timing

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

GPIO or EBI_CSn = NAND CEn

EBI_NANDWEn = NAND REn

DATA OUT

EBI_AD[7:0] = NAND IO

RDHOLD

(0, 1, 2, ...)

tRHOH

tRP

tREH

GPIO = NAND R/B

tRR

tCEA

tREA tRHZ

tRC

The EBI_RDTIMING(n) setting requirements for satisfying the NAND Flash timing parameters for data

output timing are shown in Table 14.6 (p. 194) .

Table 14.6. EBI NAND Flash Read Timing

NAND Read Timing Parameter EBI Read Timing Parameter Requirements

tCEA <= t(RDSETUP) + t(RDSTRB)

tREA <= t(RDSTRB)

tRP <= t(RDSTRB)

tRHZ <= t(RDHOLD)

tREH <= t(RDHOLD) + t(RDSETUP)

tRC <= t(RDHOLD) + t(RDSETUP) + t(RDSTRB)

tRR <= t(RDSETUP) (assuming software wait for R/B high)

tAR <= t(RDSETUP)

tCLR <= t(RDSETUP)

tIR <= t(RDSETUP)

The NAND Flash timing parameters tWHR and tRHW define separation of read and write pulses and

therefore they can be satisfied by a combination of EBI_RDTIMING(n) and EBI_WRTIMING(n) settings

as shown in Table 14.7 (p. 194) .

Table 14.7. EBI NAND Flash Read/Write Timing Requirements

NAND Timing Parameter EBI Timing Parameter

tWHR <= t(WRHOLD) + t(RDSETUP)

tRHW <= t(RDHOLD) + t(WRSETUP)

Remaining NAND Flash timing parameters, e.g. tRST and tPROG, should be dealt with in software.

14.3.14.3 Application examples

A typical 528-byte page read sequence for an 8-bit wide NAND Flash is as follows:

• Configuration: Enable and select the memory bank connected to the NAND Flash device via the

EN and BANKSEL bitfields in the EBI_NANDCTRL register. Set the MODE field of the EBI_CTRL

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EBI_WRTIMING registers to fulfill the NAND timing requirements.

• Command and address phase: Program the NAND Command register to the page read command

and program the NAND Address register to the required read address. This can be done via Cortex-

M3 or DMA writes to the memory mapped NAND Command and Address registers. The automatic

data access width conversions described in Section 14.3.11 (p. 186) can be used if desired to for

example automatically perform 4 consecutive address byte transactions in response to one 32-bit

word AHB write to the NAND Address register (in this case the 2 address LSBs should not be used

to map onto the NAND ALE/CLE signals).

• Data transfer phase: Wait for the NAND Flash internal data transfer phase to complete as indicated

via its ready/busy (R/B) pin. The user can use the GPIO interrupt functionality for this. The 528-byte

data is now ready for sequential transfer from the NAND Flash Data register.

• Read phase: Clear the ECC_PARITY register and start Error Code Correction (ECC) parity generation

by setting both the ECCSTART and ECCCLEAR bitfields in the EBI_CMD register to 1. Now all

subsequently transferred data to/from the NAND Flash devices is used to generate the ECC parity

code into the EBI_ECCPARITY register. Read 512 subsequent bytes of main area data from the

NAND Flash Data register via DMA transfers. This can for example be done via 32-bit word DMA

transfers (as long as the two address LSBs are not used to map onto the NAND ALE/CLE signals).

Stop ECC parity generation by setting the ECCSTOP bitfield in the EBI_CMD register to 1 so that

following transactions will not modify the parity result. Read out the final 16 bytes from the NAND

Flash spare data area.

• Error correction phase: Compare the ECC code contained in the read spare area data against the

computed ECC code from the EBI_ECCPARITY register. The user software can accept, correct, or

discard the read data according the comparison result. No automatic correction is performed.

A typical 528-byte page program sequence for an 8-bit wide NAND Flash is as follows:

• Configuration: Configure the EBI for NAND Flash support via the EBI_NANDCTRL, EBI_CTRL,

EBI_RDTIMING and EBI_WRTIMING registers.

• Command and address phase: Program the NAND Command register to command for page

programming (serial data input) and program the NAND Address register to the desired write address.

• Write phase: Clear the ECC_PARITY register and start Error Code Correction (ECC) parity generation

by setting both the ECCSTART and ECCCLEAR bitfields in the EBI_CMD register to 1. Now all

subsequently transferred data to/from the NAND Flash devices is used to generate the ECC parity

code into the EBI_ECCPARITY register. Write 512 subsequent bytes of user main data to the NAND

Flash Data register via for example DMA transfers. Stop ECC parity generation and read out the

computed ECC parity data from EBI_ECCPARITY. Write the final 16 bytes of spare data including

the computed ECC parity data bytes.

• Program phase: Write the auto program command to the NAND Flash Command register after which

the NAND Flash will indicate that it is busy via its read/busy (R/B) pin. After read/busy goes high again,

the success of the program command can be verified by programming the read status command.

14.3.15 Error Correction Code

The EBI provides provides hardware support for generation of an Error Correction Code (ECC). The used

ECC is a Hamming (Hsiao) code providing single bit error correction and double error detection (SEC-

DED). ECC can be used to detect and/or correct failing bits in a NAND Flash page. ECC generation

is enabled by setting bitfield ECCSTART in the EBI_CMD register to 1. All subsequent data traffic

to/from the memory bank specified in the BANKSEL bitfield of the EBI_NANDCTRL register is then

used for generation of the ECC into the EBI_ECCPARITY register independent of the address in that

bank. ECC generation is stopped by writing 1 to the ECCSTOP bitfield in the EBI_CMD register. The

EBI_ECCPARITY register is cleared by writing 1 to the ECCCLEAR register. The ECCACT status bit in

the EBI_STATUS register shows whether ECC generation is active or not.

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The ECC computation is as shown in Figure 14.31 (p. 196) and Table 14.8 (p. 196) . Although the

table only shows the ECC generation for 8-bit data transfers, the ECC hardware also works for 16-bit

data transfers. In that case only the interpretation of the parity bits is different.

Figure 14.31. EBI ECC Generation

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

Byte 0

Byte 1

Byte 2

Byte 3

Byte N-4

Byte N-3

Byte N-2

Byte N-1

P8'

P32'

P16

P16'

P8'

P32

P16

P16'

...

P1 P1' P1 P1' P1 P1' P1 P1'

P2 P2' P2 P2'

P4 P4'

Table 14.8. EBI ECC Bit/Column Parity

Parity bit Generation for 8-bit data

P1' Bit 6 xor Bit 4 xor Bit 2 xor Bit 0 xor P1'

P1 Bit 7 xor Bit 5 xor Bit 3 xor Bit 1 xor P1

P2' Bit 5 xor Bit 4 xor Bit 1 xor Bit 0 xor P2'

P2 Bit 7 xor Bit 6 xor Bit 3 xor Bit 2 xor P2

P4' Bit 3 xor Bit 2 xor Bit 1 xor Bit 0 xor P4'

P4 Bit 7 xor Bit 6 xor Bit 5 xor Bit 4 xor P4

Table 14.9. EBI ECC Byte/Row Parity

Parity bit Generation for 8-bit data

RP(x) Byte(x)(7) xor Byte(x)(6) xor Byte(x)(5) xor Byte(x)(4) xor

Byte(x)(3) xor Byte(x)(2) xor Byte(x)(1) xor Byte(x)(0)

P8' RP(0) xor RP(2) xor RP(4) xor RP(6) xor ... xor RP(N-4) xor

RP(N-2)

P8 RP(1) xor RP(3) xor RP(5) xor RP(7) xor ... xor RP(N-3)xor

RP(N-1)

P16' RP(0) xor RP(1) xor RP(4) xor RP(5) xor ... xor RP(N-4) xor

RP(N-3)

P16 RP(2) xor RP(3) xor RP(6) xor RP(7) xor ... xor RP(N-2) xor

RP(N-1)

Etc. Etc.

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The generated ECC code can be read from the EBI_ECCPARITY register according to the format shown

in Figure 14.32 (p. 197) . The number of valid ECC bits depends on the number of transferred bytes

during the time that the ECC hardware is running as indicated in Table 14.10 (p. 197) .

Figure 14.32. EBI EBI_ECCPARITY Format

P32768 P32768' P16384 P16384' P8192 P8192' P4096 P4096'EBI_ECCPARITY[31:24]

MSB LSB

P2048 P2048' P1024 P1024' P512 P512' P256 P256'EBI_ECCPARITY[23:16]

P128 P128' P64 P64' P32 P32' P16 P16'EBI_ECCPARITY[15:8]

P8 P8' P4 P4' P2 P2' P1 P1'EBI_ECCPARITY[7:0]

Table 14.10. EBI EBI_ECCPARITY valid bits

Number of data bytes used for ECC generation Valid EBI_ECCPARITY bits

256 EBI_ECCPARITY[21:0]

512 EBI_ECCPARITY[23:0]

1024 EBI_ECCPARITY[25:0]

2048 EBI_ECCPARITY[27:0]

4096 EBI_ECCPARITY[29:0]

8192 EBI_ECCPARITY[31:0]

Software can compare, XOR, the parity data generated in EBI_ECCPARITY with the parity information

stored in the spare area for the used data set. The syndrome resulting from XOR'ing the valid

EBI_ECCPARITY bits with the ECC code read from the spare area can be used for error detection and

correction as shown in Table 14.11 (p. 197) .

Table 14.11. EBI Error Detection Result

Error Detection Result Syndrome Interpretation

No Error Syndrome has all valid Pn, Pn' bits 0 No error has been detected

1-bit Correctable Error For all valid syndrome (Pn, Pn') pairs:

Pn = not(Pn') 1 bit in the user main data is incorrect

and it can be corrected. For 8-bit wide

data the position of the incorrect bit is

indicated by bit pattern (P4, P2, P1); the

position of the incorrect byte is indicated

by (..., P32, P16, P8). For 16-bit wide

data the position of the incorrect bit

is (P8, P4, P2, P1); the incorrect byte

number is indicated by (..., P64, P32,

P16)

ECC Error 1 bit of the XOR result is high An error has been detected in the ECC

itself. No error has been detected in the

user data

Uncorrectable Error Other cases Multiple (2 or more) bits are incorrect.

This error cannot be corrected

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14.3.16 TFT Direct Drive

TFT Direct Drive can be used to automatically transfer frame data stored in either internal or external

memory to a TFT display without frame buffer. The EBI generates the necessary RGB control signals

for the TFT display and it coordinates and aligns the pixel data transfers accordingly. The Direct Drive

engine is enabled by setting the DD bitfield in the EBI_TFTCTRL register to either INTERNAL or

EXTERNAL. The RGB interface consists of 8 or 16 data lines on EBI_AD together with the EBI_DATAEN,

EBI_VSYNC, EBI_HSYNC and EBI_DCLK control signals. EBI_TFTCSn indicates whether the DD

bitfield is programmed to DISABLED or not. Whether Direct Drive is active or not can also be read via

the DDACT status bit in the EBI_STATUS register.

The dimensions of the visible display are defined in the VSZ and HSZ bitfields of the EBI_TFTSIZE

porch sizes are defined in the HFPORCH, HBPORCH, VFPORCH and VBPORCH bitfields of the

EBI_TFTHPORCH and EBI_TFTVPORCH registers. The porch and visible display sizes define the

number of EBI_DCLK pulses per line and the number of lines per frame according to Equation 14.1 (p.

198) and Equation 14.2 (p. 198) respectively.

EBI TFT Total Width

Number of EBI_DCLK pulses per line = HBPORCH + (HSZ + 1) + HFPORCH (14.1)

EBI TFT Total Height

Number of lines per frame = VBPORCH + (VSZ + 1) + VFPORCH (14.2)

The horizontal and vertical synchronization pulses begin at the starts of the horizontal and vertical

back porch intervals respectively. For the HSYNC pulse a delayed start position can be defined in the

HSYNCSTART bitfield of the EBI_TFTHPORCH register. The end of the HSYNC pulse is not delayed

and therefore the HSYNC pulse width is shortened when using a non-zero HSYNCSTART. The widths,

or rather end positions, of the HSYNC and VSYNC synchronization pulses are defined in the HSYNC

and VSYNC bitfields of the EBI_TFTSIZE register respectively. The horizontal synchronization pulse

width is specified in pixels. The vertical synchronization pulse width is specified in lines. Hardware

automatically adds 1 to the width programmed in these bitfields. The EBI_TFTSIZE bitfields are shown

in Figure 14.33 (p. 199) . When Direct Drive is enabled, the VCNT and HCNT bitfields in the

EBI_TFTSTATUS register show how the frame display progresses. VCNT is a counter containing the

current line position in a frame. It counts from 0 (first line in the vertical back porch) to VBPORCH + VSZ

+ VFPORCH (last line in the vertical front porch). HCNT is a counter containing the current pixel position

within a line. It counts from 0 (first pixel in the horizonal back porch) to HBPORCH + HSZ + HFPORCH

(last pixel in the horizontal front porch).

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Figure 14.33. EBI TFT Size

Visible Display

HSZ+1

HFPORCH

HBPORCH

VSZ+1

VFPORCH VBPORCH

Total width = HBPORCH + (HSZ + 1) + HFPORCH

Total height = VBPORCH + (VSZ + 1) + VFPORCH

HSYNC+1

VSYNC+1

HCNT = 0 HCNT = HBPORCH+HSZ+HFPORCH

VCNT = VBPORCH+VSZ+VFPORCHVCNT = VBPORCH+VSZ+VFPORCH

HCNT = 0

VCNT = 0 HCNT = HBPORCH+HSZ+HFPORCH

VCNT = 0

While the Direct Drive engine is transferring frame data from internal or external memory to the TFT, the

EBI can still be used for other EBI transfers to external devices. The interleaving of such EBI transfers

with transfers originating from the Direct Drive engine is controlled via the INTERLEAVE field in the

EBI_TFTCTRL register. Interleaving can be limited to occur only during the vertical and horizontal porch

intervals by setting the INTERLEAVE field to PORCH. EBI accesses outside the porch intervals while

INTERLEAVE is set to PORCH can cause the insertion of a high number of wait states on the AHB bus.

In case the TFT dot clock EBI_DCLK is relatively slow compared to the external device access time,

interleaving can also be allowed during the active interval of the TFT by setting the INTERLEAVE bitfield

to ONEPERDCLK or UNLIMITED. In both cases interleaving during the porch intervals is unlimited as

it is when the PORCH setting is used. If INTERLEAVE is set to ONEPERDCLK then at most 1 EBI

access is inserted per EBI_DCLK period in the active display interval at the point immediately after

the pixel transfer. Wait states are inserted on the AHB bus while waiting for this insertion point. The

access time of such an interleaved transfer should be guaranteed by software to fit in the free interval

between pixel transfers as indicated in Figure 14.39 (p. 206) . If INTERLEAVE is set to UNLIMITED,

which is the default, then there are no restrictions on performing EBI transactions during Direct Drive

operation. Although transactions related to Direct Drive have priority over other EBI transactions, jitter

on the EBI_DCLK can be introduced in case an EBI transaction is ongoing while the Direct Drive engine

wants to insert its next transaction. In case the programmed EBI_DCLK period can not be met, the

DDJIT interrupt flag in the EBI_IF register is set and the EBI_DCLK period is stretched to accommodate

the delayed pixel data.

Note

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If INTERLEAVE is limited to PORCH only and zero porch sizes are programmed in

the EBI_TFTHPORCH and EBI_TFTVPORCH registers, then no slots are left open for

interleaving traffic and therefore interleaving EBI accesses can never finish.

14.3.16.1 Direct Drive from Internal Memory

Any internal memory can be used as the frame source location for Direct Drive. Direct Drive display

from internal memory is started by setting the DD bitfield in the EBI_TFTCTRL register to INTERNAL.

The TFT controller indicates that the pixel buffer EBI_TFTDD is empty and needs to be filled by raising

the corresponding DMA request. This DMA request is initially set and it is cleared when EBI_TFTDD

is written. It is set again once the pixel data has been transferred to the display. One DMA request

is generated for each visible pixel. The Direct Drive engine will automatically align the data written to

EBI_TFTDD according to the setup and hold requirements with respect to EBI_DCLK and send it out

to the TFT via the EBI_AD lines. Whether the EBI_TFTDD buffer is full or empty is also signaled by the

DDEMPTY interrupt flag in the EBI_IF register and by the TFTDDEMPTY status bit in the EBI_STATUS

DMA, these non-DMA mechanisms are only advised for very low pixel rates. If pixel data is not provided

in time the EBI_DCLK will be stretched to accommodate the late pixel data and the Direct Drive Jitter

interrupt flag DDJIT in the EBI_IF register is set. Figure 14.34 (p. 200) shows the setup for Direct

Drive from internal memory.

Figure 14.34. EBI TFT Direct Drive from Internal Memory

EBI_AD

TFT

EBI_DCLK

EBI_DATAEN

EBI_VSYNC, EBI_HSYNC

EBI_TFTCSn

DATA

Memory

MCU

EBI

14.3.16.2 Direct Drive from External Memory

Direct Drive can also use an external memory bank as the frame source location. The used bank is

defined in the BANKSEL bitfield of the EBI_TFTCTRL register. Direct Drive display from external memory

is started by setting the DD bitfield in the EBI_TFTCTRL register to EXTERNAL. Data is then streamed

directly from the external memory to the TFT. Figure 14.35 (p. 201) and Figure 14.36 (p. 201) show

the setup for Direct Drive from external memory when using non-multiplexed and multiplexed address

and data lines respectively.

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Figure 14.35. EBI TFT Direct Drive from External Memory (non-multiplexed address/data)

EBI

(MCU)

External

Memory

Device

EBI_AD

ADDR

DATA

Control

TFT

EBI_DCLK

EBI_DATAEN

EBI_VSYNC, EBI_HSYNC

EBI_TFTCSn

DATA

EBI_A

Figure 14.36. EBI TFT Direct Drive from External Memory (multiplexed address/data)

EBI

(MCU)

External

Memory

Device

Latch

EBI_AD

ADDR

DATA

Control

EBI_ALE

TFT

EBI_DCLK

EBI_DATAEN

EBI_VSYNC, EBI_HSYNC

EBI_TFTCSn

DATA

The start address for the frame transfer is defined in the EBI_TFTFRAMEBASE register. The Direct

Drive address is automatically incremented for each visible pixel and it does therefore not depend

on the programmed porch sizes. The address increment depends on the WIDTH bitfield in the

EBI_TFTCTRL register. The increment per visible pixel is 1 if the WIDTH bitfield in the EBI_TFTCTRL

horizontal stride is added to the Direct Drive address at the end of each visible line. This stride can

be programmed in the HSTRIDE bitfield of the EBI_TFTSTRIDE register. The first visible pixel always

corresponds to the address defined in the EBI_TFTFRAMEBASE register. On either the vertical or

horizontal synchronization event, as defined in the FBCTRIG bitfield of the EBI_TFTCTRL register,

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the EBI_TFTFRAMEBASE register is copied into an internal frame base buffer (FBC). This allows

software to reprogram the EBI_TFTFRAMEBASE register based on VSYNC or HSYNC interrupts, which

in turn can be used to for example implement double buffering or scrolling schemes. The HSYNC

and VSYNC interrupts are generated at the same time as the local copy of EBI_TFTFRAMEBASE is

made. If software reprograms EBI_TFTFRAMEBASE in the interrupt service routine, then the new value

will only be used for address generation of the next line (in case FBCTRIG equals HSYNC) or the

next frame (in case FBCTRIG equals VSYNC). For example, when FBCTRIG equals HSYNC and the

interrupt service routine triggered by the HSYNC interrupt reads VCNT as 0, then a software update

of EBI_TFTFRAMEBASE will take effect for Direct Drive addresses of the line which corresponds to a

VCNT value of 1. Note that the EBI_TFTSTRIDE register is not relevant in case the FBCTRIG is set to

HSYNC as the HSYNC events reloads the internal frame base copy (FBC) with EBI_TFTFRAMEBASE

at the start of each line. The Direct Drive address computation is summarized in Figure 14.37 (p. 202) .

Figure 14.37. EBI Direct Drive Address

Visible Display

P(0,0)

Local frame base copy FBC gets assigned with EBI_TFTFRAMEBASE on every EBI_VSYNC stobe.

P(1,0) P(2,0) P(3,0) P(HSZ,0)

P(0,1) P(1,1) P(2,1) P(3,1) P(HSZ,1)

P(0,2) P(1,2) P(2,2) P(3,2) P(HSZ,2)

P(0,VSZ) P(1,VSZ) P(2,VSZ) P(3,VSZ) P(HSZ,VSZ)

HFPORCH

HBPORCH

VFPORCH VBPORCH

The address increment per pixel (PSZ) is 1 if the WIDTH bitfield in EBI_TFTCTRL is programmed to BYTE and 2 if the

WIDTH bitfield is programmed to HALFWORD.

Local frame base copy FBC gets assigned with EBI_TFTFRAMEBASE on every EBI_HSYNC stobe.

FBCTRIG = VSYNC:

Direct Drive Address for pixel P(x,y) = FBC + (x * PSZ)

Direct Drive Address for pixel P(x,y) = FBC + (x * PSZ) + (y * ((PSZ * (HSZ + 1)) + HSTRIDE))

FBCTRIG = HSYNC:

Note In case that the memory bank used for external Direct Drive is defined as 16-bit wide, then

the Direct Drive address is internally shifted one bit to the right before being output on the

EBI_AD or EBI_A lines.

14.3.17 Alpha Blending and Masking

Automatic alpha blending and masking can be performed on AHB data written to or via the EBI. Alpha

blending combines a foreground color with a background color into a new blended color and is further

described in Section 14.3.17.1 (p. 203) . Masking is a mechanism to suppress writes matching a

specific color. It is used to preserve the background color and is further described in Section 14.3.17.2 (p.

204) . Masking, if enabled, is applied before alpha blending as shown in Figure 14.38 (p. 203) .

Masking and alpha blending can be used for both internal and external data transfers.

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Figure 14.38. EBI TFT Alpha Blending and Masking

EBI_AD

EBI_TFTMASK EBI_TFTALPHA

EBI_TFTPIXEL

EBI_TFTPIXEL0 EBI_TFTPIXEL1

Mask

Check

Alpha Blend

EBI_AD

AHB WDATA

COLOR1SRC

blend

COLOR0 COLOR1

mask match

external = (MASKBLEND == EMASK) or (MASKBLEND == EALPHA) or (MASKBLEND == EMASKEALPHA)

blend = (MASKBLEND == IALPHA) or (MASKBLEND == EALPHA)

external

0 1

mask match 0 1

14.3.17.1 Alpha blending

Automatic alpha blending can be performed on AHB data written to or via the EBI. Alpha blending can

be enabled for either internal or external writes by setting the MASKBLEND bitfield in the EBI_TFTCTRL

the external device attached to the bank defined in the BANKSEL bitfield of the EBI_TFTCTRL register.

Alpha blending works on two data items: a foreground Color0 = {R0, G0, B0} and a background Color1

= {R1, G1, B1}. These data items are encoded in either 565 RGB or 555 RGB format as defined in the

RGBMODE bitfield of the EBI_TFTCTRL register. In case that the 555 RGB format is used, only the

15 least significant bits of Color0 and Color1 are used for the alpha blending operation itself. The most

significant bit of the foreground Color0 is passed on unmodified as the most significant bit of the alpha

blending result. Alpha blending is performed according to formula Equation 14.3 (p. 203) .

EBI Alpha Blending Equation

AlphaBlend(Color0, Color1) = (({R0, G0, B0} x EBI_TFTALPHA)

+ ({R1, G1, B1} x (256 - EBI_TFTALPHA))) / 256 (14.3)

The 9-bit alpha blending factor is defined in the EBI_TFTALPHA register. The maximum allowed value

for EBI_TFTALPHA is 256. An alpha value of 0 corresponds to a fully transparent color, whereas an alpha

value of 256 corresponds to a fully opaque color. The RGB Color0 data is taken from either the internal

write data (written to EBI_TFTPIXEL0) or from the external write data (written to bank BANKSEL). The

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Color0 source selection is based on the MASKBLEND bitfield of the EBI_TFTCTRL register. Internal

write data is used for MASKBLEND settings equal to IMASK, IALPHA, or IMASKIALPHA. External write

data is used for MASKBLEND settings equal to EMASK, EALPHA, or EMASKEALPHA. The RGB data

for Color1 is read from either the BANKSEL memory bank or from the EBI_TFTPIXEL1 register as

defined in the COLOR1SRC bitfield of the EBI_TFTCTRL register. The alpha blended result will be

written to the BANKSEL memory bank for external writes or to the EBI_TFTPIXEL register for internal

writes. For transactions involving an external memory device, the automatic transaction translation rules

as described in Section 14.3.11 (p. 186) apply. For example, 1 32-bit wide AHB write to a 16-bit wide

external memory can be used to automatically perform 2 16-bit alpha blending operations into external

memory. Three configurations of data source and destination are supported as described next.

In-place alpha blending into external memory is performed by writing RGB data D to address A

in bank BANKSEL with COLOR1SRC set to MEM and MASKBLEND set to EMASK, EALPHA, or

EMASKEALPHA. Note that in this case the EBI automatically translates the AHB write transaction into

a read-modify-write sequence for the external memory.

EBI In-place Alpha Blending into External Memory

Memory[A] = AlphaBlend(D, Memory[A]) (14.4)

Alpha blending into external memory with a Color1 from register is performed by writing RGB data D

to address A in bank BANKSEL with COLOR1SRC set to PIXEL1 and MASKBLEND set to EMASK,

EALPHA, or EMASKEALPHA:

EBI Alpha Blending into External Memory with Background Color1 from Register

Memory[A] = AlphaBlend(D, EBI_TFTPIXEL1) (14.5)

Internal alpha blending into register EBI_TFTPIXEL is performed by writing RGB data D to

EBI_TFTPIXEL0 with COLOR1SRC set to PIXEL1 and MASKBLEND set to IMASK, IALPHA, or

IMASKEALPHA. This alpha blending interface is intended for use by both the Cortex-M3 and the

DMA controller. For DMA operation three DMA requests are generated. One DMA request indicating

that EBI_TFTPIXEL0 requires new data, one DMA request indicating that EBI_TFTPIXEL1 requires

new data, and one DMA request indicating that new blended data is available in EBI_TFTPIXEL.

The write into EBI_TFTPIXEL0 triggers the alpha blending operation. If software wants to reprogram

EBI_TFTPIXEL1, then this should be done before the EBI_TFTPIXEL0 write, which triggers the alpha

blending. The status of the internal alpha blending interface can also be read via the TFTPIXEL0EMPTY,

TFTPIXEL1EMPTY, and TFTPIXELFULL bits in the EBI_STATUS register.

EBI Internal Alpha Blending from Registers into Register

EBI_TFTPIXEL = AlphaBlend(EBI_TFTPIXEL0, EBI_TFTPIXEL1) (14.6)

14.3.17.2 Masking

The masking feature can be used to suppress writes. Instead of the write data, the original background

color of a pixel is kept. Masking is supported for writes to an external device and for writes to internal

in the EBI_TFTMASK register. Masking is always based on 16-bit data and it does not depend on the

RGB mode defined in the RGBMODE bitfield of the EBI_TFTCTRL register. For transactions involving an

external memory device, the automatic transaction translation rules as described in Section 14.3.11 (p.

186) apply. For example, 1 32-bit wide AHB write to a 16-bit wide external memory can be used to

perform masking operations on both 16-bit transactions to the external device. Masking can for example

be used when drawing an icon with rounded corners into an external frame buffer. Such an icon can be

written to the frame buffer using a 2-dimensional copy action. If the color of a pixel outside the rounded

corners is set to match the value defined in the EBI_TFTMASK register, then such a matching data

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transfer is suppressed. The resulting image in the frame buffer will keep its original background around

the corners of the icon.

External masking is enabled by setting the EMASK bit in the EBI_TFTCTRL register to 1. If enabled,

writes to the memory bank defined in the BANKSEL bitfield of the EBI_TFTCTRL register are suppressed

in case the write data matches the value in EBI_TFTMASK.

Internal masking is enabled by setting the IMASK bit in the EBI_TFTCTRL register to 1. If enabled

and EBI_TFTPIXEL0 is written with data matching EBI_TFTMASK, then the background color from

EBI_TFTPIXEL1 is copied into EBI_TFTPIXEL. If enabled and EBI_TFTPIXEL0 is written with data

not matching EBI_TFTMASK, then the color from EBI_TFTPIXEL0 (possibly alpha blended with

EBI_TFTPIXEL1) is written into EBI_TFTPIXEL. The three DMA requests and EBI_STATUS bits as

described for internal alpha blending also apply for internal masking.

14.3.18 Direct Drive Timing

The timing definition for operating a TFT display in Direct Drive mode depends on where the frame buffer

source is located. In case internal memory is used as source, then only the TFT timing as defined in the

EBI_TFTTIMING register is relevant. In case external memory is used as the source memory, then both

the timing parameters of the TFT display and the timing parameters of the memory bank defined in the

BANKSEL bitfield of the EBI_TFTCTRL register are relevant.

The minimum dot clock, EBI_DCLK, period is defined in the DCLKPERIOD bitfield of the

EBI_TFTTIMING register. This parameter has a minimum duration of 1 cycle, which is set by HW, and

writing a value n to this bitfield results in an extended duration of 1+n cycles. At cycle 0 (and then

periodically with period DCLKPERIOD + 1) the EBI_DCLK inactive edges are generated. At the cycle

defined in the TFTSTART bitfield of the EBI_TFTTIMING the TFT Direct Drive transaction is started. The

TFTSTART bitfield can be used to define the duty cycle of the EBI_DCLK. This parameter has a minimum

duration of 1 cycle, which is set by HW, and writing a value n to this bitfield results in an extended

duration of 1+n cycles. After performing the required actions to produce the required TFT pixel data on

the EBI_AD lines, the TFT transaction will pass through its TFTSETUP and TFTHOLD states as indicated

in Figure 14.39 (p. 206) . In this figure, the duration of the states in the TFT transaction is defined by

the corresponding uppercase name above the state and it is expressed in internal clock cycles. The TFT

setup and hold times are set in the TFTHOLD and TFTSETUP bitfields in the EBI_TFTTIMING register.

Writing a value m to one of these bitfields results in a duration of the corresponding state of m internal

clock cycles. If these parameters are set to 0, it effectively means that the state is skipped. The TFT

setup and hold timing is with respect to the active edge of EBI_DCLK as defined in the DCLKPOL bitfield

in the EBI_TFTPOLARITY register. The TFT setup and hold timing applies to all TFT signals: EBI_AD,

EBI_DATAEN, EBI_VSYNC, EBI_HSYNC and EBI_TFTCSn. The active EBI_DCLK edge is generated

in between the TFTSETUP and TFTHOLD states. The TFTSTART bitfield therefore impacts the position

of the active EBI_DCLK edge. The later the TFT transaction is started, the later it will transition from

its TFTSETUP to TFTHOLD state. If needed, the EBI_DCLK period is automatically stretched beyond

the DCLKPERIOD to complete the TFT transaction. EBI_DCLK period stretching occurs when the TFT

transaction does not complete in the specified time, which in turn can occur because of the following

reasons:

• Specified timing parameters are conflicting. This can for example happen if the TFT setup plus hold

time is programmed to be longer than the EBI_DCLK period.

• TFT transaction is delayed by an ongoing EBI transaction. This transaction interference can

be controlled by setting the transaction interleaving strategy in the INTERLEAVE bitfield of the

EBI_TFTCTRL register.

• TFT transaction data is not delivered in time. For internal Direct Drive this is caused by the Cortex-M3

or DMA not delivering the data in time. For external Direct Drive the timing parameters defining the

external device read access might not allow the TFT transaction to complete in time.

In case the specified DCLK_PERIOD is not met, the DDJIT interrupt flag in the EBI_IF register will be set.

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Figure 14.39. EBI TFT Pixel Timing

PIXEL N

TFTSETUP

(0, 1, 2, ...)

DCLKPERIOD

(1, 2, 3, ...)

EBI_AD[15:0]

EBI_DCLK

TFTHOLD

(0, 1, 2, ...)

ZPIXEL N+1

TFTSETUP

(0, 1, 2, ...)

TFTHOLD

(0, 1, 2, ...)

DCLKPERIOD

(1, 2, 3, ...)

Z Z

When driving the TFT from internal memory, the TFT timing is defined in the EBI_TFTTIMING register

as shown in Figure 14.40 (p. 206) . Before each TFT transaction to the visible part of the display, the

EBI will request new pixel data via an interrupt or DMA request. At the time specified in the TFTSTART

bitfield of the EBI_TFTTIMING register (and when pixel data has been provided), the TFT transaction will

start. For internal Direct Drive the TFT state machine will place the pixel data on the EBI_AD lines during

the TFTWDATA state after which the state machine will pass through the programmable TFTSETUP

and TFTHOLD states.

Figure 14.40. EBI TFT Direct Drive Internal Timing

EBI_AD[15:0] ZDATA[15:0] Z

TFTWDATA

(1)

EBI_DCLK

TFTHOLD

(0, 1, 2, ...)

TFTSETUP

(0, 1, 2, ...)

TFTSTART

(1, 2, 3, ...)

When the TFT is driven directly from an external memory, the timing definitions for the bank defined in

the BANKSEL bitfield of the EBI_TFTCTRL register and those for the TFT are both used by Direct Drive

to generate transactions satisfying the requirements of both the memory device and the TFT display. The

timing definition for the external memory device should be programmed according to its requirements

independent of the TFT timing. Figure 14.41 (p. 206) shows an example of the Direct Drive engine

accessing an external memory using the multiplexed 16-bit data, 16-bit address (D16A16ALE) mode.

The TFTSETUP and TFTHOLD states are now enclosed within the read transaction states of the chosen

mode. The external device read transaction is started at a time as defined by TFTSTART. The read

strobe on EBI_REn is automatically extended in duration to satisfy the TFT setup and hold requirements

defined in the TFTSETUP and TFTHOLD bitfields.

Figure 14.41. EBI TFT Direct Drive External Timing

ADDR[16:1]

EBI_AD[15:0]

EBI_ALE

ADDRSETUP

(1, 2, 3, ...)

Z DATA[15:0]

EBI_CSn

EBI_REn

RDSETUP

(0, 1, 2, ...)

RDSTRB

(1, 2, 3, ...)

RDHOLD

(0, 1, 2, ...)

EBI_DCLK

TFTHOLD

(0, 1, 2, ...)

TFTSETUP

(0, 1, 2, ...)

TFTSTART

(1, 2, 3, ...)

The timing parameters related to the horizontal timing are shown in Figure 14.42 (p. 207) . These

parameters are defined as pixel or EBI_DCLK counts. The horizontal porch widths are defined in the

HBPORCH and HFPORCH bitfields of the EBI_TFTHPORCH register. A porch which has its width

parameter programmed to 0 will be skipped. The width and start position of the horizontal synchronization

pulse EBI_HSYNC is programmed via the HSYNC and HSYNCSTART bitfields in the EBI_TFTHPORCH

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Figure 14.42. EBI TFT Horizontal Porch Timing

EBI_AD[15:0]

EBI_HSYNC

EBI_DATAEN

EBI_DCLK

HSZ

(1, 2, 3, ...)

HORIZONTAL BACK PORCH P1 ...

...

PHSZ HORIZONTAL FRONT PORCH

HBPORCH

(0, 1, 2, ...)

HFPORCH

(0, 1, 2, ...)

...

... ...

...

... ...

...

HSYNC

(1, 2, 3, ...)

HSYNCSTART

(0, 1, 2, ...)

The timing parameters related to the vertical timing are shown in Figure 14.43 (p. 207) . These

parameters are defined as line or EBI_HSYNC counts. The vertical porch widths are defined in the

VBPORCH and VFPORCH bitfields of the EBI_TFTVPORCH register. A porch which has its width

parameter programmed to 0 will be skipped. The width of the vertical synchronization pulse EBI_VSYNC

is programmed via the VSYNC bitfield in the EBI_TFTVPORCH register.

Figure 14.43. EBI TFT Vertical Porch Timing

LINES

EBI_HSYNC

VSZ

(1, 2, 3, ...)

VERTICAL BACK PORCH L1 ... LVSZ VERTICAL FRONT PORCH

VBPORCH

(0, 1, 2, ...) VFPORCH

(0, 1, 2, ...)

...

... ...

...

... ...

EBI_VSYNC

VSYNC

(1, 2, 3, ...)

The active edge of the EBI_DCLK and the other TFT related signals are by default driven off the positive

edge of the internal clock. The edges of the EBI_DCLK can also be driven off the negative edge of the

internal clock by setting the SHIFTDCLK bitfield in the EBI_TFTCTRL register to 1. The Direct Drive

engine then shifts the active DCLK edge 1/2 an internal cycle into the TFTHOLD state. Effectively the

length of TFTSETUP state is increased by 1/2 an internal cycle, whereas the length of the TFTHOLD

state is decreased by 1/2 an internal cycle. SHIFTDCLK should not be set if TFTHOLD is set to zero

cycles. The effect of the SHIFTDCLK bitfield is shown in Figure 14.44 (p. 207) and Figure 14.45 (p.

208) for a setup using the falling EBI_DCLK clock as its active edge.

Figure 14.44. EBI TFT Pixel Timing: EBI_DCLK driven off Positive Edge Internal Clock

EBI_AD[15:0]

EBI_DCLK

TFTHOLD

(0, 1, 2, ...)

PIXEL N

TFTSETUP

(0, 1, 2, ...)

INTERNAL CLOCK

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Figure 14.45. EBI TFT Pixel Timing: EBI_DCLK driven off Negative Edge Internal Clock

EBI_AD[15:0]

EBI_DCLK

TFTHOLD

(0, 1, 2, ...)

PIXEL N

TFTSETUP

(0, 1, 2, ...)

INTERNAL CLOCK

TFTSETUPHOLD

(½ + ½)

14.3.19 Control Signal Polarity

It is possible to individually configure the control signals to be active high/low by setting or clearing the

appropriate bits in the EBI_POLARITY register. When the ITS bitfield in the EBI_CTRL register is set to

0, the polarities defined in the EBI_POLARITY register applies to all 4 memory banks. When ITS is set

to 1 each memory bank uses an individual polarity definition. In this case register EBI_POLARITY only

applies to bank 0. Timing for bank n is then defined in the EBI_POLARITYn register.

The TFT control signals can also be individually configured to be active high/low by setting or clearing

the appropriate bits in the EBI_TFTPOLARITY register.

14.3.20 Pin Configuration

In order to give the EBI access to the external pins of the EFM32LG, the GPIO must be configured

accordingly. The lines must be set to Push-Pull, which is described in detail in the GPIO section.

All the EBI pins are enabled in the EBI_ROUTE register. The EBI_AD, EBI_WEn and EBI_REn pins

are all enabled by the EBIPEN bit, the EBI_CSn pins are enabled by the corresponding CSxPEN bit,

the EBI_ALE pin is enabled by the ALEPEN bit , the EBI_BL pins are enabled by the BLPEN bit, the

EBI_NANDWEn and EBI_NANDREn pins are enabled by the NANDPEN bit, the TFT pins EBI_DCLK,

EBI_VSYNC and EBI_HSYNC are all enabled by the TFTPEN bit, the EBI_DATAEN pin is enabled

by the DATAENPEN bit, the EBI_CSTFT pin is enabled by the CSTFTPEN bit, the EBI_A pins are

enabled by the ALB and APEN bitfields, and the EBI_ARDY pin is enabled by the ARDYPEN bit of the

EBI_ROUTE register.

For some of the EBI pins, alternative pin locations can be chosen by setting the LOCATION bitfield in

the EBI_ROUTE register. These alternative locations are specified in the datasheet.

14.3.21 Interrupts

The TFT controller has 6 separate interrupt flags (VSYNC, HSYNC, VBPORCH, VFPORCH, DDEMPTY,

DDJIT) in EBI_IF.

The VSYNC, HSYNC, VBPORCH, and VFPORCH interrupt flags indicate various synchronization points

during the display of a frame. Figure 14.46 (p. 209) shows the timing of the VSYNC, HSYNC,

VBPORCH, and VFPORCH interrupt flags. The VSYNC and HSYNC flags are set at the beginning of

a frame and at the beginning of a line respectively. The VBPORCH and VFPORCH flags are set at the

end of the vertical back porch and at the beginning of the vertical front porch respectively (provided that

the related porch is defined with a non-zero width).

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Figure 14.46. EBI TFT Interrupts

Visible Display

HSZ+1

HFPORCH

HBPORCH

VSZ+1

VFPORCH VBPORCH

VSYNC, HSYNC

HSYNC

... ...

VBPORCH

HSYNC

... ...

HSYNC

... ...

VFPORCH, HSYNC

The DDEMPTY interrupt flag indicates that the EBI_TFTDD register is empty during Direct Drive from

internal memory. The DDJIT interrupt flag indicates that the DCLKPERIOD is not met during Direct Drive

operation.

Setting one of the interrupt flags will result in an EBI interrupt if the corresponding interrupt enable bit is

set in the EBI_IEN register. All generated interrupts from the EBI will activate the same interrupt vector

when enabled.

14.3.22 DMA Request

In internal Direct Drive mode, when the DD bitfield in EBI_TFTCTRL register is INTERNAL, the TFT

controller sends out a DMA request when the pixel buffer EBI_TFTDD is empty and needs to be filled.

This request is initially set and it is cleared when EBI_TFTDD is written. It is set again once the pixel

data has been transferred to the display. One DMA request is generated for each visible pixel.

The masking and alpha blending hardware uses three DMA requests related to the status of thee internal

masking and alpha blending registers EBI_TFTPIXEL0, EBI_TFTPIXEL1, and EBI_TFTPIXEL. The

DMA request for EBI_TFTPIXEL0 indicates that new data can be written to be used for internal masking

or alpha blending. This request is initially set and it is cleared when EBI_TFTPIXEL0 is written. The

request is set again when EBI_TFTPIXEL is read. The DMA request for EBI_TFTPIXEL1 is initially set

and it is cleared when EBI_TFTPIXEL1 is written. Only when both EBI_TFTPIXEL0 and EBI_TFTPIXEL1

have been written, will a EBI_TFTPIXEL read set the DMA request for EBI_TFTPIXEL1 again. The DMA

request for EBI_TFTPIXEL indicates whether new masked and/or blended data is available for reading

in EBI_TFTPIXEL or not. It is set after completion of internal masking and alpha blending in reaction to

a write to EBI_TFTPIXEL0. It is cleared when EBI_TFTPIXEL is read.

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14.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 EBI_CTRL RW Control Register

0x004 EBI_ADDRTIMING RW Address Timing Register

0x008 EBI_RDTIMING RW Read Timing Register

0x00C EBI_WRTIMING RW Write Timing Register

0x010 EBI_POLARITY RW Polarity Register

0x014 EBI_ROUTE RW I/O Routing Register

0x018 EBI_ADDRTIMING1 RW Address Timing Register 1

0x01C EBI_RDTIMING1 RW Read Timing Register 1

0x020 EBI_WRTIMING1 RW Write Timing Register 1

0x024 EBI_POLARITY1 RW Polarity Register 1

0x028 EBI_ADDRTIMING2 RW Address Timing Register 2

0x02C EBI_RDTIMING2 RW Read Timing Register 2

0x030 EBI_WRTIMING2 RW Write Timing Register 2

0x034 EBI_POLARITY2 RW Polarity Register 2

0x038 EBI_ADDRTIMING3 RW Address Timing Register 3

0x03C EBI_RDTIMING3 RW Read Timing Register 3

0x040 EBI_WRTIMING3 RW Write Timing Register 3

0x044 EBI_POLARITY3 RW Polarity Register 3

0x048 EBI_PAGECTRL RW Page Control Register

0x04C EBI_NANDCTRL RW NAND Control Register

0x050 EBI_CMD W1 Command Register

0x054 EBI_STATUS R Status Register

0x058 EBI_ECCPARITY R ECC Parity register

0x05C EBI_TFTCTRL RW TFT Control Register

0x060 EBI_TFTSTATUS R TFT Status Register

0x064 EBI_TFTFRAMEBASE RW TFT Frame Base Register

0x068 EBI_TFTSTRIDE RW TFT Stride Register

0x06C EBI_TFTSIZE RW TFT Size Register

0x070 EBI_TFTHPORCH RW TFT Horizontal Porch Register

0x074 EBI_TFTVPORCH RW TFT Vertical Porch Register

0x078 EBI_TFTTIMING RW TFT Timing Register

0x07C EBI_TFTPOLARITY RW TFT Polarity Register

0x080 EBI_TFTDD RW TFT Direct Drive Data Register

0x084 EBI_TFTALPHA RW TFT Alpha Blending Register

0x088 EBI_TFTPIXEL0 RW TFT Pixel 0 Register

0x08C EBI_TFTPIXEL1 RW TFT Pixel 1 Register

0x090 EBI_TFTPIXEL R TFT Alpha Blending Result Pixel Register

0x094 EBI_TFTMASK RW TFT Masking Register

0x098 EBI_IF R Interrupt Flag Register

0x09C EBI_IFS W1 Interrupt Flag Set Register

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Offset Name Type Description

0x0A0 EBI_IFC W1 Interrupt Flag Clear Register

0x0A4 EBI_IEN RW Interrupt Enable Register

14.5 Register Description

14.5.1 EBI_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

ALTMAP

ITS

BL3

BL2

BL1

ARDYTO3DIS

ARDY3EN

ARDYTO2DIS

ARDY2EN

ARDYTO1DIS

ARDY1EN

ARDYTODIS

ARDYEN

NOIDLE3

NOIDLE2

NOIDLE1

NOIDLE

BANK3EN

BANK2EN

BANK1EN

BANK0EN

MODE3

MODE2

MODE1

MODE

Bit Name Reset Access Description

31 ALTMAP 0 RW Alternative Address Map Enable

This field enables or disables the alternative (256 MB per bank) address map.

30 ITS 0 RW Individual Timing Set, Line Polarity and Mode Definition Enable

This field enables or disables individual timing sets, line polarities and modes per bank.

29:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27 BL3 0 RW Byte Lane Enable for bank 3

Enables or disables the Byte Lane functionality for bank 3. Ignored when ITS = 0.

26 BL2 0 RW Byte Lane Enable for bank 2

Enables or disables the Byte Lane functionality for bank 2. Ignored when ITS = 0.

25 BL1 0 RW Byte Lane Enable for bank 1

Enables or disables the Byte Lane functionality for bank 1. Ignored when ITS = 0.

24 BL 0 RW Byte Lane Enable for bank 0

Enables or disables the Byte Lane functionality for bank 0. Applies to all banks when ITS = 0. Applies to only bank 0 when ITS = 1.

23 ARDYTO3DIS 0 RW ARDY Timeout Disable for bank 3

Enables or disables the ARDY timeout functionality for bank 3. The timeout value is 32 internal clock cycles. Ignored when ITS = 0.

22 ARDY3EN 0 RW ARDY Enable for bank 3

Enables or disables the ARDY functionality for bank 3. Ignored when ITS = 0.

21 ARDYTO2DIS 0 RW ARDY Timeout Disable for bank 2

Enables or disables the ARDY timeout functionality for bank 2. The timeout value is 32 internal clock cycles. Ignored when ITS = 0.

20 ARDY2EN 0 RW ARDY Enable for bank 2

Enables or disables the ARDY functionality for bank 2. Ignored when ITS = 0.

19 ARDYTO1DIS 0 RW ARDY Timeout Disable for bank 1

Enables or disables the ARDY timeout functionality for bank 1. The timeout value is 32 internal clock cycles. Ignored when ITS = 0.

18 ARDY1EN 0 RW ARDY Enable for bank 1

Enables or disables the ARDY functionality for bank 1. Ignored when ITS = 0.

17 ARDYTODIS 0 RW ARDY Timeout Disable

Enables or disables the ARDY timeout functionality. The timeout value is 32 internal clock cycles. Applies to all banks when ITS =

0. Applies to only bank 0 when ITS = 1.

16 ARDYEN 0 RW ARDY Enable

Enables or disables the ARDY functionality. Applies to all banks when ITS = 0. Applies to only bank 0 when ITS = 1.

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Bit Name Reset Access Description

15 NOIDLE3 0 RW No idle cycle insertion on bank 3.

Enables or disables idle state insertion between transfers for bank 3. Ignored when ITS = 0.

14 NOIDLE2 0 RW No idle cycle insertion on bank 2.

Enables or disables idle state insertion between transfers for bank 2. Ignored when ITS = 0.

13 NOIDLE1 0 RW No idle cycle insertion on bank 1.

Enables or disables idle state insertion between transfers for bank 1. Ignored when ITS = 0.

12 NOIDLE 0 RW No idle cycle insertion on bank 0.

Enables or disables idle state insertion between transfers for bank 0. Applies to all banks when ITS = 0. Applies to only bank 0

when ITS = 1.

11 BANK3EN 0 RW Bank 3 Enable

This field enables or disables bank 3.

10 BANK2EN 0 RW Bank 2 Enable

This field enables or disables bank 2.

9 BANK1EN 0 RW Bank 1 Enable

This field enables or disables bank 1.

8 BANK0EN 0 RW Bank 0 Enable

This field enables or disables bank 0.

7:6 MODE3 0x0 RW Mode 3

This field sets the access mode the EBI will use for interfacing devices on bank 3. Ignored when ITS = 0.

Value Mode Description

0 D8A8 EBI_AD drives 8 bit data, 8 bit address, ALE not used. Extended address bits can be

enabled on EBI_A in the EBI_ROUTE register.

1 D16A16ALE EBI_AD drives 16 bit data, 16 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

2 D8A24ALE EBI_AD drives 8 bit data, 24 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

3 D16 EBI_AD drives 16 bit data, ALE not used. Extended address bits can be enabled on

EBI_A in the EBI_ROUTE register.

5:4 MODE2 0x0 RW Mode 2

This field sets the access mode the EBI will use for interfacing devices on bank 2. Ignored when ITS = 0.

Value Mode Description

0 D8A8 EBI_AD drives 8 bit data, 8 bit address, ALE not used. Extended address bits can be

enabled on EBI_A in the EBI_ROUTE register.

1 D16A16ALE EBI_AD drives 16 bit data, 16 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

2 D8A24ALE EBI_AD drives 8 bit data, 24 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

3 D16 EBI_AD drives 16 bit data, ALE not used. Extended address bits can be enabled on

EBI_A in the EBI_ROUTE register.

3:2 MODE1 0x0 RW Mode 1

This field sets the access mode the EBI will use for interfacing devices on bank 1. Ignored when ITS = 0.

Value Mode Description

0 D8A8 EBI_AD drives 8 bit data, 8 bit address, ALE not used. Extended address bits can be

enabled on EBI_A in the EBI_ROUTE register.

1 D16A16ALE EBI_AD drives 16 bit data, 16 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

2 D8A24ALE EBI_AD drives 8 bit data, 24 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

3 D16 EBI_AD drives 16 bit data, ALE not used. Extended address bits can be enabled on

EBI_A in the EBI_ROUTE register.

1:0 MODE 0x0 RW Mode

This field sets the access mode the EBI will use for interfacing devices. Applies to all banks when ITS = 0. Applies to only bank

0 when ITS = 1.

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Bit Name Reset Access Description

Value Mode Description

0 D8A8 EBI_AD drives 8 bit data, 8 bit address, ALE not used. Extended address bits can be

enabled on EBI_A in the EBI_ROUTE register.

1 D16A16ALE EBI_AD drives 16 bit data, 16 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

2 D8A24ALE EBI_AD drives 8 bit data, 24 bit address, ALE is used for address latching. Extended

address bits can be enabled on EBI_A in the EBI_ROUTE register.

3 D16 EBI_AD drives 16 bit data, ALE not used. Extended address bits can be enabled on

EBI_A in the EBI_ROUTE register.

14.5.2 EBI_ADDRTIMING - Address Timing Register

Offset Bit Position

0x004

Reset

0x3

Access

Name

HALFALE

ADDRHOLD

ADDRSETUP

Bit Name Reset Access Description

31:29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 HALFALE 0 RW Half Cycle ALE Strobe Duration Enable

Enables or disables half cycle duration of the ALE strobe in the last ADDRSETUP cycle.

27:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 ADDRHOLD 0x3 RW Address Hold Time

Sets the number of cycles the address is held after ALE is asserted.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 ADDRSETUP 0x3 RW Address Setup Time

Sets the number of cycles the address is driven onto the ADDRDAT bus before ALE is asserted. If set to 0, 1 cycle is inserted by HW.

14.5.3 EBI_RDTIMING - Read Timing Register

Offset Bit Position

0x008

Reset

0x3

0x3F

0x3

Access

Name

PAGEMODE

PREFETCH

HALFRE

RDHOLD

RDSTRB

RDSETUP

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30 PAGEMODE 0 RW Page Mode Access Enable

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Bit Name Reset Access Description

Enables or disables page mode reads.

29 PREFETCH 0 RW Prefetch Enable

Enables or disables prefetching of data from sequential address.

28 HALFRE 0 RW Half Cycle REn Strobe Duration Enable

Enables or disables half cycle duration of the REn strobe in the last RDSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 RDHOLD 0x3 RW Read Hold Time

Sets the number of cycles CSn is held active after the REn is deasserted. This interval is used for bus turnaround.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 RDSTRB 0x3F RW Read Strobe Time

Sets the number of cycles the REn is held active. After the specified number of cycles, data is read. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 RDSETUP 0x3 RW Read Setup Time

Sets the number of cycles the address setup before REn is asserted.

14.5.4 EBI_WRTIMING - Write Timing Register

Offset Bit Position

0x00C

Reset

0x3

0x3F

0x3

Access

Name

WBUFDIS

HALFWE

WRHOLD

WRSTRB

WRSETUP

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29 WBUFDIS 0 RW Write Buffer Disable

Enables or disables the write buffer.

28 HALFWE 0 RW Half Cycle WEn Strobe Duration Enable

Enables or disables half cycle duration of the WEn strobe in the last WRSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 WRHOLD 0x3 RW Write Hold Time

Sets the number of cycles CSn is held active after the WEn is deasserted.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 WRSTRB 0x3F RW Write Strobe Time

Sets the number of cycles the WEn is held active. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 WRSETUP 0x3 RW Write Setup Time

Sets the number of cycles the address setup before WEn is asserted.

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14.5.5 EBI_POLARITY - Polarity Register

Offset Bit Position

0x010

Reset

Access

Name

BLPOL

ARDYPOL

ALEPOL

WEPOL

REPOL

CSPOL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 BLPOL 0 RW BL Polarity

Sets the polarity of the EBI_BLn lines.

Value Mode Description

0 ACTIVELOW BLn[1:0] are active low.

1 ACTIVEHIGH BLn[1:0] are active high.

4 ARDYPOL 0 RW ARDY Polarity

Sets the polarity of the EBI_ARDY line.

Value Mode Description

0 ACTIVELOW ARDY is active low.

1 ACTIVEHIGH ARDY is active high.

3 ALEPOL 0 RW Address Latch Polarity

Sets the polarity of the EBI_ALE line.

Value Mode Description

0 ACTIVELOW ALE is active low.

1 ACTIVEHIGH ALE is active high.

2 WEPOL 0 RW Write Enable Polarity

Sets the polarity of the EBI_WEn and EBI_NANDWEn lines.

Value Mode Description

0 ACTIVELOW WEn and NANDWEn are active low.

1 ACTIVEHIGH WEn and NANDWEn are active high.

1 REPOL 0 RW Read Enable Polarity

Sets the polarity of the EBI_REn and EBI_NANDREn lines.

Value Mode Description

0 ACTIVELOW REn and NANDREn are active low.

1 ACTIVEHIGH REn and NANDREn are active high.

0 CSPOL 0 RW Chip Select Polarity

Sets the polarity of the EBI_CSn line.

Value Mode Description

0 ACTIVELOW CSn is active low.

1 ACTIVEHIGH CSn is active high.

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14.5.6 EBI_ROUTE - I/O Routing Register

Offset Bit Position

0x014

Reset

0x0

0x00

0x0

Access

Name

LOCATION

CSTFTPEN

DATAENPEN

TFTPEN

APEN

ALB

NANDPEN

BLPEN

ARDYPEN

ALEPEN

CS3PEN

CS2PEN

CS1PEN

CS0PEN

EBIPEN

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:28 LOCATION 0x0 RW I/O Location

Decides the location of the EBI I/O pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 CSTFTPEN 0 RW EBI_CSTFT Pin Enable

When set, the EBI_CSTFT pin is enabled

25 DATAENPEN 0 RW EBI_TFT Pin Enable

When set, the EBI_DATAEN pin is enabled

24 TFTPEN 0 RW EBI_TFT Pin Enable

When set, the EBI_DCLK, EBI_VSYNC and EBI_HSYNC pins are enabled

23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:18 APEN 0x00 RW EBI_A Pin Enable

Selects which non-multiplexed address lines are enabled on EBI_A. The lower bound L is set to 0, 8, 16 or 24 as defined in the

ALB field.

Value Mode Description

0 A0 All EBI_A pins are disabled.

5 A5 EBI_A[4:L] pins enabled.

6 A6 EBI_A[5:L] pins enabled.

7 A7 EBI_A[6:L] pins enabled.

8 A8 EBI_A[7:L] pins enabled.

9 A9 EBI_A[8:L] pins enabled.

10 A10 EBI_A[9:L] pins enabled.

11 A11 EBI_A[10:L] pins enabled.

12 A12 EBI_A[11:L] pins enabled.

13 A13 EBI_A[12:L] pins enabled.

14 A14 EBI_A[13:L] pins enabled.

15 A15 EBI_A[14:L] pins enabled.

16 A16 EBI_A[15:L] pins enabled.

17 A17 EBI_A[16:L] pins enabled.

18 A18 EBI_A[17:L] pins enabled.

19 A19 EBI_A[18:L] pins enabled.

20 A20 EBI_A[19:L] pins enabled.

21 A21 EBI_A[20:L] pins enabled.

22 A22 EBI_A[21:L] pins enabled.

23 A23 EBI_A[22:L] pins enabled.

24 A24 EBI_A[23:L] pins enabled.

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Bit Name Reset Access Description

Value Mode Description

25 A25 EBI_A[24:L] pins enabled.

26 A26 EBI_A[25:L] pins enabled.

27 A27 EBI_A[26:L] pins enabled.

28 A28 EBI_A[27:L] pins enabled.

17:16 ALB 0x0 RW Sets the lower bound for EBI_A enabling

Sets the lower bound of the EBI_A lines which can be enabled in the APEN field.

Value Mode Description

0 A0 Address lines from EBI_A[0] and upwards can be enabled via APEN.

1 A8 Address lines from EBI_A[8] and upwards can be enabled via APEN.

2 A16 Address lines from EBI_A[16] and upwards can be enabled via APEN.

3 A24 Address lines from EBI_A[24] and upwards can be enabled via APEN.

15:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 NANDPEN 0 RW NANDRE and NANDWE Pin Enable

When set, the NANDREn and NANDWEn Pin pins are enabled

11:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 BLPEN 0 RW EBI_BL[1:0] Pin Enable

When set, the EBI_BL[1:0] pins are enabled

6 ARDYPEN 0 RW EBI_ARDY Pin Enable

When set, the EBI_ARDY pin is enabled

5 ALEPEN 0 RW EBI_ALE Pin Enable

When set, the EBI_ALE pin is enabled

4 CS3PEN 0 RW EBI_CS3 Pin Enable

When set, the EBI_CS3 pin is enabled

3 CS2PEN 0 RW EBI_CS2 Pin Enable

When set, the EBI_CS2 pin is enabled

2 CS1PEN 0 RW EBI_CS1 Pin Enable

When set, the EBI_CS1 pin is enabled

1 CS0PEN 0 RW EBI_CS0 Pin Enable

When set, the EBI_CS0 pin is enabled

0 EBIPEN 0 RW EBI Pin Enable

When set, the EBI_AD[15:0], EBI_WEn and EBI_REn pins are enabled

14.5.7 EBI_ADDRTIMING1 - Address Timing Register 1

Offset Bit Position

0x018

Reset

0x3

Access

Name

HALFALE

ADDRHOLD

ADDRSETUP

Bit Name Reset Access Description

31:29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 HALFALE 0 RW Half Cycle ALE Strobe Duration Enable

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Bit Name Reset Access Description

Enables or disables half cycle duration of the ALE strobe in the last address setup cycle.

27:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 ADDRHOLD 0x3 RW Address Hold Time

Sets the number of cycles the address is held after ALE is asserted.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 ADDRSETUP 0x3 RW Address Setup Time

Sets the number of cycles the address is driven onto the ADDRDAT bus before ALE is asserted. If set to 0, 1 cycle is inserted by HW.

14.5.8 EBI_RDTIMING1 - Read Timing Register 1

Offset Bit Position

0x01C

Reset

0x3

0x3F

0x3

Access

Name

PAGEMODE

PREFETCH

HALFRE

RDHOLD

RDSTRB

RDSETUP

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30 PAGEMODE 0 RW Page Mode Access Enable

Enables or disables page mode reads.

29 PREFETCH 0 RW Prefetch Enable

Enables or disables prefetching of data from sequential address.

28 HALFRE 0 RW Half Cycle REn Strobe Duration Enable

Enables or disables half cycle duration of the REn strobe in the last RDSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 RDHOLD 0x3 RW Read Hold Time

Sets the number of cycles CSn is held active after the REn is deasserted. This interval is used for bus turnaround.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 RDSTRB 0x3F RW Read Strobe Time

Sets the number of cycles the REn is held active. After the specified number of cycles, data is read. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 RDSETUP 0x3 RW Read Setup Time

Sets the number of cycles the address setup before REn is asserted.

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14.5.9 EBI_WRTIMING1 - Write Timing Register 1

Offset Bit Position

0x020

Reset

0x3

0x3F

0x3

Access

Name

WBUFDIS

HALFWE

WRHOLD

WRSTRB

WRSETUP

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29 WBUFDIS 0 RW Write Buffer Disable

Enables or disables the write buffer.

28 HALFWE 0 RW Half Cycle WEn Strobe Duration Enable

Enables or disables half cycle duration of the WEn strobe in the last WRSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 WRHOLD 0x3 RW Write Hold Time

Sets the number of cycles CSn is held active after the WEn is deasserted.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 WRSTRB 0x3F RW Write Strobe Time

Sets the number of cycles the WEn is held active. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 WRSETUP 0x3 RW Write Setup Time

Sets the number of cycles the address setup before WEn is asserted.

14.5.10 EBI_POLARITY1 - Polarity Register 1

Offset Bit Position

0x024

Reset

Access

Name

BLPOL

ARDYPOL

ALEPOL

WEPOL

REPOL

CSPOL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 BLPOL 0 RW BL Polarity

Sets the polarity of the EBI_BLn lines.

Value Mode Description

0 ACTIVELOW BLn[1:0] are active low.

1 ACTIVEHIGH BLn[1:0] are active high.

4 ARDYPOL 0 RW ARDY Polarity

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Bit Name Reset Access Description

Sets the polarity of the EBI_ARDY line.

Value Mode Description

0 ACTIVELOW ARDY is active low.

1 ACTIVEHIGH ARDY is active high.

3 ALEPOL 0 RW Address Latch Polarity

Sets the polarity of the EBI_ALE line.

Value Mode Description

0 ACTIVELOW ALE is active low.

1 ACTIVEHIGH ALE is active high.

2 WEPOL 0 RW Write Enable Polarity

Sets the polarity of the EBI_WEn and EBI_NANDWEn lines.

Value Mode Description

0 ACTIVELOW WEn and NANDWEn are active low.

1 ACTIVEHIGH WEn and NANDWEn are active high.

1 REPOL 0 RW Read Enable Polarity

Sets the polarity of the EBI_REn and EBI_NANDREn lines.

Value Mode Description

0 ACTIVELOW REn and NANDREn are active low.

1 ACTIVEHIGH REn and NANDREn are active high.

0 CSPOL 0 RW Chip Select Polarity

Sets the polarity of the EBI_CSn line.

Value Mode Description

0 ACTIVELOW CSn is active low.

1 ACTIVEHIGH CSn is active high.

14.5.11 EBI_ADDRTIMING2 - Address Timing Register 2

Offset Bit Position

0x028

Reset

0x3

Access

Name

HALFALE

ADDRHOLD

ADDRSETUP

Bit Name Reset Access Description

31:29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 HALFALE 0 RW Half Cycle ALE Strobe Duration Enable

Enables or disables half cycle duration of the ALE strobe in the last address setup cycle.

27:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 ADDRHOLD 0x3 RW Address Hold Time

Sets the number of cycles the address is held after ALE is asserted.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 ADDRSETUP 0x3 RW Address Setup Time

Sets the number of cycles the address is driven onto the ADDRDAT bus before ALE is asserted. If set to 0, 1 cycle is inserted by HW.

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14.5.12 EBI_RDTIMING2 - Read Timing Register 2

Offset Bit Position

0x02C

Reset

0x3

0x3F

0x3

Access

Name

PAGEMODE

PREFETCH

HALFRE

RDHOLD

RDSTRB

RDSETUP

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30 PAGEMODE 0 RW Page Mode Access Enable

Enables or disables page mode reads.

29 PREFETCH 0 RW Prefetch Enable

Enables or disables prefetching of data from sequential address.

28 HALFRE 0 RW Half Cycle REn Strobe Duration Enable

Enables or disables half cycle duration of the REn strobe in the last RDSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 RDHOLD 0x3 RW Read Hold Time

Sets the number of cycles CSn is held active after the REn is deasserted. This interval is used for bus turnaround.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 RDSTRB 0x3F RW Read Strobe Time

Sets the number of cycles the REn is held active. After the specified number of cycles, data is read. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 RDSETUP 0x3 RW Read Setup Time

Sets the number of cycles the address setup before REn is asserted.

14.5.13 EBI_WRTIMING2 - Write Timing Register 2

Offset Bit Position

0x030

Reset

0x3

0x3F

0x3

Access

Name

WBUFDIS

HALFWE

WRHOLD

WRSTRB

WRSETUP

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29 WBUFDIS 0 RW Write Buffer Disable

Enables or disables the write buffer.

28 HALFWE 0 RW Half Cycle WEn Strobe Duration Enable

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Bit Name Reset Access Description

Enables or disables half cycle duration of the WEn strobe in the last WRSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 WRHOLD 0x3 RW Write Hold Time

Sets the number of cycles CSn is held active after the WEn is deasserted.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 WRSTRB 0x3F RW Write Strobe Time

Sets the number of cycles the WEn is held active. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 WRSETUP 0x3 RW Write Setup Time

Sets the number of cycles the address setup before WEn is asserted.

14.5.14 EBI_POLARITY2 - Polarity Register 2

Offset Bit Position

0x034

Reset

Access

Name

BLPOL

ARDYPOL

ALEPOL

WEPOL

REPOL

CSPOL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 BLPOL 0 RW BL Polarity

Sets the polarity of the EBI_BLn lines.

Value Mode Description

0 ACTIVELOW BLn[1:0] are active low.

1 ACTIVEHIGH BLn[1:0] are active high.

4 ARDYPOL 0 RW ARDY Polarity

Sets the polarity of the EBI_ARDY line.

Value Mode Description

0 ACTIVELOW ARDY is active low.

1 ACTIVEHIGH ARDY is active high.

3 ALEPOL 0 RW Address Latch Polarity

Sets the polarity of the EBI_ALE line.

Value Mode Description

0 ACTIVELOW ALE is active low.

1 ACTIVEHIGH ALE is active high.

2 WEPOL 0 RW Write Enable Polarity

Sets the polarity of the EBI_WEn and EBI_NANDWEn lines.

Value Mode Description

0 ACTIVELOW WEn and NANDWEn are active low.

1 ACTIVEHIGH WEn and NANDWEn are active high.

1 REPOL 0 RW Read Enable Polarity

Sets the polarity of the EBI_REn and EBI_NANDREn lines.

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Bit Name Reset Access Description

Value Mode Description

0 ACTIVELOW REn and NANDREn are active low.

1 ACTIVEHIGH REn and NANDREn are active high.

0 CSPOL 0 RW Chip Select Polarity

Sets the polarity of the EBI_CSn line.

Value Mode Description

0 ACTIVELOW CSn is active low.

1 ACTIVEHIGH CSn is active high.

14.5.15 EBI_ADDRTIMING3 - Address Timing Register 3

Offset Bit Position

0x038

Reset

0x3

Access

Name

HALFALE

ADDRHOLD

ADDRSETUP

Bit Name Reset Access Description

31:29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 HALFALE 0 RW Half Cycle ALE Strobe Duration Enable

Enables or disables half cycle duration of the ALE strobe in the last address setup cycle.

27:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 ADDRHOLD 0x3 RW Address Hold Time

Sets the number of cycles the address is held after ALE is asserted.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 ADDRSETUP 0x3 RW Address Setup Time

Sets the number of cycles the address is driven onto the ADDRDAT bus before ALE is asserted. If set to 0, 1 cycle is inserted by HW.

14.5.16 EBI_RDTIMING3 - Read Timing Register 3

Offset Bit Position

0x03C

Reset

0x3

0x3F

0x3

Access

Name

PAGEMODE

PREFETCH

HALFRE

RDHOLD

RDSTRB

RDSETUP

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

30 PAGEMODE 0 RW Page Mode Access Enable

Enables or disables page mode reads.

29 PREFETCH 0 RW Prefetch Enable

Enables or disables prefetching of data from sequential address.

28 HALFRE 0 RW Half Cycle REn Strobe Duration Enable

Enables or disables half cycle duration of the REn strobe in the last RDSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 RDHOLD 0x3 RW Read Hold Time

Sets the number of cycles CSn is held active after the REn is deasserted. This interval is used for bus turnaround.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 RDSTRB 0x3F RW Read Strobe Time

Sets the number of cycles the REn is held active. After the specified number of cycles, data is read. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 RDSETUP 0x3 RW Read Setup Time

Sets the number of cycles the address setup before REn is asserted.

14.5.17 EBI_WRTIMING3 - Write Timing Register 3

Offset Bit Position

0x040

Reset

0x3

0x3F

0x3

Access

Name

WBUFDIS

HALFWE

WRHOLD

WRSTRB

WRSETUP

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29 WBUFDIS 0 RW Write Buffer Disable

Enables or disables the write buffer.

28 HALFWE 0 RW Half Cycle WEn Strobe Duration Enable

Enables or disables half cycle duration of the WEn strobe in the last WRSTRB cycle.

27:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 WRHOLD 0x3 RW Write Hold Time

Sets the number of cycles CSn is held active after the WEn is deasserted.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 WRSTRB 0x3F RW Write Strobe Time

Sets the number of cycles the WEn is held active. If set to 0, 1 cycle is inserted by HW.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 WRSETUP 0x3 RW Write Setup Time

Sets the number of cycles the address setup before WEn is asserted.

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14.5.18 EBI_POLARITY3 - Polarity Register 3

Offset Bit Position

0x044

Reset

Access

Name

BLPOL

ARDYPOL

ALEPOL

WEPOL

REPOL

CSPOL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 BLPOL 0 RW BL Polarity

Sets the polarity of the EBI_BLn lines.

Value Mode Description

0 ACTIVELOW BLn[1:0] are active low.

1 ACTIVEHIGH BLn[1:0] are active high.

4 ARDYPOL 0 RW ARDY Polarity

Sets the polarity of the EBI_ARDY line.

Value Mode Description

0 ACTIVELOW ARDY is active low.

1 ACTIVEHIGH ARDY is active high.

3 ALEPOL 0 RW Address Latch Polarity

Sets the polarity of the EBI_ALE line.

Value Mode Description

0 ACTIVELOW ALE is active low.

1 ACTIVEHIGH ALE is active high.

2 WEPOL 0 RW Write Enable Polarity

Sets the polarity of the EBI_WEn and EBI_NANDWEn lines.

Value Mode Description

0 ACTIVELOW WEn and NANDWEn are active low.

1 ACTIVEHIGH WEn and NANDWEn are active high.

1 REPOL 0 RW Read Enable Polarity

Sets the polarity of the EBI_REn and EBI_NANDREn lines.

Value Mode Description

0 ACTIVELOW REn and NANDREn are active low.

1 ACTIVEHIGH REn and NANDREn are active high.

0 CSPOL 0 RW Chip Select Polarity

Sets the polarity of the EBI_CSn line.

Value Mode Description

0 ACTIVELOW CSn is active low.

1 ACTIVEHIGH CSn is active high.

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14.5.19 EBI_PAGECTRL - Page Control Register

Offset Bit Position

0x048

Reset

0x00

0x7

0x0

Access

Name

KEEPOPEN

RDPA

INCHIT

PAGELEN

Bit Name Reset Access Description

31:27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26:20 KEEPOPEN 0x00 RW Maximum Page Open Time.

Sets the maximum number of consecutive cycles a page can be considered open. Needs to be larger than 0 in order to be able

to benefit from RDPA timing.

19:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 RDPA 0x7 RW Page Read Access Time

Sets the number of cycles needed for intrapage page access time. If set to 0, 1 cycle is inserted by HW.

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 INCHIT 0 RW Intrapage hit only on incremental addresses

Sets whether page hits occur on any member in a page or only on incremental addresses.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 PAGELEN 0x0 RW Page Length

Sets the page length.

Value Mode Description

0 MEMBER4 4 members in a page.

1 MEMBER8 8 members in a page.

2 MEMBER16 16 members in a page.

3 MEMBER32 32 members in a page.

14.5.20 EBI_NANDCTRL - NAND Control Register

Offset Bit Position

0x04C

Reset

0x0

Access

Name

BANKSEL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 BANKSEL 0x0 RW NAND Flash Bank

This field sets the Memory Bank which is connected to a NAND Flash device

Value Mode Description

0 BANK0 Memory bank 0 is connected to a NAND Flash device.

1 BANK1 Memory bank 1 is connected to a NAND Flash device.

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Bit Name Reset Access Description

Value Mode Description

2 BANK2 Memory bank 2 is connected to a NAND Flash device.

3 BANK3 Memory bank 3 is connected to a NAND Flash device.

3:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 EN 0 RW NAND Flash control enable

This field enables NAND Flash control for the memory bank defined in BANK.

14.5.21 EBI_CMD - Command Register

Offset Bit Position

0x050

Reset

Access

Name

ECCCLEAR

ECCSTOP

ECCSTART

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 ECCCLEAR 0 W1 Error Correction Code Clear

Write to 1 to clear ECCPARITY.

1 ECCSTOP 0 W1 Error Correction Code Generation Stop

Write to 1 to stop ECC generation.

0 ECCSTART 0 W1 Error Correction Code Generation Start

Write to 1 to start ECC generation.

14.5.22 EBI_STATUS - Status Register

Offset Bit Position

0x054

Reset

Access

Name

TFTDDEMPTY

DDACT

TFTPIXELFULL

TFTPIXEL1EMPTY

TFTPIXEL0EMPTY

ECCACT

AHBACT

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 TFTDDEMPTY 0 R EBI_TFTDD register is empty.

Indicates that EBI_TFTDD register is empty.

12 DDACT 0 R EBI Busy with Direct Drive Transactions.

Indicates that EBI is busy with Direct Drive Transactions.

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 TFTPIXELFULL 0 R EBI_TFTPIXEL0 is full.

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Bit Name Reset Access Description

Indicates that EBI_TFTPIXEL is full.

9 TFTPIXEL1EMPTY 0 R EBI_TFTPIXEL1 is empty.

Indicates that EBI_TFTPIXEL1 is empty.

8 TFTPIXEL0EMPTY 0 R EBI_TFTPIXEL0 is empty.

Indicates that EBI_TFTPIXEL0 is empty.

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 ECCACT 0 R EBI ECC Generation Active.

Indicates that EBI is generating ECC.

3:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 AHBACT 0 R EBI Busy with AHB Transaction.

Indicates that EBI is busy with an AHB Transaction.

14.5.23 EBI_ECCPARITY - ECC Parity register

Offset Bit Position

0x058

Reset

0x00000000

Access

Name

ECCPARITY

Bit Name Reset Access Description

31:0 ECCPARITY 0x00000000 R ECC Parity Data

ECC Parity Data.

14.5.24 EBI_TFTCTRL - TFT Control Register

Offset Bit Position

0x05C

Reset

0x0

Access

Name

RGBMODE

BANKSEL

WIDTH

COLOR1SRC

INTERLEAVE

FBCTRIG

SHIFTDCLKEN

MASKBLEND

Bit Name Reset Access Description

31:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24 RGBMODE 0 RW TFT RGB Mode

This field sets TFT RGB Mode.

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Bit Name Reset Access Description

Value Mode Description

0 RGB565 RGB data is 565.

1 RGB555 RGB data is 555.

23:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:20 BANKSEL 0x0 RW Graphics Bank

This field sets the Memory Bank containing the Frame Buffer

Value Mode Description

0 BANK0 Memory bank 0 is used for Direct Drive, Masking, and Alpha Blending.

1 BANK1 Memory bank 1 is used for Direct Drive, Masking, and Alpha Blending.

2 BANK2 Memory bank 2 is used for Direct Drive, Masking, and Alpha Blending.

3 BANK3 Memory bank 3 is used for Direct Drive, Masking, and Alpha Blending.

19:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 WIDTH 0 RW TFT Transaction Width

This field sets TFT tranaction width.

Value Mode Description

0 BYTE TFT Data is 8 bit wide.

1 HALFWORD TFT Data is 16 bit wide.

15:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 COLOR1SRC 0 RW Masking/Alpha Blending Color1 Source

This field sets the Masking/Alpha Blending Color1 Source.

Value Mode Description

0 MEM Masking/Alpha Blending color 1 is read from external memory.

1 PIXEL1 Masking/Alpha Blending color 1 is read from EBI_TFTPIXEL1.

11:10 INTERLEAVE 0x0 RW Interleave Mode

This field sets the TFT Direct Drive Interleave mode.

Value Mode Description

0 UNLIMITED Allow unlimited interleaved EBI accesses per EBI_DCLK period. This can cause jitter

on the EBI_DCLK

1 ONEPERDCLK Allow 1 interleaved EBI access per EBI_DCLK period.

2 PORCH Only allow EBI accesses during TFT porches.

9 FBCTRIG 0 RW TFT Frame Base Copy Trigger

Sets the trigger on which the TFTFRAMEBASE is copied into an internal buffer. Direct Drive address generation is based on the

internal buffer.

Value Mode Description

0 VSYNC TFTFRAMEBASE is buffered on the vertical synchronization event EBI_VSYNC.

1 HSYNC TFTFRAMEBASE is buffered on the horizontal synchronization event EBI_HSYNC.

8 SHIFTDCLKEN 0 RW TFT EBI_DCLK Shift Enable

When this bit is set, EBI_DCLK edges are driven off the negative (instead of the positive) edge of the internal clock. SHIFTDCLKEN

is only allowed to be set to 1 if TFTHOLD in EBI_TFTTIMING is at least 1.

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4:2 MASKBLEND 0x0 RW TFT Mask and Blend Mode

This field sets the Mask and Blend Mode.

Value Mode Description

0 DISABLED Masking and Blending are disabled.

1 IMASK Internal Masking is enabled.

2 IALPHA Internal Alpha Blending is enabled.

3 IMASKIALPHA Internal Masking and Alpha Blending are enabled.

5 EMASK External Masking is enabled.

6 EALPHA External Alpha Blending is enabled.

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Bit Name Reset Access Description

Value Mode Description

7 EMASKEALPHA External Masking and Alpha Blending are enabled.

1:0 DD 0x0 RW TFT Direct Drive Mode

This field sets the Direct Mode.

Value Mode Description

0 DISABLED Direct Drive is disabled.

1 INTERNAL Direct Drive from internal memory enabled and started.

2 EXTERNAL Direct Drive from external memory enabled and started.

14.5.25 EBI_TFTSTATUS - TFT Status Register

Offset Bit Position

0x060

Reset

0x000

Access

Name

VCNT

HCNT

Bit Name Reset Access Description

31:27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26:16 VCNT 0x000 R Vertical Count

Contains the current line position within a frame (initial line in vertical back porch has VCNT = 0).

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:0 HCNT 0x000 R Horizontal Count

Contains the current pixel position within a line (initial pixel in horizontal backporch has HCNT = 0).

14.5.26 EBI_TFTFRAMEBASE - TFT Frame Base Register

Offset Bit Position

0x064

Reset

0x0000000

Access

Name

FRAMEBASE

Bit Name Reset Access Description

31:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27:0 FRAMEBASE 0x0000000 RW Frame Base Address

Sets the frame base address.

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14.5.27 EBI_TFTSTRIDE - TFT Stride Register

Offset Bit Position

0x068

Reset

0x000

Access

Name

HSTRIDE

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 HSTRIDE 0x000 RW Horizontal Stride

Sets the horizontal stride added to the Direct Drive address at the end of each line.

14.5.28 EBI_TFTSIZE - TFT Size Register

Offset Bit Position

0x06C

Reset

0x000

Access

Name

VSZ

HSZ

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 VSZ 0x000 RW Vertical Size (excluding porches)

Sets the vertical size in lines. Set to required size minus 1.

15:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:0 HSZ 0x000 RW Horizontal Size (excluding porches)

Sets the horizontal size in pixels. Set to required size minus 1.

14.5.29 EBI_TFTHPORCH - TFT Horizontal Porch Register

Offset Bit Position

0x070

Reset

0x0

0x00

Access

Name

HSYNCSTART

HBPORCH

HFPORCH

HSYNC

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Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29:28 HSYNCSTART 0x0 RW HSYNC Start Delay

Sets the HSYNC start position into the horizontal back porch in DCLK cycles.

27:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:18 HBPORCH 0x00 RW Horizontal Back Porch Size

Sets the horizontal back porch size in pixels.

17:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:8 HFPORCH 0x00 RW Horizontal Front Porch Size

Sets the horizontal front porch size in pixels.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:0 HSYNC 0x00 RW Horizontal Synchronization Pulse Width

Sets the horizontal synchronization pulse width. Set to required width minus 1. Width is reduced in case HSYNCSTART > 0.

14.5.30 EBI_TFTVPORCH - TFT Vertical Porch Register

Offset Bit Position

0x074

Reset

0x00

Access

Name

VBPORCH

VFPORCH

VSYNC

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:18 VBPORCH 0x00 RW Vertical Back Porch Size

Sets the Vertical back porch size in pixels.

17:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:8 VFPORCH 0x00 RW Vertical Front Porch Size

Sets the Vertical front porch size in pixels.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:0 VSYNC 0x00 RW Vertical Synchronization Pulse Width

Sets the Vertical synchronization pulse width. Set to required width minus 1.

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14.5.31 EBI_TFTTIMING - TFT Timing Register

Offset Bit Position

0x078

Reset

0x0

0x000

Access

Name

TFTHOLD

TFTSETUP

TFTSTART

DCLKPERIOD

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29:28 TFTHOLD 0x0 RW TFT Hold Time

Sets the number of internal clock cycles the RGB data is held after the active edge of EBI_DCLK.

27:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:24 TFTSETUP 0x0 RW TFT Setup Time

Sets the number of internal clock cycles the RGB data is driven before the active edge of EBI_DCLK.

23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:12 TFTSTART 0x000 RW TFT Direct Drive Transaction Start

Sets the starting position of the External Direct Drive Transaction relative to the DCLK inactive edge.

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:0 DCLKPERIOD 0x000 RW TFT Direct Drive Transaction (EBI_DCLK) Period

Sets the Direct Drive transaction (EBI_DCLK) period in internal cycles. Set to required cycle count minus 1.

14.5.32 EBI_TFTPOLARITY - TFT Polarity Register

Offset Bit Position

0x07C

Reset

Access

Name

VSYNCPOL

HSYNCPOL

DATAENPOL

DCLKPOL

CSPOL

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 VSYNCPOL 0 RW VSYNC Polarity

Sets the polarity of the EBI_VSYNC line.

Value Mode Description

0 ACTIVELOW VSYNC is active low.

1 ACTIVEHIGH VSYNC is active high.

3 HSYNCPOL 0 RW Address Latch Polarity

Sets the polarity of the EBI_HSYNC line.

Value Mode Description

0 ACTIVELOW HSYNC is active low.

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Bit Name Reset Access Description

Value Mode Description

1 ACTIVEHIGH HSYNC is active high.

2 DATAENPOL 0 RW TFT DATAEN Polarity

Sets the polarity of the EBI_DATAEN line.

Value Mode Description

0 ACTIVELOW DATAEN is active low.

1 ACTIVEHIGH DATAEN is active high.

1 DCLKPOL 0 RW TFT DCLK Polarity

Sets the active edge polarity of the EBI_DCLK line.

Value Mode Description

0 ACTIVEFALLING DCLK falling edge is the active edge.

1 ACTIVERISING DCLK rising edge the active edge.

0 CSPOL 0 RW TFT Chip Select Polarity

Sets the polarity of the EBI_CSTFT line.

Value Mode Description

0 ACTIVELOW CSTFT is active low.

1 ACTIVEHIGH CSTFT is active high.

14.5.33 EBI_TFTDD - TFT Direct Drive Data Register

Offset Bit Position

0x080

Reset

0x0000

Access

Name

DATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DATA 0x0000 RW TFT Direct Drive Data from Internal Memory

Sets the RGB value used when Direct Drive from internal memory is used (DD = INTERNAL)

14.5.34 EBI_TFTALPHA - TFT Alpha Blending Register

Offset Bit Position

0x084

Reset

0x000

Access

Name

ALPHA

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Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 ALPHA 0x000 RW TFT Alpha Blending Factor

Sets the alpha blending factor. The maximum value is 256.

14.5.35 EBI_TFTPIXEL0 - TFT Pixel 0 Register

Offset Bit Position

0x088

Reset

0x0000

Access

Name

DATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DATA 0x0000 RW RGB data.

Sets the RGB data value according to the format defined in RGBMODE.

14.5.36 EBI_TFTPIXEL1 - TFT Pixel 1 Register

Offset Bit Position

0x08C

Reset

0x0000

Access

Name

DATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DATA 0x0000 RW RGB data.

Sets the RGB data value according to the format defined in RGBMODE.

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14.5.37 EBI_TFTPIXEL - TFT Alpha Blending Result Pixel Register

Offset Bit Position

0x090

Reset

0x0000

Access

Name

DATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DATA 0x0000 R Alpha Blending Result

RGB result of Alpha Blending operation according to the format defined in RGBMODE.

14.5.38 EBI_TFTMASK - TFT Masking Register

Offset Bit Position

0x094

Reset

0x0000

Access

Name

TFTMASK

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 TFTMASK 0x0000 RW TFT Mask Value

Sets the mask value. Data write transactions matching this value are suppressed.

14.5.39 EBI_IF - Interrupt Flag Register

Offset Bit Position

0x098

Reset

Access

Name

DDJIT

DDEMPTY

VFPORCH

VBPORCH

HSYNC

VSYNC

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Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DDJIT 0 R Direct Drive Jitter Interrupt Flag

Set when DCLKPERIOD is not met.

4 DDEMPTY 0 R Direct Drive Data Empty Interrupt Flag

Set when Direct Drive engine EBI_TFTDD data is empty.

3 VFPORCH 0 R Vertical Front Porch Interrupt Flag

Set at beginning of Vertical Front Porch.

2 VBPORCH 0 R Vertical Back Porch Interrupt Flag

Set at end of Vertical Back Porch.

1 HSYNC 0 R Horizontal Sync Interrupt Flag

Set at Horizontal Sync pulse.

0 VSYNC 0 R Vertical Sync Interrupt Flag

Set at Vertical Sync pulse.

14.5.40 EBI_IFS - Interrupt Flag Set Register

Offset Bit Position

0x09C

Reset

Access

Name

DDJIT

DDEMPTY

VFPORCH

VBPORCH

HSYNC

VSYNC

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DDJIT 0 W1 Direct Drive Jitter Interrupt Flag Set

Write to 1 to set Direct Drive Jitter Interrupt flag.

4 DDEMPTY 0 W1 Direct Drive Data Empty Interrupt Flag Set

Write to 1 to set Direct Drive Data Empty Interrupt flag.

3 VFPORCH 0 W1 Vertical Front Porch Interrupt Flag Set

Write to 1 to set Vertical Front Porch Interrupt flag.

2 VBPORCH 0 W1 Vertical Back Porch Interrupt Flag Set

Write to 1 to set Vertical Back Porch Interrupt flag.

1 HSYNC 0 W1 Horizontal Sync Interrupt Flag Set

Write to 1 to set Horizontal Sync interrupt flag.

0 VSYNC 0 W1 Vertical Sync Interrupt Flag Set

Write to 1 to set Vertical Sync interrupt flag.

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14.5.41 EBI_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x0A0

Reset

Access

Name

DDJIT

DDEMPTY

VFPORCH

VBPORCH

HSYNC

VSYNC

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DDJIT 0 W1 Direct Drive Jitter Interrupt Flag Clear

Write to 1 to clear Direct Drive Jitter Interrupt flag.

4 DDEMPTY 0 W1 Direct Drive Data Empty Interrupt Flag Clear

Write to 1 to clear Direct Drive Data Empty Interrupt flag.

3 VFPORCH 0 W1 Vertical Front Porch Interrupt Flag Clear

Write to 1 to clear Vertical Front Porch interrupt flag.

2 VBPORCH 0 W1 Vertical Back Porch Interrupt Flag Clear

Write to 1 to clear Vertical Back Porch interrupt flag.

1 HSYNC 0 W1 Horizontal Sync Interrupt Flag Clear

Write to 1 to clear Horizontal Sync interrupt flag.

0 VSYNC 0 W1 Vertical Sync Interrupt Flag Clear

Write to 1 to clear Vertical Sync interrupt flag.

14.5.42 EBI_IEN - Interrupt Enable Register

Offset Bit Position

0x0A4

Reset

Access

Name

DDJIT

DDEMPTY

VFPORCH

VBPORCH

HSYNC

VSYNC

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DDJIT 0 RW Direct Drive Jitter Interrupt Enable

Set to enable interrupt on Direct Drive Jitter Interrupt flag.

4 DDEMPTY 0 RW Direct Drive Data Empty Interrupt Enable

Set to enable interrupt on Direct Drive Data Empty Interrupt flag.

3 VFPORCH 0 RW Vertical Front Porch Interrupt Enable

Set to enable interrupt on beginning of Vertical Front Porch interrupt flag.

2 VBPORCH 0 RW Vertical Back Porch Interrupt Enable

Set to enable interrupt on end of Vertical Back Porch interrupt flag.

1 HSYNC 0 RW Horizontal Sync Interrupt Enable

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Bit Name Reset Access Description

Set to enable interrupt on Horizontal Sync interrupt flag.

0 VSYNC 0 RW Vertical Sync Interrupt Enable

Set to enable interrupt on Vertical Sync interrupt flag.

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15 USB - Universal Serial Bus Controller

01 2 3 4

Quick Facts

What?

The USB is a full-speed/low-speed USB 2.0

compliant USB Controller that can be used

in various OTG Dual Role Device, Host and

Device configurations. The on-chip 3.3V

regulator delivers up to 50 mA and can also

be used to power external components,

eliminating the need for an external LDO. The

on-chip regulator allows the system to run

from a battery utilizing the full voltage range

of the EFM32 still being compliant with the

3.3V +/- 10% USB voltage range.

Why?

USB provides a robust, industry-standard

way to interface PCs and other portable

devices.

How?

The flexible and highly software-configurable

architecture of the USB Controller makes it

easy to implement both device- and host-

capable solutions. The on-chip OTG PHY

with software controllable pull-up and pull-

down resistors, VBUS comparators and

ID-line detection reduces the number of

external components to a minimum. Third-

party USB software stacks are also available,

reducing the development time substantially.

By utilizing the very low energy consumption

in EM2, the USB device will be able to wake

up and perform tasks several times a second

without violating the 2.5 mA maximum

average current during suspend.

15.1 Introduction

The USB is a full-speed/low-speed USB 2.0 compliant OTG host/device controller. The architecture is

very flexible and allows the USB to be used in various On-the-go (OTG) Dual-Role Device, Host- and

Device-only configurations. The USB supports HNP and SRP protocols and both OTG Revisions 1.3

and 2.0 are supported A switchable external 5V supply or step-up regulator is needed for OTG Dual

Role Device and Host configurations. The on-chip voltage regulator and PHY reduces the number of

external components to a minimum.

15.2 Features

• Fully compliant with Universal Serial Bus Specification, Revision 2.0

• Supports full-speed (12 Mbit/s) and low-speed (1.5 Mbit/s) host and device

• Dedicated Internal DMA Controller

• 12 software-configurable endpoints (6 IN, 6 OUT) in addition to endpoint 0

• 2 KB endpoint memory

• Resume/Reset detection in EM2 (during suspend)

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• SRP detection in EM2 (during host session off)

• Soft connect/disconnect

• Full OTG support

• Compliant with On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification,

Revision 2.0

• Compliant with USB On-The-Go Supplement, Revision 1.3

• Supports Host Negotiation Protocol (HNP) and Session Request Protocol (SRP)

• On-chip PHY

• Internal pull-up and pull-down resistors

• Voltage comparators for monitoring VBUS voltage

• A/B Device identification using ID line

• Charge/discharge of VBUS for VBUS-pulsing

• Internal 3.3V Regulator

• Output voltage: 3.3V

• Output current: 50 mA

• Input voltage range: 4.0 - 5.5V

• Enabled automatically when input voltage applied

• Low quiescent current: 100 uA

• Dedicated input pin allows regulator to be used in OTG and host configurations

• Output pin can be used to power the EFM32 itself as well as external components

• Regulator voltage output sense feature for detecting USB plug/unplug events (also available in

EM2/3)

15.3 USB System Description

A block diagram of the USB is shown in Figure 15.1 (p. 241) .

Figure 15.1. USB Block Diagram

OTG

PHY

USB_VBUS

Voltage

Regulator

(3.3 V)

USB_DP

USB_DM

USB_ID

USB_VREGI

USB_VREGO

AHB Master

AHB Slave

AHB

2 KB

FIFO RAM

USB_VBUSEN

VREGO

Sense

USB Core

w/ DMA Controller

APB Slave

APB

USB Interrupt

SOF PRS USB_DMPU

USB System

(control)

The USB consists of a digital logic part, an endpoint RAM, PHY and a voltage regulator with output

voltage sensor. The voltage regulator provides a stable 3.3 V supply for the PHY, but can also be used

to power the EFM32 itself as well as external components.

The digital logic of the USB is split into two parts: system and core.

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The system part is accessed using USB registers from offset 0x000 to 0x018 and controls the voltage

regulator and enabling/disabling of the PHY and USB pins. This part is clocked by HFCORECLKUSB and

is accessed using an APB slave interface. The system part can thus be accessed independently of the

core part, without HFCORECLKUSBC running.

The core part is clocked by HFCORECLKUSBC and is accessed using an AHB slave interface. This

interface is used for accessing the FIFO contents and the registers in the core part starting at offset

0x3C000. An additional master interface is used by the internal DMA controller of the core. The core

part takes care of all the USB protocol related functionality. The clock to the system part must not be

disabled when the core part is active.

There are several pins associated with the USB. USB_DP and USB_DM are the USB D+ and D- pins.

These are the USB data signaling pins. USB_VBUS should be connected to the VBUS (5V) pin on

the USB receptacle. It is connected to the voltage comparators and current sink/source in the PHY.

USB_ID is the OTG ID pin used to detect the device type (A or B). This pin can be left unconnected

when not used. USB_VBUSEN is used to turn on and off VBUS power when operating as host-only or

OTG A-Device. USB_VREGI is the input to the voltage regulator and USB_VREGO is the regulated

output. USB_DMPU is used to enable/disable an external D- pull-up resistor. This is needed for low-

speed device only. USB_VBUSEN and USB_DMPU will be high-impedance until enabled from software.

Thus, if a defined level is required during start-up an external pull-up/pull-down can be used.

15.3.1 USB Clocks

The USB requires the device to run a 48 MHz crystal (2500 ppm or better). The core part of the USB

will always run from HFCORECLKUSBC, which is 48 MHz. The current consumption for the rest of

the device can be reduced by dividing down HFCORECLK using the CMU_HFCORECLKDIV register.

Bandwidth requirements for the specific USB application must be taken into account when dividing down

HFCORECLK.

15.3.2 USB Initialization

Follow these steps to enable the USB:

1. Enable the clock to the system part by setting USB in CMU_HFCORECLKEN0.

2. If the internal USB regulator is bypassed (by applying 3.3V on USB_VREGI and USB_VREGO

externally), disable the regulator by setting VREGDIS in USB_CTRL.

3. If the PHY is powered from VBUS using the internal regulator, the VREGO sense circuit should be

enabled by setting VREGOSEN in USB_CTRL.

4. Enable the USB PHY pins by setting PHYPEN in USB_ROUTE.

5. If host or OTG dual-role device, set VBUSENAP in USB_CTRL to the desired value and then enable

the USB_VBUSEN pin in USB_ROUTE. Set the MODE for the pin to PUSHPULL.

6. If low-speed device, set DMPUAP in USB_CTRL to the desired value and then enable the

USB_DMPU pin in USB_ROUTE. Set the MODE for the pin to PUSHPULL.

7. Make sure the oscillator is ready and selected in CMU_CMD_USBCCLKSEL.

8. Enable the clock to the core part by setting USBC in CMU_HFCORECLKEN0.

9. Wait for the core to come out of reset. This is easiest done by polling a core register with non-zero

reset value until it reads a non-zero value. This takes approximately 20 48-MHz cycles.

10.Start initializing the USB core as described in USB Core Description.

15.3.3 Configurations

The USB can be used as Device, OTG Dual Role Device or Host. The sections below describe

the different configurations. External ESD protection and series resistors for impedance matching are

required. The voltage regulator requires a 4.7 uF external decoupling capacitor on the input and a 1 uF

external decoupling capacitor on the output. Decoupling not related to USB is not shown in the figures.

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15.3.3.1 Bus-powered Device

A bus-powered device configuration is shown in Figure 15.2 (p. 243) . In this configuration the voltage

regulator powers the PHY and the EFM32 at 3.3 V. The voltage regulator output (USB_VREGO) can

also be used to power other components of the system.

In this configuration, the VREGO sense circuit should be left disabled.

Figure 15.2. Bus-powered Device

USB_DP

USB_DM

Standard B

VBUS

D+

D-

GND

USB_VBUS

MCU USB_VREGI

USB_VREGO

(ESD Protection)

VDD

15.3.3.2 Self-powered Device

A self-powered device configuration is shown in Figure 15.3 (p. 243) . When the USB is configured as

a self-powered device, the voltage regulator is typically used to power the PHY only, although it may also

be used to power other 3.3 V components. When the USB is connected to a host, the voltage regulator is

activated. Software can detect this event by enabling the VREGO Sense High (VREGOSH) interrupt. The

PHY pins can then be enabled and USB traffic can start. The VREGO Sense Low (VREGOSL) interrupt

can be used to detect when VBUS voltage disappears (for example if the USB cable is unplugged).

In this configuration, the VREGO sense circuit must be enabled.

Figure 15.3. Self-powered Device

USB_DP

USB_DM

Standard B

VBUS

D+

D-

GND

USB_VBUS

MCU USB_VREGI

USB_VREGO

(ESD Protection)

VDD

1.8V – 3.6V

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15.3.3.3 Self-powered Device (with bus-power switch)

A self-powered device (with bus-power switch) may switch power supply to VBUS when connected to

a host. This is typically useful for extending the life of battery-powered devices and enables the use of

coin-cell driven systems with low maximum peak current. The external components required typically

include 2 transistors, 2 diodes and a few resistors. See application note for details. This allows seamless

power supply switching between a battery and the voltage regulator output.

The VREGO Sense High interrupt is used to detect when VBUS becomes present. Software can then

enable the external transistor connected to USB_VREGO, effectively switching the power source. A

regular GPIO pin is used to control this transistor. If necessary, the application may have to reduce the

current consumption before switching to the USB power source. If VBUS voltage is removed, the circuit

switches automatically back to the battery power supply. If necessary software must react quickly to

this event and reduce the current consumption (for example by reducing the clock frequency) to avoid

excessive voltage drop. This configuration is shown in Figure 15.4 (p. 244) .

In this configuration, the VREGO sense circuit must be enabled.

Figure 15.4. Self-powered Device (with bus-power switch)

USB_DP

USB_DM

Standard B

VBUS

D+

D-

GND

USB_VBUS

MCU USB_VREGI

USB_VREGO

(ESD Protection)

VDD

1.8V – 3.6V

Dual- Power

Circuit

(enable) GPIO

15.3.3.4 OTG Dual Role Device (5V)

An OTG Dual Role Device (5V) configuration is shown in Figure 15.5 (p. 245) . When 5V is available,

the internal regulator can be used to power the EFM32. An external power switch is needed to control

VBUS power. For over-current detection a regular GPIO input pin with interrupt is used. The application

should turn off or limit VBUS power when over-current is detected. In OTG mode, the maximum VBUS

decoupling capacitance is 6.5 uF.

In this configuration, the VREGO sense circuit should be left disabled.

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Figure 15.5. OTG Dual Role Device (5V)

USB_DP

USB_DM

Micro-AB

VBUS

D+

D-

USB_VBUS

MCU

USB_VREGI

USB_VREGO

(ESD Protection)

VDD

USB_ID

GND

USB_VBUSEN

GPIO (over-current)

Power switch +

over-current detection

Vin

Vout

15.3.3.5 OTG Dual Role Device (5V step-up regulator)

An OTG Dual Role Device (5V step-up regulator) configuration is shown in Figure 15.6 (p. 245) . When

5V is not available, an external 5V step-up regulator is needed. In this configuration, the voltage for the

EFM32 must be in the range 3.0V - 3.6V. In this mode the voltage regulator is bypassed by connecting

both the input and output to the external supply. This effectively causes the PHY to be powered directly

from the external 3.0 - 3.6 V supply. The voltage regulator should be disabled when operating in

this mode. For over-current detection a regular GPIO input pin with interrupt is used. The application

should turn off or limit VBUS power when over-current is detected. In OTG mode, the maximum VBUS

decoupling capacitance is 6.5 uF.

In this configuration, the VREGO sense circuit should be left disabled.

Figure 15.6. OTG Dual Role Device (5V step-up regulator)

USB_DP

USB_DM

Micro-AB

VBUS

D+

D-

USB_VBUS

MCU

USB_VREGO

USB_VREGI

(ESD Protection)

VDD

USB_ID

GND

3.0V – 3.6V

USB_VBUSEN

GPIO (over-current)

EN Vout

Vin

5V step-up

15.3.3.6 Host

A host configuration is shown in Figure 15.7 (p. 246) . In this example a 5V step-up regulator is used.

If 5V is available, a power switch can be used instead, as shown in Figure 15.5 (p. 245) . The host

configuration is equal to OTG Dual Role Device, except for the USB_ID pin which is not used and the

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USB connector which is a USB Standard-A Connector. In host mode, the minimum VBUS decoupling

capacitance is 96 uF.

In this configuration, the VREGO sense circuit should be left disabled.

Figure 15.7. Host

USB_DP

USB_DM

Standard A

VBUS

D+

D-

USB_VBUS

MCU

USB_VREGO

USB_VREGI

(ESD Protection)

VDD

GND

3.0V – 3.6V

USB_VBUSEN

GPIO (over-current)

EN Vout

Vin

5V step-up

15.3.4 PHY

The USB includes an internal full-speed/low-speed PHY with built-in pull-up/pull-down resistors, VBUS

comparators and ID line state sensing. During suspend, the PHY enters a low-power state where only

the single-ended receivers are active. The PHY is disabled by default and should be enabled by setting

PHYPEN in USB_ROUTE before the USB core clock is enabled.

The PHY is powered by the internal voltage regulator output (USB_VREGO). To power the PHY

directly from an external source (for example an external 3.3 V LDO), connect both USB_VREGO and

USB_VREGI to the external 3.3 V supply voltage. To stop the quiescent current present with the voltage

regulator enabled in this configuration, disable the the regulator by setting VREGDIS in USB_CTRL after

power up. Then the regulator is effectively bypassed.

When VREGO Sense is enabled, the PHY is automatically disabled internally when the VREGO Sense

output is low. This will happen if VBUS-power disappears. The application can detect this by keeping

the VREGO Sense Low Interrupt enabled. Note that PHYPEN in USB_ROUTE will not be set to 0 in this

case. Also, the PHY must always be disabled manually when there is no voltage applied to VREGO.

15.3.5 Voltage Regulator

The voltage regulator is used to regulate the 5 V VBUS voltage down to 3.3 V which is the operating

voltage for the PHY.

A decoupling capacitor is required on USB_VREGI and USB_VREGO. Note that the USB standard

requires the total capacitance on VBUS to be 1 uF minimum and 10 uF maximum for regular devices.

OTG devices can have maximum 6.5 uF capacitance on VBUS.

The voltage regulator is enabled by default and can thus be used to power the EFM32 itself. Systems not

using the USB should disable the regulator by setting VREGDIS in USB_CTRL. A voltage sense circuit

monitors the output voltage and can be used to detect when the voltage regulator becomes active. This

sense circuit can also be used to detect when the voltage drops (typically due to the USB cable being

unplugged). If regulator voltage monitoring is not required (i.e. it is known that the VREGO voltage is

always present), the sense circuit should be left disabled.

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During suspend, the bias current for the regulator can be reduced if the current requirements in EM2/3 are

low. The bias current in EM2/3 is controlled by BIASPROGEM23 in USB_CTRL. When EM2/3 is entered,

the bias current for the regulator switches to what is specified in BIASPROGEM23 in USB_CTRL. When

entering EM0 again (due to USB resume/reset signaling or any other wake-up interrupt) the regulator

switches back to using the value specified in BIASPROGEM01 in USB_CTRL.

15.3.6 Interrupts and PRS

Interrupts from the core and system part share a common USB interrupt line to the CPU. The interrupt

flags for the system part are grouped together in the USB_IF register. The interrupt events from the core

are controlled by several core interrupt flag registers.

There are two PRS outputs from the USB: SOF and SOFSR. In Host mode, SOF toggles every time an

SOF is generated and SOFSR toggles every time an SOF is successfully transmitted. In Device mode,

SOF toggles every time an SOF token is received from the USB host or when an SOF token is missed

at the start of frame, while SOFSR toggles only when a valid SOF token is received from the USB host.

Both PRS outputs must be synchronized in the PRS when used (i.e. it is an asynchronous PRS output).

The edge-to-pulse converter in the PRS can be used to convert the edges into pulses if needed. The

PRS outputs go to 0 in EM2/3.

15.3.7 USB in EM2

During suspend and session-off EM2 should be used to save power and meet the average current

requirements dictated by the USB standard. Before entering EM2, HFCORECLKUSBC must be switched

from 48 MHz to 32 kHz (LFXO or LFRCO). This is done using the CMU_CMD and CMU_STATUS

registers. Upon EM2 wake-up, HFCORECLKUSBC must be switched back to 48 MHz before accessing

the core registers. The device always starts up from HFRCO so software must restart HFXO and switch

from HFRCO to HFXO. The USB system clock, HFCORECLKUSB, must be kept enabled during EM2. The

USB system registers can be accessed immediately upon EM2 wake-up, while running from HFRCO.

Follow the steps outlined the USB Core Description when entering EM2 during suspend and session-off.

The FIFO content is lost when entering EM2. In addition, most of the USB core registers are reset and

therefore need to be backed up in RAM.

EM3 cannot be used when the USB is active. However, EM3 can be used while waiting for the internal

voltage regulator to be activated (i.e. VBUS becomes 5V).

15.4 USB Core Description

This section describes the programming requirements for the USB Corein Host and Device modes.

Important features/parameters for the core are:

• HNP- and SRP-Capable OTG (Device and Host)

• Internal DMA (Buffer Pointer Based)

• Dedicated TX FIFOS for each endpoint in device mode

• 6 IN/OUT endpoints in addition to endpoint 0 (in device mode)

• 14 host channels (in host mode)

• Dynamic FIFO sizing

• Non-Periodic Request Queue Depth: 8

• Host Mode Periodic Request Queue Depth: 8

The core has the following limitations:

• Link Power Management (LPM) is not supported

• ADP is not supported

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registered trademarks of Synopsys, Inc.

15.4.1 Overview: Programming the Core

Each significant programming feature of the core is discussed in a separate section.

This chapter uses abbreviations for register names and their fields. For detailed information on registers,

see Section 15.6 (p. 351) .

The application must perform a core initialization sequence. If the cable is connected during power-up,

the Current Mode of Operation bit in the Core Interrupt register (USB_GINTSTS.CURMOD) reflects the

mode. The core enters Host mode when an “A” plug is connected, or Device mode when a “B” plug

is connected.

This section explains the initialization of the core after power-on. The application must follow the

initialization sequence irrespective of Host or Device mode operation. All core global registers are

initialized according to the core’s configuration.

1. Program the following fields in the Global AHB Configuration (USB_GAHBCFG) register.

• DMA Mode bit

• AHB Burst Length field

• Global Interrupt Mask bit = 1

• Non-periodic TxFIFO Empty Level (can be enabled only when the core is operating in Slave mode

as a host.)

• Periodic TxFIFO Empty Level (can be enabled only when the core is operating in Slave mode)

2. Program the following field in the Global Interrupt Mask (USB_GINTMSK) register:

• USB_GINTMSK.RXFLVLMSK = 0

3. Program the following fields in USB_GUSBCFG register.

• HNP Capable bit

• SRP Capable bit

• External HS PHY or Internal FS Serial PHY Selection bit

• Time-Out Calibration field

• USB Turnaround Time field

4. The software must unmask the following bits in the USB_GINTMSK register.

• OTG Interrupt Mask

• Mode Mismatch Interrupt Mask

5. The software can read the USB_GINTSTS.CURMOD bit to determine whether the core is operating

in Host or Device mode. The software the follows either the Section 15.4.1.1 (p. 248) or Device

Initialization (p. 249) sequence.

Note The core is designed to be interrupt-driven. Polling interrupt mechanism is not

recommended: this may result in undefined resolutions.

Note In device mode, just after Power On Reset or a Soft Reset, the USB_GINTSTS.SOF bit is

set to 1 for debug purposes. This status must be cleared and can be ignored.

15.4.1.1 Host Initialization

To initialize the core as host, the application must perform the following steps.

1. Program USB_GINTMSK.PRTINT to unmask.

2. Program the USB_HCFG register to select full-speed host.

3. Program the USB_HPRT.PRTPWR bit to 1. This drives VBUS on the USB.

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4. Wait for the USB_HPRT.PRTCONNDET interrupt. This indicates that a device is connect to the port.

5. Program the USB_HPRT.PRTRST bit to 1. This starts the reset process.

6. Wait at least 10 ms for the reset process to complete.

7. Program the USB_HPRT.PRTRST bit to 0.

8. Wait for the USB_HPRT.PRTENCHNG interrupt.

9. Read the USB_HPRT.PRTSPD field to get the enumerated speed.

10.Program the USB_HFIR register with a value corresponding to the selected PHY clock. At this point,

the host is up and running and the port register begins to report device disconnects, etc. The port is

active with SOFs occurring down the enabled port.

11.Program the RXFSIZE register to select the size of the receive FIFO.

12.Program the NPTXFSIZE register to select the size and the start address of the Non-periodic Transmit

FIFO for non-periodic transactions.

13.Program the USB_HPTXFSIZ register to select the size and start address of the Periodic Transmit

FIFO for periodic transactions.

To communicate with devices, the system software must initialize and enable at least one channel as

described in Device Initialization (p. 249) .

15.4.1.1.1 Host Connection

The following steps explain the host connection flow:

1. When the USB Cable is plugged to the Host port, the core triggers USB_GINTSTS.CONIDSTSCHNG

interrupt.

2. When the Host application detects USB_GINTSTS.CONIDSTSCHNG interrupt, the application can

perform one of the following actions:

• Turn on VBUS by setting USB_HPRT.PRTPWR = 1 or

• Wait for SRP Signaling from Device to turn on VBUS.

3. The PHY indicates VBUS power-on by detecting a VBUS valid voltage level.

4. When the Host Core detects the device connection, it triggers the Host Port Interrupt

(USB_GINTSTS.PRTINT) to the application.

5. When USB_GINTSTS.PRTINT is triggered, the application reads the USB_HPRT register to check if

the Port Connect Detected (USB_HPRT.PRTCONNDET) bit is set or not.

15.4.1.1.2 Host Disconnection

The following steps explain the host disconnection flow:

1. When the Device is disconnected from the USB Cable (but the cable is still connected to the USB

host), the Core triggers USB_GINTSTS.DISCONNINT (Disconnect Detected) interrupt.

Note If the USB cable is disconnected from the Host port without removing the device, the

core generates an additional interrupt - USB_GINTSTS.CONIDSTSCHNG (Connector ID

Status Change).

2. The Host application can choose to turn off the VBUS by programming USB_HPRT.PRTPWR = 0.

15.4.1.2 Device Initialization

The application must perform the following steps to initialize the core at device on, power on, or after

a mode change from Host to Device.

1. Program the following fields in USB_DCFG register.

• Device Speed

• Non-Zero-Length Status OUT Handshake

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• Periodic Frame Interval

2. Program the USB_GINTMSK register to unmask the following interrupts.

• USB Reset

• Enumeration Done

• Early Suspend

• USB Suspend

3. Wait for the USB_GINTSTS.USBRST interrupt, which indicates a reset has been detected on the

USB and lasts for about 10 ms. On receiving this interrupt, the application must perform the steps

listed in Initialization on USB Reset (p. 283)

4. Wait for the USB_GINTSTS.ENUMDONE interrupt. This interrupt indicates the end of reset on the

USB. On receiving this interrupt, the application must read the USB_DSTS register to determine the

enumeration speed and perform the steps listed in Initialization on Enumeration Completion (p. 283)

At this point, the device is ready to accept SOF packets and perform control transfers on control endpoint

15.4.1.2.1 Device Connection

The device connect process varies depending on the if the VBUS is on or off when the device is

connected to the USB cable.

When VBUS is on When the Device is Connected

If VBUS is on when the device is connected to the USB cable, there is no SRP from the device. The

device connection flow is as follows:

1. The device triggers the USB_GINTSTS.SESSREQINT [bit 30] interrupt bit.

2. When the device application detects the USB_GINTSTS.SESSREQINT interrupt, it programs the

required bits in the USB_DCFG register.

3. When the Host drives Reset, the Device triggers USB_GINTSTS.USBRST [bit 12] on detecting the

Reset. The host then follows the USB 2.0 Enumeration sequence.

When VBUS is off When the Device is Connected

If VBUS is off when the device is connected to the USB cable, the device initiates SRP in OTG Revision

1.3 mode. The device connection flow is as follows:

1. The application initiates SRP by writing the Session Request bit in the OTG Control and Status

2. The host starts a new session by turning on VBUS, indicating SRP success. The core interrupts the

application by setting the Session Request Success Status Change bit in the OTG Interrupt Status

3. The application reads the Session Request Success bit in the OTG Control and Status register and

programs the required bits in USB_DCFG register.

4. When Host drives Reset, the Device triggers USB_GINTSTS.USBRST on detecting the Reset. The

host then follows the USB 2.0 Enumeration sequence.

15.4.1.2.2 Device Disconnection

The device session ends when the USB cable is disconnected or if the VBUS is switched off by the Host.

The device disconnect flow is as follows:

1. When the USB cable is unplugged or when the VBUS is switched off by the Host, the Device core

trigger USB_GINTSTS.OTGINT [bit 2] interrupt bit.

2. When the device application detects USB_GINTSTS.OTGINT interrupt, it checks that the

USB_GOTGINT.SESENDDET (Session End Detected) bit is set to 1.

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15.4.1.2.3 Device Soft Disconnection

The application can perform a soft disconnect by setting the Soft disconnect bit (SFTDISCON) in Device

Control Register (USB_DCTL).

Send/Receive USB Transfers -> Soft disconnect->Soft reset->USB Device Enumeration

Sequence of operations:

1. The application configures the device to send or receive transfers.

2. The application sets the Soft disconnect bit (SFTDISCON) in the Device Control Register

(USB_DCTL).

3. The application sets the Soft Reset bit (CSFTRST) in the Reset Register (USB_GRSTCTL).

4. Poll the USB_GRSTCTL register until the core clears the soft reset bit, which ensures the soft reset

is completed properly.

5. Initialize the core according to the instructions in Device Initialization (p. 249) .

Suspend-> Soft disconnect->Soft reset->USB Device Enumeration

Sequence of operations:

1. The core detects a USB suspend and generates a Suspend Detected interrupt.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register, the core

puts the PHY in suspend mode, and the PHY clock stops.

3. The application clears the Stop PHY Clock bit in the Power and Clock Gating Control register, and

waits for the PHY clock to come back. The core takes the PHY back to normal mode, and the PHY

clock comes back.

4. The application sets the Soft disconnect bit (SFTDISCON) in Device Control Register (USB_DCTL).

5. The application sets the Soft Reset bit (CSFTRST) in the Reset Register (USB_GRSTCTL).

6. Poll the USB_GRSTCTL register until the core clears the soft reset bit, which ensures the soft reset

is completed properly.

7. Initialize the core according to the instructions in Device Initialization (p. 249) .

15.4.2 Modes of operation

• Overview: DMA/Slave modes (p. 251)

• DMA Mode (p. 251)

• Slave Mode (p. 252)

15.4.2.1 Overview: DMA/Slave modes

The application can operate the core in either of two modes:

• In DMA Mode (p. 251) - The core fetches the data to be transmitted or updates the received data

on the AHB.

• In Slave Mode (p. 252) — The application initiates the data transfers for data fetch and store.

15.4.2.2 DMA Mode

In DMA Mode, the OTG host uses the AHB master Interface for transmit packet data fetch (AHB to

USB) and receive data update (USB to AHB). The AHB master uses the programmed DMA address

(USB_HCx_DMAADDR register in host mode and USB_DIEPx_DMAADDR/USB_DOEPx_DMAADDR

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15.4.2.2.1 Transfer-Level Operation

In DMA mode, the application is interrupted only after the programmed transfer size is transmitted or

received (provided the core detects no NAK/Timeout/Error response in Host mode, or Timeout/CRC

Error in Device mode). The application must handle all transaction errors. In Device mode, all the USB

errors are handled by the core itself.

15.4.2.2.2 Transaction-Level Operation

This mode is similar to transfer-level operation with the programmed transfer size equal to one packet

size (either maximum packet size, or a short packet size).

15.4.2.3 Slave Mode

In Slave mode, the application can operate the core either in transaction-level (packet-level) operation

or in pipelined transaction-level operation.

15.4.2.3.1 Transaction-Level Operation

The application handles one data packet at a time per channel/endpoint in transaction-level operations.

Based on the handshake response received on the USB, the application determines whether to retry

the transaction or proceed with the next, until the end of the transfer. The application is interrupted on

completion of every packet. The application performs transaction-level operations for a channel/endpoint

for a transmission (host: OUT/device: IN) or reception (host: IN/device: OUT) as shown in Figure 15.8 (p.

253) and Figure 15.9 (p. 253) .

Host Mode

For an OUT transaction, the application enables the channel and writes the data packet into the

corresponding (Periodic or Non-periodic) transmit FIFO. The core automatically writes the channel

number into the corresponding (Periodic or Non-periodic) Request Queue, along with the last DWORD

write of the packet. For an IN transaction, the application enables the channel and the core automatically

writes the channel number into the corresponding Request queue. The application must wait for the

packet received interrupt, then empty the packet from the receive FIFO.

Device Mode

For an IN transaction, the application enables the endpoint, writes the data packet into the corresponding

transmit FIFO, and waits for the packet completion interrupt from the core. For an OUT transaction, the

application enables the endpoint, waits for the packet received interrupt from the core, then empties the

packet from the receive FIFO.

Note The application has to finish writing one complete packet before switching to a different

channel/endpoint FIFO. Violating this rule results in an error.

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Figure 15.8. Transmit Transaction-Level Operation in Slave Mode

Set up the

channel/endpoint

Write 1 packet to the

Transmit FIFO

Get channel/endpoint

interrupt status

Done

Start

Rewrite packet to

the Transmit FIFO

Yes

Transfer

complete?

Retry

required?

Get

interrupt?

Figure 15.9. Receive Transaction-Level Operation in Slave Mode

Done

Start

Yes

Retry

required ?

Transfer

complete ?

Yes

Read Receive

Status Queue

RXFLVL or

Ch/EP interrupt ?

Yes

Set up the

Channel / endpoint

Read the packet

from the

Receive FIFO

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15.4.2.3.2 Pipelined Transaction-Level Operation

The application can pipeline more than one transaction (IN or OUT) with pipelined transaction-level

operation, which is analogous to Transfer mode in DMA mode. In pipelined transaction-level operation,

the application can program the core to perform multiple transactions. The advantage of this mode

compared to transaction-level operation is that the application is not interrupted on a packet basis.

15.4.2.3.2.1 Host mode

For an OUT transaction, the application sets up a transfer and enables the channel. The application can

write multiple packets back-to-back for the same channel into the transmit FIFO, based on the space

availability. It can also pipeline OUT transactions for multiple channels by writing into the HCHARn

last DWORD write for the packet, into the Request queue and schedules transactions on the USB in

the same order.

For an IN transaction, the application sets up a transfer and enables the channel, and the core writes

the channel number into the Request queue. The application can schedule IN transactions on multiple

channels, provided space is available in the Request queue. The core initiates an IN token on the USB

only when there is enough space to receive at least of one maximum-packet-size packet of the channel

in the top of the Request queue.

15.4.2.3.2.2 Device mode

For an IN transaction, the application sets up a transfer and enables the endpoint. The application can

write multiple packets back-to-back for the same endpoint into the transmit FIFO, based on available

space. It can also pipeline IN transactions for multiple channels by writing into the USB_DIEPx_CTL

last DWORD write for the packet into the Request queue. The core transmits the data in the transmit

FIFO when an IN token is received on the USB.

For an OUT transaction, the application sets up a transfer and enables the endpoint. The core receives

the OUT data into the receive FIFO, when it has available space. As the packets are received into the

FIFO, the application must empty data from it.

From this point on in this chapter, the terms “Pipelined Transaction mode” and “Transfer mode” are used

interchangeably.

15.4.3 Host Programming Model

Before you program the Host, read Overview: Programming the Core (p. 248) and Modes of

operation (p. 251) .

This section discusses the following topics:

• Channel Initialization (p. 254)

• Halting a Channel (p. 255)

• Zero-Length Packets (p. 256)

• Handling Babble Conditions (p. 256)

• Handling Disconnects (p. 256)

• Host Programming Operations (p. 256)

• Writing the Transmit FIFO in Slave Mode (p. 257)

• Reading the Receive FIFO in Slave Mode (p. 258)

15.4.3.1 Channel Initialization

The application must initialize one or more channels before it can communicate with connected devices.

To initialize and enable a channel, the application must perform the following steps.

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1. Program the USB_GINTMSK register to unmask the following:

2. Channel Interrupt

• Non-periodic Transmit FIFO Empty for OUT transactions (applicable for Slave mode that operates

in pipelined transaction-level with the Packet Count field programmed with more than one).

• Non-periodic Transmit FIFO Half-Empty for OUT transactions (applicable for Slave mode that

operates in pipelined transaction-level with the Packet Count field programmed with more than one).

3. Program the USB_USB_HAINTMSK register to unmask the selected channels’ interrupts.

4. Program the HCINTMSK register to unmask the transaction-related interrupts of interest given in the

Host Channel Interrupt register.

5. Program the selected channel’s USB_HCx_TSIZ register.

Program the register with the total transfer size, in bytes, and the expected number of packets,

including short packets. The application must program the PID field with the initial data PID (to be

used on the first OUT transaction or to be expected from the first IN transaction).

6. Program the selected channels’ USB_HCx_DMAADDR register(s) with the buffer start address (DMA

mode only).

7. Program the USB_HCx_CHAR register of the selected channel with the device’s endpoint

characteristics, such as type, speed, direction, and so forth. (The channel can be enabled by setting

the Channel Enable bit to 1 only when the application is ready to transmit or receive any packet).

Repeat the above steps for other channels.

Note De-allocate channel means after the transfer has completed, the channel is disabled. When

the application is ready to start the next transfer, the application re-initializes the channel by

following these steps.

15.4.3.2 Halting a Channel

The application can disable any channel by programming the USB_HCx_CHAR register with the

USB_HCx_CHAR.CHDIS and USB_HCx_CHAR.CHENA bits set to 1. This enables the host to flush

the posted requests (if any) and generates a Channel Halted interrupt. The application must wait for the

USB_HCx_INT.CHHLTD interrupt before reallocating the channel for other transactions. The host does

not interrupt the transaction that has been already started on USB.

In Slave mode operation, before disabling a channel, the application must ensure that there is at

least one free space available in the Non-periodic Request Queue (when disabling a non-periodic

channel) or the Periodic Request Queue (when disabling a periodic channel). The application can

simply flush the posted requests when the Request queue is full (before disabling the channel), by

programming the USB_HCx_CHAR register with the USB_HCx_CHAR.CHDIS bit set to 1, and the

USB_HCx_CHAR.CHENA bit reset to 0.

The core generates a RXFLVL interrupt when there is an entry in the queue. The application must read/

pop the USB_GRXSTSP register to generate the Channel Halted interrupt.

To disable a channel in DMA mode operation, the application need not check for space in the Request

queue. The host checks for space in which to write the Disable request on the disabled channel’s

turn during arbitration. Meanwhile, all posted requests are dropped from the Request queue when the

USB_HCx_CHAR.CHDIS bit is set to 1.

The application is expected to disable a channel under any of the following conditions:

1. When a USB_HCx_INT.XFERCOMPL interrupt is received during a non-periodic IN transfer or high-

bandwidth interrupt IN transfer (Slave mode only)

2. When a USB_HCx_INT.STALL, USB_HCx_INT.XACTERR, USB_HCx_INT.BBLERR, or

USB_HCx_INT.DATATGLERR interrupt is received for an IN or OUT channel (Slave mode only).

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For high-bandwidth interrupt INs in Slave mode, once the application has received a DATATGLERR

interrupt it must disable the channel and wait for a Channel Halted interrupt. The application must

be able to receive other interrupts (DATATGLERR, NAK, Data, XACTERR, BBLERR) for the same

channel before receiving the halt.

3. When a USB_GINTSTS.DISCONNINT (Disconnect Device) interrupt is received. The application

must check for the USB_HPRT.PRTCONNSTS, because when the device directly connected to the

host is disconnected, USB_HPRT.PRTCONNSTS is reset. The software must issue a soft reset to

ensure that all channels are cleared. When the device is reconnected, the host must issue a USB

Reset.

4. When the application aborts a transfer before normal completion (Slave and DMA modes).

Note In DMA mode, keep the following guideline in mind:

• Channel disable must not be programmed for periodic channels. At the end of the next

frame (in the worst case), the core generates a channel halted and disables the channel

automatically.

15.4.3.3 Sending a Zero-Length Packet in Slave/DMA Modes

To send a zero-length data packet, the application must initialize an OUT channel as follows.

1. Program the USB_HCx_TSIZ register of the selected channel with a correct PID, XFERSIZE = 0,

and PKTCNT = 1.

2. Program the USB_HCx_CHAR register of the selected channel with CHENA = 1 and the device’s

endpoint characteristics, such as type, speed, and direction.

The application must treat a zero-length data packet as a separate transfer, and cannot combine it with

a non-zero-length transfer.

15.4.3.4 Handling Babble Conditions

The core handles two cases of babble: packet babble and port babble. Packet babble occurs if the device

sends more data than the maximum packet size for the channel. Port babble occurs if the core continues

to receive data from the device at EOF2 (the end of frame 2, which is very close to SOF).

When the core detects a packet babble, it stops writing data into the Rx buffer and waits for the end of

packet (EOP). When it detects an EOP, it flushes already-written data in the Rx buffer and generates

a Babble interrupt to the application.

When detects a port babble, it flushes the RxFIFO and disables the port. The core then generates a Port

Disabled Interrupt (USB_GINTSTS.PRTINT, USB_HPRT.PRTENCHNG). On receiving this interrupt,

the application must determine that this is not due to an overcurrent condition (another cause of the Port

Disabled interrupt) by checking USB_HPRT.PRTOVRCURRACT, then perform a soft reset. The core

does not send any more tokens after it has detected a port babble condition.

15.4.3.5 Handling Disconnects

If the device is disconnected suddenly, a USB_GINTSTS.DISCONNINT interrupt is generated.

When the application receives this interrupt, it must issue a soft reset by programming the

USB_GRSTCTL.CSFTRST bit.

15.4.3.6 Host Programming Operations

Table 15.1 (p. 257) provides links to the programming sequence for the different types of USB

transactions.

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Table 15.1. Host Programming Operations

Mode IN OUT/SETUP

Control

Slave Bulk and Control IN Transactions in

Slave Mode (p. 261) Bulk and Control OUT/SETUP

Transactions in Slave Mode (p. 259)

DMA Bulk and Control IN Transactions in

DMA Mode (p. 267) Bulk and Control OUT/SETUP

Transactions in DMA Mode (p. 263)

Bulk

Slave Bulk and Control IN Transactions in

Slave Mode (p. 261) Bulk and Control OUT/SETUP

Transactions in Slave Mode (p. 259)

DMA Bulk and Control IN Transactions in

DMA Mode (p. 267) Bulk and Control OUT/SETUP

Transactions in DMA Mode (p. 263)

Interrupt

Slave Interrupt IN Transactions in Slave

Mode (p. 271) Interrupt OUT Transactions in Slave

Mode (p. 269)

DMA Interrupt IN Transactions in DMA

Mode (p. 275) Interrupt OUT Transactions in DMA

Mode (p. 273)

Isochronous

Slave Isochronous IN Transactions in Slave

Mode (p. 279) Isochronous OUT Transactions in Slave

Mode (p. 277)

DMA Isochronous IN Transactions in DMA

Mode (p. 281) Isochronous OUT Transactions in DMA

Mode (p. 280)

15.4.3.6.1 Writing the Transmit FIFO in Slave Mode

Figure 15.10 (p. 258) shows the flow diagram for writing to the transmit FIFO in Slave mode. The host

automatically writes an entry (OUT request) to the Periodic/Non-periodic Request Queue, along with the

last DWORD write of a packet. The application must ensure that at least one free space is available in

the Periodic/Non-periodic Request Queue before starting to write to the transmit FIFO. The application

must always write to the transmit FIFO in DWORDs. If the packet size is non-DWORD aligned, the

application must use padding. The host determines the actual packet size based on the programmed

maximum packet size and transfer size.

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Figure 15.10. Transmit FIFO Write Task in Slave Mode

1 MPS

or LPS FIFO space

available?

Wait for

USB_GAHBCFG .NPTXFEMPLVL

USB_GAHBCFG .PTXFEMPLVL

interrupt

Write 1 packet

data to

Transmit FIFO

Yes

MPS : Max Packet Size

LPS : Last Packet Size

Start

Done

Read USB_GNPTXSTS /

USB_HPTXFSIZ registers

for available FIFO and

Queue spaces

More packets

to send?

15.4.3.6.2 Reading the Receive FIFO in Slave Mode

Figure 15.11 (p. 258) shows the flow diagram for reading the receive FIFO in Slave mode. The

application must ignore all packet statuses other than IN Data Packet (0b0010).

Figure 15.11. Receive FIFO Read Task in Slave Mode

Read

USB_GRXSTSP

PKTSTS =

0b0010 ?

Yes

Unmask RXFLVL

interrupt

BCNT > 0 ?

Mask RXFLVL

interrupt

Yes

Unmask RXFLVL

interrupt

Start

RXFLVL

Interrupt?

Read the received

packet from the

Receive FIFO

15.4.3.6.3 Control Transactions in Slave Mode

Setup, Data, and Status stages of a control transfer must be performed as three separate transfers.

Setup- Data- or Status-stage OUT transactions are performed similarly to the bulk OUT transactions

explained in Bulk and Control OUT/SETUP Transactions in Slave Mode (p. 259) . Data- or Status-

stage IN transactions are performed similarly to the bulk IN transactions explained in Bulk and Control

IN Transactions in Slave Mode (p. 261) For all three stages, the application is expected to set the

USB_HC1_CHAR.EPTYPE field to Control. During the Setup stage, the application is expected to set

the USB_HC1_TSIZ.PID field to SETUP.

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15.4.3.6.4 Bulk and Control OUT/SETUP Transactions in Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must

initialize a channel as described in Channel Initialization (p. 254) . See Figure 15.10 (p. 258) and

Figure 15.11 (p. 258) for Read or Write data to and from the FIFO in Slave mode.

A typical bulk or control OUT/SETUP pipelined transaction-level operation in Slave mode is shown in

Figure 15.12 (p. 260) . See channel 1 (ch_1). Two bulk OUT packets are transmitted. A control SETUP

transaction operates the same way but has only one packet. The assumptions are:

• The application is attempting to send two maximum-packet-size packets (transfer size = 1,024 bytes).

• The Non-periodic Transmit FIFO can hold two packets (128 bytes for FS).

• The Non-periodic Request Queue depth = 4.

15.4.3.6.4.1 Normal Bulk and Control OUT/SETUP Operations

The sequence of operations in Figure 15.12 (p. 260) (channel 1) is as follows:

1. Initialize channel 1 as explained in Channel Initialization (p. 254) .

2. Write the first packet for channel 1.

3. Along with the last DWORD write, the core writes an entry to the Non-periodic Request Queue.

4. As soon as the non-periodic queue becomes non-empty, the core attempts to send an OUT token

in the current frame.

5. Write the second (last) packet for channel 1.

6. The core generates the XFERCOMPL interrupt as soon as the last transaction is completed

successfully.

7. In response to the XFERCOMPL interrupt, de-allocate the channel for other transfers.

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Figure 15.12. Normal Bulk/Control OUT/SETUP and Bulk/Control IN Transactions in Slave Mode

ACK

HostApplication DeviceAHB USB

OUT

DATA0

MPS

write_tx_fifo

(ch_1)

init_reg(ch_1)

set_ch_en

(ch_2)

init_reg(ch_2)

write_tx_fifo

(ch_1)

set_ch_en

(ch_2)

ch_2

ch_1

De- a llocate

(ch_1)

ch_2

ch_1

ACK

OUT

set_ch_en

(ch_2)

ACK

DATA0

ACK

read_rx_sts

read_rx_fifo

MPS

set_ch_en

(ch_2)

MPS

read_rx_stsre

ad_rx_fifo

read_rx_sts

Disable

(ch_2)

234

De- allocate

(ch_2)

ch_2

read_rx_sts 10

DATA1

MPS

DATA1

RXFLVL interrupt

XFERCOMPL interrupt

RXFLVL interrupt

XFERCOMPL interrupt

RXFLVL interrupt

CHHLTD interrupt

Non-Periodic Reques t

Queue

Assume that this queue can

hold 4 entries.

15.4.3.6.4.2 Handling Interrupts

The channel-specific interrupt service routine for bulk and control OUT/SETUP transactions in Slave

mode is shown in the following code samples.

Interrupt Service Routine for Bulk/Control OUT/SETUP Transactions in Slave Mode

Bulk/Control OUT/SETUP

Unmask (NAK/XACTERR/STALL/XFERCOMPL)

if (XFERCOMPL)

{

Reset Error Count

Mask ACK

De-allocate Channel

}

else if (STALL)

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{

Transfer Done = 1

Unmask CHHLTD

Disable Channel

}

else if (NAK or XACTERR)

{

Rewind Buffer Pointers

Unmask CHHLTD

Disable Channel

if (XACTERR)

{

Increment Error Count

Unmask ACK

}

else

{

Reset Error Count

}

else if (CHHLTD)

{

Mask CHHLTD

if (Transfer Done or (Error_count == 3))

{

De-allocate Channel

}

else

{

Re-initialize Channel

}

else if (ACK)

{

Reset Error Count

Mask ACK

}

The application is expected to write the data packets into the transmit FIFO when space is available in the

transmit FIFO and the Request queue. The application can make use of USB_GINTSTS.NPTXFEMP

interrupt to find the transmit FIFO space.

The application is expected to write the requests as and when the Request queue space is available

and until the XFERCOMPL interrupt is received.

15.4.3.6.5 Bulk and Control IN Transactions in Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must

initialize a channel as described in Channel Initialization (p. 254) . See Figure 15.10 (p. 258) and

Figure 15.11 (p. 258) for read or write data to and from the FIFO in Slave mode.

A typical bulk or control IN pipelined transaction-level operation in Slave mode is shown in

Figure 15.12 (p. 260) . See channel 2 (ch_2). The assumptions are:

1. The application is attempting to receive two maximum-sized packets (transfer size = 1,024 bytes).

2. The receive FIFO can contain at least one maximum-packet-size packet and two status DWORDs

per packet (72 bytes for FS).

3. The Non-periodic Request Queue depth = 4.

15.4.3.6.5.1 Normal Bulk and Control IN Operations

The sequence of operations in Figure 15.12 (p. 260) is as follows:

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1. Initialize channel 2 as explained in Channel Initialization (p. 254) .

2. Set the USB_HC2_CHAR.CHENA bit to write an IN request to the Non-periodic Request Queue.

3. The core attempts to send an IN token after completing the current OUT transaction.

4. The core generates an RXFLVL interrupt as soon as the received packet is written to the receive FIFO.

5. In response to the RXFLVL interrupt, mask the RXFLVL interrupt and read the received packet status

to determine the number of bytes received, then read the receive FIFO accordingly. Following this,

unmask the RXFLVL interrupt.

6. The core generates the RXFLVL interrupt for the transfer completion status entry in the receive FIFO.

7. The application must read and ignore the receive packet status when the receive packet status is not

an IN data packet (USB_GRXSTSR.PKTSTS != 0b0010).

8. The core generates the XFERCOMPL interrupt as soon as the receive packet status is read.

9. In response to the XFERCOMPL interrupt, disable the channel (see Halting a Channel (p. 255) )

and stop writing the USB_HC2_CHAR register for further requests. The core writes a channel disable

request to the non-periodic request queue as soon as the USB_HC2_CHAR register is written.

10.The core generates the RXFLVL interrupt as soon as the halt status is written to the receive FIFO.

11.Read and ignore the receive packet status.

12.The core generates a CHHLTD interrupt as soon as the halt status is popped from the receive FIFO.

13.In response to the CHHLTD interrupt, de-allocate the channel for other transfers.

Note For Bulk/Control IN transfers, the application must write the requests when the Request

queue space is available, and until the XFERCOMPL interrupt is received.

15.4.3.6.5.2 Handling Interrupts

The channel-specific interrupt service routine for bulk and control IN transactions in Slave mode is shown

in the following code samples.

Interrupt Service Routine for Bulk/Control IN Transactions in Slave Mode

Unmask (XACTERR/XFERCOMPL/BBLERR/STALL/DATATGLERR)

if (XFERCOMPL)

{

Reset Error Count

Unmask CHHLTD

Disable Channel

Reset Error Count

Mask ACK

}

else if (XACTERR or BBLERR or STALL)

{

Unmask CHHLTD

Disable Channel

if (XACTERR)

{

Increment Error Count

Unmask ACK

}

else if (CHHLTD)

{

Mask CHHLTD

if (Transfer Done or (Error_count == 3))

{

De-allocate Channel

}

else

{

Re-initialize Channel

}

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}

else if (ACK)

{

Reset Error Count

Mask ACK

}

else if (DATATGLERR)

{

Reset Error Count

}

15.4.3.6.6 Control Transactions in DMA Mode

Setup, Data, and Status stages of a control transfer must be performed as three separate transfers.

Setup- and Data- or Status-stage OUT transactions are performed similarly to the bulk OUT transactions

explained in Bulk and Control OUT/SETUP Transactions in DMA Mode (p. 263) . Data- or Status-

stage IN transactions are performed similarly to the bulk IN transactions explained in Bulk and Control

IN Transactions in DMA Mode (p. 267) . For all three stages, the application is expected to set the

USB_HC1_CHAR.EPTYPE field to Control. During the Setup stage, the application is expected to set

the USB_HC1_TSIZ.PID field to SETUP.

15.4.3.6.7 Bulk and Control OUT/SETUP Transactions in DMA Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) .

This section discusses the following topics:

• Overview (p. 263)

• Normal Bulk and Control OUT/SETUP Operations (p. 263)

• NAK Handling with DMA (p. 263)

• Handling Interrupts (p. 265)

15.4.3.6.7.1 Overview

• The application is attempting to send two maximum-packet-size packets (transfer size = 1,024 bytes).

• The Non-periodic Transmit FIFO can hold two packets (128 bytes for FS).

• The Non-periodic Request Queue depth = 4.

15.4.3.6.7.2 Normal Bulk and Control OUT/SETUP Operations

The sequence of operations in Figure 15.12 (p. 260) is as follows:

1. Initialize and enable channel 1 as explained in Channel Initialization (p. 254) .

2. The host starts fetching the first packet as soon as the channel is enabled. For DMA mode, the host

uses the programmed DMA address to fetch the packet.

3. After fetching the last DWORD of the second (last) packet, the host masks channel 1 internally for

further arbitration.

4. The host generates a CHHLTD interrupt as soon as the last packet is sent.

5. In response to the CHHLTD interrupt, de-allocate the channel for other transfers.

The channel-specific interrupt service routine for bulk and control OUT/SETUP transactions in DMA

mode is shown in Handling Interrupts (p. 265) .

15.4.3.6.7.3 NAK Handling with DMA

1. The Host sends a Bulk OUT Transaction.

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2. The Device responds with NAK.

3. If the application has unmasked NAK, the core generates the corresponding interrupt(s) to the

application.

The application is not required to service these interrupts, since the core takes care of rewinding of

buffer pointers and re-initializing the Channel without application intervention.

4. When the Device returns an ACK, the core continues with the transfer.

Optionally, the application can utilize these interrupts. If utilized by the application:

• The NAK interrupt is masked by the application.

• The core does not generate a separate interrupt when NAK is received by the Host functionality.

Application Programming Flow

1. The application programs a channel to do a bulk transfer for a particular data size in each transaction.

• Packet Data size can be up to 512 KBytes

• Zero-length data must be programmed as a separate transaction.

2. Program the transfer size register with:

• Transfer size

• Packet Count

3. Program the DMA address.

4. Program the USB_HCx_CHAR to enable the channel.

5. The Interrupt handling by the application is as depicted in the flow diagram.

Note The NAK interrupts are still generated internally. The application can mask off these

interrupts from reaching it. The application can use these interrupts optionally.

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Figure 15.13. Normal Bulk/Control OUT/SETUP and Bulk/Control IN Transactions in DMA Mode

ACK

HostApplication DeviceAHB USB

OUT

DATA0

MPS

init_reg(ch_1)

init_reg(ch_2)

ch_2

ch_1

De- allocate

(ch_1)

ch_2

ch_1

ACK

OUT

DATA1

MPS

ACK

DATA0

ACK

DATA1

MPS

De- allocate

(ch_2)

ch_2

CHHLTD interrupt

Non-Periodic Request

Queue

Assume that this queue can

hold 4 entries.

15.4.3.6.7.4 Handling Interrupts

The channel-specific interrupt service routine for bulk and control OUT/SETUP transactions in DMA

mode is shown in the following code samples.

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Figure 15.14. Interrupt Service Routine for Bulk/Control OUT Transaction in DMA Mode

Interrupt

yes

Start

Yes ,

No Yes

Deallocate

Channel

Yes

Yes,

USB_HCx_INT.

ACK = 1?

USB_HCx_INT.XACTERR = 1

USB_HCx_INT.XFERCOMPL = 1

USB_HCx_INT.STALL = 1 or

USB_HCx_INT.ACK = 1

USB_HCx_INT.NAK = 1

Reset Err_cnt

Err_cnt =

Err_cnt +1

Err_cnt ==

3 ?

1. Reprogram

Buffer pointers

2. Re-initialize

Channel

1. Err_cnt = 1

2. Re-initialize

channel

3. Reprogram

Buffer pointers

1. Reset Err_cnt

2. Deallocate

channel

Service based on the

other interrupt status

bits namely: AHBERR,

FRMOVRERR,

BBLERR and

DATATGLERR

Unmasked the required

USB_HAINTMSK and

USB_HCx_INTMSK status

bits

Read USB_HAINT to

determine the channel

which caused the

Interrupt and read the

corresponding USB_HCx_INT

USB_HCx_INT.

CHHLTD = 1 ?

In Figure 15.14 (p. 266) that the Interrupt Service Routine is not required to handle NAK responses.

This is the difference of proposed flow with respect to current flow. Similar flow is applicable for Control

flow also.

The NAK status bits in USB_HCx_INT registers are updated. The application can unmask these

interrupts when it requires the core to generate an interrupt for NAK. The NAK status is updated because

during Xact_err scenarios, this status provides a means for the application to determine whether the

Xact_err occurred three times consecutively or there were NAK responses in between two Xact_err.

This provides a mechanism for the application to reset the error counter accordingly. The application

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must read the NAK/ACK along with the xact_err. If NAK/ACK is not set, the Xact_err count must be

incremented otherwise application must initialize the Xact_err count to 1.

Bulk/Control OUT/SETUP

Unmask (CHHLTD)

if (CHHLTD)

{

if (XFERCOMPL or STALL)

{

Reset Error Count (Error_count=1)

Mask ACK

De-allocate Channel

}

else if (XACTERR)

{

if (NAK/ACK)

{

Error_count = 1

Re-initialize Channel

Rewind Buffer Pointers

}

else

{

Error_count = Error_count + 1

if (Error_count == 3)

{

De allocate channel

}

else

{

Re-initialize Channel

Rewind Buffer Pointers

}

else if (ACK)

{

Reset Error Count (Error_count=1)

Mask ACK

}

As soon as the channel is enabled, the core attempts to fetch and write data packets, in multiples of

the maximum packet size, to the transmit FIFO when space is available in the transmit FIFO and the

Request queue. The core stops fetching as soon as the last packet is fetched.

15.4.3.6.8 Bulk and Control IN Transactions in DMA Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) .

A typical bulk or control IN operation in DMA mode is shown in Figure 15.13 (p. 265) . See channel

2 (ch_2).

The assumptions are:

1. The application is attempting to receive two maximum-packet-size packets (transfer size = 1,024

bytes).

2. The receive FIFO can hold at least one maximum-packet-size packet and two status DWORDs per

packet (72 bytes for FS).

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3. The Non-periodic Request Queue depth = 4.

15.4.3.6.8.1 Normal Bulk and Control IN Operations

The sequence of operations in Figure 15.13 (p. 265) is as follows:

1. Initialize and enable channel 2 as explained in Channel Initialization (p. 254) .

2. The host writes an IN request to the Request queue as soon as channel 2 receives the grant from

the arbiter. (Arbitration is performed in a round-robin fashion, with fairness.).

3. The host starts writing the received data to the system memory as soon as the last byte is received

with no errors.

4. When the last packet is received, the host sets an internal flag to remove any extra IN requests from

the Request queue.

5. The host flushes the extra requests.

6. The final request to disable channel 2 is written to the Request queue. At this point, channel 2 is

internally masked for further arbitration.

7. The host generates the CHHLTD interrupt as soon as the disable request comes to the top of the

queue.

8. In response to the CHHLTD interrupt, de-allocate the channel for other transfers.

15.4.3.6.8.2 Handling Interrupts

The channel-specific interrupt service routine for bulk and control IN transactions in DMA mode is shown

in the following flow:

Interrupt Service Routines for Bulk/Control Bulk/Control IN Transactions in DMA Mode

Bulk/Control IN

Unmask (CHHLTD)

if (CHHLTD)

{

if (XFERCOMPL or STALL or BBLERR)

{

Reset Error Count Mask ACK De-allocate Channel

}

else if (XACTERR)

{

if (Error_count == 2)

{

De-allocate Channel

}

else

{

Unmask ACK

Unmask NAK

Unmask DATATGLERR

Increment Error

Count Re-initialize Channel

}

else if (ACK or NAK or DATATGLERR)

{

Reset Error Count

Mask ACK

Mask NAK

Mask DATATGLERR

}

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15.4.3.6.9 Interrupt OUT Transactions in Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must

initialize a channel as described in Channel Initialization (p. 254) . See Figure 15.10 (p. 258) and

Figure 15.11 (p. 258) for read or write data to and from the FIFO in Slave mode.

A typical interrupt OUT operation in Slave mode is shown in Figure 15.15 (p. 270) . See channel 1

(ch_1). The assumptions are:

• The application is attempting to send one packet in every frame (up to 1 maximum packet size),

starting with the odd frame (transfer size = 1,024 bytes).

• The Periodic Transmit FIFO can hold one packet.

• Periodic Request Queue depth = 4.

15.4.3.6.9.1 Normal Interrupt OUT Operation

The sequence of operations in Figure 15.15 (p. 270) is as follows:

1. Initialize and enable channel 1 as explained in Channel Initialization (p. 254) . The application must

set the USB_HC1_CHAR.ODDFRM bit.

2. Write the first packet for channel 1. For a high-bandwidth interrupt transfer, the application must write

the subsequent packets up to MC (maximum number of packets to be transmitted in the next frame

times before switching to another channel).

3. Along with the last DWORD write of each packet, the host writes an entry to the Periodic Request

Queue.

4. The host attempts to send an OUT token in the next (odd) frame.

5. The host generates an XFERCOMPL interrupt as soon as the last packet is transmitted successfully.

6. In response to the XFERCOMPL interrupt, reinitialize the channel for the next transfer.

15.4.3.6.9.2 Handling Interrupts

The channel-specific interrupt service routine for Interrupt OUT transactions in Slave mode is shown in

the following flow:

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Figure 15.15. Normal Interrupt OUT/IN Transactions in Slave Mode

Host

Application DeviceAHB USB

OUT

DATA0

MPS

write_tx_fifo

(ch_1)

init_reg(ch_1)

set_ch_en

(ch_2)

init_reg(ch_2)

write_tx_fifo

(ch_1)

OUT

DATA1

MPS

Periodic Request Queue

Assume that this queue

can hold 4 entries.

DATA0

MPS

read_rx_sts

read_rx_fifo

read_rx_sts

Odd

frame

Even

frame

init_reg(ch_1)

set_ch_en

(ch_2)

init_reg(ch_2)

write_tx_fifo

(ch_1)

init_reg(ch_1)

MPS

DATA1

ACK

ch_1

ch_2

ch_1

XFERCOMPL interrupt

RXFLVL interrupt

Interrupt Service Routine for Interrupt OUT Transactions in Slave Mode

Interrupt OUT

Unmask (NAK/XACTERR/STALL/XFERCOMPL/FRMOVRUN)

if (XFERCOMPL)

{

Reset Error Count

Mask ACK

De-allocate Channel

}

else if (STALL or FRMOVRUN)

{

Mask ACK

Unmask CHHLTD

Disable Channel

if (STALL)

{

Transfer Done = 1

}

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}

else if (NAK or XACTERR)

{

Rewind Buffer Pointers

Reset Error Count

Mask ACK

Unmask CHHLTD

Disable Channel

}

else if (CHHLTD)

{

Mask CHHLTD

if (Transfer Done or (Error_count == 3))

{

De-allocate Channel

}

else

{

Re-initialize Channel (in next b_interval - 1 Frame)

}

else if (ACK)

{

Reset Error Count

Mask ACK

}

The application is expected to write the data packets into the transmit FIFO when the space is available

in the transmit FIFO and the Request queue up to the count specified in the MC field before switching

to another channel. The application uses the USB_GINTSTS.NPTXFEMP interrupt to find the transmit

FIFO space.

15.4.3.6.10 Interrupt IN Transactions in Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) . See Transmit FIFO Write Task in Slave Mode

and Receive FIFO Read Task in Slave Mode for read or write data to and from the FIFO in Slave mode.

A typical interrupt-IN operation in Slave mode is shown in Figure 15.15 (p. 270) . See channel 2 (ch_2).

The assumptions are:

1. The application is attempting to receive one packet (up to 1 maximum packet size) in every frame,

starting with odd. (transfer size = 1,024 bytes).

2. The receive FIFO can hold at least one maximum-packet-size packet and two status DWORDs per

packet (1,031 bytes for FS).

3. Periodic Request Queue depth = 4.

15.4.3.6.10.1 Normal Interrupt IN Operation

The sequence of operations in Figure 15.15 (p. 270) (channel 2) is as follows:

1. Initialize channel 2 as explained in Channel Initialization (p. 254) . The application must set the

USB_HC2_CHAR.ODDFRM bit.

2. Set the USB_HC2_CHAR.CHENA bit to write an IN request to the Periodic Request Queue. For

a high-bandwidth interrupt transfer, the application must write the USB_HC2_CHAR register MC

(maximum number of expected packets in the next frame) times before switching to another channel.

3. The host writes an IN request to the Periodic Request Queue for each USB_HC2_CHAR register

write with a CHENA bit set.

4. The host attempts to send an IN token in the next (odd) frame.

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5. As soon as the IN packet is received and written to the receive FIFO, the host generates an RXFLVL

interrupt.

6. In response to the RXFLVL interrupt, read the received packet status to determine the number of bytes

received, then read the receive FIFO accordingly. The application must mask the RXFLVL interrupt

before reading the receive FIFO, and unmask after reading the entire packet.

7. The core generates the RXFLVL interrupt for the transfer completion status entry in the receive FIFO.

The application must read and ignore the receive packet status when the receive packet status is not

an IN data packet (USB_GRXSTSR.PKTSTS != 0b0010).

8. The core generates an XFERCOMPL interrupt as soon as the receive packet status is read.

9. In response to the XFERCOMPL interrupt, read the USB_HC2_TSIZ.PKTCNT field. If

USB_HC2_TSIZ.PKTCNT != 0, disable the channel (as explained in Halting a Channel (p. 255)

) before re-initializing the channel for the next transfer, if any). If USB_HC2_TSIZ.PKTCNT ==

0, reinitialize the channel for the next transfer. This time, the application must reset the

USB_HC2_CHAR.ODDFRM bit.

15.4.3.6.10.2 Handling Interrupts

The channel-specific interrupt service routine for an interrupt IN transaction in Slave mode is a follows.

Interrupt IN

Unmask (NAK/XACTERR/XFERCOMPL/BBLERR/STALL/FRMOVRUN/DATATGLERR)

if (XFERCOMPL)

{

Reset Error Count

Mask ACK

if (USB_HCx_TSIZ.PKTCNT == 0)

{

De-allocate Channel

}

else

{

Transfer Done = 1

Unmask CHHLTD

Disable Channel

}

else if (STALL or FRMOVRUN or NAK or DATATGLERR or BBLERR)

{

Mask ACK

Unmask CHHLTD

Disable Channel

if (STALL or BBLERR)

{

Reset Error Count

Transfer Done = 1

}

else if (!FRMOVRUN)

{

Reset Error Count

}

else if (XACTERR)

{

Increment Error Count

Unmask ACK

Unmask CHHLTD

Disable Channel

}

else if (CHHLTD)

{

Mask CHHLTD

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if (Transfer Done or (Error_count == 3))

{

De-allocate Channel

}

else

{

Re-initialize Channel (in next b_interval - 1 Frame)

}

else if (ACK)

{

Reset Error Count

Mask ACK

}

The application is expected to write the requests for the same channel when the Request queue space

is available up to the count specified in the MC field before switching to another channel (if any).

15.4.3.6.11 Interrupt OUT Transactions in DMA Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) .

A typical interrupt OUT operation in DMA mode is shown in Figure 15.16 (p. 274) . See channel 1

(ch_1). The assumptions are:

• The application is attempting to transmit one packet in every frame (up to 1 maximum packet size

of 1,024 bytes).

• The Periodic Transmit FIFO can hold one packet (1 KB for FS).

• Periodic Request Queue depth = 4.

15.4.3.6.11.1 Normal Interrupt OUT Operation

1. Initialize and enable channel 1 as explained in Channel Initialization (p. 254) .

2. The host starts fetching the first packet as soon the channel is enabled and writes the OUT request

along with the last DWORD fetch. In high-bandwidth transfers, the host continues fetching the next

packet (up to the value specified in the MC field) before switching to the next channel.

3. The host attempts to send the OUT token in the beginning of the next odd frame.

4. After successfully transmitting the packet, the host generates a CHHLTD interrupt.

5. In response to the CHHLTD interrupt, reinitialize the channel for the next transfer.

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Figure 15.16. Normal Interrupt OUT/IN Transactions in DMA Mode

DATA1

MPS

HostApplication DeviceAHB USB

OUT

DATA0

MPS

init_reg(ch_1)

init_reg(ch_2)

ch_2

ch_1

OUT

Periodic Request

Queue

Assume that this

queue can hold

4 entries.

DATA0

MPS

ch_1

init_reg(ch_1)

init_reg(ch_2)

init_reg(ch_1)

MPS

DATA1

ch_2

ACK

Odd

frame

Even

frame

CHHLTD interrupt

15.4.3.6.11.2 Handling Interrupts

The following code sample shows the channel-specific ISR for an interrupt OUT transaction in DMA

mode.

Interrupt OUT

Unmask (CHHLTD)

if (CHHLTD)

{

if (XFERCOMPL)

{

Reset Error Count

Mask ACK

if (Transfer Done)

{

De-allocate Channel

}

else

{

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Re-initialize Channel (in next b_interval - 1 Frame)

}

else if (STALL)

{

Transfer Done = 1

Reset Error Count

Mask ACK

De-allocate Channel

}

else if (NAK or FRMOVRUN)

{

Mask ACK

Rewind Buffer Pointers

Re-initialize Channel (in next b_interval - 1 Frame)

if (NAK)

{

Reset Error Count

}

else if (XACTERR)

{

if (Error_count == 2)

{

De-allocate Channel

}

else

{

Increment Error Count

Rewind Buffer Pointers

Unmask ACK

Re-initialize Channel (in next b_interval - 1 Frame)

}

else if (ACK)

{

Reset Error Count

Mask ACK

}

As soon as the channel is enabled, the core attempts to fetch and write data packets, in maximum

packet size multiples, to the transmit FIFO when the space is available in the transmit FIFO and the

Request queue. The core stops fetching as soon as the last packet is fetched (the number of packets

is determined by the MC field of the USB_HCx_CHAR register).

15.4.3.6.12 Interrupt IN Transactions in DMA Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) .

A typical interrupt IN operation in DMA mode is shown in Figure 15.16 (p. 274) . See channel 2 (ch_2).

The assumptions are:

• The application is attempting to receive one packet in every frame (up to 1 maximum packet size of

1,024 bytes).

• The receive FIFO can hold at least one maximum-packet-size packet and two status DWORDs per

packet (1,032 bytes for FS).

• Periodic Request Queue depth = 4.

15.4.3.6.12.1 Normal Interrupt IN Operation

The sequence of operations in Figure 15.16 (p. 274) (channel 2) is as follows:

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1. Initialize and enable channel 2 as explained in Channel Initialization (p. 254) .

2. The host writes an IN request to the Request queue as soon as the channel 2 gets the grant from

the arbiter (round-robin with fairness). In high-bandwidth transfers, the host writes consecutive writes

up to MC times.

3. The host attempts to send an IN token at the beginning of the next (odd) frame.

4. As soon the packet is received and written to the receive FIFO, the host generates a CHHLTD

interrupt.

5. In response to the CHHLTD interrupt, reinitialize the channel for the next transfer.

15.4.3.6.12.2 Handling Interrupts

The channel-specific interrupt service routine for Interrupt IN transactions in DMA mode is as follows.

Interrupt Service Routine for Interrupt IN Transactions in DMA Mode

Unmask (CHHLTD)

if (CHHLTD)

{

if (XFERCOMPL)

{

Reset Error Count

Mask ACK

if (Transfer Done)

{

De-allocate Channel

}

else

{

Re-initialize Channel (in next b_interval - 1 Frame)

}

else if (STALL or BBLERR)

{

Reset Error Count

Mask ACK

De-allocate Channel

}

else if (NAK or DATATGLERR or FRMOVRUN)

{

Mask ACK

Re-initialize Channel (in next b_interval - 1 Frame)

if (DATATGLERR or NAK)

{

Reset Error Count

}

else if (XACTERR)

{

if (Error_count == 2)

{

De-allocate Channel

}

else

{

Increment Error Count

Unmask ACK

Re-initialize Channel (in next b_interval - 1 Frame)

}

else if (ACK)

{

Reset Error Count

Mask ACK

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}

As soon as the channel is enabled, the core attempts to write the requests into the Request queue when

the space is available up to the count specified in the MC field.

15.4.3.6.13 Isochronous OUT Transactions in Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must

initialize a channel as described in Channel Initialization (p. 254) . See TFigure 15.10 (p. 258) and

Figure 15.11 (p. 258) for read or write data to and from the FIFO in Slave mode.

A typical isochronous OUT operation in Slave mode is shown in Figure 15.17 (p. 278) . See channel

1 (ch_1). The assumptions are:

• The application is attempting to send one packet every frame (up to 1 maximum packet size), starting

with an odd frame. (transfer size = 1,024 bytes).

• The Periodic Transmit FIFO can hold one packet (1 KB).

• Periodic Request Queue depth = 4.

15.4.3.6.13.1 Normal Isochronous OUT Operation

The sequence of operations in Figure 15.17 (p. 278) (channel 1) is as follows:

1. Initialize and enable channel 1 as explained in Channel Initialization (p. 254) . The application must

set the USB_HC1_CHAR.ODDFRM bit.

2. Write the first packet for channel 1. For a high-bandwidth isochronous transfer, the application must

write the subsequent packets up to MC (maximum number of packets to be transmitted in the next

frame) times before switching to another channel.

3. Along with the last DWORD write of each packet, the host writes an entry to the Periodic Request

Queue.

4. The host attempts to send the OUT token in the next frame (odd).

5. The host generates the XFERCOMPL interrupt as soon as the last packet is transmitted successfully.

6. In response to the XFERCOMPL interrupt, reinitialize the channel for the next transfer.

15.4.3.6.13.2 Handling Interrupts

The channel-specific interrupt service routine for isochronous OUT transactions in Slave mode is shown

in the following flow:

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Figure 15.17. Normal Isochronous OUT/IN Transactions in Slave Mode

HostApplication DeviceAHB USB

OUT

DATA0

MPS

write_tx_fifo

(ch_1)

init_reg(ch_1)

set_ch_en

(ch_2)

init_reg(ch_2)

write_tx_fifo

(ch_1)

ch_2

ch_1

OUT

DATA0

MPS

DATA0

MPS

read_rx_sts

read_rx_fifo

read_rx_sts

init_reg(ch_1)

set_ch_en

(ch_2)

init_reg(ch_2)

write_tx_fifo

(ch_1)

init_reg(ch_1)

MPS

DATA

ch_2

ch_1

Even

frame

Odd

frame

XFERCOMPL interrupt

RXFLVL interrupt

Periodic Reques ts

Queue

Asume that this queue

can hold 4 entries.

Interrupt Service Routine for Isochronous OUT Transactions in Slave Mode

Isochronous OUT

Unmask (FRMOVRUN/XFERCOMPL)

if (XFERCOMPL)

{

De-allocate Channel

}

else if (FRMOVRUN)

{

Unmask CHHLTD

Disable Channel

}

else if (CHHLTD)

{

Mask CHHLTD

De-allocate Channel

}

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15.4.3.6.14 Isochronous IN Transactions in Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must

initialize a channel as described in Channel Initialization (p. 254) . See Figure 15.10 (p. 258) and

Figure 15.11 (p. 258) for read or write data to and from the FIFO in Slave mode.

A typical isochronous IN operation in Slave mode is shown in Figure 15.17 (p. 278) . See channel 2

(ch_2). The assumptions are:

• The application is attempting to receive one packet (up to 1 maximum packet size) in every frame

starting with the next odd frame. (transfer size = 1,024 bytes).

• The receive FIFO can hold at least one maximum-packet-size packet and two status DWORDs per

packet (1,031 bytes for FS).

• Periodic Request Queue depth = 4.

15.4.3.6.14.1 Normal Isochronous IN Operation

The sequence of operations in Figure 15.17 (p. 278) (channel 2) is as follows:

1. Initialize channel 2 as explained in Channel Initialization (p. 254) . The application must set the

USB_HC2_CHAR.ODDFRM bit.

2. Set the USB_HC2_CHAR.CHENA bit to write an IN request to the Periodic Request Queue. For a

high-bandwidth isochronous transfer, the application must write the USB_HC2_CHAR register MC

(maximum number of expected packets in the next frame) times before switching to another channel.

3. The host writes an IN request to the Periodic Request Queue for each USB_HC2_CHAR register

write with the CHENA bit set.

4. The host attempts to send an IN token in the next odd frame.

5. As soon as the IN packet is received and written to the receive FIFO, the host generates an RXFLVL

interrupt.

6. In response to the RXFLVL interrupt, read the received packet status to determine the number of bytes

received, then read the receive FIFO accordingly. The application must mask the RXFLVL interrupt

before reading the receive FIFO, and unmask it after reading the entire packet.

7. The core generates an RXFLVL interrupt for the transfer completion status entry in the receive FIFO.

This time, the application must read and ignore the receive packet status when the receive packet

status is not an IN data packet (USB_GRXSTSR.PKTSTS != 0b0010).

8. The core generates an XFERCOMPL interrupt as soon as the receive packet status is read.

9. In response to the XFERCOMPL interrupt, read the USB_HC2_TSIZ.PKTCNT field. If

USB_HC2_TSIZ.PKTCNT != 0, disable the channel (as explained in Halting a Channel (p. 255)

) before re-initializing the channel for the next transfer, if any. If USB_HC2_TSIZ.PKTCNT ==

0, reinitialize the channel for the next transfer. This time, the application must reset the

USB_HC2_CHAR.ODDFRM bit.

15.4.3.6.14.2 Handling Interrupts

The channel-specific interrupt service routine for an isochronous IN transaction in Slave mode is as

follows.

Isochronous IN

Unmask (XACTERR/XFERCOMPL/FRMOVRUN/BBLERR)

if (XFERCOMPL or FRMOVRUN)

{

if (XFERCOMPL and (USB_HCx_TSIZ.PKTCNT == 0))

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{

Reset Error Count

De-allocate Channel

}

else

{

Unmask CHHLTD

Disable Channel

}

else if (XACTERR or BBLERR)

{

Increment Error Count

Unmask CHHLTD

Disable Channel

}

else if (CHHLTD)

{

Mask CHHLTD

if (Transfer Done or (Error_count == 3))

{

De-allocate Channel

}

else

{

Re-initialize Channel

}

15.4.3.6.15 Isochronous OUT Transactions in DMA Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) .

A typical isochronous OUT operation in DMA mode is shown in Figure 15.18 (p. 281) . See channel

1 (ch_1). The assumptions are:

• The application is attempting to transmit one packet every frame (up to 1 maximum packet size of

1,024 bytes).

• The Periodic Transmit FIFO can hold one packet (1 KB).

• Periodic Request Queue depth = 4.

15.4.3.6.15.1 Normal Isochronous OUT Operation

1. Initialize and enable channel 1 as explained in Channel Initialization (p. 254) .

2. The host starts fetching the first packet as soon as the channel is enabled, and writes the OUT request

along with the last DWORD fetch. In high-bandwidth transfers, the host continues fetching the next

packet (up to the value specified in the MC field) before switching to the next channel.

3. The host attempts to send an OUT token in the beginning of the next (odd) frame.

4. After successfully transmitting the packet, the host generates a CHHLTD interrupt.

5. In response to the CHHLTD interrupt, reinitialize the channel for the next transfer.

15.4.3.6.15.2 Handling Interrupts

The channel-specific interrupt service routine for Isochronous OUT transactions in DMA mode is shown

in the following flow:

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Figure 15.18. Normal Isochronous OUT/IN Transactions in DMA Mode

HostApplication DeviceAHB USB

OUT

DATA0

MPS

init_reg(ch_1)

init_reg(ch_2)

ch_2

ch_1

OUT

DATA0

MPS

Periodic Request

Queue

Assume that this

queue can hold

4 entries.

DATA0

MPS

ch_1

init_reg(ch_1)

init_reg(ch_2)

init_reg(ch_1)

MPS

DATA0

ch_2

Odd

frame

Even

frame

CHHLTD interrupt

Interrupt Service Routine for Isochronous OUT Transactions in DMA Mode

Isochronous OUT

Unmask (CHHLTD)

if (CHHLTD)

{

if (XFERCOMPL or FRMOVRUN)

{

De-allocate Channel

}

15.4.3.6.16 Isochronous IN Transactions in DMA Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the connected device, it must initialize

a channel as described in Channel Initialization (p. 254) .

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A typical isochronous IN operation in DMA mode is shown in Figure 15.18 (p. 281) . See channel 2

(ch_2). The assumptions are:

• The application is attempting to receive one packet in every frame (up to 1 maximum packet size of

1,024 bytes).

• The receive FIFO can hold at least one maximum-packet-size packet and two status DWORDS per

packet (1,031 bytes).

• Periodic Request Queue depth = 4.

15.4.3.6.16.1 Normal Isochronous IN Operation

The sequence of operations in Figure 15.18 (p. 281) (channel 2) is as follows:

1. Initialize and enable channel 2 as explained in Channel Initialization (p. 254) .

2. The host writes an IN request to the Request queue as soon as the channel 2 gets the grant from the

arbiter (round-robin with fairness). In high-bandwidth transfers, the host performs consecutive writes

up to MC times.

3. The host attempts to send an IN token at the beginning of the next (odd) frame.

4. As soon the packet is received and written to the receive FIFO, the host generates a CHHLTD

interrupt.

5. In response to the CHHLTD interrupt, reinitialize the channel for the next transfer.

15.4.3.6.16.2 Handling Interrupts

The channel-specific interrupt service routine for an isochronous IN transaction in DMA mode is as

follows.

Isochronous IN

Unmask (CHHLTD)

if (CHHLTD)

{

if (XFERCOMPL or FRMOVRUN)

{

if (XFERCOMPL and (USB_HCx_TSIZ.PKTCNT == 0))

{

Reset Error Count

De-allocate Channel

}

else

{

De-allocate Channel

}

else if (XACTERR or BBLERR)

{

if (Error_count == 2)

{

De-allocate Channel

}

else

{

Increment Error Count

Re-enable Channel (in next b_interval - 1 Frame)

}

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15.4.4 Device Programming Model

Before you program the Device, be sure to read Overview: Programming the Core (p. 248) and Modes

of operation (p. 251)

15.4.4.1 Endpoint Initialization

This section addresses the following topics:

• Initialization on USB Reset (p. 283)

• Initialization on Enumeration Completion (p. 283)

• Initialization on SetAddress Command (p. 284)

• Initialization on SetConfiguration/SetInterface Command (p. 284)

• Endpoint Activation (p. 284)

• Endpoint Deactivation (p. 284)

• Device DMA/Slave Mode Initialization (p. 285)

15.4.4.1.1 Initialization on USB Reset

1. Set the NAK bit for all OUT endpoints

• USB_DOEPx_CTL.SNAK = 1 (for all OUT endpoints)

2. Unmask the following interrupt bits:

• USB_USB_DAINTMSK.INEP0 = 1 (control 0 IN endpoint)

• USB_USB_DAINTMSK.OUTEP0 = 1 (control 0 OUT endpoint)

• USB_DOEPMSK.SETUP = 1

• USB_DOEPMSK.XFERCOMPL = 1

• USB_DIEPMSK.XFERCOMPL = 1

• USB_DIEPMSK.TIMEOUTMSK = 1

3. To transmit or receive data, the device must initialize more registers as specified in Device DMA/

Slave Mode Initialization (p. 285) .

4. Set up the Data FIFO RAM for each of the FIFOs

• Program the USB_GRXFSIZ Register, to be able to receive control OUT data and setup data. At

a minimum, this must be equal to 1 max packet size of control endpoint 0 + 2 DWORDs (for the

status of the control OUT data packet) + 10 DWORDs (for setup packets).

• Program the Device IN Endpoint Transmit FIFO size register (depending on the FIFO number

chosen), to be able to transmit control IN data. At a minimum, this must be equal to 1 max packet

size of control endpoint 0.

5. Program the following fields in the endpoint-specific registers for control OUT endpoint 0 to receive

a SETUP packet

• USB_DOEP0TSIZ.SUPCNT = 3 (to receive up to 3 back-to-back SETUP packets)

• In DMA mode, USB_DOEP0DMAADDR register with a memory address to store any SETUP

packets received

At this point, all initialization required to receive SETUP packets is done, except for enabling control

OUT endpoint 0 in DMA mode.

15.4.4.1.2 Initialization on Enumeration Completion

1. On the Enumeration Done interrupt (USB_GINTSTS.ENUMDONE, read the USB_DSTS register to

determine the enumeration speed.

2. Program the USB_DIEP0CTL.MPS field to set the maximum packet size. This step configures control

endpoint 0. The maximum packet size for a control endpoint depends on the enumeration speed.

3. In DMA mode, program the USB_DOEP0CTL register to enable control OUT endpoint 0, to receive

a SETUP packet.

• USB_DOEP0CTL.EPENA = 1

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At this point, the device is ready to receive SOF packets and is configured to perform control transfers

on control endpoint 0.

15.4.4.1.3 Initialization on SetAddress Command

This section describes what the application must do when it receives a SetAddress command in a SETUP

packet.

1. Program the USB_DCFG register with the device address received in the SetAddress command

2. Program the core to send out a status IN packet.

15.4.4.1.4 Initialization on SetConfiguration/SetInterface Command

This section describes what the application must do when it receives a SetConfiguration or SetInterface

command in a SETUP packet.

1. When a SetConfiguration command is received, the application must program the endpoint registers

to configure them with the characteristics of the valid endpoints in the new configuration.

2. When a SetInterface command is received, the application must program the endpoint registers of

the endpoints affected by this command.

3. Some endpoints that were active in the prior configuration or alternate setting are not valid in the new

configuration or alternate setting. These invalid endpoints must be deactivated.

4. For details on a particular endpoint’s activation or deactivation, see Endpoint Activation (p. 284)

and Endpoint Deactivation (p. 284) .

5. Unmask the interrupt for each active endpoint and mask the interrupts for all inactive endpoints in

the USB_USB_DAINTMSK register.

6. Set up the Data FIFO RAM for each FIFO. See Data FIFO RAM Allocation (p. 329) for more detail.

7. After all required endpoints are configured, the application must program the core to send a status

IN packet.

At this point, the device core is configured to receive and transmit any type of data packet.

15.4.4.1.5 Endpoint Activation

This section describes the steps required to activate a device endpoint or to configure an existing device

endpoint to a new type.

1. Program the characteristics of the required endpoint into the following fields of the USB_DIEPx_CTL

endpoints).

• Maximum Packet Size

• USB Active Endpoint = 1

• Endpoint Start Data Toggle (for interrupt and bulk endpoints)

• Endpoint Type

• TxFIFO Number

2. Once the endpoint is activated, the core starts decoding the tokens addressed to that endpoint and

sends out a valid handshake for each valid token received for the endpoint.

15.4.4.1.6 Endpoint Deactivation

This section describes the steps required to deactivate an existing endpoint.

1. In the endpoint to be deactivated, clear the USB Active Endpoint bit in the USB_DIEPx_CTL

endpoints).

2. Once the endpoint is deactivated, the core ignores tokens addressed to that endpoint, resulting in

a timeout on the USB.

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15.4.4.1.7 Device DMA/Slave Mode Initialization

The application must meed the following conditions to set up the device core to handle traffic.

• In Slave mode, USB_GINTMSK.NPTXFEMPMSK, and USB_GINTMSK.RXFLVLMSK must be unset.

• In DMA mode, the aforementioned interrupts must be masked.

15.4.4.1.8 Transfer Stop Process

When the core is operating as a device, use the following programing sequence if you want to stop any

transfers (because of an interrupt from the host, typically a reset).

15.4.4.1.8.1 Transfer Stop Programming Flow for IN Endpoints

Sequence of operations:

1. Disable the IN endpoint by programming USB_DIEP0CTL/USB_DIEPx_CTL.EPDIS = 1.

2. Wait for the USB_DIEPx_INT.EPDISBLD interrupt, which indicates that the IN endpoint is completely

disabled. When the EPDISBLD interrupt is asserted, the core clears the following bits:

• USB_DIEP0CTL/USB_DIEPx_CTL.EPDIS = 0

• USB_DIEP0CTL/USB_DIEPx_CTL.EPENA = 0

3. Flush the TX FIFO by programming the following bits:

• USB_GRSTCTL.TXFFLSH = 1

• USB_GRSTCTL.TXFNUM = FIFO number specific to endpoint

4. The application can start polling till USB_GRSTCTL.TXFFLSH is cleared. When this bit is cleared, it

ensures that there is no data left in the TX FIFO.

15.4.4.1.8.2 Transfer Stop Programming Flow for OUT Endpoints

Sequence of operations:

1. Enable all OUT endpoints by setting USB_DOEP0CTL/USB_DOEPx_CTL.EPENA = 1.

2. Before disabling any OUT endpoint, the application must enable Global OUT NAK mode in the core,

according to the instructions in Setting the Global OUT NAK (p. 293) . This ensures that data in the

RX FIFO is sent to the application successfully. Set USB_DCTL.USB_DCTL.SGOUTNAK = 1.

3. Wait for the USB_GINTSTS.GOUTNAKEFF interrupt.

4. Disable all active OUT endpoints by programming the following register bits:

• USB_DOEP0CTL/USB_DOEPx_CTL.EPENA = 1

• USB_DOEP0CTL/USB_DOEPx_CTL.EPDIS = 1

• USB_DOEP0CTL/USB_DOEPx_CTL.SNAK = 1

5. Wait for the USB_DOEP0INT/USB_DOEPx_INT.EPDISBLD interrupt for each OUT endpoint

programmed in the previous step. The USB_DOEP0INT/USB_DOEPx_INT.EPDISBLD interrupt

indicates that the corresponding OUT endpoint is completely disabled. When the EPDISBLD interrupt

is asserted, the core clears the following bits:

• USB_DOEP0CTL/USB_DOEPx_CTL.EPENA = 0

• USB_DOEP0CTL/USB_DOEPx_CTL.EPDIS = 0

Note The application must not flush the Rx FIFO, as the Global OUT NAK effective interrupt

earlier ensures that there is no data left in the Rx FIFO.

15.4.4.2 Device Programming Operations

Table 15.2 (p. 286) provides links to the programming sequence for different USB transaction types.

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Table 15.2.

Device Mode IN SETUP OUT

Control

Slave Generic Non-Periodic

(Bulk and Control) IN

Data Transfers Without

Thresholding in DMA and

Slave Mode (p. 310)

OUT Data Transfers

in Slave and DMA

Modes (p. 287)

Generic Non-Isochronous

OUT Data Transfers

Without Thresholding

in DMA and Slave

Modes (p. 295)

DMA Generic Non-Periodic

(Bulk and Control) IN

Data Transfers Without

Thresholding in DMA and

Slave Mode (p. 310)

OUT Data Transfers

in Slave and DMA

Modes (p. 287)

Generic Non-Isochronous

OUT Data Transfers

Without Thresholding

in DMA and Slave

Modes (p. 295)

Bulk

Slave Generic Non-Periodic

(Bulk and Control) IN

Data Transfers Without

Thresholding in DMA and

Slave Mode (p. 310)

Generic Non-Isochronous

OUT Data Transfers

Without Thresholding

in DMA and Slave

Modes (p. 295)

DMA Generic Non-Periodic

(Bulk and Control) IN

Data Transfers Without

Thresholding in DMA and

Slave Mode (p. 310)

Generic Non-Isochronous

OUT Data Transfers

Without Thresholding

in DMA and Slave

Modes (p. 295)

Interrupt

Slave Generic Periodic

IN (Interrupt and

Isochronous) Data

Transfers Without

Thresholding (p. 315)

and Generic Periodic IN

Data Transfers Without

Thresholding Using

the Periodic Transfer

Interrupt Feature (p.

317)

Generic Non-Isochronous

OUT Data Transfers

Without Thresholding

in DMA and Slave

Modes (p. 295)

and Generic Interrupt

OUT Data Transfers

Without Thresholding

Using Periodic Transfer

Interrupt Feature (p.

299)

DMA Generic Periodic

IN (Interrupt and

Isochronous) Data

Transfers Without

Thresholding (p. 315)

and Generic Periodic IN

Data Transfers Without

Thresholding Using

the Periodic Transfer

Interrupt Feature (p.

317)

Generic Non-Isochronous

OUT Data Transfers

Without Thresholding

in DMA and Slave

Modes (p. 295)

and Generic Interrupt

OUT Data Transfers

Without Thresholding

Using Periodic Transfer

Interrupt Feature (p.

299)

Isochronous

Slave Generic Periodic

IN (Interrupt and

Isochronous) Data

Transfers Without

Thresholding (p. 315)

Control Read Transfers

(SETUP, Data IN, Status

OUT) (p. 290) and

Incomplete Isochronous

OUT Data Transfers

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in DMA and Slave

Modes (p. 303)

DMA Generic Periodic

IN (Interrupt and

Isochronous) Data

Transfers Without

Thresholding (p. 315)

and Generic Periodic IN

Data Transfers Without

Thresholding Using

the Periodic Transfer

Interrupt Feature (p.

317)

Control Read Transfers

(SETUP, Data IN, Status

OUT) (p. 290) and

Incomplete Isochronous

OUT Data Transfers

in DMA and Slave

Modes (p. 303)

15.4.4.2.1 OUT Data Transfers in Slave and DMA Modes

This section describes the internal data flow and application-level operations during data OUT transfers

and setup transactions.

15.4.4.2.1.1 Control Setup Transactions

This section describes how the core handles SETUP packets and the application’s sequence for handling

setup transactions. To initialize the core after power-on reset, the application must follow the sequence

in Overview: Programming the Core (p. 248) . Before it can communicate with the host, it must initialize

an endpoint as described in Endpoint Initialization (p. 283) . See Packet Read from FIFO in Slave

Mode (p. 292) .

Application Requirements

1. To receive a SETUP packet, the USB_DOEPx_TSIZ.SUPCNT field in a control OUT endpoint must

be programmed to a non-zero value. When the application programs the SUPCNT field to a non-

zero value, the core receives SETUP packets and writes them to the receive FIFO, irrespective of

the USB_DOEPx_CTL.NAK status and USB_DOEPx_CTL.EPENA bit setting. The SUPCNT field is

decremented every time the control endpoint receives a SETUP packet. If the SUPCNT field is not

programmed to a proper value before receiving a SETUP packet, the core still receives the SETUP

packet and decrements the SUPCNT field, but the application possibly is not be able to determine

the correct number of SETUP packets received in the Setup stage of a control transfer.

• USB_DOEPx_TSIZ.SUPCNT = 3

2. In DMA mode, the OUT endpoint must also be enabled, to transfer the received SETUP packet data

from the internal receive FIFO to the external memory.

• USB_DOEPx_CTL.EPENA = 1

3. The application must always allocate some extra space in the Receive Data FIFO, to be able to

receive up to three SETUP packets on a control endpoint.

• The space to be Reserved is (4 * n) + 6 DWORDs, where n is the number of control endpoints

supported by the device. Three DWORDs are required for the first SETUP packet, 1 DWORD is

required for the Setup Stage Done DWORD, and 6 DWORDs are required to store two extra SETUP

packets among all control endpoints.

• 3 DWORDs per SETUP packet are required to store 8 bytes of SETUP data and 4 bytes of SETUP

status (Setup Packet Pattern). The core reserves this space in the receive data

• FIFO to write SETUP data only, and never uses this space for data packets.

4. In Slave mode, the application must read the 2 DWORDs of the SETUP packet from the receive FIFO.

In DMA mode, the core writes the 2 DWORDs of SETUP data to the memory.

5. The application must read and discard the Setup Stage Done DWORD from the receive FIFO.

Internal Data Flow

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1. When a SETUP packet is received, the core writes the received data to the receive FIFO, without

checking for available space in the receive FIFO and irrespective of the endpoint’s NAK and Stall

bit settings.

• The core internally sets the IN NAK and OUT NAK bits for the control IN/OUT endpoints on which

the SETUP packet was received.

2. For every SETUP packet received on the USB, 3 DWORDs of data is written to the receive FIFO,

and the SUPCNT field is decremented by 1.

• The first DWORD contains control information used internally by the core

• The second DWORD contains the first 4 bytes of the SETUP command

• The third DWORD contains the last 4 bytes of the SETUP command

3. When the Setup stage changes to a Data IN/OUT stage, the core writes an entry (Setup Stage Done

DWORD) to the receive FIFO, indicating the completion of the Setup stage.

4. On the AHB side, SETUP packets are emptied either by the DMA or the application. In DMA

mode, the SETUP packets (2 DWORDs) are written to the memory location programmed in the

USB_DOEPx_DMAADDR register, only if the endpoint is enabled. If the endpoint is not enabled, the

data remains in the receive FIFO until the enable bit is set.

5. When either the DMA or the application pops the Setup Stage Done DWORD from the receive FIFO,

the core interrupts the application with a USB_DOEPx_INT.SETUP interrupt, indicating it can process

the received SETUP packet.

• The core clears the endpoint enable bit for control OUT endpoints.

Application Programming Sequence

1. Program the USB_DOEPx_TSIZ register.

• USB_DOEPx_TSIZ.SUPCNT = 3

2. In DMA mode, program the USB_DOEPx_DMAADDR register and USB_DOEPx_CTL register with

the endpoint characteristics and set the Endpoint Enable bit (USB_DOEPx_CTL.EPENA).

• Endpoint Enable = 1

3. In Slave mode, wait for the USB_GINTSTS.RXFLVL interrupt and empty the data packets from the

receive FIFO, as explained in Packet Read from FIFO in Slave Mode (p. 292) . This step can be

repeated many times.

4. Assertion of the USB_DOEPx_INT.SETUP interrupt marks a successful completion of the SETUP

Data Transfer.

• On this interrupt, the application must read the USB_DOEPx_TSIZ register to determine the number

of SETUP packets received and process the last received SETUP packet.

• In DMA mode, the application must also determine if the interrupt bit

USB_DOEPx_INT.BACK2BACKSETUP is set. This bit is set if the core has received more

than three back-to-back SETUP packets. If this is the case, the application must ignore the

USB_DOEPx_TSIZ.SUPCNT value and use the USB_DOEPx_DMAADDR directly to read out the

last SETUP packet received. USB_DOEPx_DMAADDR-8 provides the pointer to the last valid

SETUP data.

Note If the application has not enabled EP0 before the host sends the SETUP packet, the core

ACKs the SETUP packet and stores it in the FIFO, but does not write to the memory until

EP0 is enabled. When the application enables the EP0 (first enable) and clears the NAK

bit at the same time the Host sends DATA OUT, the DATA OUT is stored in the RxFIFO.

The OTG core then writes the setup data to the memory and disables the endpoint. Though

the application expects a Transfer Complete interrupt for the Data OUT phase, this does

not occur, because the SETUP packet, rather than the DATA OUT packet, enables EP0 the

first time. Thus, the DATA OUT packet is still in the RxFIFO until the application re-enables

EP0. The application must enable EP0 one more time for the core to process the DATA

OUT packet.

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Figure 15.19 (p. 289) charts this flow.

Figure 15.19. Processing a SETUP Packet

Wait for

USB_DOEPx_INT.SETUP

rem_supcnt =

Rd_Reg(USB_DOEPx_TSIZ)

Find setup cmd type

Write

2-stage

Read

No Back2Back Setup

Interrupt bit set ?

Setup_addr =

Rd_Reg(USB_DOEPx_DMA

Yes

setup_cmd[31:0] = mem[setup_addr-8]

setup_cmd[63:32] = mem[setup_addr-4]

setup_cmd[31:0] = mem[4-2 * rem_supcnt]

setup_cmd[63:32] = mem[5-2 * rem_supcnt]

ctr-rd/wr/2 stage

setup_np_in_pkt

Data IN phase setup_np_in_pkt

Sata IN phase rcv_out_pkt

Data OUT phase

15.4.4.2.1.2 Handling More Than Three Back-to-Back SETUP Packets

Per the USB 2.0 specification, normally, during a SETUP packet error, a host does not send more

than three back-to-back SETUP packets to the same endpoint. However, the USB 2.0 specification

does not limit the number of back-to-back SETUP packets a host can send to the same endpoint.

When this condition occurs, the core generates an interrupt (USB_DOEPx_INT.BACK2BACKSETUP).

In DMA mode, the core also rewinds the DMA address for that endpoint (USB_DOEPx_DMAADDR)

and overwrites the first SETUP packet in system memory with the fourth, second with the fifth, and so

on. If the BACK2BACKSETUP interrupt is asserted, the application must read the OUT endpoint DMA

In DMA mode, the application can mask the BACK2BACKSETUP interrupt, but after receiving the

DOEPINT.SETUP interrupt, the application can read the DOEPINT.BACK2BACKSETUP interrupt bit.

In Slave mode, the application can use the USB_GINTSTS.RXFLVL interrupt to read out the SETUP

packets from the FIFO whenever the core receives the SETUP packet.

15.4.4.2.2 Control Transfers

This section describes the various types of control transfers.

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15.4.4.2.2.1 Control Write Transfers (SETUP, Data OUT, Status IN)

This section describes control write transfers.

Application Programming Sequence

1. Assertion of the USB_DOEPx_INT.SETUP Packet interrupt indicates that a valid SETUP packet

has been transferred to the application. See OUT Data Transfers in Slave and DMA Modes (p.

287) for more details. At the end of the Setup stage, the application must reprogram the

USB_DOEPx_TSIZ.SUPCNT field to 3 to receive the next SETUP packet.

2. If the last SETUP packet received before the assertion of the SETUP interrupt indicates a data OUT

phase, program the core to perform a control OUT transfer as explained in Generic Non-Isochronous

OUT Data Transfers Without Thresholding in DMA and Slave Modes (p. 295) .

In DMA mode, the application must reprogram the USB_DOEPx_DMAADDR register to receive a

control OUT data packet to a different memory location.

3. In a single OUT data transfer on control endpoint 0, the application can receive up to 64 bytes. If the

application is expecting more than 64 bytes in the Data OUT stage, the application must re-enable

the endpoint to receive another 64 bytes, and must continue to do so until it has received all the data

in the Data stage.

4. Assertion of the USB_DOEPx_INT.Transfer Completed interrupt on the last data OUT transfer

indicates the completion of the data OUT phase of the control transfer.

5. On completion of the data OUT phase, the application must do the following.

• To transfer a new SETUP packet in DMA mode, the application must re-enable the control OUT

endpoint as explained in OUT Data Transfers in Slave and DMA Modes (p. 287) .

• USB_DOEPx_CTL.EPENA = 1

• To execute the received Setup command, the application must program the required registers in

the core. This step is optional, based on the type of Setup command received.

6. For the status IN phase, the application must program the core as described in Generic Non-Periodic

(Bulk and Control) IN Data Transfers Without Thresholding in DMA and Slave Mode (p. 310) to

perform a data IN transfer.

7. Assertion of the USB_DIEPx_INT.XFERCOMPL interrupt indicates completion of the status IN phase

of the control transfer.

8. The previous step must be repeated until the USB_DIEPx_INT.XFERCOMPL interrupt is detected on

the endpoint, marking the completion of the control write transfer.

15.4.4.2.2.2 Control Read Transfers (SETUP, Data IN, Status OUT)

This section describes control read transfers.

Application Programming Sequence

1. Assertion of the USB_DOEPx_INT.SETUP Packet interrupt indicates that a valid SETUP packet

has been transferred to the application. See OUT Data Transfers in Slave and DMA Modes (p.

287) for more details. At the end of the Setup stage, the application must reprogram the

USB_DOEPx_TSIZ.SUPCNT field to 3 to receive the next SETUP packet.

2. If the last SETUP packet received before the assertion of the SETUP interrupt indicates a data IN

phase, program the core to perform a control IN transfer as explained in Generic Non-Periodic (Bulk

and Control) IN Data Transfers Without Thresholding in DMA and Slave Mode (p. 310) .

3. On a single IN data transfer on control endpoint 0, the application can transmit up to 64 bytes. To

transmit more than 64 bytes in the Data IN stage, the application must re-enable the endpoint to

transmit another 64 bytes, and must continue to do so, until it has transmitted all the data in the Data

stage.

4. The previous step must be repeated until the USB_DIEPx_INT.XFERCOMPL interrupt is detected

for every IN transfer on the endpoint.

5. The USB_DIEPx_INT.XFERCOMPL interrupt on the last IN data transfer marks the completion of the

control transfer’s Data stage.

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6. To perform a data OUT transfer in the status OUT phase, the application must program the core as

described in OUT Data Transfers in Slave and DMA Modes (p. 287) .

• The application must program the USB_DCFG.NZSTSOUTHSHK handshake field to a proper

setting before transmitting an data OUT transfer for the Status stage.

• In DMA mode, the application must reprogram the USB_DOEPx_DMAADDR register to receive

the control OUT data packet to a different memory location.

7. Assertion of the USB_DOEPx_INT.XFERCOMPL interrupt indicates completion of the status OUT

phase of the control transfer. This marks the successful completion of the control read transfer.

• To transfer a new SETUP packet in DMA mode, the application must re-enable the control OUT

endpoint as explained in OUT Data Transfers in Slave and DMA Modes (p. 287) .

• USB_DOEPx_CTL.EPENA = 1

15.4.4.2.2.3 Two-Stage Control Transfers (SETUP/Status IN)

This section describes two-stage control transfers.

Application Programming Sequence

1. Assertion of the USB_DOEPx_INT.SETUP interrupt indicates that a valid SETUP packet has

been transferred to the application. See OUT Data Transfers in Slave and DMA Modes (p.

287) for more detail. To receive the next SETUP packet, the application must reprogram the

USB_DOEPx_TSIZ.SUPCNT field to 3 at the end of the Setup stage.

2. Decode the last SETUP packet received before the assertion of the SETUP interrupt. If the packet

indicates a two-stage control command, the application must do the following.

• To transfer a new SETUP packet in DMA mode, the application must re-enable the control OUT

endpoint. See OUT Data Transfers in Slave and DMA Modes (p. 287) for details.

• USB_DOEPx_CTL.EPENA = 1

• Depending on the type of Setup command received, the application can be required to program

registers in the core to execute the received Setup command.

3. For the status IN phase, the application must program the core described in Generic Non-Periodic

(Bulk and Control) IN Data Transfers Without Thresholding in DMA and Slave Mode (p. 310) to

perform a data IN transfer.

4. Assertion of the USB_DIEPx_INT.XFERCOMPL interrupt indicates the completion of the status IN

phase of the control transfer.

5. The previous step must be repeated until the USB_DIEPx_INT.XFERCOMPL interrupt is detected on

the endpoint, marking the completion of the two-stage control transfer.

Example: Two-Stage Control Transfer

These notes refer to Figure 15.20 (p. 292) .

1. SETUP packet #1 is received on the USB and is written to the receive FIFO, and the core responds

with an ACK handshake. This handshake is lost and the host detects a timeout.

2. The SETUP packet in the receive FIFO results in a USB_GINTSTS.RXFLVL interrupt to the

application, causing the application to empty the receive FIFO.

3. SETUP packet #2 on the USB is written to the receive FIFO, and the core responds with an ACK

handshake.

4. The SETUP packet in the receive FIFO sends the application the USB_GINTSTS.RXFLVL interrupt

and the application empties the receive FIFO.

5. After the second SETUP packet, the host sends a control IN token for the status phase. The core

issues a NAK response to this token, and writes a Setup Stage Done entry to the receive FIFO. This

entry results in a USB_GINTSTS.RXFLVL interrupt to the application, which empties the receive FIFO.

After reading out the Setup Stage Done DWORD, the core asserts the USB_DOEPx_INT.SETUP

packet interrupt to the application.

6. On this interrupt, the application processes SETUP Packet #2, decodes it to be a two-stage control

command, and clears the control IN NAK bit.

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• USB_DIEPx_CTL.CNAK = 1

7. When the application clears the IN NAK bit, the core interrupts the application with a

USB_DIEPx_INT.INTKNTXFEMP. On this interrupt, the application enables the control IN endpoint

with a USB_DIEPx_TSIZ.XFERSIZE of 0 and a USB_DIEPx_TSIZ.PKTCNT of 1. This results in a

zero-length data packet for the status IN token on the USB.

8. At the end of the status IN phase, the core interrupts the application with a

USB_DIEPx_INT.XFERCOMPL interrupt.

Figure 15.20. Two-Stage Control Transfer

setup data2

Hos t ApplicationDevice

USB

SETUP

IN(STATUS)

8 bytes

ACK

status_ xact_2

ACKLost

RXFLVL

INTR

setup_ xact_1

NAK

setup_xact_2

status_xact_2

setup data1

SETUP

ACK

FLVL

INTR

NAK

setup data1

setup done

SETUP

Intr

Clear IN

NAK

INTKNTXFEMP

INTR

FERCOMPL

INTR

idle until intr

setup_ in_ np_ pkt

stsdatardy

proc_ setup_pkt

idle until intr

rcv_out_data

idle until intr

rcv_out_data

idle until intr

rcv_out_data

idle until intr

RXFL

VLINTR

Ctl- IN NAK = 1 Ctl- OUT NAK = 1

Control IN NAK = 1

Control OUT NAK = 1

8 bytes

setup data1

XFERSIZE = 0 bytes

PKTCNT = 1

EPENA = 1

15.4.4.2.2.4 Packet Read from FIFO in Slave Mode

This section describes how to read packets (OUT data and SETUP packets) from the receive FIFO in

Slave mode.

1. On catching a USB_GINTSTS.RXFLVL interrupt, the application must read the Receive Status Pop

2. The application can mask the USB_GINTSTS.RXFLVL interrupt by writing to

USB_GINTMSK.RXFLVL = 0, until it has read the packet from the receive FIFO.

3. If the received packet’s byte count is not 0, the byte count amount of data is popped from the receive

Data FIFO and stored in memory. If the received packet byte count is 0, no data is popped from the

Receive Data FIFO.

4. The receive FIFO’s packet status readout indicates one of the following.

5. Global OUT NAK Pattern: PKTSTS = Global OUT NAK, BCNT = 0x000, EPNUM = Dont Care (0x0),

DPID = Dont Care (0b00). This data indicates that the global OUT NAK bit has taken effect.

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a. SETUP Packet Pattern: PKTSTS = SETUP, BCNT = 0x008, EPNUM = Control EP Num,

DPID = D0. This data indicates that a SETUP packet for the specified endpoint is now available

for reading from the receive FIFO.

b. Setup Stage Done Pattern: PKTSTS = Setup Stage Done, BCNT = 0x0, EPNUM = Control EP

Num, DPID = Don’t Care (0b00). This data indicates that the Setup stage for the specified endpoint

has completed and the Data stage has started. After this entry is popped from the receive FIFO,

the core asserts a Setup interrupt on the specified control OUT endpoint.

c. Data OUT Packet Pattern: PKTSTS = DataOUT, BCNT = size of the Received data OUT packet,

EPNUM = EPNum on which the packet was received, DPID = Actual Data PID.

d. Data Transfer Completed Pattern: PKTSTS = Data OUT Transfer Done, BCNT = 0x0,

EPNUM = OUT EP Num on which the data transfer is complete, DPID = Dont Care (0b00). This

data indicates that a OUT data transfer for the specified OUT endpoint has completed. After this

entry is popped from the receive FIFO, the core asserts a Transfer Completed interrupt on the

specified OUT endpoint.

The encoding for the PKTSTS is listed in Section 15.6 (p. 351) .

6. After the data payload is popped from the receive FIFO, the USB_GINTSTS.RXFLVL interrupt must

be unmasked.

7. Steps 1–5 are repeated every time the application detects assertion of the interrupt line due to

USB_GINTSTS.RXFLVL. Reading an empty receive FIFO can result in undefined core behavior.

Figure 15.21 (p. 293) provides a flow chart of this procedure.

Figure 15.21. Receive FIFO Packet Read in Slave Mode

wait until USB_GINTSTS.RXFLVL

packet

store in

memory

mem[0:dword_cnt-1] =

rd_rxfifo(rd_data.EPNUM,

dword_cnt)

rd_data.BCNT = 0

rd_data = rd_reg(USB_RXSTSP)

rcv_out_pkt()

dword_cnt =

BCNT[11:2] +

(BCNT[1] | BCNT[0])

15.4.4.2.2.5 Setting the Global OUT NAK

Internal Data Flow

1. When the application sets the Global OUT NAK (USB_DCTL.SGOUTNAK), the core stops writing

data, except SETUP packets, to the receive FIFO. Irrespective of the space availability in the receive

FIFO, non-isochronous OUT tokens receive a NAK handshake response, and the core ignores

isochronous OUT data packets

2. The core writes the Global OUT NAK pattern to the receive FIFO. The application must reserve

enough receive FIFO space to write this data pattern. See Data FIFO RAM Allocation (p. 329) .

3. When either the core (in DMA mode) or the application (in Slave mode) pops the Global OUT NAK

pattern DWORD from the receive FIFO, the core sets the USB_GINTSTS.GOUTNAKEFF interrupt.

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4. Once the application detects this interrupt, it can assume that the core is in Global OUT NAK mode.

The application can clear this interrupt by clearing the USB_DCTL.SGOUTNAK bit.

Application Programming Sequence

1. To stop receiving any kind of data in the receive FIFO, the application must set the Global OUT NAK

bit by programming the following field.

• USB_DCTL.SGOUTNAK = 1

2. Wait for the assertion of the interrupt USB_GINTSTS.GOUTNAKEFF. When asserted, this interrupt

indicates that the core has stopped receiving any type of data except SETUP packets.

3. The application can receive valid OUT packets after it has set USB_DCTL.SGOUTNAK and before

the core asserts the USB_GINTSTS.GOUTNAKEFF interrupt.

4. The application can temporarily mask this interrupt by writing to the

USB_GINTMSK.GOUTNAKEFFMSK bit.

• USB_GINTMSK.GINNAKEFFMSK = 0

5. Whenever the application is ready to exit the Global OUT NAK mode, it must clear the

USB_DCTL.SGOUTNAK bit. This also clears the USB_GINTSTS.GOUTNAKEFF interrupt.

• USB_DCTL.CGOUTNAK = 1

6. If the application has masked this interrupt earlier, it must be unmasked as follows:

• USB_GINTMSK.GOUTNAKEFFMSK = 1

15.4.4.2.2.6 Disabling an OUT Endpoint

The application must use this sequence to disable an OUT endpoint that it has enabled.

Application Programming Sequence

1. Before disabling any OUT endpoint, the application must enable Global OUT NAK mode in the core,

as described in Setting the Global OUT NAK (p. 293) .

• USB_DCTL.SGOUTNAK = 1

• Wait for the USB_GINTSTS.GOUTNAKEFF interrupt

2. Disable the required OUT endpoint by programming the following fields.

• USB_DOEPx_CTL.EPDIS = 1

• USB_DOEPx_CTL.SNAK = 1

3. Wait for the USB_DOEPx_INT.EPDISBLD interrupt, which indicates that the OUT endpoint is

completely disabled. When the EPDISBLD interrupt is asserted, the core also clears the following bits.

• USB_DOEPx_CTL.EPDIS = 0

• USB_DOEPx_CTL.EPENA = 0

4. The application must clear the Global OUT NAK bit to start receiving data from other non-disabled

OUT endpoints.

• USB_DCTL.SGOUTNAK = 0

15.4.4.2.2.7 Stalling a Non-Isochronous OUT Endpoint

This section describes how the application can stall a non-isochronous endpoint.

1. Put the core in the Global OUT NAK mode, as described in Setting the Global OUT NAK (p. 293) .

2. Disable the required endpoint, as described in Section 15.4.4.2.2.6 (p. 294) .

• When disabling the endpoint, instead of setting the USB_DOEPx_CTL.SNAK bit, set

USB_DOEPx_CTL.STALL = 1.

• The Stall bit always takes precedence over the NAK bit.

3. When the application is ready to end the STALL handshake for the endpoint, the

USB_DOEPx_CTL.STALL bit must be cleared.

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4. If the application is setting or clearing a STALL for an endpoint due to a SetFeature.Endpoint Halt or

ClearFeature.Endpoint Halt command, the Stall bit must be set or cleared before the application sets

up the Status stage transfer on the control endpoint.

15.4.4.2.2.8 Generic Non-Isochronous OUT Data Transfers in DMA and Slave Modes

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

as described in Endpoint Initialization (p. 283) . See Packet Read from FIFO in Slave Mode (p. 292) .

This section describes a regular non-isochronous OUT data transfer (control, bulk, or interrupt).

Application Requirements

1. Before setting up an OUT transfer, the application must allocate a buffer in the memory to

accommodate all data to be received as part of the OUT transfer, then program that buffer’s size and

start address (in DMA mode) in the endpoint-specific registers.

1. For OUT transfers, the Transfer Size field in the endpoint’s Transfer Size register must be a multiple

of the maximum packet size of the endpoint, adjusted to the DWORD boundary.

if (mps[epnum] mod 4) == 0

transfer size[epnum] = n * (mps[epnum]) //Dword Aligned

else

transfer size[epnum] = n * (mps[epnum] + 4 - (mps[epnum] mod 4)) //Non Dword Aligned

packet count[epnum] = n

n > 0

2. In DMA mode, the core stores a received data packet in the memory, always starting on a DWORD

boundary. If the maximum packet size of the endpoint is not a multiple of 4, the core inserts byte pads

at end of a maximum-packet-size packet up to the end of the DWORD.

3. On any OUT endpoint interrupt, the application must read the endpoint’s Transfer Size register to

calculate the size of the payload in the memory. The received payload size can be less than the

programmed transfer size.

• Payload size in memory = application-programmed initial transfer size – core updated final transfer

size

• Number of USB packets in which this payload was received = application-programmed initial packet

count – core updated final packet count

Internal Data Flow

1. The application must set the Transfer Size and Packet Count fields in the endpoint-specific registers,

clear the NAK bit, and enable the endpoint to receive the data.

2. Once the NAK bit is cleared, the core starts receiving data and writes it to the receive FIFO, as long

as there is space in the receive FIFO. For every data packet received on the USB, the data packet

and its status are written to the receive FIFO. Every packet (maximum packet size or short packet)

written to the receive FIFO decrements the Packet Count field for that endpoint by 1.

• OUT data packets received with Bad Data CRC are flushed from the receive FIFO automatically.

• After sending an ACK for the packet on the USB, the core discards non-isochronous OUT data

packets that the host, which cannot detect the ACK, re-sends. The application does not detect

multiple back-to-back data OUT packets on the same endpoint with the same data PID. In this case

the packet count is not decremented.

• If there is no space in the receive FIFO, isochronous or non-isochronous data packets are ignored

and not written to the receive FIFO. Additionally, non-isochronous OUT tokens receive a NAK

handshake reply.

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• In all the above three cases, the packet count is not decremented because no data is written to

the receive FIFO.

3. When the packet count becomes 0 or when a short packet is received on the endpoint, the NAK bit

for that endpoint is set. Once the NAK bit is set, the isochronous or non-isochronous data packets

are ignored and not written to the receive FIFO, and non-isochronous OUT tokens receive a NAK

handshake reply.

4. After the data is written to the receive FIFO, either the application (in Slave mode) or the core’s DMA

engine (in DMA mode), reads the data from the receive FIFO and writes it to external memory, one

packet at a time per endpoint.

5. At the end of every packet write on the AHB to external memory, the transfer size for the endpoint

is decremented by the size of the written packet.

6. The OUT Data Transfer Completed pattern for an OUT endpoint is written to the receive FIFO on

one of the following conditions.

• The transfer size is 0 and the packet count is 0

• The last OUT data packet written to the receive FIFO is a short packet (0 <= packet size < maximum

packet size)

7. When either the application or the DMA pops this entry (OUT Data Transfer Completed), a Transfer

Completed interrupt is generated for the endpoint and the endpoint enable is cleared.

Application Programming Sequence

1. Program the USB_DOEPx_TSIZ register for the transfer size and the corresponding packet count.

Additionally, in DMA mode, program the USB_DOEPx_DMAADDR register.

2. Program the USB_DOEPx_CTL register with the endpoint characteristics, and set the Endpoint

Enable and ClearNAK bits.

• USB_DOEPx_CTL.EPENA = 1

• USB_DOEPx_CTL.CNAK = 1

3. In Slave mode, wait for the USB_GINTSTS.RXFLVL level interrupt and empty the data packets from

the receive FIFO as explained in Packet Read from FIFO in Slave Mode (p. 292) .

• This step can be repeated many times, depending on the transfer size.

4. Asserting the USB_DOEPx_INT.XFERCOMPL interrupt marks a successful completion of the non-

isochronous OUT data transfer.

5. Read the USB_DOEPx_TSIZ register to determine the size of the received data payload.

Note The XFERSIZE is not decremented for the last packet. This is as per design behavior.

Slave Mode Bulk OUT Transaction

Figure 15.22 (p. 297) depicts the reception of a single bulk OUT data packet from the USB to the AHB

and describes the events involved in the process.

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Figure 15.22. Slave Mode Bulk OUT Transaction

init_ out_ ep

Host DeviceUSB

OUT

ACK

RXFLVL

INTR

wr_reg(USB_DOEPx_TSIZ)

wr_reg(USB_DOEPx_CTL)

512 bytes

OUT

NAK

xact_1

Applicatio

XFERCOMP

INTR

_DOEPx_CTNAK=1

XFERSIZE=0

idle until intr

rcv_out_pkt()

idle until intr

On new xfer

or RxFIFO

not empty

XFERSIZE= 512 bytes

PKTCNT= 1

EPENA = 1

CNAK = 1

PKTCNT = 0

After a SetConfiguration/SetInterface command, the application initializes all OUT endpoints by setting

USB_DOEPx_CTL.CNAK = 1 and USB_DOEPx_CTL.EPENA = 1, and setting a suitable XFERSIZE

and PKTCNT in the USB_DOEPx_TSIZ register.

1. Host attempts to send data (OUT token) to an endpoint.

2. When the core receives the OUT token on the USB, it stores the packet in the RxFIFO because space

is available there.

3. After writing the complete packet in the RxFIFO, the core then asserts the USB_GINTSTS.RXFLVL

interrupt.

4. On receiving the PKTCNT number of USB packets, the core sets the NAK bit for this endpoint

internally to prevent it from receiving any more packets.

5. The application processes the interrupt and reads the data from the RxFIFO.

6. When the application has read all the data (equivalent to XFERSIZE), the core generates a

USB_DOEPx_INT.XFERCOMPL interrupt.

7. The application processes the interrupt and uses the setting of the USB_DOEPx_INT.XFERCOMPL

interrupt bit to determine that the intended transfer is complete.

15.4.4.2.2.9 Generic Isochronous OUT Data Transfer in DMA and Slave Modes

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

as described in Endpoint Initialization (p. 283) . See Packet Read from FIFO in Slave Mode (p. 292) .

This section describes a regular isochronous OUT data transfer.

Application Requirements:

1. All the application requirements for non-isochronous OUT data transfers also apply to isochronous

OUT data transfers

2. For isochronous OUT data transfers, the Transfer Size and Packet Count fields must always be set

to the number of maximum-packet-size packets that can be received in a single frame and no more.

Isochronous OUT data transfers cannot span more than 1 frame.

• 1 <= packet count[epnum] <= 3

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3. In Slave mode, when isochronous OUT endpoints are supported in the device, the application must

read all isochronous OUT data packets from the receive FIFO (data and status) before the end of

the periodic frame (USB_GINTSTS.EOPF interrupt). In DMA mode, the application must guarantee

enough bandwidth to allow emptying the isochronous OUT data packet from the receive FIFO before

the end of each periodic frame.

4. To receive data in the following frame, an isochronous OUT endpoint must be enabled after the

USB_GINTSTS.EOPF and before the USB_GINTSTS.SOF.

Internal Data Flow

1. The internal data flow for isochronous OUT endpoints is the same as that for non-isochronous OUT

endpoints, but for a few differences.

2. When an isochronous OUT endpoint is enabled by setting the Endpoint Enable and clearing the NAK

bits, the Even/Odd frame bit must also be set appropriately. The core receives data on a isochronous

OUT endpoint in a particular frame only if the following condition is met.

• USB_DOEPx_CTL.DPIDEOF (Even/Odd frame) = USB_DSTS.SOFFN[0]

3. When either the application or the internal DMA completely reads an isochronous OUT data packet

(data and status) from the receive FIFO, the core updates the USB_DOEPx_TSIZ.RXDPIDSUPCNT

(Received DPID) field with the data PID of the last isochronous OUT data packet read from the receive

FIFO.

Application Programming Sequence

1. Program the USB_DOEPx_TSIZ register for the transfer size and the corresponding packet count.

When in DMA mode, also program the USB_DOEPx_DMAADDR register.

2. Program the USB_DOEPx_CTL register with the endpoint characteristics and set the Endpoint

Enable, ClearNAK, and Even/Odd frame bits.

• Endpoint Enable = 1

• CNAK = 1

• Even/Odd frame = (0: Even/1: Odd)

1. In Slave mode, wait for the USB_GINTSTS.Rx StsQ level interrupt and empty the data packets from

the receive FIFO as explained in Packet Read from FIFO in Slave Mode (p. 292) .

• This step can be repeated many times, depending on the transfer size.

1. The assertion of the USB_DOEPx_INT.XFERCOMPL interrupt marks the completion of the

isochronous OUT data transfer. This interrupt does not necessarily mean that the data in memory

is good.

2. This interrupt can not always be detected for isochronous OUT transfers. Instead, the application can

detect the USB_GINTSTS.INCOMPLP (Incomplete Isochronous OUT data) interrupt. See Incomplete

Isochronous OUT Data Transfers in DMA and Slave Modes (p. 303) , for more details

3. Read the USB_DOEPx_TSIZ register to determine the size of the received transfer and to determine

the validity of the data received in the frame. The application must treat the data received in memory

as valid only if one of the following conditions is met.

• USB_DOEPx_TSIZ.RXDPID = D0 and the number of USB packets in which this payload was

received = 1

• USB_DOEPx_TSIZ.RXDPID = D1 and the number of USB packets in which this payload was

received = 2

• USB_DOEPx_TSIZ.RXDPID = D2 and the number of USB packets in which this payload was

received = 3

• The number of USB packets in which this payload was received = App Programmed Initial Packet

Count – Core Updated Final Packet Count

The application can discard invalid data packets.

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15.4.4.2.2.10 Generic Interrupt OUT Data Transfers Using Periodic Transfer Interrupt Feature

This section describes a regular INTR OUT data transfer with the Periodic Transfer Interrupt feature.

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

as described in Endpoint Initialization (p. 283) . See Packet Read from FIFO in Slave Mode (p. 292) .

Application Requirements

1. Before setting up a periodic OUT transfer, the application must allocate a buffer in the memory to

accommodate all data to be received as part of the OUT transfer, then program that buffer’s size and

start address in the endpoint-specific registers.

2. For Interrupt OUT transfers, the Transfer Size field in the endpoint’s Transfer Size register must be a

multiple of the maximum packet size of the endpoint, adjusted to the DWORD boundary. The Transfer

Size programmed can span across multiple frames based on the periodicity after which the application

want to receive the USB_DOEPx_INT.XFERCOMPL interrupt

• transfer size[epnum] = n * (mps[epnum] + 4 - (mps[epnum] mod 4))

• packet count[epnum] = n

• n > 0 (Higher value of n reduces the periodicity of the USB_DOEPx_INT.XFERCOMPL interrupt)

• 1 < packet count[epnum] < n (Higher value of n reduces the periodicity of the

USB_DOEPx_INT.XFERCOMPL interrupt)

3. In DMA mode, the core stores a received data packet in the memory, always starting on a DWORD

boundary. If the maximum packet size of the endpoint is not a multiple of 4, the core inserts byte pads

at end of a maximum-packet-size packet up to the end of the DWORD. The application will not be

informed about the frame number on which a specific packet has been received.

4. On USB_DOEPx_INT.XFERCOMPL interrupt, the application must read the endpoint’s Transfer Size

than the programmed transfer size.

• Payload size in memory = application-programmed initial transfer size – core updated final transfer

size

• Number of USB packets in which this payload was received = application-programmed initial packet

count – core updated final packet count.

• If for some reason, the host stops sending tokens, there are no interrupts to the application, and

the application must timeout on its own.

5. The assertion of the USB_DOEPx_INT.XFERCOMPL interrupt marks the completion of the interrupt

OUT data transfer. This interrupt does not necessarily mean that the data in memory is good.

6. Read the USB_DOEPx_TSIZ register to determine the size of the received transfer and to determine

the validity of the data received in the frame.

Internal Data Flow

1. The application must set the Transfer Size and Packet Count fields in the endpoint-specific registers,

clear the NAK bit, and enable the endpoint to receive the data.

• The application must enable the USB_DCTL.IGNRFRMNUM

2. When an interrupt OUT endpoint is enabled by setting the Endpoint Enable and clearing the NAK

bits, the Even/Odd frame will be ignored by the core.

1. Once the NAK bit is cleared, the core starts receiving data and writes it to the receive FIFO, as long

as there is space in the receive FIFO. For every data packet received on the USB, the data packet

and its status are written to the receive FIFO. Every packet (maximum packet size or short packet)

written to the receive FIFO decrements the Packet Count field for that endpoint by 1.

• OUT data packets received with Bad Data CRC or any packet error are flushed from the receive

FIFO automatically.

• Interrupt packets with PID errors are not passed to application. Core discards the packet, sends

ACK and does not decrement packet count.

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• If there is no space in the receive FIFO, interrupt data packets are ignored and not written to the

receive FIFO. Additionally, interrupt OUT tokens receive a NAK handshake reply.

2. When the packet count becomes 0 or when a short packet is received on the endpoint, the NAK bit

for that endpoint is set. Once the NAK bit is set, the isochronous or interrupt data packets are ignored

and not written to the receive FIFO, and interrupt OUT tokens receive a NAK handshake reply.

3. After the data is written to the receive FIFO, the core’s DMA engine reads the data from the receive

FIFO and writes it to external memory, one packet at a time per endpoint.

4. At the end of every packet write on the AHB to external memory, the transfer size for the endpoint

is decremented by the size of the written packet.

5. The OUT Data Transfer Completed pattern for an OUT endpoint is written to the receive FIFO on

one of the following conditions.

• The transfer size is 0 and the packet count is 0.

• The last OUT data packet written to the receive FIFO is a short packet (0 < packet size < maximum

packet size)

6. When either the application or the DMA pops this entry (OUT Data Transfer Completed), a Transfer

Completed interrupt is generated for the endpoint and the endpoint enable is cleared.

15.4.4.2.2.11 Generic Isochronous OUT Data Transfers Using Periodic Transfer Interrupt Feature

This section describes a regular isochronous OUT data transfer with the Periodic Transfer Interrupt

feature.

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

as described in Endpoint Initialization (p. 283) . For packet writes in Slave mode, see: Packet Read

from FIFO in Slave Mode (p. 292) .

Application Requirements

1. Before setting up ISOC OUT transfers spanned across multiple frames, the application must allocate

buffer in the memory to accommodate all data to be received as part of the OUT transfers, then

program that buffer’s size and start address in the endpoint-specific registers.

• The application must mask the USB_GINTSTS.INCOMPLP (Incomplete ISO OUT).

• The application must enable the USB_DCTL.IGNRFRMNUM

2. For ISOC transfers, the Transfer Size field in the USB_DOEPx_TSIZ.XFERSIZE register must be a

multiple of the maximum packet size of the endpoint, adjusted to the DWORD boundary. The Transfer

Size programmed can span across multiple frames based on the periodicity after which the application

wants to receive the USB_DOEPx_INT.XFERCOMPL interrupt

• transfer size[epnum] = n * (mps[epnum] + 4 - (mps[epnum] mod 4))

• packet count[epnum] = n

• n > 0 (Higher value of n reduces the periodicity of the USB_DOEPx_INT.XFERCOMPL interrupt)

• 1 =< packet count[epnum] =< n (Higher value of n reduces the periodicity of the

USB_DOEPx_INT.XFERCOMPL interrupt).

3. In DMA mode, the core stores a received data packet in the memory, always starting on a DWORD

boundary. If the maximum packet size of the endpoint is not a multiple of 4, the core inserts byte

pads at end of a maximum-packet-size packet up to the end of the DWORD. The application will not

be informed about the frame number and the PID value on which a specific OUT packet has been

received.

4. The assertion of the USB_DOEPx_INT.XFERCOMPL interrupt marks the completion of the

isochronous OUT data transfer. This interrupt does not necessarily mean that the data in memory

is good.

• On USB_DOEPx_INT.XFERCOMPL, the application must read the endpoint’s Transfer Size

• Payload size in memory = application-programmed initial transfer size - core updated final transfer

size

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• Number of USB packets in which this payload was received = application-programmed initial packet

count – core updated final packet count.

• If for some reason, the host stop sending tokens, there will be no interrupt to the application, and

the application must timeout on its own.

5. The assertion of the USB_DOEPx_INT.XFERCOMPL can also mark a packet drop on USB due to

unavailability of space in the RxFifo or due to any packet errors.

• The application must read the USB_DOEPx_INT.PKTDRPSTS (USB_DOEPx_INT.Bit[11] is

now used as the USB_DOEPx_INT.PKTDRPSTS) register to differentiate whether the

USB_DOEPx_INT.XFERCOMPL was generated due to the normal end of transfer or due to

dropped packets. In case of packets being dropped on the USB due to unavailability of space in

the RxFifo or due to any packet errors the endpoint enable bit is cleared.

• In case of packet drop on the USB application must re-enable the endpoint after recalculating the

values USB_DOEPx_TSIZ.XFERSIZE and USB_DOEPx_TSIZ.PKTCNT.

• Payload size in memory = application-programmed initial transfer size - core updated final transfer

size

• Number of USB packets in which this payload was received = application-programmed initial packet

count - core updated final packet count.

Note Due to application latencies it is possible that DOEPINT.XFERCOMPL interrupt is

generated without DOEPINT.PKTDRPSTS being set, This scenario is possible only if back-

to-back packets are dropped for consecutive frames and the PKTDRPSTS is merged, but

the XFERSIZE and PktCnt values for the endpoint are nonzero. In this case, the application

must proceed further by programming the PKTCNT and XFERSIZE register for the next

frame, as it would if PKTDRPSTS were being set.

Figure 15.23 (p. 302) gives the application flow for Isochronous OUT Periodic Transfer Interrupt

feature.

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Figure 15.23. ISOC OUT Application Flow for Periodic Transfer Interrupt Feature

Note:

1 . The (m icro-) fram e number and PID field are not updated for Periodic OUT

packets

2 . In Periodic OUT transfers, any s hort packet results in an XferCom plete

Interrupt and disables the endpoint. The application mus t reenable the

endpoint with recalculated values of XferSize and PktCnt

3 . The application mus t reenable the endpoint after dropped packets for

IS OC OU

START

Program the DMA address

START Address of the Data Mem ory

Program Xfer _ size register

USB_DOEPx_TSIZ.XFERSIZE = XferSize Spanning across m ultiple Xfers

USB_DOEPx_TSIZ. .PKTCNT = Program PktCnt for m ultiple Xfers

Program the Global INT STS

GINTMSK.. INCOMPLPMSK = 0 // Mask IncompIS OCOUT Interrupt

Intialize variables Allocate a buffer in the S ys tem Memory for m ultiple Xfers.

Buffer s ize m us t be a m ultiple of MaxPktSize.

Program EP Ctrl register to start the xfer

USB_DOEPx_CTL . CNAK = 1

USB_DOEPx_CTL .EPENA = 1

= 0

Wait for USB_DOEPx_INT. XFERCOMPL interrupt and report error if timeout expires

If USB_DOEPx_TSIZ. XFERSIZE== 0

If USB_DOEPx_INT.PKTDRPSTS== 1

YES

End of Transfer

If USB_DOEPx_TSIZ.PKTCNT

==0

YES

Return

ISOC OUT PktDrop

YES

If USB_DOEPx_TSIZ.XFERSIZE != 0

Received Short Packet

YES

Received Short Packet

Re- compute XFERSIZE and

ERROR

USB_DOEPx_CTL . SNAK

USB_DOEPx_CTL .EPDIS

USB_DOEPx_DMA =

PKTCNT

Internal Data Flow

1. The application must set the Transfer Size, Packets to be received in a frame and Packet Count Fields

in the endpoint-specific registers, clear the NAK bit, and enable the endpoint to receive the data.

2. When an isochronous OUT endpoint is enabled by setting the Endpoint Enable and clearing the NAK

bits, the Even/Odd frame will be ignored by the core.

3. Once the NAK bit is cleared, the core starts receiving data and writes it to the receive FIFO, as long

as there is space in the receive FIFO. For every data packet received on the USB, the data packet

and its status are written to the receive FIFO. Every packet (maximum packet size or short packet)

written to the receive FIFO decrements the Packet Count field for that endpoint by 1.

4. When the packet count becomes 0 or when a short packet is received on the endpoint, the NAK bit

for that endpoint is set. Once the NAK bit is set, the ISOC packets are ignored and not written to

the receive FIFO.

5. After the data is written to the receive FIFO, the core’s DMA engine, reads the data from the receive

FIFO and writes it to external memory, one packet at a time per endpoint.

6. At the end of every packet write on the AHB to external memory, the transfer size for the endpoint

is decremented by the size of the written packet.

7. The OUT Data Transfer Completed pattern for an OUT endpoint is written to the receive FIFO on

one of the following conditions.

• The transfer size is 0 and the packet count is 0

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• The last OUT data packet written to the receive FIFO is a short packet (0 < packet size < maximum

packet size).

8. When the DMA pops this entry (OUT Data Transfer Completed), a Transfer Completed interrupt is

generated for the endpoint or the endpoint enable is cleared.

9. OUT data packets received with Bad Data CRC or any packet error are flushed from the receive FIFO

automatically.

• In these two cases, the packet count and transfer size registers are not decremented because no

data is written to the receive FIFO.

Figure 15.24. Isochronous OUT Core Internal Flow for Periodic Transfer Interrupt Feature

If (USB_DOEPx_CTL.CNAK = 0b1) &&

(USB_DOEPx_CTL.EPENA = 0b1) &&

(DCTL.IGNRFRMNUM = 0b1) &&

NOTE

1 . Core will write data to only DWORD Aligned addres ses

2 . Core will not tag Periodic OUT Packets with ( m icro) frame num ber and PID

3 . Any S hort Packet (SP ) Received will generate XferComplete Interrupt

including zero length packet

4 . PacketDrop due to unAvailability of S pace in RxFifo will generate

XferCom plete Imm ediately.

5 . PktDrop due to EndPoint being dis abled will generate XferComplete at

End of periodic Frame interval.

START

OUT Token From Hos t

Check RXFifo Space

Available

return

Receive Pkt and Store in RXFifo

PktCnt = PktCnt -1

DMA Pop RxFifo

XferSize = XferSize - MaxPktSize

PKtSize == MaxPktSize

Received Short Packet

PktCnt = PktCnt - 1

If PktCnt == 0 &&

XferSize == 0

USB_DOEPx_INT.XFERCOMPL = 1

DMA Pop RxFifo

XferSize = XferSize - ActPktSize

YES

If End Of PerFrInt &&

ISOC Out Packet Naked

Disable endpoint

YES

ANO NO

YES

Disable endpoint

15.4.4.2.2.12 Incomplete Isochronous OUT Data Transfers in DMA and Slave Modes

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

as described in Endpoint Initialization (p. 283) . See Packet Read from FIFO in Slave Mode (p. 292) .

This section describes the application programming sequence when isochronous OUT data packets are

dropped inside the core.

Internal Data Flow

1. For isochronous OUT endpoints, the USB_DOEPx_INT.XFERCOMPL interrupt possibly is not always

asserted. If the core drops isochronous OUT data packets, the application could fail to detect the

USB_DOEPx_INT.XFERCOMPL interrupt under the following circumstances.

• When the receive FIFO cannot accommodate the complete ISO OUT data packet, the core drops

the received ISO OUT data.

• When the isochronous OUT data packet is received with CRC errors

• When the isochronous OUT token received by the core is corrupted

• When the application is very slow in reading the data from the receive FIFO

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2. When the core detects an end of periodic frame before transfer completion to all isochronous OUT

endpoints, it asserts the USB_GINTSTS.INCOMPLP (Incomplete Isochronous OUT data) interrupt,

indicating that a USB_DOEPx_INT.XFERCOMPL interrupt is not asserted on at least one of the

isochronous OUT endpoints. At this point, the endpoint with the incomplete transfer remains enabled,

but no active transfers remains in progress on this endpoint on the USB.

3. This step is applicable only if the core is operating in slave mode. Application Programming Sequence

4. This step is applicable only if the core is operating in slave mode. Asserting the

USB_GINTSTS.INCOMPLP (Incomplete Isochronous OUT data) interrupt indicates that in the current

frame, at least one isochronous OUT endpoint has an incomplete transfer.

5. If this occurs because isochronous OUT data is not completely emptied from the endpoint, the

application must ensure that the DMA or the application empties all isochronous OUT data (data and

status) from the receive FIFO before proceeding.

• When all data is emptied from the receive FIFO, the application can detect the

USB_DOEPx_INT.XFERCOMPL interrupt. In this case, the application must re-enable the endpoint

to receive isochronous OUT data in the next frame, as described in Control Read Transfers

(SETUP, Data IN, Status OUT) (p. 290) .

6. When it receives a USB_GINTSTS.incomplete Isochronous OUT data interrupt, the application must

read the control registers of all isochronous OUT endpoints (USB_DOEPx_CTL) to determine which

endpoints had an incomplete transfer in the current frame. An endpoint transfer is incomplete if both

the following conditions are met.

• USB_DOEPx_CTL.DPIDEOF (Even/Odd frame) = USB_DSTS.SOFFN[0]

• USB_DOEPx_CTL.EPENA (Endpoint Enable) = 1

7. The previous step must be performed before the USB_GINTSTS.SOF interrupt is detected, to ensure

that the current frame number is not changed.

8. For isochronous OUT endpoints with incomplete transfers, the application must discard the data in

the memory and disable the endpoint by setting the USB_DOEPx_CTL.EPDIS (Endpoint Disable) bit.

9. Wait for the USB_DOEPx_INT.EPDIS (Endpoint Disabled) interrupt and enable the endpoint to

receive new data in the next frame as explained in Control Read Transfers (SETUP, Data IN, Status

OUT) (p. 290) .

• Because the core can take some time to disable the endpoint, the application possibly is not able

to receive the data in the next frame after receiving bad isochronous data.

15.4.4.2.3 IN Data Transfers in Slave and DMA Modes

This section describes the internal data flow and application-level operations during IN data transfers.

• Packet Write in Slave Mode (p. 305)

• Setting Global Non-Periodic IN Endpoint NAK (p. 305)

• Setting IN Endpoint NAK (p. 305)

• IN Endpoint Disable (p. 306)

• Bulk IN Stall (p. 307)

• Incomplete Isochronous IN Data Transfers (p. 307)

• Stalling Non-Isochronous IN Endpoints (p. 308)

• Worst-Case Response Time (p. 309)

• Choosing the Value of USB_GUSBCFG.USBTRDTIM (p. 309)

• Handling Babble Conditions (p. 310)

• Generic Non-Periodic (Bulk and Control) IN Data Transfers Without Thresholding in DMA and Slave

Mode (p. 310)

• Examples (p. 312)

•

• Generic Periodic IN Data Transfers Without Thresholding Using the Periodic Transfer Interrupt

Feature (p. 317)

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15.4.4.2.3.1 Packet Write in Slave Mode

This section describes how the application writes data packets to the endpoint FIFO in Slave mode.

1. The application can either choose polling or interrupt mode.

• In polling mode, application monitors the status of the endpoint transmit data FIFO, by reading the

USB_DIEPx_TXFSTS register, to determine, if there is enough space in the data FIFO.

• In interrupt mode, application waits for the USB_DIEPx_INT.TXFEMP interrupt and then reads the

USB_DIEPx_TXFSTS register, to determine, if there is enough space in the data FIFO.

• To write a single non-zero length data packet, there must be space to write the entire packet is

the data FIFO.

• For writing zero length packet, application must not look for FIFO space.

2. Using one of the above mentioned methods, when the application determines that there is enough

space to write a transmit packet, the application must first write into the endpoint control register,

before writing the data into the data FIFO. The application, typically must do a read modify write on

the USB_DIEPx_CTL, to avoid modifying the contents of the register, except for setting the Endpoint

Enable bit.

The application can write multiple packets for the same endpoint, into the transmit FIFO, if space is

available. For periodic IN endpoints, application must write packets only for one frame. It can write

packets for the next periodic transaction, only after getting transfer complete for the previous transaction.

15.4.4.2.3.2 Setting Global Non-Periodic IN Endpoint NAK

Internal Data Flow

1. When the application sets the Global Non-periodic IN NAK bit (USB_DCTL.SGNPINNAK), the core

stops transmitting data on the non-periodic endpoint, irrespective of data availability in the Non-

periodic Transmit FIFO.

2. Non-isochronous IN tokens receive a NAK handshake reply

3. The core asserts the USB_GINTSTS.GINNAKEFF interrupt in response to the

USB_DCTL.SGNPINNAK bit.

4. Once the application detects this interrupt, it can assume that the core is in the Global Non-periodic

IN NAK mode. The application can clear this interrupt by clearing the USB_DCTL.SGNPINNAK bit.

Application Programming Sequence

1. To stop transmitting any data on non-periodic IN endpoints, the application must set the

USB_DCTL.SGNPINNAK bit. To set this bit, the following field must be programmed

• USB_DCTL.SGNPINNAK = 1

2. Wait for the assertion of the USB_GINTSTS.GINNAKEFF interrupt. This interrupt indicates the core

has stopped transmitting data on the non-periodic endpoints.

3. The core can transmit valid non-periodic IN data after the application has set the

USB_DCTL.SGNPINNAK bit, but before the assertion of the USB_GINTSTS.GINNAKEFF interrupt.

4. The application can optionally mask this interrupt temporarily by writing to the

USB_GINTMSK.GINNAKEFFMSK bit.

• USB_GINTMSK.GINNAKEFFMSK = 0

5. To exit Global Non-periodic IN NAK mode, the application must clear the USB_DCTL.SGNPINNAK.

This also clears the USB_GINTSTS.GINNAKEFF interrupt.

• USB_DCTL.SGNPINNAK = 1

6. If the application has masked this interrupt earlier, it must be unmasked as follows:

• USB_GINTMSK.GINNAKEFFMSK = 1

15.4.4.2.3.3 Setting IN Endpoint NAK

Internal Data Flow

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1. When the application sets the IN NAK for a particular endpoint, the core stops transmitting data on

the endpoint, irrespective of data availability in the endpoint’s transmit FIFO.

2. Non-isochronous IN tokens receive a NAK handshake reply

• Isochronous IN tokens receive a zero-data-length packet reply

3. The core asserts the USB_DIEPx_INT.INEPNAKEFF (IN NAK Effective) interrupt in response to the

USB_DIEPx_CTL.SNAK (Set NAK) bit.

4. Once this interrupt is seen by the application, the application can assume that the endpoint is in IN

NAK mode. This interrupt can be cleared by the application by setting the USB_DIEPx_CTL. Clear

NAK bit.

Application Programming Sequence

1. To stop transmitting any data on a particular IN endpoint, the application must set the IN NAK bit. To

set this bit, the following field must be programmed.

• USB_DIEPx_CTL.SNAK = 1

2. Wait for assertion of the USB_DIEPx_INT.INEPNAKEFF (NAK Effective) interrupt. This interrupt

indicates the core has stopped transmitting data on the endpoint.

3. The core can transmit valid IN data on the endpoint after the application has set the NAK bit, but

before the assertion of the NAK Effective interrupt.

4. The application can mask this interrupt temporarily by writing to the

USB_DIEPMSK.INEPNAKEFFMSK (NAK Effective) bit.

• USB_DIEPMSK.INEPNAKEFFMSK (NAK Effective) = 0

5. To exit Endpoint NAK mode, the application must clear the USB_DIEPx_CTL.NAK status. This also

clears the USB_DIEPx_INT.INEPNAKEFF (NAK Effective) interrupt.

• USB_DIEPx_CTL.CNAK = 1

6. If the application masked this interrupt earlier, it must be unmasked as follows:

• USB_DIEPMSK.INEPNAKEFFMSK (NAK Effective) = 1

15.4.4.2.3.4 IN Endpoint Disable

Use the following sequence to disable a specific IN endpoint (periodic/non-periodic) that has been

previously enabled.

Application Programming Sequence:

1. In Slave mode, the application must stop writing data on the AHB, for the IN endpoint to be disabled.

2. The application must set the endpoint in NAK mode. See Setting IN Endpoint NAK (p. 305) .

• USB_DIEPx_CTL.SNAK = 1

3. Wait for USB_DIEPx_INT.INEPNAKEFF (NAK Effective) interrupt.

4. Set the following bits in the USB_DIEPx_CTL register for the endpoint that must be disabled.

• USB_DIEPx_CTL.EPDIS (Endpoint Disable) = 1

• USB_DIEPx_CTL.SNAK = 1

5. Assertion of USB_DIEPx_INT.EPDISBLD (Endpoint Disabled) interrupt indicates that the core has

completely disabled the specified endpoint. Along with the assertion of the interrupt, the core also

clears the following bits.

• USB_DIEPx_CTL.EPENA = 0

• USB_DIEPx_CTL.EPDIS = 0

6. The application must read the USB_DIEPx_TSIZ register for the periodic IN EP, to calculate how

much data on the endpoint was transmitted on the USB.

7. The application must flush the data in the Endpoint transmit FIFO, by setting the following fields in

the USB_GRSTCTL register.

• USB_GRSTCTL.TXFNUM = Endpoint Transmit FIFO Number

• USB_GRSTCTL.TXFFLSH = 1

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The application must poll the USB_GRSTCTL register, until the TXFFLSH bit is cleared by the core,

which indicates the end of flush operation. To transmit new data on this endpoint, the application can

re-enable the endpoint at a later point.

15.4.4.2.3.5 Bulk IN Stall

These notes refer to Figure 15.25 (p. 307)

1. The application has scheduled an IN transfer on receiving the USB_DIEPx_INT.INTKNTXFEMP (IN

Token Received When TxFIFO Empty) interrupt.

2. When the transfer is in progress, the application must force a STALL on the endpoint. This could be

because the application has received a SetFeature.Endpoint Halt command. The application sets the

Stall bit, disables the endpoint and waits for the USB_DIEPx_INT.EPDISBLD (Endpoint Disabled)

interrupt. This generates STALL handshakes for the endpoint on the USB.

3. On receiving the interrupt, the application flushes the Non-periodic Transmit FIFO and clears the

USB_DCTL.SGNPINNAK (Global IN NP NAK) bit.

4. On receiving the ClearFeature.Endpoint Halt command, the application clears the Stall bit.

5. The endpoint behaves normally and the application can re-enable the endpoint for new transfers

Figure 15.25. Bulk IN Stall

Host ApplicationDeviceUSB

NAK

INTKNTXFEMP

INTR

512 bytes

ACK

do_in_xfer

xact_ 1 data rdy

xact_ 2 data rdy

xact_1 of 2

xact_2 of 2

NPTXFEMP INT

STALL

512 bytes

ACK

new xact

EPDisabled intr

STALL

idle (wait_intr)

setup_ np_in_ pkt

set_stall

ep_ disable ;

flush_ nper_tx_ fifo;

Clr Global IN NP Nak

wait_for_ host/

app to clr stall

clr_stall

do_ in_ xfer

setup_ np_in_ pkt

XferSize = 1025 bytes

PktCnt = 3

EPEna = 1

NAK

INTKNTXFEMP

INTR

15.4.4.2.3.6 Incomplete Isochronous IN Data Transfers

This section describes what the application must do on an incomplete isochronous IN data transfer.

Internal Data Flow

1. An isochronous IN transfer is treated as incomplete in one of the following conditions.

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a. The core receives a corrupted isochronous IN token on at least one isochronous IN endpoint. In

this case, the application detects a USB_GINTSTS.INCOMPISOIN (Incomplete Isochronous IN

Transfer) interrupt.

b. The application or DMA is slow to write the complete data payload to the transmit FIFO

and an IN token is received before the complete data payload is written to the FIFO. In this

case, the application detects a USB_DIEPx_INT.INTKNTXFEMP (IN Token Received When

TxFIFO Empty) interrupt. The application can ignore this interrupt, as it eventually results in

a USB_GINTSTS.INCOMPISOIN (Incomplete Isochronous IN Transfer) interrupt at the end of

periodic frame.

i. The core transmits a zero-length data packet on the USB in response to the received IN token.

2. In either of the aforementioned cases, in Slave mode, the application must stop writing the data

payload to the transmit FIFO as soon as possible.

3. The application must set the NAK bit and the disable bit for the endpoint. In DMA mode, the core

automatically stops fetching the data payload when the endpoint disable bit is set.

4. The core disables the endpoint, clears the disable bit, and asserts the Endpoint Disable interrupt for

the endpoint.

Application Programming Sequence

1. The application can ignore the USB_DIEPx_INT.INTKNTXFEMP (IN Token Received When

TxFIFO empty) interrupt on any isochronous IN endpoint, as it eventually results in a

USB_GINTSTS.INCOMPISOIN (Incomplete Isochronous IN Transfer) interrupt.

2. Assertion of the USB_GINTSTS.INCOMPISOIN (Incomplete Isochronous IN Transfer) interrupt

indicates an incomplete isochronous IN transfer on at least one of the isochronous IN endpoints.

3. The application must read the Endpoint Control register for all isochronous IN endpoints to detect

endpoints with incomplete IN data transfers.

4. In Slave mode, the application must stop writing data to the Periodic Transmit FIFOs associated with

these endpoints on the AHB.

5. In both modes of operation, program the following fields in the USB_DIEPx_CTL register to disable

the endpoint.

• USB_DIEPx_CTL.SNAK = 1

• USB_DIEPx_CTL.EPDIS (Endpoint Disable) = 1

6. The USB_DIEPx_INT.EPDISBLD (Endpoint Disabled) interrupt’s assertion indicates that the core has

disabled the endpoint.

• At this point, the application must flush the data in the associated transmit FIFO or overwrite the

existing data in the FIFO by enabling the endpoint for a new transfer in the next frame. To flush the

data, the application must use the USB_GRSTCTL register.

15.4.4.2.3.7 Stalling Non-Isochronous IN Endpoints

This section describes how the application can stall a non-isochronous endpoint.

Application Programming Sequence

1. Disable the IN endpoint to be stalled. Set the Stall bit as well.

2. USB_DIEPx_CTL.EPDIS (Endpoint Disable) = 1, when the endpoint is already enabled

• USB_DIEPx_CTL.STALL = 1

• The Stall bit always takes precedence over the NAK bit

3. Assertion of the USB_DIEPx_INT.EPDISBLD (Endpoint Disabled) interrupt indicates to the

application that the core has disabled the specified endpoint.

4. The application must flush the Non-periodic or Periodic Transmit FIFO, depending on the endpoint

type. In case of a non-periodic endpoint, the application must re-enable the other non-periodic

endpoints, which do not need to be stalled, to transmit data.

5. Whenever the application is ready to end the STALL handshake for the endpoint, the

USB_DIEPx_CTL.STALL bit must be cleared.

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6. If the application sets or clears a STALL for an endpoint due to a SetFeature.Endpoint Halt command

or ClearFeature.Endpoint Halt command, the Stall bit must be set or cleared before the application

sets up the Status stage transfer on the control endpoint.

Special Case: Stalling the Control IN/OUT Endpoint

The core must stall IN/OUT tokens if, during the Data stage of a control transfer, the host sends more

IN/OUT tokens than are specified in the SETUP packet. In this case, the application must to enable

USB_DIEPx_INT.INTKNTXFEMP and USB_DOEPx_INT.OUTTKNEPDIS interrupts during the Data

stage of the control transfer, after the core has transferred the amount of data specified in the SETUP

packet. Then, when the application receives this interrupt, it must set the STALL bit in the corresponding

endpoint control register, and clear this interrupt.

15.4.4.2.3.8 Worst-Case Response Time

When the acts as a device, there is a worst case response time for any tokens that follow an isochronous

OUT. This worst case response time depends on the AHB clock frequency.

The core registers are in the AHB domain, and the core does not accept another token before updating

these register values. The worst case is for any token following an isochronous OUT, because for an

isochronous transaction, there is no handshake and the next token could come sooner. This worst case

value is 7 PHY clocks in FS mode.

If this worst case condition occurs, the core responds to bulk/interrupt tokens with a NAK and drops

isochronous and SETUP tokens. The host interprets this as a timeout condition for SETUP and retries

the SETUP packet. For isochronous transfers, the INCOMPISOIN and INCOMPLP interrupts inform the

application that isochronous IN/OUT packets were dropped.

15.4.4.2.3.9 Choosing the Value of USB_GUSBCFG.USBTRDTIM

The value in USB_GUSBCFG.USBTRDTIM is the time it takes for the MAC, in terms of PHY clocks

after it has received an IN token, to get the FIFO status, and thus the first data from PFC (Packet FIFO

Controller) block. This time involves the synchronization delay between the PHY and AHB clocks. This

delay is 5 clocks.

Once the MAC receives an IN token, this information (token received) is synchronized to the AHB clock

by the PFC (the PFC runs on the AHB clock). The PFC then reads the data from the SPRAM and writes

it into the dual clock source buffer. The MAC then reads the data out of the source buffer (4 deep).

If the AHB is running at a higher frequency than the PHY (in Low-speed mode), the application can use

a smaller value for USB_GUSBCFG.USBTRDTIM. Figure 15.26 (p. 310) explains the 5-clock delay.

This diagram has the following signals:

• tkn_rcvd: Token received information from MAC to PFC

• dynced_tkn_rcvd: Doubled sync tkn_rcvd, from pclk to hclk domain

• spr_read: Read to SPRAM

• spr_addr: Address to SPRAM

• spr_rdata: Read data from SPRAM

• srcbuf_push: Push to the source buffer

• srcbuf_rdata: Read data from the source buffer. Data seen by MAC

The application can use the following formula to calculate the value of USB_GUSBCFG.USBTRDTIM:

4 * AHB Clock + 1 PHY Clock = (2 clock sync + 1 clock memory address + 1 clock memory data from

sync RAM) + (1 PHY Clock (next PHY clock MAC can sample the 2-clock FIFO output)

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Figure 15.26. USBTRDTIM Max Timing Case ERROR wrong image

Host ApplicationDeviceUSB

NAK

INTKNTXFEMP

INTR

512 bytes

ACK

do_in_xfer

xact_ 1 data rdy

xact_ 2 data rdy

xact_1 of 2

xact_2 of 2

NPTXFEMP INT

STALL

512 bytes

ACK

new xact

EPDisabled intr

STALL

idle (wait_intr)

setup_ np_in_ pkt

set_stall

ep_ disable ;

flush_ nper_tx_ fifo;

Clr Global IN NP Nak

wait_for_ host/

app to clr stall

clr_stall

do_ in_ xfer

setup_ np_in_ pkt

XferSize = 1025 bytes

PktCnt = 3

EPEna = 1

NAK

INTKNTXFEMP

INTR

15.4.4.2.3.10 Handling Babble Conditions

If receives a packet that is larger than the maximum packet size for that endpoint, the core stops writing

data to the Rx buffer and waits for the end of packet (EOP). When the core detects the EOP, it flushes

the packet in the Rx buffer and does not send any response to the host.

If the core continues to receive data at the EOF2 (the end of frame 2, which is very close to SOF), the

core generates an early_suspend interrupt (USB_GINTSTS.ERLYSUSP). On receiving this interrupt,

the application must check the erratic_error status bit (USB_DSTS.ERRTICERR). If this bit is set, the

application must take it as a long babble and perform a soft reset.

15.4.4.2.3.11 Generic Non-Periodic (Bulk and Control) IN Data Transfers in DMA and Slave Mode

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

as described in Endpoint Initialization (p. 283) . For packet writes in Slave mode, see: Packet Write

in Slave Mode (p. 305) .

Application Requirements

1. Before setting up an IN transfer, the application must ensure that all data to be transmitted as part of

the IN transfer is part of a single buffer, and must program the size of that buffer and its start address

(in DMA mode) to the endpoint-specific registers.

2. For IN transfers, the Transfer Size field in the Endpoint Transfer Size register denotes a payload

that constitutes multiple maximum-packet-size packets and a single short packet. This short packet

is transmitted at the end of the transfer.

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• To transmit a few maximum-packet-size packets and a short packet at the end of the transfer:

• Transfer size[epnum] = n * mps[epnum] + sp

(where n is an integer >= 0, and 0 <= sp < mps[epnum])

• If (sp > 0), then packet count[epnum] = n + 1. Otherwise, packet count[epnum] = n

a. To transmit a single zero-length data packet:

• Transfer size[epnum] = 0

• Packet count[epnum] = 1

b. To transmit a few maximum-packet-size packets and a zero-length data packet at the end of the

transfer, the application must split the transfer in two parts. The first sends maximum-packet-size

data packets and the second sends the zero-length data packet alone.

c. First transfer: transfer size[epnum] = n * mps[epnum]; packet count = n;

d. Second transfer: transfer size[epnum] = 0; packet count = 1;

3. In DMA mode, the core fetches an IN data packet from the memory, always starting at a DWORD

boundary. If the maximum packet size of the IN endpoint is not a multiple of 4, the application must

arrange the data in the memory with pads inserted at the end of a maximum-packet-size packet so

that a new packet always starts on a DWORD boundary.

4. Once an endpoint is enabled for data transfers, the core updates the Transfer Size register. At the end

of IN transfer, which ended with a Endpoint Disabled interrupt, the application must read the Transfer

Size register to determine how much data posted in the transmit FIFO was already sent on the USB.

5. Data fetched into transmit FIFO = Application-programmed initial transfer size – core-updated final

transfer size

• Data transmitted on USB = (application-programmed initial packet count – Core updated final

packet count) * mps[epnum]

• Data yet to be transmitted on USB = (Application-programmed initial transfer size – data transmitted

on USB)

Internal Data Flow

1. The application must set the Transfer Size and Packet Count fields in the endpoint-specific registers

and enable the endpoint to transmit the data.

2. In Slave mode, the application must also write the required data to the transmit FIFO for the endpoint.

In DMA mode, the core fetches the data from memory according to the application setting for the

endpoint.

3. Every time a packet is written into the transmit FIFO, either by the core’s internal DMA (in DMA

mode) or the application (in Slave Mode), the transfer size for that endpoint is decremented by the

packet size. The data is fetched from the memory (DMA/Application), until the transfer size for the

endpoint becomes 0. After writing the data into the FIFO, the “number of packets in FIFO” count is

incremented (this is a 3-bit count, internally maintained by the core for each IN endpoint transmit

FIFO. The maximum number of packets maintained by the core at any time in an IN endpoint FIFO

is eight). For zero-length packets, a separate flag is set for each FIFO, without any data in the FIFO.

4. Once the data is written to the transmit FIFO, the core reads it out upon receiving an IN token. For

every non-isochronous IN data packet transmitted with an ACK handshake, the packet count for the

endpoint is decremented by one, until the packet count is zero. The packet count is not decremented

on a TIMEOUT.

5. For zero length packets (indicated by an internal zero length flag), the core sends out a zero-length

packet for the IN token and decrements the Packet Count field.

6. If there is no data in the FIFO for a received IN token and the packet count field for that endpoint is

zero, the core generates a IN Tkn Rcvd When FIFO Empty Interrupt for the endpoint, provided the

endpoint NAK bit is not set. The core responds with a NAK handshake for non-isochronous endpoints

on the USB.

7. For Control IN endpoint, if there is a TIMEOUT condition, the USB_DIEPx_INT.TIMEOUT interrupt

is generated.

8. When the transfer size is 0 and the packet count is 0, the transfer complete interrupt for the endpoint

is generated and the endpoint enable is cleared.

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Application Programming Sequence

1. Program the USB_DIEPx_TSIZ register with the transfer size and corresponding packet count. In

DMA mode, also program the USB_DIEPx_DMAADDR register.

2. Program the USB_DIEPx_CTL register with the endpoint characteristics and set the CNAK and

Endpoint Enable bits.

3. In slave mode when transmitting non-zero length data packet, the application must poll the

USB_DIEPx_TXFSTS register (where x is the FIFO number associated with that endpoint) to

determine whether there is enough space in the data FIFO. The application can optionally use

USB_DIEPx_INT.TXFEMP before writing the data.

15.4.4.2.3.12 Examples

Slave Mode Bulk IN Transaction

These notes refer to Figure 15.27 (p. 312) .

1. The host attempts to read data (IN token) from an endpoint.

2. On receiving the IN token on the USB, the core returns a NAK handshake, because no data is available

in the transmit FIFO.

3. To indicate to the application that there was no data to send, the core generates a

USB_DIEPx_INT.INTKNTXFEMP (IN Token Received When TxFIFO Empty) interrupt.

4. When data is ready, the application sets up the USB_DIEPx_TSIZ register with the Transfer Size and

Packet Count fields.

5. The application writes one maximum packet size or less of data to the Non-periodic TxFIFO.

6. The host reattempts the IN token.

7. Because data is now ready in the FIFO, the core now responds with the data and the host ACKs it.

8. Because the XFERSIZE is now zero, the intended transfer is complete. The device core generates

a USB_DIEPx_INT.XFERCOMPL interrupt.

9. The application processes the interrupt and uses the setting of the USB_DIEPx_INT.XFERCOMPL

interrupt bit to determine that the intended transfer is complete.

Figure 15.27. Slave Mode Bulk IN Transaction

ApplicationDeviceUSB

INTKNTXFEMP

INTR

512 bytes

ACK

new xfer

rdy?

xact_1

IN Tkn = 0

Timeout =0

XferComp = 1

1IN 3

NAK

NAK 4

xfer_ cnt = 512 bytes

pkt cnt = 1

EP Enable = 1

idle until intr

setup _np_ in_pkt()

wr_reg(ep. DIEPTSIZn)

idle until intr

wait for

xfer

Yes

XFERCOMPL

INTR

Hos t

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Slave Mode Bulk IN Transfer (Pipelined Transaction)

These notes refer to Figure 15.28 (p. 314)

1. The host attempts to read data (IN token) from an endpoint.

2. On receiving the IN token on the USB, the core returns a NAK handshake, because no data is available

in the transmit FIFO.

3. To indicate that there was no data to send, the core generates an USB_DIEPx_INT.INTKNTXFEMP

(In Token Received When TxFIFO Empty) interrupt.

4. When data is ready, the application sets up the USB_DIEPx_TSIZ register with the transfer size and

packet count.

5. The application writes one maximum packet size or less of data to the Non-periodic TxFIFO.

6. The host reattempts the IN token.

7. Because data is now ready in the FIFO, the core responds with the data, and the host ACKs it.

8. When the TxFIFO level falls below the halfway mark, the core generates a

USB_GINTSTS.NPTXFEMP (NonPeriodic TxFIFO Empty) interrupt. This triggers the application to

start writing additional data packets to the FIFO.

9. A data packet for the second transaction is ready in the TxFIFO.

10.A data packet for third transaction is ready in the TxFIFO while the data for the second packet is

being sent on the bus.

11.The second data packet is sent to the host.

12.The last short packet is sent to the host.

13.Because the last packet is sent and XFERSIZE is now zero, the intended transfer is complete. The

core generates a USB_DIEPx_INT.XFERCOMPL interrupt.

14.The application processes the interrupt and uses the setting of the USB_DIEPx_INT.XFERCOMPL

interrupt bit to determine that the intended transfer is complete

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Figure 15.28. Slave Mode Bulk IN Transfer (Pipelined Transaction)

xact_2

Host ApplicationDevice

USB

ACK

1 byte

ACK

xact_

1 of

xact_2

xact_3

wr_reg(xfer_ size _reg)

NAK

512 bytes

13 14

idle until intr

setup_ np_in_pkt

IN Token = 0

Timeout =0

ACK = 0

XferCompl = 1

xact_2

xact_3

xact_1

xfer_ cnt = 1025 bytes

pkt_ cnt = 3

EP Enable = 1

idle until intr

NPTXFEMP

INTR

INTKNTXFEMP

INTR

XFERCOMPL

INTR

Slave Mode Bulk IN Two-Endpoint Transfer

These notes refer to Figure 15.29 (p. 315)

1. The host attempts to read data (IN token) from endpoint 1.

2. On receiving the IN token on the USB, the core returns a NAK handshake, because no data is available

in the transmit FIFO for endpoint 1, and generates a USB_DIEP1_INT.INTKNTXFEMP (In Token

Received When TxFIFO Empty) interrupt.

3. The application processes the interrupt and initializes USB_DIEP1_TSIZ register with the Transfer

Size and Packet Count fields. The application starts writing the transaction data to the transmit FIFO.

4. The application writes one maximum packet size or less of data for endpoint 1 to the Non-periodic

TxFIFO.

5. Meanwhile, the host attempts to read data (IN token) from endpoint 2.

6. On receiving the IN token on the USB, the core returns a NAK handshake, because no data is available

in the transmit FIFO for endpoint 2, and the core generates a USB_DIEP2_INT.INTKNTXFEMP (In

Token Received When TxFIFO Empty) interrupt.

7. Because the application has completed writing the packet for endpoint 1, it initializes the

USB_DIEP2_TSIZ register with the Transfer Size and Packet Count fields. The application starts

writing the transaction data into the transmit FIFO for endpoint 2.

8. The host repeats its attempt to read data (IN token) from endpoint 1.

9. Because data is now ready in the TxFIFO, the core returns the data, which the host ACKs.

10.Meanwhile, the application has initialized the data for the next two packets in the TxFIFO (ep2.xact1

and ep1.xact2, in order).

11.The host repeats its attempt to read data (IN token) from endpoint 2.

12.Because endpoint 2’s data is ready, the core responds with the data (ep2.xact_1), which the host

ACKs.

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13.Meanwhile, the application has initialized the data for the next two packets in the TxFIFO (ep2.xact2

and ep1.xact3, in order). The application has finished initializing data for the two endpoints involved

in this scenario.

14.The host repeats its attempt to read data (IN token) from endpoint 1.

15.Because data is now ready in the FIFO, the core responds with the data, which the host ACKs.

16.The host repeats its attempt to read data (IN token) from endpoint 2.

17.With data now ready in the FIFO, the core responds with the data, which the host ACKs.

18.With the last packet for endpoint 2 sent and its XFERSIZE now zero, the intended transfer is complete.

The core generates a USB_DIEP2_INT.XFERCOMPL interrupt for this endpoint.

19.The application processes the interrupt and uses the setting of the USB_DIEP2_INT.XFERCOMPL

interrupt bit to determine that the intended transfer on endpoint 2 is complete.

20.The host repeats its attempt to read data (IN token) from endpoint 1 (last transaction).

21.With data now ready in the FIFO, the core responds with the data, which the host ACKs.

22.Because the last endpoint one packet has been sent and XFERSIZE is now zero, the intended transfer

is complete. The core generates a USB_DIEP1_INT.XFERCOMPL interrupt for this endpoint.

23.The application processes the interrupt and uses the setting of the USB_DIEP1_INT.XFERCOMPL

interrupt bit to determine that the intended transfer on endpoint 1 is complete.

Figure 15.29. Slave Mode Bulk IN Two-Endpoint Transfer

10 bytes

ep2 drvr

Hos t

Application

Device

USB

IN, ep1

NAK

IN,ep1

512 bytes

ACK

ep1.xact_1

ep2.xact_1

ep1.xact_2

ep2.xact_2

ep1.xact_2

wr_reg(ep1.USB_DI EPx_TSIZ)

wr_reg(ep2.USB_DI EPx_TSIZ)

ep1.xact_3

ep1.xact_2

IN, ep2

ep2.InTknTxFEmp intr

NAK

IN, ep2

512 bytes

1 byte

ep1.setup_np_in_pkt

xfer_complete =1

EP_NUM 1 register set

XferSize = 1025 bytes

PktCnt = 3

EPEna = 1

EP_NUM 2 registers

XferSize = 522 bytes

PktCnt = 2

EPEna = 1

xfer_complete = 1

idle

until intr

idle

until intr

ep2.setup_np_in_pkt

idle

until intr

idle

until intr

ep1.Xfer

Comp intr

ACK

IN,ep1

IN, ep2

ACK

IN, ep1

ACK

ep1.InTkn

TxF Emp intr

ep2.XferCompl intr

15.4.4.2.3.13 Generic Periodic IN (Interrupt and Isochronous) Data Transfers

To initialize the core after power-on reset, the application must follow the sequence in Overview:

Programming the Core (p. 248) . Before it can communicate with the host, it must initialize an endpoint

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as described in Endpoint Initialization (p. 283) . For packet writes in Slave mode, see: Packet Write

in Slave Mode (p. 305) .

Application Requirements

1. Application requirements 1, 2, 3, and 4 of Generic Non-Periodic (Bulk and Control) IN Data Transfers

Without Thresholding in DMA and Slave Mode (p. 310) also apply to periodic IN data transfers,

except for a slight modification of Requirement 2.

• The application can only transmit multiples of maximum-packet-size data packets or multiples of

maximum-packet-size packets, plus a short packet at the end. To transmit a few maximum-packet-

size packets and a short packet at the end of the transfer, the following conditions must be met.

• transfer size[epnum] = n * mps[epnum] + sp(where n is an integer # 0, and 0 >= sp < mps[epnum])

• If (sp > 0), packet count[epnum] = n + 1Otherwise, packet count[epnum] = n;

• mc[epnum] = packet count[epnum]

• The application cannot transmit a zero-length data packet at the end of transfer. It can transmit a

single zero-length data packet by it self. To transmit a single zero-length data packet,

• transfer size[epnum] = 0

• packet count[epnum] = 1

• mc[epnum] = packet count[epnum]

2. The application can only schedule data transfers 1 frame at a time.

• (USB_DIEPx_TSIZ.MC – 1) * USB_DIEPx_CTL.MPS =< USB_DIEPx_TSIZ.XFERSIZE =<

USB_DIEPx_TSIZ.MC * USB_DIEPx_CTL.MPS

• USB_DIEPx_TSIZ.PKTCNT = USB_DIEPx_TSIZ.MC

• If USB_DIEPx_TSIZ.XFERSIZE < USB_DIEPx_TSIZ.MC * USB_DIEPx_CTL.MPS, the last data

packet of the transfer is a short packet.

3. This step is not applicable for isochronous data transfers, only for interrupt transfers.

The application can schedule data transfers for multiple frames, only if multiples of max packet sizes

(up to 3 packets), must be transmitted every frame. This is can be done, only when the core is

operating in DMA mode. This is not a recommended mode though.

• ((n*USB_DIEPx_TSIZ.MC) - 1)*USB_DIEPx_CTL.MPS <= USB_DIEPx_TSIZ.XFERSIZE <=

n*USB_DIEPx_TSIZ.MC*USB_DIEPx_CTL.MPS

• USB_DIEPx_TSIZ.PKTCNT = n*USB_DIEPx_TSIZ.MC

• n is the number of frames for which the data transfers are scheduled

Data Transmitted per frame in this case would be USB_DIEPx_TSIZ.MC*USB_DIEPx_CTL.MPS,

in all the frames except the last one. In the frame “n”, the data transmitted would be

(USB_DIEPx_TSIZ.XFERSIZE - (n-1)*USB_DIEPx_TSIZ.MC*USB_DIEPx_CTL.MPS)

4. For Periodic IN endpoints, the data must always be prefetched 1 frame ahead for transmission in the

next frame. This can be done, by enabling the Periodic IN endpoint 1 frame ahead of the frame in

which the data transfer is scheduled.

5. The complete data to be transmitted in the frame must be written into the transmit FIFO (either by the

application or the DMA), before the Periodic IN token is received. Even when 1 DWORD of the data

to be transmitted per frame is missing in the transmit FIFO when the Periodic IN token is received,

the core behaves as when the FIFO was empty. When the transmit FIFO is empty,

6. A zero data length packet would be transmitted on the USB for ISO IN endpoints

• A NAK handshake would be transmitted on the USB for INTR IN endpoints

7. For a High Bandwidth IN endpoint with three packets in a frame, the application can program the

endpoint FIFO size to be 2*max_pkt_size and have the third packet load in after the first packet has

been transmitted on the USB.

Internal Data Flow

1. The application must set the Transfer Size and Packet Count fields in the endpoint-specific registers

and enable the endpoint to transmit the data.

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2. In Slave mode, the application must also write the required data to the associated transmit FIFO for

the endpoint. In DMA mode, the core fetches the data for the endpoint from memory, according to

the application setting.

3. Every time either the core’s internal DMA (in DMA mode) or the application (in Slave mode) writes a

packet to the transmit FIFO, the transfer size for that endpoint is decremented by the packet size. The

data is fetched from DMA or application memory until the transfer size for the endpoint becomes 0.

4. When an IN token is received for an periodic endpoint, the core transmits the data in the FIFO, if

available. If the complete data payload (complete packet) for the frame is not present in the FIFO,

then the core generates an IN Token Received When TxFIFO Empty Interrupt for the endpoint.

• A zero-length data packet is transmitted on the USB for isochronous IN endpoints

• A NAK handshake is transmitted on the USB for interrupt IN endpoints

5. The packet count for the endpoint is decremented by 1 under the following conditions:

• For isochronous endpoints, when a zero- or non-zero-length data packet is transmitted

• For interrupt endpoints, when an ACK handshake is transmitted

• When the transfer size and packet count are both 0, the Transfer Completed interrupt for the

endpoint is generated and the endpoint enable is cleared.

6. At the “Periodic frame Interval” (controlled by USB_DCFG.PERFRINT), when the core finds non-

empty any of the isochronous IN endpoint FIFOs scheduled for the current frame non-empty, the core

generates a USB_GINTSTS.INCOMPISOIN interrupt.

Application Programming Sequence (Transfer Per Frame)

1. Program the USB_DIEPx_TSIZ register. In DMA mode, also program the USB_DIEPx_DMAADDR

2. Program the USB_DIEPx_CTL register with the endpoint characteristics and set the CNAK and

Endpoint Enable bits.

3. In Slave mode, write the data to be transmitted in the next frame to the transmit FIFO.

4. Asserting the USB_DIEPx_INT.INTKNTXFEMP (In Token Received When TxFifo Empty) interrupt

indicates that either the DMA or application has not yet written all data to be transmitted to the transmit

FIFO.

5. If the interrupt endpoint is already enabled when this interrupt is detected, ignore the interrupt. If it is

not enabled, enable the endpoint so that the data can be transmitted on the next IN token attempt.

• If the isochronous endpoint is already enabled when this interrupt is detected, see Incomplete

Isochronous IN Data Transfers (p. 307) for more details.

6. The core handles timeouts internally on interrupt IN endpoints programmed as periodic endpoints

without application intervention. The application, thus, never detects a USB_DIEPx_INT.TIMEOUT

interrupt for periodic interrupt IN endpoints.

7. Asserting the USB_DIEPx_INT.XFERCOMPL interrupt with no USB_DIEPx_INT.INTKNTXFEMP (In

Token Received When TxFifo Empty) interrupt indicates the successful completion of an isochronous

IN transfer. A read to the USB_DIEPx_TSIZ register must indicate transfer size = 0 and packet

count = 0, indicating all data is transmitted on the USB.

8. Asserting the USB_DIEPx_INT.XFERCOMPL interrupt, with or without the

USB_DIEPx_INT.INTKNTXFEMP (In Token Received When TxFifo Empty) interrupt, indicates the

successful completion of an interrupt IN transfer. A read to the USB_DIEPx_TSIZ register must

indicate transfer size = 0 and packet count = 0, indicating all data is transmitted on the USB.

9. Asserting the USB_GINTSTS.INCOMPISOIN (Incomplete Isochronous IN Transfer) interrupt with

none of the aforementioned interrupts indicates the core did not receive at least 1 periodic IN token

in the current frame.

10.For isochronous IN endpoints, see Incomplete Isochronous IN Data Transfers (p. 307) , for more

details.

15.4.4.2.3.14 Generic Periodic IN Data Transfers Using the Periodic Transfer Interrupt Feature

This section describes a typical Periodic IN (ISOC / INTR) data transfer with the Periodic Transfer

Interrupt feature.

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1. Before setting up an IN transfer, the application must ensure that all data to be transmitted as part of

the IN transfer is part of a single buffer, and must program the size of that buffer and its start address

(in DMA mode) to the endpoint-specific registers.

2. For IN transfers, the Transfer Size field in the Endpoint Transfer Size register denotes a payload

that constitutes multiple maximum-packet-size packets and a single short packet. This short packet

is transmitted at the end of the transfer.

a. To transmit a few maximum-packet-size packets and a short packet at the end of the transfer:

• Transfer size[epnum] = n * mps[epnum] + sp

(where n is an integer > 0, and 0 < sp < mps[epnum]. A higher value of n reduces the periodicity

of the USB_DOEPx_INT.XFERCOMPL interrupt)

• If (sp > 0), then packet count[epnum] = n + 1. Otherwise, packet count[epnum] = n

b. To transmit a single zero-length data packet:

• Transfer size[epnum] = 0

• Packet count[epnum] = 1

c. To transmit a few maximum-packet-size packets and a zero-length data packet at the end of the

transfer, the application must split the transfer in two parts. The first sends maximum-packet-size

data packets and the second sends the zero-length data packet alone.

• First transfer: transfer size[epnum] = n * mps[epnum]; packet count = n;

• Second transfer: transfer size[epnum] = 0; packet count = 1;

d. The application can only transmit multiples of maximum-packet-size data packets or multiples of

maximum-packet-size packets, plus a short packet at the end. To transmit a few maximum-packet-

size packets and a short packet at the end of the transfer, the following conditions must be met.

• transfer size[epnum] = n * mps[epnum] + sp (where n is an integer > 0, and 0 < sp < mps[epnum])

• If (sp > 0), packet count[epnum] = n + 1 Otherwise, packet count[epnum] = n;

• mc[epnum] = number of packets to be sent out in a frame.

e. The application cannot transmit a zero-length data packet at the end of transfer. It can transmit a

single zero-length data packet by itself. To transmit a single zero-length data packet,

• transfer size[epnum] = 0

• packet count[epnum] = 1

• mc[epnum] = packet count[epnum]

3. In DMA mode, the core fetches an IN data packet from the memory, always starting at a DWORD

boundary. If the maximum packet size of the IN endpoint is not a multiple of 4, the application must

arrange the data in the memory with pads inserted at the end of a maximum-packet-size packet so

that a new packet always starts on a DWORD boundary.

4. Once an endpoint is enabled for data transfers, the core updates the Transfer Size register. At the end

of IN transfer, which ended with a Endpoint Disabled interrupt, the application must read the Transfer

Size register to determine how much data posted in the transmit FIFO was already sent on the USB.

• Data fetched into transmit FIFO = Application-programmed initial transfer size - core-updated final

transfer size

• Data transmitted on USB = (application-programmed initial packet count - Core updated final packet

count) * mps[epnum]

• Data yet to be transmitted on USB = (Application-programmed initial transfer size - data transmitted

on USB)

5. The application can schedule data transfers for multiple frames, only if multiples of max packet sizes

(up to 3 packets), must be transmitted every frame. This is can be done, only when the core is

operating in DMA mode.

• ((n*USB_DIEPx_TSIZ.MC) - 1)*USB_DIEPx_CTL.MPS <= USB_DIEPx_TSIZ.XFERSIZE <=

n*USB_DIEPx_TSIZ.MC*USB_DIEPx_CTL.MPS

• USB_DIEPx_TSIZ.PKTCNT = n*USB_DIEPx_TSIZ.MC

• n is the number of frames for which the data transfers are scheduled. Data Transmitted per frame

in this case is USB_DIEPx_TSIZ.MC*USB_DIEPx_CTL.MPS in all frames except the last one. In

frame n, the data transmitted is (USB_DIEPx_TSIZ.XFERSIZE – (n – 1) * USB_DIEPx_TSIZ.MC

* USB_DIEPx_CTL.MPS)

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6. For Periodic IN endpoints, the data must always be prefetched 1 frame ahead for transmission in the

next frame. This can be done, by enabling the Periodic IN endpoint 1 frame ahead of the frame in

which the data transfer is scheduled.

7. The complete data to be transmitted in the frame must be written into the transmit FIFO, before the

Periodic IN token is received. Even when 1 DWORD of the data to be transmitted per frame is missing

in the transmit FIFO when the Periodic IN token is received, the core behaves as when the FIFO was

empty. When the transmit FIFO is empty,

• A zero data length packet would be transmitted on the USB for ISOC IN endpoints

• A NAK handshake would be transmitted on the USB for INTR IN endpoints

• USB_DIEPx_TSIZ.PKTCNT is not decremented in this case.

8. For a High Bandwidth IN endpoint with three packets in a frame, the application can program the

endpoint FIFO size to be 2 * max_pkt_size and have the third packet load in after the first packet has

been transmitted on the USB.

Figure 15.30. Periodic IN Application Flow for Periodic Transfer Interrupt Feature

NOTE

Requirem ents For XferSize and PktCnt program ming

1 . Packet Size has to be of MaxPktSize for all ( micro) frames except for las t

packet which can be a Short Packet.

2 . Short Packets are not allowed in between Xfers

5 . Core will read packets from System Mem ory only from DWORD aligned

address es.

6 . If MaxPktSize is not DWORD aligned, Application mus t ins ert pads at the

end of the packet s o that new packet is always DWORD aligned.

7 . Thres holding in not s upported for the Periodic Transfer Interrupt

enhancem ent

START

De- allocate Data Ram Memory

· Program EP Ctrl register to start the xfer

USB_DIEPx_CTL.CNAK= 0b1

USB_DIEPx_CTL.TXFNUM = tx_fifo_num;

USB_DIEPx_CTL.EPENA = 0b1

USB_DIEPx_CTL.SNAK = 0b0

USB_DIEPx_CTL.EPDIS = 0b0

·Wait for USB_DOEPX_INT XFERCOMPL interrupt & report error if timeout expires

If USB_DIEPx_TSIZ

XFERSIZE != 0 or

USB_DIEPx_TSIZ

PKTCNT != 0

return

· Check for error_ scenario

· If no error_ scenario set report error

Yes

· Intialize variables

·Allocate a buffer in the S ys tem Memory for multiple Xfers. Buffer s ize should be multiple ot MaxPktSize.

· Program the DMA address

DIEPDMA = S TART Address of the Data Mem ory

· Program Xfer_ size register

USB_DIEPx_TSIZ XFERSIZE = XferS ize S panning acros s m ultiple Xfers

USB_DIEPx_TSIZ PKTCNT = Program PktCnt for multiple Xfers

USB_DIEPx_TSIZ.MC = Max Number of Packets in a ( m icro)fram e

· Program the Global INT STS

USB_GINTMSK. INCOMPLSOCINMSK = 0b0 // Mask Incom pISOCIN Interrupt

Internal Data Flow

1. The application must set the Transfer Size and Packet Count fields in the endpoint-specific registers

and enable the endpoint to transmit the data.

• The application must enable the USB_DCTL.IGNRFRMNUM

2. When an isochronous OUT endpoint is enabled by setting the Endpoint Enable and clearing the NAK

bits, the Even/Odd frame will be ignored by the core.

• Subsequently the core updates the Even / Odd bit on its own

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3. Every time either the core’s internal DMA writes a packet to the transmit FIFO, the transfer size for

that endpoint is decremented by the packet size. The data is fetched from DMA or application memory

until the transfer size for the endpoint becomes 0.

4. When an IN token is received for a periodic endpoint, the core transmits the data in the FIFO, if

available. If the complete data payload (complete packet) for the frame is not present in the FIFO,

then the core generates an IN Token Received When TxFifo Empty Interrupt for the endpoint.

• A zero-length data packet is transmitted on the USB for isochronous IN endpoints

• A NAK handshake is transmitted on the USB for interrupt IN endpoints

5. If an IN token comes for an endpoint on the bus, and if the corresponding TxFIFO for that endpoint

has at least 1 packet available, and if the USB_DIEPx_CTL.NAK bit is not set, and if the internally

maintained even/odd bit match with the bit 0 of the current frame number, then the core will send this

data out on the USB. The core will also decrement the packet count. Core also toggles the MultCount

in USB_DIEPx_CTL register and based on the value of MultCount the next PID value is sent.

• If the IN token results in a timeout (core did not receive the handshake or handshake error),

core rewind the FIFO pointers. Core does not decrement packet count. It does not toggle PID.

USB_DIEPx_INT.TIMEOUT interrupt will be set which the application could check.

• At the end of periodic frame interval (Based on the value programmed in the

USB_DCFG.PERFRINT register, core will internally set the even/odd internal bit to match the next

frame.

6. The packet count for the endpoint is decremented by 1 under the following conditions:

• For isochronous endpoints, when a zero- or non-zero-length data packet is transmitted

• For interrupt endpoints, when an ACK handshake is transmitted

7. The data PID of the transmitted data packet is based on the value of USB_DIEPx_TSIZ.MC

programmed by the application. In case the USB_DIEPx_TSIZ.MC value is set to 3 then, for a

particular frame the core expects to receive 3 Isochronous IN token for the respective endpoint. The

data PIDs transmitted will be D2 followed by D1 and D0 respectively for the tokens.

• If any of the tokens responded with a zero-length packet due to non-availability of data in the

TxFIFO, the packet is sent in the next frame with the pending data PID. For example, in a frame,

the first received token is responded to with data and data PID value D2. If the second token is

responded to with a zero-length packet, the host is expected not to send any more tokens for the

respective endpoint in the current frame. When a token arrives in the next frame it will be responded

to with the pending data PID value of D1.

• Similarly the second token of the current frame gets responded with D0 PID. The host is expected

to send only two tokens for this frame as the first token got responded with D1 PID.

8. When the transfer size and packet count are both 0, the Transfer Completed interrupt for the endpoint

is generated and the endpoint enable is cleared.

9. The USB_GINTSTS.INCOMPISOIN will be masked by the application hence at the Periodic Frame

interval (controlled by USB_DCFG.PERFRINT), even though the core finds non-empty any of the

isochronous IN endpoint FIFOs, USB_GINTSTS.INCOMPISOIN interrupt will not be generated.

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Figure 15.31. Periodic IN Core Internal Flow for Periodic Transfer Interrupt Feature

If (US B_DIEPx_CTL.CNAK = 0b1) &&

(USB_DIEPxCTL.EPENA = 0b1) &&

(USB_DCTL.IGNRFRMNUM = 0b1)

NOTE

1 . Core will fetch data only from DWORD Aligned addres s es

2 . Core will not tag Periodic IN Packets to a s pecific (micro) frame number

3 . In case core is not able to send out data for the current (micro) frame the

data will not be flus hed and will be s ent out in the next (m icro) frame

4 . The DATA PID of the packet which was not sent in the previous

( m icro) fram e will remain the s ame

5 . S hort Packets are not allowed in between transfers. Only the last packet

can have a Short Packet

START

IN Token From Hos t Check Data AvailableYES

WAIT

YES

NO · ISOC IN Transmit Zero Length Packet (ZLP)

· Interrupt IN Xmit NAK Packet

· MultCnt = MultCnt

· PktCnt = PktCnt

· XferSize = XferSize

// MultCnt, PktCnt and XferSize values will

not change

· Transmit Data Packet

· MultCnt = MultCnt -1

· PktCnt = PktCnt - 1

· XferSize = XferSize - MaxPktSize

MultCnt = 0 If PktCnt == 0 &&

XferSize == 0

MultCnt = USB_DIEPx_TSIZ.MC

USB_DIEPx_INT.XFERCOMPL = 1

YES

return

15.4.5 OTG Revision 1.3 Programming Model

This section describes the OTG programming model when the core is configured to support OTG

Revision 1.3 of the specification.

The core is an OTG device supporting HNP and SRP. When the core is connected to an “A” plug, it is

referred to as an A-device. When the core is connected to a “B” plug it is referred to as a B-device. In

Host mode, the core turns off Vbus to conserve power. SRP is a method by which the B-device signals

the A-device to turn on Vbus power. A device must perform both data-line pulsing and Vbus pulsing,

but a host can detect either data-line pulsing or Vbus pulsing for SRP. HNP is a method by which the

B-device negotiates and switches to host role. In Negotiated mode after HNP, the B-device suspends

the bus and reverts to the device role.

15.4.5.1 A-Device Session Request Protocol

The application must set the SRP-Capable bit in the Core USB Configuration register. This enables the

core to detect SRP as an A-device.

1. To save power, the application suspends and turns off port power when the bus is idle by writing the

Port Suspend and Port Power bits in the Host Port Control and Status register.

2. PHY indicates port power off by detecting that VBUS voltage level is no longer valid.

3. The device must detect SE0 for at least 2 ms to start SRP when Vbus power is off.

4. To initiate SRP, the device turns on its data line pull-up resistor for 5 to 10 ms. The core detects

data-line pulsing.

5. The device drives Vbus above the A-device session valid (2.0 V minimum) for Vbus pulsing.

The core interrupts the application on detecting SRP. The Session Request Detected bit is set in

Global Interrupt Status register (USB_GINTSTS.SESSREQINT).

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6. The application must service the Session Request Detected interrupt and turn on the Port Power bit

by writing the Port Power bit in the Host Port Control and Status register. The PHY indicates port

power-on by detecting a valid VBUS level.

7. When the USB is powered, the device connects, completing the SRP process.

15.4.5.2 B-Device Session Request Protocol

The application must set the SRP-Capable bit in the Core USB Configuration register. This enables the

core to initiate SRP as a B-device. SRP is a means by which the core can request a new session from

the host.

1. To save power, the host suspends and turns off port power when the bus is idle. PHY indicates port

power off by detecting a not valid VBUS level.

The core sets the Early Suspend bit in the Core Interrupt register after 3 ms of bus idleness. Following

this, the core sets the USB Suspend bit in the Core Interrupt register.

The PHY indicates the end of the B-device session by detecting a VBUS level below session valid.

2. PHY to enables the VBUS discharge function to speed up Vbus discharge.

3. The PHY indicates the session’s end by detecting a session end voltage level on VBUS. This is the

initial condition for SRP. The core requires 2 ms of SE0 before initiating SRP.

The application must wait until Vbus discharges to 0.2 V after USB_GOTGCTL.BSESVLD is

deasserted. This discharge time can be obtained from the datasheet.

4. The application initiates SRP by writing the Session Request bit in the OTG Control and Status

5. The host detects SRP from either the data-line or Vbus pulsing, and turns on Vbus. The PHY indicates

Vbus power-on by detecting a valid VBUS level.

6. The core performs Vbus pulsing.

The host starts a new session by turning on Vbus, indicating SRP success. The core interrupts the

application by setting the Session Request Success Status Change bit in the OTG Interrupt Status

7. When the USB is powered, the core connects, completing the SRP process.

15.4.5.3 A-Device Host Negotiation Protocol

HNP switches the USB host role from the A-device to the B-device. The application must set the HNP-

Capable bit in the Core USB Configuration register to enable the core to perform HNP as an A#device.

1. The core sends the B-device a SetFeature b_hnp_enable descriptor to enable HNP support. The

B-device’s ACK response indicates that the B-device supports HNP. The application must set Host

Set HNP Enable bit in the OTG Control and Status register to indicate to the core that the B-device

supports HNP.

2. When it has finished using the bus, the application suspends by writing the Port Suspend bit in the

Host Port Control and Status register.

3. When the B-device observes a USB suspend, it disconnects, indicating the initial condition for HNP.

The B-device initiates HNP only when it must switch to the host role; otherwise, the bus continues

to be suspended.

The core sets the Host Negotiation Detected interrupt in the OTG Interrupt Status register, indicating

the start of HNP.

The PHY turns off the D+ and D- pulldown resistors to indicate a device role. The PHY enable the D

+ pull-up resistor indicates a connect for B-device.

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The application must read the Current Mode bit in the OTG Control and Status register to determine

Device mode operation.

4. The B-device detects the connection, issues a USB reset, and enumerates the core for data traffic.

5. The B-device continues the host role, initiating traffic, and suspends the bus when done.

The core sets the Early Suspend bit in the Core Interrupt register after 3 ms of bus idleness. Following

this, the core sets the USB Suspend bit in the Core Interrupt register.

6. In Negotiated mode, the core detects the suspend, disconnects, and switches back to the host role.

The core turns on the D+ and D- pulldown resistors to indicate its assumption of the host role.

7. The core sets the Connector ID Status Change interrupt in the OTG Interrupt Status register. The

application must read the connector ID status in the OTG Control and Status register to determine

the core’s operation as an A-device. This indicates the completion of HNP to the application. The

application must read the Current Mode bit in the OTG Control and Status register to determine Host

mode operation.

8. The B-device connects, completing the HNP process.

15.4.5.4 B-Device Host Negotiation Protocol

HNP switches the USB host role from B-device to A-device. The application must set the HNP-Capable

bit in the Core USB Configuration register to enable the core to perform HNP as a B-device.

1. The A-device sends the SetFeature b_hnp_enable descriptor to enable HNP support. The core’s ACK

response indicates that it supports HNP. The application must set the Device HNP Enable bit in the

OTG Control and Status register to indicate HNP support.

The application sets the HNP Request bit in the OTG Control and Status register to indicate to the

core to initiate HNP.

2. When it has finished using the bus, the A-device suspends by writing the Port Suspend bit in the Host

Port Control and Status register.

The core sets the Early Suspend bit in the Core Interrupt register after 3 ms of bus idleness. Following

this, the core sets the USB Suspend bit in the Core Interrupt register.

The core disconnects and the A-device detects SE0 on the bus, indicating HNP. The core enables

the D+ and D- pulldown resistors to indicate its assumption of the host role.

The A-device responds by activating its D+ pull-up resistor within 3 ms of detecting SE0. The core

detects this as a connect.

The core sets the Host Negotiation Success Status Change interrupt in the OTG Interrupt Status

OTG Control and Status register to determine host negotiation success. The application must read the

Current Mode bit in the Core Interrupt register (USB_GINTSTS) to determine Host mode operation.

3. The application sets the reset bit (USB_HPRT.PRTRST) and the core issues a USB reset and

enumerates the A-device for data traffic

4. The core continues the host role of initiating traffic, and when done, suspends the bus by writing the

Port Suspend bit in the Host Port Control and Status register.

5. In Negotiated mode, when the A-device detects a suspend, it disconnects and switches back to the

host role. The core disables the D+ and D- pulldown resistors to indicate the assumption of the device

role.

6. The application must read the Current Mode bit in the Core Interrupt (USB_GINTSTS) register to

determine the Host mode operation.

7. The core connects, completing the HNP process.

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15.4.6 OTG Revision 2.0 Programming Model

OTG Revision 2.0 supports the new Attach Detection Protocol (ADP). This protocol enables a local

device (an OTG device or Embedded Host) to detect when a remote device is attached or detached.

Note ADP is not supported by the core.

In addition to ADP, OTG Revision 2.0 also supports enhanced SRP and HNP, which are described in

the following sections:

• OTG Revision 2.0 Session Request Protocol (p. 324)

• OTG Revision 2.0 Host Negotiation Protocol (p. 326)

Note VBUS pulsing is not supported in OTG Revision 2.0 mode.

15.4.6.1 OTG Revision 2.0 Session Request Protocol

When the core is behaving as an A-device, it can power off VBUS when no session is active until the

B-device initiates a SRP. The SRP detection is handled by the core.

Figure 15.32 (p. 325) illustrates the programming steps that need to be performed by A-device’s

application (core as A-device) when B-device initiates a SRP to establish a connection.

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Figure 15.32. SRP Detection by Core When Operating as A-device

Read USB_GINTSTS

Yes

Interrupt ?

Yes

Host Transactions

If host’s application decides to

turn on VBUS voluntarily,

then the application need

not wait for SRP from

device.

Note: If MODEMIS interrupt

is detected during this

process, it means that the

connector has been

plugged out or

interchanged . This can be

confirmed by reading

Host mode (PHY

not driving VBUS)

Program USB_GINTMSK.

(Unmask OTGINT, MODEMIS,

SESSREQINT)

GINTSTS.

SESSREQINT = 1 ?

USB_GINTSTS.CONIDSTSCHNG

Host Initialization Steps. Refer to the Host

Initialization section of this chapter for

more information.

(In this step the OTG FSM is in a_host

state.)

Figure 15.33 (p. 326) illustrates the steps that need to be performed by B-device’s application (core

as B-device) in order to establishing a connection with A-device by signaling a SRP.

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Figure 15.33. SRP Initiation by the Core When Acting as a B-Device

1. Program USB_GINTMSK

(unmask OTGINT)

2. Read USB_GOTGCTL

Yes ( This indicates that

VBUS is already being driven

and hence there is no need for

a SRP)

Device Initialization

Steps . For more

information , see

Device Initialization

section of this

chapter.

Interrupt ?

Yes

Read

USB_GINTSTS

Yes

Read

USB_GOTGINT

USB_GOTGINT.

SESREQSUCS

TSCHNG = 1?

Yes

1. Read USB_GOTGCTL

2. Clear

USB_GOTGINT.SESREQSU

CSTSCHNG by writing

a 1

USB_GOTGCTL.

SESREQSCS

= 1?

Yes

Device Initialization

Steps . For more

information, see

Device Initialization

section of this

chapter.

Device

Transactions

Device (OTG

FSM in b_idle state)

USB_GOTGCTL.

BSESVLD = 1 ?

Set USB_GOTGCTL.

SESREQ = 1

USB_GINTSTS.

OTGINT = 1?

Note The programming flow illustrated in Figure 15.33 (p. 326) is similar to OTG revision 1.3.

This is because the presence or absence of VBUS pulsing is transparent to the application.

15.4.6.2 OTG Revision 2.0 Host Negotiation Protocol

When the core is operating as A-device, the application must execute a GetStatus() operation to the B-

device with a frequency of THOST_REQ_POLL to determine the state of the host request flag in the

B-device. If the host request flag is set in B-device it must program the core to change its role within

THOST_REQ_SUSP.

Figure 15.34 (p. 327) shows the programming steps that need to be performed by A-device’s

application (core as A-device) in order to change its role to device. In Figure 15.34 (p. 327) , the A-

device performs a role change, becomes a B-device and then reverts back to host (A-device) mode of

operation.

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Figure 15.34. HNP When the Core is an A-Device

Read

USB_GINTSTS

USB_GOTGINT.

HSTNEGDET

=1?

Yes

Read

USB_GINTSTS.CURMOD

Program USB_HPRT.PRTSUSP = 1

Unmask USB_GINTSTS.OTGINT

Interrupt ?

Yes

Host to Device to Host

Program

USB_GOTGCTL.HSTSETHNPEN = 1

USB_GINTSTS.

OTGINT =1 ?

Interrupt ?

Yes No

Yes

USB_GINTSTS.

CURMOD = 0?No

Remain as

Host (The host’s

application can

take a call whether

to switch off VBUS

or not) Yes

End of Device

transactions

Read

USB_GINTSTS

1. Unmask

USB_GINTSTS.ERLYSUSP

2. Device Initialization Steps.

For more information

Device Initialization section

of this chapter.

Start of Device

transactions

Interrupt ?

Yes

Read

USB_GINTSTS

Interrupt ?

Yes

A-Device as USB Host

Read

USB_GINTSTS

Interrupt

within

200 ms

yes

Yes

A-Device as USB Device

Read USB_GINTSTS

Check that CURMOD

= 0

Host Mode

Transactions

Yes

Application starts

200 ms timer

Host Initialization

Steps .

For more

information , see Host

Initialization section

of this chapter.

USB_GINTSTS.

ERLYSUSP = 1 ?

USB_GINTSTS.

USBSUSP = 1 ?

USB_GINTSTS.WKUPINT = 1

USB_GINTSTS.RESETDET ?

Host mode

(Send SetFeature Command to enable

b_hnp_enable feature in HNP capable

devices. HNP polling mechanism is also

involved. This is done when OTG FSM

is in a_host state) , see

Figure 15.35 (p. 328) shows the programming steps that need to be performed by B-device’s

application (core as B-device) in order to change its role to Host. In Figure 15.35 (p. 328) , the B-

device performs a role change, becomes a Host and then reverts back to Device mode of operation.

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Figure 15.35. HNP When the Core is a B-Device

1. Program

2. Program

Read

USB_GINTSTS

Interrupt ?

Yes

Read

USB_GINTSTS

Interrupt ?

Yes

Read

USB_GINTSTS

Interrupt ?

Yes

Read

USB_GOTGINT

Yes

Read

USB_GOTGCTL

Yes

No Remain as

Device

Start of Host

transactions

End of Host

transactions

Does B-

device want

to remain

host ?

Yes

6.1. 1

Host Initialization

Read

USB_GINTSTS

Interrupt ?

Yes

Device Mode

Transactions

The application

should ensure that

this process happens

within 200 ms

Read USB_GINTSTS.CURMOD

and ensure it is 0.

Device Initialization Steps.

For more information, see

Device Initialization

section in this chapter.

USB_GOTGINT.

HSTNEGSUCSTSCHNG = 1 ?

USB_GOTGCTL.DEVSETHNPEN = 1

USB_GOTGCTL.HNPREQ = 1

USB_GINTSTS.

ERLYSUSP = 1?

USB_GINTSTS.

USBSUSP = 1?

USB_GINTSTS.

OTGINT = 1?

Clear USB_GOTGINT.

HSTNEGSUCSTSCHNG

USB_GOTGCTL.

HSTNEGSUCS = 1 ?

Read USB_GINTSTS. Check

that CURMOD = 1.

Host Initialization Steps

(USB_HPRT.PRTPWR should

not be programmed). For more

information, see Host

Initialization section in this

chapter.

Set USB_HPRT.PRTSUSP = 1.

Unmask GINTSTS.OTGINT. (USB_HPRT.PRTPWR should

not be programmed)

Program

USB_HPRT.PRTRES = 1 for

a predefined time.

USB_GINTSTS.

DISCONNINT = 1 ?

Device mode

(Receive SetFeature

Command and OTG FSM

is in b_peripheral state)

Note During HNP process where the B-device is going to assume the role of a host, the B-device

application needs to ensure that a USB reset process is programmed (in USB_HPRT

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interrupt.

15.4.7 FIFO RAM Allocation

15.4.7.1 Data FIFO RAM Allocation

External RAM must be allocated among different FIFOs in the core before any transactions can start.

The application must follow this procedure every time it changes core FIFO RAM allocation.

The application must allocate data RAM per FIFO based on the AHB’s operating frequency, the PHY

Clock frequency, the available AHB bandwidth, and the performance required on the USB. Based on

the above mentioned criteria, the application must provide a table as described below with RAM sizes

for each FIFO in each mode.

The core shares a single FIFO RAM between transmit FIFO(s) and receive FIFO.

In DMA mode—The FIFO RAM is also used for storing the some register information.

The Device mode Endpoint DMA address registers (USB_DIEP0DMAADDR, USB_DOEP0DMAADDR,

USB_DIEPx_DMAADDR, USB_DOEPx_DMAADDR) and Host mode Channel DMA registers

(USB_HCx_DMAADDR) are stored in the FIFO RAM.

• These register information are stored at the end of the FIFO RAM after the space allocated for receive

and Transmit FIFO. These register space must also be taken into account when calculating the total

FIFO depth of the core as explained in the following sections.

The registers USB_DIEPx_DMAADDR/USB_DOEPx_DMAADDR are maintained in RAM.

The following rules apply while calculating how much RAM space must be allocated to store these

registers.

Host Mode:

• Slave mode only: No space needed.

• DMA mode: One location per channel.

Device Mode:

• Slave mode only: No space needed.

• DMA mode: One location per end point direction.

15.4.7.1.1 Device Mode

15.4.7.1.1.1 Tx FIFO Operation

When allocating data RAM for FIFOs in Device mode keep in mind these factors:

1. Receive FIFO RAM allocation:

• RAM for SETUP Packets: 4 * n + 6 locations must be Reserved in the receive FIFO to receive up

to n SETUP packets on control endpoints, where n is the number of control endpoints the device

core supports. The core does not use these locations, which are Reserved for SETUP packets,

to write any other data.

• One location for Global OUT NAK

• Status information is written to the FIFO along with each received packet. Therefore, a minimum

space of (Largest Packet Size / 4) + 1 must be allotted to receive packets. If a high-bandwidth

endpoint is enabled, or multiple isochronous endpoints are enabled, then at least two (Largest

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Packet Size / 4) + 1 spaces must be allotted to receive back-to-back packets. Typically, two (Largest

Packet Size / 4) + 1 spaces are recommended so that when the previous packet is being transferred

to AHB, the USB can receive the subsequent packet. If AHB latency is high, you must allocate

enough space to receive multiple packets. This is critical to prevent dropping any isochronous

packets.

• Along with each endpoint's last packet, transfer complete status information is also pushed to the

FIFO. Typically, one location for each OUT endpoint is recommended.

2. Transmit FIFO RAM Allocation:

The minimum RAM space required for each IN Endpoint Transmit FIFO is the maximum packet size

for that particular IN endpoint.

More space allocated in the transmit IN Endpoint FIFO results in a better performance on the USB

and can hide latencies on the AHB.

Table 15.3.

FIFO Name Data RAM Size

Receive data FIFO rx_fifo_size. This must include RAM for setup packets, OUT

endpoint control information and data OUT packets, as

mentioned earlier.

Transmit FIFO 0 tx_fifo_size[0]

Transmit FIFO 1 tx_fifo_size[1]

Transmit FIFO 2 tx_fifo_size[2]

... ...

Transmit FIFO i tx_fifo_size[i]

With this information, the following registers must be programmed as follows:

1. Receive FIFO Size Register (USB_GRXFSIZ)

USB_GRXFSIZ.Receive FIFO Depth = rx_fifo_size;

2. Device IN Endpoint Transmit FIFO0 Size Register (USB_GNPTXFSIZ)

USB_GNPTXFSIZ.non-periodic Transmit FIFO Depth = tx_fifo_size[0];

USB_GNPTXFSIZ.non-periodic Transmit RAM Start Address = rx_fifo_size;

3. Device IN Endpoint Transmit FIFO#1 Size Register (USB_DIEPTXF1)

USB_DIEPTXF1. Transmit RAM Start Address = USB_GNPTXFSIZ.FIFO0 Transmit RAM Start

Address + tx_fifo_size[0];

4. Device IN Endpoint Transmit FIFO#2 Size Register (USB_DIEPTXF2)

USB_DIEPTXF2.Transmit RAM Start Address = USB_DIEPTXF1.Transmit RAM Start Address +

tx_fifo_size[1];

5. Device IN Endpoint Transmit FIFO#i Size Register (USB_DIEPTXFi)

USB_DIEPTXFm.Transmit RAM Start Address = USB_DIEPTXFi-1.Transmit RAM Start Address +

tx_fifo_size[i-1];

6. The transmit FIFOs and receive FIFO must be flushed after the RAM allocation is done, for the proper

functioning of the FIFOs.

• USB_GRSTCTL.TXFNUM = 0x10

• USB_GRSTCTL.TXFFLSH = 1

• USB_GRSTCTL.RXFFLSH = 1

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The application must wait until the TXFFLSH bit and the RXFFLSH bits are cleared before performing

any operation on the core.

15.4.7.1.2 Host Mode

Considerations for allocating data RAM for Host Mode FIFOs are listed here:

Receive FIFO RAM allocation:

Status information is written to the FIFO along with each received packet. Therefore, a minimum space of

(Largest Packet Size / 4) + 2 must be allotted to receive packets. If a high-bandwidth channel is enabled,

or multiple isochronous channels are enabled, then at least two (Largest Packet Size / 4) + 2 spaces

must be allotted to receive back-to-back packets. Typically, two (Largest Packet Size / 4) + 2 spaces are

recommended so that when the previous packet is being transferred to AHB, the USB can receive the

subsequent packet. If AHB latency is high, you must allocate enough space to receive multiple packets.

Along with each host channel’s last packet, information on transfer complete status and channel halted

is also pushed to the FIFO. So two locations must be allocated for this.

For handling NAK in DMA mode, the application must determine the number of Control/Bulk OUT

endpoint data that must fit into the TX_FIFO at the same instant. Based on this, one location each is

required for Control/Bulk OUT endpoints.

For example, when the host addresses one Control OUT endpoint and three Bulk OUT endpoints, and

all these must fit into the non-periodic TX_FIFO at the same time, then four extra locations are required

in the RX FIFO to store the rewind status information for each of these endpoints.

Transmit FIFO RAM allocation

The minimum amount of RAM required for the Host Non-periodic Transmit FIFO is the largest maximum

packet size among all supported non-periodic OUT channels.

More space allocated in the Transmit Non-periodic FIFO results in better performance on the USB and

can hide AHB latencies. Typically, two Largest Packet Sizes’ worth of space is recommended, so that

when the current packet is under transfer to the USB, the AHB can get the next packet. If the AHB

latency is large, then you must allocate enough space to buffer multiple packets.

The minimum amount of RAM required for Host periodic Transmit FIFO is the largest maximum packet

size among all supported periodic OUT channels. If there is at lease one High Bandwidth Isochronous

OUT endpoint, then the space must be at least two times the maximum packet size of that channel.

15.4.7.1.2.1 Internal Register Storage Space Allocation

When operating in DMA mode, the DMA address register for each host channel (USB_HCx_DMAADDR)

is stored in the FIFO RAM. One location for each channel must be reserved for this.

Table 15.4.

FIFO Name Data RAM Size

Receive Data FIFO rx_fifo_size

Non-periodic Transmit FIFO tx_fifo_size[0]

IN Endpoint Transmit FIFO tx_fifo_size[1]

With this information, the following registers must be programmed:

1. Receive FIFO Size Register (USB_GRXFSIZ)

• USB_GRXFSIZ.RXFDEP = rx_fifo_size;

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2. Non-periodic Transmit FIFO Size Register (USB_GNPTXFSIZ)

• USB_GNPTXFSIZ.NPTXFDEP = tx_fifo_size[0];

• USB_GNPTXFSIZ.NPTXFSTADDR = rx_fifo_size;

3. Host Periodic Transmit FIFO Size Register (USB_HPTXFSIZ)

• USB_HPTXFSIZ.PTXFSIZE = tx_fifo_size[1];

• USB_HPTXFSIZ.PTXFSTADDR = USB_GNPTXFSIZ.NPTXFSTADDR + tx_fifo_size[0];

4. The transmit FIFOs and receive FIFO must be flushed after RAM allocation for proper FIFO function.

• USB_GRSTCTL.TXFNUM = 0x10

• USB_GRSTCTL.TXFFLSH = 1

• USB_GRSTCTL.RXFFLSH = 1

• The application must wait until the TXFFLSH bit and the RXFFLSH bits are cleared before

performing any operation on the core.

15.4.7.1.3 Summary of Guidelines for Choosing Data FIFO RAM Depth in Host Mode

15.4.7.1.3.1 RX FIFO size

The RX FIFO size must be equal to at least twice the largest value of MPS size used. The recommended

minimum RXFIFO depth = ((largest packet size/4)*2)+2. (+2) is required by the core for the status

quadlets internally.

15.4.7.1.3.2 Non periodic TX FIFO size

This should be equal to at least twice the largest value of MPS size used. The recommended minimum

non-periodic TXFIFO depth = ((largest packet size/4)*2).

15.4.7.1.3.3 Periodic TX FIFO size

The recommended size for Periodic TXFIFO is sum total of (MPS*MC)/4 for all the channels.

Note Note: In the above recommendations, always round off the MPS value to the nearest

multiple of 4. For example, if the largest value of MPS=125, use the rounded-off value,

which is 128.

15.4.7.1.4 Calculating the Total FIFO Size

The RxFIFO is shared between the host and device. The Host TxFIFOs are also shared with Device

IN endpoint TxFIFOs 0 through n.

There are three ways to calculate the total FIFO size.

Method 1

Use this method if you are using the following conditions:

• Minimum FIFO depth allocation

• The FIFO must equal at least one MaxPacketSize (MPS).

Device RxFIFO =

• (4 * number of control endpoints + 6) + ((largest USB packet used / 4) + 1 for status information) +

(2 * number of OUT endpoints) + 1 for Global NAK

Note Include the Control OUT endpoint in the number of OUT endpoints.

Host RxFIFO =

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• Slave mode

Minimum requirement: (largest USB packet used / 4) + 1 for status information + 1 transfer complete

• DMA mode

(largest USB packet used / 4) + 1 for status information + 1 transfer complete + 1 location each bulk/

control out endpoint for handling NAK scenario

Host Non-Periodic TxFIFO =

• largest non-periodic USB packet used / 4

Host Periodic TxFIFO =

• Sum total of (MPS*MC)/4 of all periodic channels or 1500 locations, whichever is lower.

Device IN Endpoint TxFIFOs (a separate FIFO is allocated to each IN endpoint) =

• IN Endpoints Max packet Size / 4

Method 2

Use this method if you are using the recommended minimum FIFO depth allocation with support for

high-bandwidth endpoints. This FIFO allocation enables the core to transfer a packet on the USB while

the previous (next) packet is simultaneously transferred to the AHB. This FIFO allocation improves the

core’s performance.

Device RxFIFO =

• (4 * number of control endpoints + 6) + 2 * ((largest USB packet used / 4) + 1) +(2 * number of OUT

endpoints) + 1

Host RxFIFO =

• Slave mode

2 * ((largest USB packet used / 4) + 1 + 1)

• DMA mode

2 * ((largest USB packet used / 4) + 1 + 1) + 1 location each bulk/control out endpoint for handling

NAK scenario

Host Non-Periodic TxFIFO =

• 2 * (largest non-periodic USB packet used / 4)

Host Periodic TxFIFO =

• Sum total of (MPS*MC)/4 for all periodic channels or 1500 location, whichever is lower.

Device IN Endpoint-Specific TxFIFOs (a separate FIFO is allocated to each endpoint) =

• 2 * (max_pkt_size for the endpoint) / 4.

//DMA mode

OTG Total RAM = (Device RxFIFO or Host RxFIFO; choose the largest one) +

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((Host Non-Periodic TxFIFO + Host peiodic TxFIFO) or

(Device IN Endpoint TxFIFO #0 + #1 + #2 + #n)); choose the largest one +

(1 location per Host channel or 1 location per Device Endpoint direction; choose

the largest one)

//Slave mode

OTG Total RAM = (Device RxFIFO or Host RxFIFO; choose the largest one) +

((Host Non-Periodic TxFIFO + Host peiodic TxFIFO) or

(Device IN Endpoint TxFIFO #0 + #1 + #2 + #n)); choose the largest one

Method 3

Use this method if you are using the recommended FIFO depth allocation that supports high-bandwidth

endpoints and high AHB latency.

Note • x = (AHB latency + time to transfer largest packet on AHB) / time to transfer largest

packet on USB.

• The value of x is an integer. Any fractional value is rounded to the nearest integer. For

example: x = 20 ms / 17,039 ms = 1.17 ms = 2 ms.

Device RxFIFO =

• (4 * number of control endpoints + 6) + (x + 1) * ((largest USB packet used / 4) + 1)+ (2 * number

of OUT endpoints) + 1

Note Include the Control OUT endpoint in the number of OUT endpoints.

Host RxFIFO =

• Slave mode

(x + 1) * ((largest USB packet used / 4) + 1 + 1)

• DMA mode

(x + 1) * ((largest USB packet used / 4) + 1 + 1) + 1 location each bulk/control out endpoint for handling

NAK scenario

Host Non-Periodic TxFIFO =

• (x + 1) * (largest non-periodic USB packet used / 4)

Host Periodic TxFIFO =

• (x+1) * (Sum total of (MPS*MC)/4 of all periodic channels or 1500 locations, whichever is lower).

Device IN Endpoint-Specific TxFIFOs (a separate FIFO is allocated to each endpoint) =

• (x+1)*(max_pkt_size for the endpoint)/4

//DMA mode

OTG Total RAM = (Device RxFIFO or Host RxFIFO; choose the largest one) +

((Host Non-Periodic TxFIFO + Host periodic TxFIFO) OR

(Device IN Endpoint TxFIFO #0 + #1 + #2 + #n); choose the largest one) +

(1 location per Host channel or 1 location per Device Endpoint direction; choose

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the largest one)

//Slave mode

OTG Total RAM = (Device RxFIFO or Host RxFIFO; choose the largest one) +

((Host Non-Periodic TxFIFO + Host periodic TxFIFO) OR

(Device IN Endpoint TxFIFO #0 + #1 + #2 + #n); choose the largest one)

15.4.7.2 Dynamic FIFO Allocation

The application can change the RAM allocation for each FIFO during the operation of the core.

15.4.7.2.1 Host Mode

In Host mode, before changing FIFO data RAM allocation, the application must determine the following.

All channels are disabled

• All FIFOs are empty

Once these conditions are met, the application can reallocate FIFO data RAM as explained in Data FIFO

RAM Allocation (p. 329) .

After reallocating the FIFO data RAM, the application must flush all FIFOs in the core using the

USB_GRSTCTL.TXFFLSH (TxFIFO Flush) and USB_GRSTCTL.RXFFLSH (RxFIFO Flush) fields.

Flushing is required to reset the pointers in the FIFOs for proper FIFO operation after reallocation. For

more information on flushing FIFOs, see Flushing TxFIFOs in the Core (p. 335) and Flushing RxFIFOs

in the Core (p. 336) .

15.4.7.2.2 Device Mode

In Device mode, before changing FIFO data RAM allocation, the application must determine the

following.

• All IN and OUT endpoints are disabled

• NAK mode is enabled in the core on all IN endpoints

• Global OUT NAK mode is enabled in the core

• All FIFOs are empty

Once these conditions are met, the application can reallocate FIFO data RAM as explained in Data FIFO

RAM Allocation (p. 329) . When NAK mode is enabled in the core, the core responds with a NAK

handshake on all tokens received on the USB, except for SETUP packets.

After the reallocating the FIFO data RAM, the application must flush all FIFOs in the core using

the USB_GRSTCTL.TXFFLSH (TxFIFO Flush) and USB_GRSTCTL.RXFFLSH (RxFIFO Flush) fields.

Flushing is required to reset the pointers in the FIFOs for proper FIFO operation after reallocation. For

more information on flushing FIFOs, see Flushing TxFIFOs in the Core (p. 335) and Flushing RxFIFOs

in the Core (p. 336) .

15.4.7.2.3 Flushing TxFIFOs in the Core

The application can flush all TxFIFOs in the core using USB_GRSTCTL.TXFFLSH as follows:

1. Check that USB_GINTSTS.GINNAKEFF=0. If this bit is cleared then set USB_DCTL.SGNPINNAK=1.

2. Wait for USB_GINTSTS.GINNAKEFF=1, which indicates the NAK setting has taken effect to all IN

endpoints.

3. Poll USB_GRSTCTL.AHBIDLE until it is 1.

AHBIdle = H indicates that the core is not writing anything to the FIFO.

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4. Check that USB_GRSTCTL.TXFFLSH =0. If it is 0, then write the TxFIFO number you want to flush

to USB_GRSTCTL.TXFNUM.

5. Set USB_GRSTCTL.TXFFLSH=1and wait for it to clear.

6. Set the USB_DCTL.GCNPINNAK bit.

15.4.7.2.4 Flushing RxFIFOs in the Core

The application can flush all RxFIFOs in the core using USB_GRSTCTL.RXFFLSH as follows:

1. Check the status of the USB_GINTSTS.GOUTNAKEFF bit. If it has been cleared, then set

USB_DCTL.SGOUTNAK=1. Else, clear USB_GINTSTS.GOUTNAKEFF.

NAK Effective interrupt = 1 indicates that the core is not writing to FIFO.

2. Wait for USB_GINTSTS.GOUTNAKEFF=1, which indicates the NAK setting has taken effect to all

OUT endpoints.

3. Poll the USB_GRSTCTL.AHBIDLE until it is 1.

AHBIDLE = 1 indicates that the core is not reading anything from the FIFO.

4. Set USB_GRSTCTL.RXFFLSH=1 and wait for it to clear.

5. Set the USB_DCTL.GCOUTNAK bit.

The Core Interrupt Handler

Figure 15.36. Core Interrupt Handler

otg_intr_ handler

Wait for interrupt

OTG

interrupt?

Read

USB_GINTSTS

Yes

Read

USB_GOTGCTL.

Generate OTG

software interrupt

Clear

interrupt

Host/

Device common

interrupt?

Yes Generate gobal

software interrupt

RTL

in Device

mode ?

Device

global

interrupt?

Host

global

interrupt?

YesNo

Clear interrupt

Generate host

global software

interrupt

Generate device

global software

interrupt

YesYes

No No

Host Port

Interrupt?

Read USB_HPRT

Generate port-

specific software

interrupt.

Yes

Read

USB_HAINT

Read USB_HCx_INT

Generate channel-

specific software

interrupt.

Read

USB_DAINT

IN endpoint

interrupt?

Read USB_DIEPx_INT

Generate IN-

endpoint- specific

software interrupt.

Yes

Read USB_DOEPx_INT

Generate OUT -

endpoint- specific

software interrupt.

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15.4.8 Suspend/Resume and SRP

This chapter describes different methods of saving power when the USB is suspended. This chapter

discusses the following topics:

• Placing PHY in Low Power Mode Without Entering Suspend (p. 337)

• When the Core is in Host Mode (p. 337)

• When the Core is in Device Mode (p. 338)

• Suspend (p. 338)

• Using EM2 (p. 338)

• Overview of the EM2 Programming Model (p. 338)

• Using EM2 when the Core is in Host Mode (p. 338)

• EM2 when the Core is in Device Mode (p. 341)

• Clock Gating (EM0 and EM1) (p. 343)

• Internal Clock Gating when the Core is in Host Mode (p. 343)

• Internal Clock Gating when the Core is in Device Mode (p. 344)

15.4.8.1 Placing PHY in Low Power Mode Without Entering Suspend

The core can place the PHY in low power mode (the differential receiver is disabled) without entering

suspend.

15.4.8.1.1 When the Core is in Host Mode

Programming flow for the Host Core to put PHY in low power mode

1. To turn off port power, perform write operation to set the following bits in the USB_HPRT register:

• USB_HPRT.PRTPWR = 0;

• USB_HPRT.PRTENA = 0;

2. To put PHY in low power mode, perform read-modify-write operation to set the following bits in the

USB_PCGCCTL register:

• USB_PCGCCTL.STOPPCLK = 1

• USB_PCGCCTL.GATEHCLK = 0

Programming flow for the Host Core to make PHY exit low power mode

If your device is non-SRP capable, the host must implement polling to detect the device connection by

turning on the port and exiting PHY low power mode periodically and checking for connect.

1. To turn on port power, perform write operation to set the following bits in the USB_HPRT register:

• USB_HPRT.PRTPWR = 1

• USB_HPRT.PRTENA = 0

2. To exit PHY low power mode, perform read-modify-write operation to set the following bits in the

USB_PCGCCTL register:

• USB_PCGCCTL.STOPPCLK = 0

• USB_PCGCCTL.STOPHCLK = 0

3. Wait for the USB_HPRT Port Connect Detected (PRTCONNDET) bit to be set and do the enumeration

of the device.

If your device is SRP-capable, when the device initiates SRP request, the Host core asynchronously

detects SRP and the PHY exits low power mode.

1. Wait for Session Request from the device, or New Session Detected Interrupt (SESSREQINT) in the

USB_GINTSTS register.

2. To turn on port power, perform write operation to set the following bits in the USB_HPRT register:

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• USB_HPRT.PRTPWR = 1

• USB_HPRT.PRTENA = 0

3. Wait for the USB_HPRT Port Connect Detected (PRTCONNDET) bit to be set and do the enumeration

of Device.

15.4.8.1.2 When the Core is in Device Mode

To make PHY enter low power mode, complete the following steps:

1. Ensure that the following signals are set as follows:

• VBUS voltage level must be below the session valid level (VBUS is not active)

• DP/DM must be SE0

2. From the application, perform read-modify-write operation to set USB_PCGCCTL.STOPPCLK = 1.

15.4.8.2 Suspend

When the core is in Suspend, the following power conservation options are available to use:

• Using EM2 (p. 338) : You can enter EM2, turning off power (and reseting) parts of the core

• Clock Gating (EM0 and EM1) (p. 343) : You can choose gate the AHB clock to some parts of the

core Internal Clock Gating when the Core is in Host Mode (p. 343)

This section discusses methods of conserving power by using one of the above methods.

15.4.8.2.1 Using EM2

15.4.8.2.1.1 Overview of the EM2 Programming Model

When the USB is suspended or the session is not valid, the PHY is driven into Suspend mode,

stopping the PHY clock to reduce power consumption in the PHY and the core. To further reduce power

consumption, the core also supports AHB clock gating and using EM2.

The following sections show the procedures you must follow to use EM2 while in suspend/session-off.

During EM2, the clock to the core must be switched to one of the 32 kHz sources (LFRCO or LFXO).

This core needs this clock to detect Resume and SRP events.

15.4.8.2.1.2 EM2 when the Core is in Host Mode

Host Mode Suspend in EM2

Sequence of operations:

1. Back up the essential registers of the core. Read and store the following core registers:

• USB_GINTMSK

• USB_GOTGCTL

• USB_GAHBCFG

• USB_GUSBCFG

• USB_GRXFSIZ

• USB_GNPTXFSIZ

• USB_DCFG

• USB_DCTL

• USB_DAINTMSK

• USB_DIEPMSK

• USB_DOEPMSK

• USB_DIEPx_CTL

• USB_DIEPx_TSIZ

• USB_DIEPx_DMAADDR

• USB_PCGCCTL

• USB_DIEPTXFn

2. The application sets the Port Suspend bit in the Host Port CSR, and the core drives a USB suspend.

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3. The application sets the Power Clamp bit in the Power and Clock Gating Control register.

4. The application sets the Reset to Power-Down Modules bit in the Power and Clock Gating Control

5. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register, the core

suspends the PHY and the PHY clock stops. If USB_HCFG.ENA32KHZS is set, switch the USBC

clock to 32 kHz.

6. Enter EM2.

Host Mode Resume in EM2

Sequence of operations:

1. The resume event starts by the application waking up from EM2 (on an interrupt)

2. Switch USBC clock back to 48 MHz.

3. The application clears the Stop PHY Clock bit and the core takes the PHY back to normal mode.

The PHY clock starts up.

4. The application clears the Power Clamp bit. The core starts driving Resume signaling on the USB.

5. The application clears the Reset to Power-Down Modules bit.

6. The application programs registers in the CSR and sets the Port Resume bit in Host Port CSR (Setting

the Port Resume bit is required by the core, although Resume signaling starts earlier).

7. The application clears the Port Resume bit and the core stops driving Resume signaling.

The core is in normal operating mode.

Note The application must insert delays of at least 2 PHY clocks between all steps in this

sequence. This requirement applies to all USB EM2 programming sequences.

Host Mode Remote Wakeup in EM2

Sequence of operations:

1. The core detects Remote Wakeup signaling on the USB. The PHY exits suspend mode and the PHY

clock restarts.

2. The core generates a Remote Wakeup Detected interrupt. The Remote Wakeup interrupt is generated

using the 32 kHz clock depending on the USB_HCFG.RESVALID (ResumeValidPeriod) programmed.

The Host Core starts resume signaling at this stage.

3. The USBC clock is switched back to normal 48 MHz clock.

4. The application clears the Stop PHY Clock bit.

5. The application clears the Power Clamp bit.

6. The application clears the Reset to Power-Down Modules bit

7. The application programs CSRs and sets the Port Resume bit. The core continues to drive Resume

signaling on the USB.

8. The application clears the Port Resume bit and the core stops driving Resume signaling.

The core enters normal operating mode.

Host Mode Session End in EM2

Sequence of operations:

1. Back up the essential registers of the core. Read and store the following core registers:

• USB_GINTMSK

• USB_GOTGCTL • USB_DCTL

• USB_DAINTMSK

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• USB_GAHBCFG

• USB_GUSBCFG

• USB_GRXFSIZ

• USB_GNPTXFSIZ

• USB_DCFG

• USB_DIEPMSK

• USB_DOEPMSK

• USB_DIEPx_CTL

• USB_DIEPx_TSIZ

• USB_DIEPx_DMAADDR

• USB_PCGCCTL

• USB_DIEPTXFn

2. The application sets the Port Suspend bit in the Host Port CSR and the core drives a USB suspend.

3. The application clears the Port Power bit.

4. The application sets the Power Clamp bit in the Power and Clock Gating Control register, and the

core clamps the signals between the internal modules on different power rails.

5. The application sets the Reset to Power-Down Modules bit in the Power and Clock Gating Control

6. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register, and the

core suspends the PHY, stopping the PHY clock.

7. Switch USBC clock to 32 kHz.

8. Enter EM2.

Host Mode Session Start (EM2 -> EM0)

Sequence of operations:

1. Exit EM2/Enter EM0).

2. Switch USBC clock back to 48 MHz.

3. The application clears the Stop PHY Clock bit.

4. The application clears the Power Clamp bit. The application clears the Reset to Power-Down Modules

bit.

5. The application programs CSRs and sets the Port Power bit to turn on VBUS.

6. The core detects the connection and drives the USB reset.

The core enters normal operating mode.

Host Mode Session End (EM0 -> EM2)

Sequence of operations:

1. Back up the essential registers of the core. Read and store the following core registers:

• USB_GINTMSK

• USB_GOTGCTL

• USB_GAHBCFG

• USB_GUSBCFG

• USB_GRXFSIZ

• USB_GNPTXFSIZ

• USB_DCFG

• USB_DCTL

• USB_DAINTMSK

• USB_DIEPMSK

• USB_DOEPMSK

• USB_DIEPx_CTL

• USB_DIEPx_TSIZ

• USB_DIEPx_DMAADDR

• USB_PCGCCTL

• USB_DIEPTXFn

2. The application sets the Port Suspend bit in the Host Port CSR and the core drives a USB suspend.

3. The application clears the Port Power bit.

4. The application sets the Power Clamp bit in the Power and Clock Gating Control register, and the

core clamps the signals between the internal modules on different power rails.

5. The application sets the Reset to Power-Down Modules bit in the Power and Clock Gating Control

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6. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register.

7. Enter EM2.

Host Mode Sessions Start (SRP) (EM2 -> EM0)

Sequence of operations:

1. The core detects SRP (data line pulsing) on the bus. The core de-asserts the suspend_n signal to

the PHY, generating the PHY clock. The SRP Detected interrupt is generated.

2. The application clears the Stop PHY Clock bit, the core deasserts the suspend_n signal to the PHY

to generate the PHY clock.

3. The power (VDD_DN) is turned on and stabilizes.

4. The application clears the Power Clamp bit.

5. The application clears the Reset to Power-Down Modules bit.

6. The application programs the CSRs, and sets the Port Power bit to turn on VBUS.

7. The core detects device connection and drives a USB reset.

The core enters normal operating mode.

15.4.8.2.1.3 EM2 when the Core is in Device Mode

Device Mode Suspend With EM2

In Device mode, the device validates the host-driven Resume signal for a period of 1.5 µs (75 clock

cycles at 48 MHz). With a 32-KHz clock, 2.34 ms is required (75 clock cycles at 32 KHz) to detect the

resume. Hence, the application programs USB_DCFG.RESVALID with a value of 4 clock cycles (125

µs). If the core is in Suspend mode, the device thus detects the resume and the host signals a resume

for a minimum of 125 µs.

If the device is being reset from suspend, it begins a high-speed detection handshake after detecting

SE0 for no fewer than 2.5 µs. With a 48-MHz clock, detection occurs after 120 clock cycles (2.5 µs).

With a 32-kHz clock, 120 clock cycles signifies 3.75 msec. Hence, a programmable value of 4 clock

cycles (125 µs) is used to detect reset.

The 32-KHz Suspend feature incorporates switching to the 32-KHz clock during suspend and resume/

remote wakeup until the system comes up and starts driving 48 MHz.

Sequence of operations:

1. Detect Suspend state. Wait for an interrupt from the device core and check that

USB_GINTSTS.USBSUSP is set to 1.

2. Back up the essential registers of the core. Read and store the following core registers:

• USB_GINTMSK

• USB_GOTGCTL

• USB_GAHBCFG

• USB_GUSBCFG

• USB_GRXFSIZ

• USB_GNPTXFSIZ

• USB_DCFG

• USB_DCTL

• USB_DAINTMSK

• USB_DIEPMSK

• USB_DOEPMSK

• USB_DIEPx_CTL

• USB_DIEPx_TSIZ

• USB_DIEPx_DMAADDR

• USB_PCGCCTL

• USB_DIEPTXFn

3. The application sets the PWRCLMP bit in the Power and Clock Gating Control (USB_PCGCCTL)

4. The application sets the USB_PCGCCTL.RSTPDWNMODULE bit.

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5. The application sets the USB_PCGCCTL.STOPPCLK bit.

6. Switch USB Core Clock (USBC) to 32 kHz.

7. Enter EM2.

Device Mode Resume (EM2 -> EM0)

Sequence if operations:

1. The core detects Resume signaling on the USB. The core generates a Resume Detected interrupt.

2. Switch USB Core Clock (USBC) back to 48 MHz.

3. The application clears the STOPPCLK bit.

4. The application clears the USB_PCGCCTL.PWRCLMP and USB_PCGCCTL.RSTPDWNMODULE

bits.

5. Restore the USB_GUSBCFG and USB_DCFG registers with the values stored during the Save

operation before entering EM2.

6. Restore the following core registers with the values stored during the Save operation before entering

EM2:

• USB_GINTMSK

• USB_GOTGCTL

• USB_GUSBCFG

• USB_GRXFSIZ

• USB_GNPTXFSIZ

• USB_DAINTMSK

• USB_DIEPMSK

• USB_DOEPMSK

• USB_DIEPx_CTL

• USB_DIEPx_TSIZ

• USB_DIEPx_DMAADDR

• USB_DIEPTXFn

7. The application programs CSRs, then sets the Power-On Programming Done bit in the Device Control

Device Mode Remote Wakeup (EM2 -> EM0)

Sequence if operations:

1. An interrupt wakes up the device from EM2.

2. Switch USB Core Clock (USBC) back to 48 MHz.

3. The application clears the STOPPCLK and GATEHCLK bits in the USB_PCGCCTL register.

4. The application clears the USB_PCGCCTL.PWRCLMP and USB_PCGCCTL.RSTPDWNMODULE

bits.

5. Restore the USB_GUSBCFG and USB_DCFG registers with the values stored during the Save

operation before entering EM2 .

6. Drive remote wakeup from the core. Program USB_DCTL by performing write-only operation with the

following values:

• USB_DCTL.RMTWKUPSIG = 1

• Other Bits = Value stored during the Save operation before entering EM2

7. Clear all interrupt status. Wait for at least 1 millisecond of remote wakeup time and then program

GINSTS register with 0xFFFFFFFF to clear all the status register fields.

8. Restore the following core registers with the values stored during the Save operation before entering

EM2:

• USB_GINTMSK

• USB_GOTGCTL

• USB_GUSBCFG

• USB_GRXFSIZ

• USB_GNPTXFSIZ

• USB_DAINTMSK

• USB_DIEPMSK

• USB_DOEPMSK

• USB_DIEPx_CTL

• USB_DIEPx_TSIZ

• USB_DIEPx_DMAADDR

• USB_DIEPTXFn

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9. Wait for remote wakeup time (1-15ms) and then program USB_DCTL by performing read-modify-

write to set USB_DCTL.RMTWKUPSIG = 0.

Device Mode Session End (EM0 -> EM2)

Sequence of operations:

1. The core detects a USB suspend and generates a Suspend Detected interrupt. The host turns off

VBUS.

2. The application sets the Power Clamp bit in the Power and Clock Gating Control register.

3. The application sets the Reset to Power-Down Modules bit in the Power and Clock Gating Control

4. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register.

5. Switch USB Core clock (USBC) to 32 kHz.

6. Enter EM2.

Device Mode Session Start (EM2 -> EM0)

Sequence of operations:

1. The core detects VBUS on (voltage level within session-valid). A New Session Detected interrupt is

generated.

2. Switch USB Core clock (USBC) back to 48 MHz.

3. The application clears the Stop PHY Clock bit.

4. The application clears the Power Clamp bit.

5. The application clears the Reset to Power-Down Modules bit.

6. The application programs CSRs.

7. The cores detects a USB reset.

The core enters normal operating mode.

15.4.8.2.2 Using Clock Gating in EM0/EM1

The core supports HCLK gating to reduce dynamic power to internal modules to the core during Suspend/

session-off state in EM0 and EM1.

15.4.8.2.2.1 Internal Clock Gating when the Core is in Host Mode

The following sections show the procedures you must follow to use the clock gating feature.

Host Mode Suspend and Resume With Clock Gating

Sequence of operations:

1. The application sets the Port Suspend bit in the Host Port CSR, and the core drives a USB suspend.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, the core gates the

hclk internally.

3. The core remains in Suspend mode.

4. The application clears the Gate hclk and Stop PHY Clock bits, and the PHY clock is generated.

5. The application sets the Port Resume bit, and the core starts driving Resume signaling.

6. The application clears the Port Resume bit after at least 20 ms.

7. The core is in normal operating mode.

Host Mode Suspend and Remote Wakeup With Clock Gating

Sequence of operations:

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1. The application sets the Port Suspend bit in the Host Port CSR, and the core drives a USB suspend.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, and the core gates

hclk internally.

3. The core remains in Suspend mode

4. The Remote Wakeup signaling from the device is detected. The core generates a Remote Wakeup

Detected interrupt.

5. The application clears the Gate hclk and Stop PHY Clock bits. The core sets the Port Resume bit.

6. The application clears the Port Resume bit after at least 20 ms.

7. The core is in normal operating mode.

Host Mode Session End and Start With Clock Gating

Sequence of operations:

1. The application sets the Port Suspend bit in the Host Port CSR, and the core drives a USB suspend.

2. The application clears the Port Power bit. The core turns off VBUS.

3. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, and the core gates

hclk internally.

4. The core remains in Low-Power mode.

5. The application clears the Gate hclk bit and the application clears the Stop PHY Clock bit to start

the PHY clock.

6. The application sets the Port Power bit to turn on VBUS.

7. The core detects device connection and drives a USB reset.

8. The core is in normal operating mode.

Host Mode Session End and SRP With Clock Gating

Sequence of operations:

1. The application sets the Port Suspend bit in the Host Port CSR, and the core drives a USB suspend.

2. The application clears the Port Power bit. The core turns off VBUS.

3. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, and the core gates

hclk internally.

4. The core remains in Low-Power mode.

5. SRP (data line pulsing) from the device is detected. An SRP Request Detected interrupt is generated.

6. The application clears the Gate hclk bit and the Stop PHY Clock bit.

7. The core sets the Port Power bit to turn on VBUS.

8. The core detects device connection and drives a USB reset.

9. The core is in normal operating mode.

15.4.8.2.2.2 Internal Clock Gating when the Core is in Device Mode

The following sections show the procedures you must follow to use the clock gating feature.

Device Mode Suspend and Resume With Clock Gating

Sequence of operations:

1. The core detects a USB suspend and generates a Suspend Detected interrupt.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, and the core gates

hclk.

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3. The core remains in Suspend mode.

4. The Resume signaling from the host is detected. A Resume Detected interrupt is generated.

5. The application clears the Gate hclk bit and the Stop PHY Clock bit.

6. The host finishes Resume signaling.

7. The core is in normal operating mode.

Device Mode Suspend and Remote Wakeup With Clock Gating

Sequence of operations:

1. The core detects a USB suspend and generates a Suspend Detected interrupt.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, the core gates hclk.

3. The core remains in Suspend mode.

4. The application clears the Gate hclk bit and the Stop PHY Clock bit.

5. The application sets the Remote Wakeup bit in the Device Control register, the core starts driving

Remote Wakeup signaling.

6. The host drives Resume signaling.

7. The core is in normal operating mode.

Device Mode Session End and Start With Clock Gating

Sequence of operations:

1. The core detects a USB suspend, and generates a Suspend Detected interrupt. The host turns off

VBUS.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, and the core gates

hclk.

3. The core remains in Low-Power mode.

4. The new session is detected (A session-valid voltage is detected). A New Session Detected interrupt

is generated.

5. The application clears the Gate hclk and Stop PHY Clock bits.

6. The core detects USB reset.

7. The core is in normal operating mode

Device Mode Session End and SRP With Clock Gating

Sequence of operations:

1. The core detects a USB suspend, and generates a Suspend Detected interrupt. The host turns off

VBUS.

2. The application sets the Stop PHY Clock bit in the Power and Clock Gating Control register. The

application sets the Gate hclk bit in the Power and Clock Gating Control register, and the core gates

hclk.

3. The core remains in Low-Power mode.

4. The application clears the Gate hclk and Stop PHY Clock bits.

5. The application sets the SRP Request bit, and the core drives data line and VBUS pulsing.

6. The host turns on VBUS, detects device connection, and drives a USB reset.

7. The core is in normal operating mode.

15.4.9 Register Usage

Only the Core Global, Power and Clock Gating, Data FIFO Access, and Host Port registers can be

accessed in both Host and Device modes. When the core is operating in one mode, either Device or

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Host, the application must not access registers from the other mode. If an illegal access occurs, a Mode

Mismatch interrupt is generated and reflected in the Core Interrupt register (USB_GINTSTS.MODEMIS).

When the core switches from one mode to another, the registers in the new mode must be reprogrammed

as they would be after a power-on reset.

The memory map for the core is as follows:

• Core Global Registers are located in the address offset-range [0x3C000, 0x3C3FF] and typically start

with first letter G.

• Host Mode Registers are located in the address offset-range [0x3C400, 0x3C7FF] and start with first

letter H.

• Device Mode Registers are located in the address offset-range [0x3C800, 0x3CDFF] and start with

first letter D.

• The Power and Clock Gating register is located at offset 0x3CE00.

• The Device EP/Host Channel FIFOs start at address offset 0x3D000 with 4K spacing. These registers,

available in both Host and Device modes, are used to read or write the FIFO space for a specific

endpoint or a channel, in a given direction. If a host channel is of type IN, the FIFO can only be read on

the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

• The Direct RAM Access area start at address offset 0x5C000.

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15.5 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 USB_CTRL RW System Control Register

0x004 USB_STATUS R System Status Register

0x008 USB_IF R Interrupt Flag Register

0x00C USB_IFS W1 Interrupt Flag Set Register

0x010 USB_IFC W1 Interrupt Flag Clear Register

0x014 USB_IEN RW Interrupt Enable Register

0x018 USB_ROUTE RW I/O Routing Register

0x3C000 USB_GOTGCTL RWH OTG Control and Status Register

0x3C004 USB_GOTGINT RW1H OTG Interrupt Register

0x3C008 USB_GAHBCFG RW AHB Configuration Register

0x3C00C USB_GUSBCFG RWH USB Configuration Register

0x3C010 USB_GRSTCTL RWH Reset Register

0x3C014 USB_GINTSTS RWH Interrupt Register

0x3C018 USB_GINTMSK RW Interrupt Mask Register

0x3C01C USB_GRXSTSR R Receive Status Debug Read Register

0x3C020 USB_GRXSTSP R Receive Status Read and Pop Register

0x3C024 USB_GRXFSIZ RW Receive FIFO Size Register

0x3C028 USB_GNPTXFSIZ RW Non-periodic Transmit FIFO Size Register

0x3C02C USB_GNPTXSTS R Non-periodic Transmit FIFO/Queue Status Register

0x3C05C USB_GDFIFOCFG RW Global DFIFO Configuration Register

0x3C100 USB_HPTXFSIZ RW Host Periodic Transmit FIFO Size Register

0x3C104 USB_DIEPTXF1 RW Device IN Endpoint Transmit FIFO 1 Size Register

0x3C108 USB_DIEPTXF2 RW Device IN Endpoint Transmit FIFO 2 Size Register

0x3C10C USB_DIEPTXF3 RW Device IN Endpoint Transmit FIFO 3 Size Register

0x3C110 USB_DIEPTXF4 RW Device IN Endpoint Transmit FIFO 4 Size Register

0x3C114 USB_DIEPTXF5 RW Device IN Endpoint Transmit FIFO 5 Size Register

0x3C118 USB_DIEPTXF6 RW Device IN Endpoint Transmit FIFO 6 Size Register

0x3C400 USB_HCFG RW Host Configuration Register

0x3C404 USB_HFIR RW Host Frame Interval Register

0x3C408 USB_HFNUM R Host Frame Number/Frame Time Remaining Register

0x3C410 USB_HPTXSTS R Host Periodic Transmit FIFO/Queue Status Register

0x3C414 USB_HAINT R Host All Channels Interrupt Register

0x3C418 USB_HAINTMSK RW Host All Channels Interrupt Mask Register

0x3C440 USB_HPRT RWH Host Port Control and Status Register

0x3C500 USB_HC0_CHAR RWH Host Channel x Characteristics Register

0x3C508 USB_HC0_INT RW1H Host Channel x Interrupt Register

0x3C50C USB_HC0_INTMSK RW Host Channel x Interrupt Mask Register

0x3C510 USB_HC0_TSIZ RW Host Channel x Transfer Size Register

0x3C514 USB_HC0_DMAADDR RW Host Channel x DMA Address Register

... USB_HCx_CHAR RWH Host Channel x Characteristics Register

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Offset Name Type Description

... USB_HCx_INT RW1H Host Channel x Interrupt Register

... USB_HCx_INTMSK RW Host Channel x Interrupt Mask Register

... USB_HCx_TSIZ RW Host Channel x Transfer Size Register

... USB_HCx_DMAADDR RW Host Channel x DMA Address Register

0x3C6A0 USB_HC13_CHAR RWH Host Channel x Characteristics Register

0x3C6A8 USB_HC13_INT RW1H Host Channel x Interrupt Register

0x3C6AC USB_HC13_INTMSK RW Host Channel x Interrupt Mask Register

0x3C6B0 USB_HC13_TSIZ RW Host Channel x Transfer Size Register

0x3C6B4 USB_HC13_DMAADDR RW Host Channel x DMA Address Register

0x3C800 USB_DCFG RW Device Configuration Register

0x3C804 USB_DCTL RWH Device Control Register

0x3C808 USB_DSTS R Device Status Register

0x3C810 USB_DIEPMSK RW Device IN Endpoint Common Interrupt Mask Register

0x3C814 USB_DOEPMSK RW Device OUT Endpoint Common Interrupt Mask Register

0x3C818 USB_DAINT R Device All Endpoints Interrupt Register

0x3C81C USB_DAINTMSK RW Device All Endpoints Interrupt Mask Register

0x3C828 USB_DVBUSDIS RW Device VBUS Discharge Time Register

0x3C82C USB_DVBUSPULSE RW Device VBUS Pulsing Time Register

0x3C834 USB_DIEPEMPMSK RW Device IN Endpoint FIFO Empty Interrupt Mask Register

0x3C900 USB_DIEP0CTL RWH Device IN Endpoint 0 Control Register

0x3C908 USB_DIEP0INT RWH Device IN Endpoint 0 Interrupt Register

0x3C910 USB_DIEP0TSIZ RW Device IN Endpoint 0 Transfer Size Register

0x3C914 USB_DIEP0DMAADDR RW Device IN Endpoint 0 DMA Address Register

0x3C918 USB_DIEP0TXFSTS R Device IN Endpoint 0 Transmit FIFO Status Register

0x3C920 USB_DIEP0_CTL RWH Device IN Endpoint x+1 Control Register

0x3C928 USB_DIEP0_INT RWH Device IN Endpoint x+1 Interrupt Register

0x3C930 USB_DIEP0_TSIZ RW Device IN Endpoint x+1 Transfer Size Register

0x3C934 USB_DIEP0_DMAADDR RW Device IN Endpoint x+1 DMA Address Register

0x3C938 USB_DIEP0_TXFSTS R Device IN Endpoint x+1 Transmit FIFO Status Register

0x3C940 USB_DIEP1_CTL RWH Device IN Endpoint x+1 Control Register

0x3C948 USB_DIEP1_INT RWH Device IN Endpoint x+1 Interrupt Register

0x3C950 USB_DIEP1_TSIZ RW Device IN Endpoint x+1 Transfer Size Register

0x3C954 USB_DIEP1_DMAADDR RW Device IN Endpoint x+1 DMA Address Register

0x3C958 USB_DIEP1_TXFSTS R Device IN Endpoint x+1 Transmit FIFO Status Register

0x3C960 USB_DIEP2_CTL RWH Device IN Endpoint x+1 Control Register

0x3C968 USB_DIEP2_INT RWH Device IN Endpoint x+1 Interrupt Register

0x3C970 USB_DIEP2_TSIZ RW Device IN Endpoint x+1 Transfer Size Register

0x3C974 USB_DIEP2_DMAADDR RW Device IN Endpoint x+1 DMA Address Register

0x3C978 USB_DIEP2_TXFSTS R Device IN Endpoint x+1 Transmit FIFO Status Register

0x3C980 USB_DIEP3_CTL RWH Device IN Endpoint x+1 Control Register

0x3C988 USB_DIEP3_INT RWH Device IN Endpoint x+1 Interrupt Register

0x3C990 USB_DIEP3_TSIZ RW Device IN Endpoint x+1 Transfer Size Register

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Offset Name Type Description

0x3C994 USB_DIEP3_DMAADDR RW Device IN Endpoint x+1 DMA Address Register

0x3C998 USB_DIEP3_TXFSTS R Device IN Endpoint x+1 Transmit FIFO Status Register

0x3C9A0 USB_DIEP4_CTL RWH Device IN Endpoint x+1 Control Register

0x3C9A8 USB_DIEP4_INT RWH Device IN Endpoint x+1 Interrupt Register

0x3C9B0 USB_DIEP4_TSIZ RW Device IN Endpoint x+1 Transfer Size Register

0x3C9B4 USB_DIEP4_DMAADDR RW Device IN Endpoint x+1 DMA Address Register

0x3C9B8 USB_DIEP4_TXFSTS R Device IN Endpoint x+1 Transmit FIFO Status Register

0x3C9C0 USB_DIEP5_CTL RWH Device IN Endpoint x+1 Control Register

0x3C9C8 USB_DIEP5_INT RWH Device IN Endpoint x+1 Interrupt Register

0x3C9D0 USB_DIEP5_TSIZ RW Device IN Endpoint x+1 Transfer Size Register

0x3C9D4 USB_DIEP5_DMAADDR RW Device IN Endpoint x+1 DMA Address Register

0x3C9D8 USB_DIEP5_TXFSTS R Device IN Endpoint x+1 Transmit FIFO Status Register

0x3CB00 USB_DOEP0CTL RWH Device OUT Endpoint 0 Control Register

0x3CB08 USB_DOEP0INT RWH Device OUT Endpoint 0 Interrupt Register

0x3CB10 USB_DOEP0TSIZ RW Device OUT Endpoint 0 Transfer Size Register

0x3CB14 USB_DOEP0DMAADDR RW Device OUT Endpoint 0 DMA Address Register

0x3CB20 USB_DOEP0_CTL RWH Device OUT Endpoint x+1 Control Register

0x3CB28 USB_DOEP0_INT RWH Device OUT Endpoint x+1 Interrupt Register

0x3CB30 USB_DOEP0_TSIZ RWH Device OUT Endpoint x+1 Transfer Size Register

0x3CB34 USB_DOEP0_DMAADDR RW Device OUT Endpoint x+1 DMA Address Register

0x3CB40 USB_DOEP1_CTL RWH Device OUT Endpoint x+1 Control Register

0x3CB48 USB_DOEP1_INT RWH Device OUT Endpoint x+1 Interrupt Register

0x3CB50 USB_DOEP1_TSIZ RWH Device OUT Endpoint x+1 Transfer Size Register

0x3CB54 USB_DOEP1_DMAADDR RW Device OUT Endpoint x+1 DMA Address Register

0x3CB60 USB_DOEP2_CTL RWH Device OUT Endpoint x+1 Control Register

0x3CB68 USB_DOEP2_INT RWH Device OUT Endpoint x+1 Interrupt Register

0x3CB70 USB_DOEP2_TSIZ RWH Device OUT Endpoint x+1 Transfer Size Register

0x3CB74 USB_DOEP2_DMAADDR RW Device OUT Endpoint x+1 DMA Address Register

0x3CB80 USB_DOEP3_CTL RWH Device OUT Endpoint x+1 Control Register

0x3CB88 USB_DOEP3_INT RWH Device OUT Endpoint x+1 Interrupt Register

0x3CB90 USB_DOEP3_TSIZ RWH Device OUT Endpoint x+1 Transfer Size Register

0x3CB94 USB_DOEP3_DMAADDR RW Device OUT Endpoint x+1 DMA Address Register

0x3CBA0 USB_DOEP4_CTL RWH Device OUT Endpoint x+1 Control Register

0x3CBA8 USB_DOEP4_INT RWH Device OUT Endpoint x+1 Interrupt Register

0x3CBB0 USB_DOEP4_TSIZ RWH Device OUT Endpoint x+1 Transfer Size Register

0x3CBB4 USB_DOEP4_DMAADDR RW Device OUT Endpoint x+1 DMA Address Register

0x3CBC0 USB_DOEP5_CTL RWH Device OUT Endpoint x+1 Control Register

0x3CBC8 USB_DOEP5_INT RWH Device OUT Endpoint x+1 Interrupt Register

0x3CBD0 USB_DOEP5_TSIZ RWH Device OUT Endpoint x+1 Transfer Size Register

0x3CBD4 USB_DOEP5_DMAADDR RW Device OUT Endpoint x+1 DMA Address Register

0x3CE00 USB_PCGCCTL RWH Power and Clock Gating Control Register

0x3D000 USB_FIFO0D0 RW Device EP 0/Host Channel 0 FIFO

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Offset Name Type Description

... USB_FIFO0Dx RW Device EP 0/Host Channel 0 FIFO

0x3D7FC USB_FIFO0D511 RW Device EP 0/Host Channel 0 FIFO

0x3E000 USB_FIFO1D0 RW Device EP 1/Host Channel 1 FIFO

... USB_FIFO1Dx RW Device EP 1/Host Channel 1 FIFO

0x3E7FC USB_FIFO1D511 RW Device EP 1/Host Channel 1 FIFO

0x3F000 USB_FIFO2D0 RW Device EP 2/Host Channel 2 FIFO

... USB_FIFO2Dx RW Device EP 2/Host Channel 2 FIFO

0x3F7FC USB_FIFO2D511 RW Device EP 2/Host Channel 2 FIFO

0x40000 USB_FIFO3D0 RW Device EP 3/Host Channel 3 FIFO

... USB_FIFO3Dx RW Device EP 3/Host Channel 3 FIFO

0x407FC USB_FIFO3D511 RW Device EP 3/Host Channel 3 FIFO

0x41000 USB_FIFO4D0 RW Device EP 4/Host Channel 4 FIFO

... USB_FIFO4Dx RW Device EP 4/Host Channel 4 FIFO

0x417FC USB_FIFO4D511 RW Device EP 4/Host Channel 4 FIFO

0x42000 USB_FIFO5D0 RW Device EP 5/Host Channel 5 FIFO

... USB_FIFO5Dx RW Device EP 5/Host Channel 5 FIFO

0x427FC USB_FIFO5D511 RW Device EP 5/Host Channel 5 FIFO

0x43000 USB_FIFO6D0 RW Device EP 6/Host Channel 6 FIFO

... USB_FIFO6Dx RW Device EP 6/Host Channel 6 FIFO

0x437FC USB_FIFO6D511 RW Device EP 6/Host Channel 6 FIFO

0x44000 USB_FIFO7D0 RW Host Channel 7 FIFO

... USB_FIFO7Dx RW Host Channel 7 FIFO

0x447FC USB_FIFO7D511 RW Host Channel 7 FIFO

0x45000 USB_FIFO8D0 RW Host Channel 8 FIFO

... USB_FIFO8Dx RW Host Channel 8 FIFO

0x457FC USB_FIFO8D511 RW Host Channel 8 FIFO

0x46000 USB_FIFO9D0 RW Host Channel 9 FIFO

... USB_FIFO9Dx RW Host Channel 9 FIFO

0x467FC USB_FIFO9D511 RW Host Channel 9 FIFO

0x47000 USB_FIFO10D0 RW Host Channel 10 FIFO

... USB_FIFO10Dx RW Host Channel 10 FIFO

0x477FC USB_FIFO10D511 RW Host Channel 10 FIFO

0x48000 USB_FIFO11D0 RW Host Channel 11 FIFO

... USB_FIFO11Dx RW Host Channel 11 FIFO

0x487FC USB_FIFO11D511 RW Host Channel 11 FIFO

0x49000 USB_FIFO12D0 RW Host Channel 12 FIFO

... USB_FIFO12Dx RW Host Channel 12 FIFO

0x497FC USB_FIFO12D511 RW Host Channel 12 FIFO

0x4A000 USB_FIFO13D0 RW Host Channel 13 FIFO

... USB_FIFO13Dx RW Host Channel 13 FIFO

0x4A7FC USB_FIFO13D511 RW Host Channel 13 FIFO

0x5C000 USB_FIFORAM0 RW Direct Access to Data FIFO RAM for Debugging (2 KB)

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Offset Name Type Description

... USB_FIFORAMx RW Direct Access to Data FIFO RAM for Debugging (2 KB)

0x5C7FC USB_FIFORAM511 RW Direct Access to Data FIFO RAM for Debugging (2 KB)

15.6 Register Description

15.6.1 USB_CTRL - System Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

BIASPROGEM23

BIASPROGEM01

VREGOSEN

VREGDIS

DMPUAP

VBUSENAP

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:24 BIASPROGEM23 0x0 RW Regulator Bias Programming Value in EM2/3

Regulator bias current setting in EM2/3 (i.e. while USB in suspend).

23:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:20 BIASPROGEM01 0x0 RW Regulator Bias Programming Value in EM0/1

Regulator bias current setting in EM0/1 (i.e. while USB active).

19:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 VREGOSEN 0 RW VREGO Sense Enable

Set this bit to enable USB_VREGO voltage level sensing.

16 VREGDIS 0 RW Voltage Regulator Disable

Set this bit to disable the voltage regulator.

15:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 DMPUAP 0 RW DMPU Active Polarity

Use this bit to select the active polarity of the USB_DMPU pin.

Value Mode Description

0 LOW USB_DMPU is active low.

1 HIGH USB_DMPU is active high.

0 VBUSENAP 0 RW VBUSEN Active Polarity

Use this bit to select the active polarity of the USB_VBUSEN pin.

Value Mode Description

0 LOW USB_VBUSEN is active low.

1 HIGH USB_VBUSEN is active high.

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15.6.2 USB_STATUS - System Status Register

Offset Bit Position

0x004

Reset

Access

Name

VREGOS

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 VREGOS 0 R VREGO Sense Output

USB_VREGO Voltage Sense output. 0 when no USB_VREGO voltage, 1 when USB_VREGO above approximately 1.8 V. Always

0 when VREGOSEN in USB_CTRL is 0.

15.6.3 USB_IF - Interrupt Flag Register

Offset Bit Position

0x008

Reset

Access

Name

VREGOSL

VREGOSH

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 VREGOSL 1 R VREGO Sense Low Interrupt Flag

Set when USB_VREGO drops below approximately 1.8 V.

0 VREGOSH 1 R VREGO Sense High Interrupt Flag

Set when USB_VREGO goes above approximately 1.8 V.

15.6.4 USB_IFS - Interrupt Flag Set Register

Offset Bit Position

0x00C

Reset

Access

Name

VREGOSL

VREGOSH

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

1 VREGOSL 0 W1 Set VREGO Sense Low Interrupt Flag

Write to 1 to set the VREGO Sense Low Interrupt Flag.

0 VREGOSH 0 W1 Set VREGO Sense High Interrupt Flag

Write to 1 to set the VREGO Sense High Interrupt Flag.

15.6.5 USB_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x010

Reset

Access

Name

VREGOSL

VREGOSH

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 VREGOSL 0 W1 Clear VREGO Sense Low Interrupt Flag

Write to 1 to clear the VREGO Sense Low Interrupt Flag.

0 VREGOSH 0 W1 Clear VREGO Sense High Interrupt Flag

Write to 1 to clear the VREGO Sense High Interrupt Flag.

15.6.6 USB_IEN - Interrupt Enable Register

Offset Bit Position

0x014

Reset

Access

Name

VREGOSL

VREGOSH

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 VREGOSL 0 RW VREGO Sense Low Interrupt Enable

Enable interrupt on VREGO Sense Low.

0 VREGOSH 0 RW VREGO Sense High Interrupt Enable

Enable interrupt on VREGO Sense High.

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15.6.7 USB_ROUTE - I/O Routing Register

Offset Bit Position

0x018

Reset

Access

Name

DMPUPEN

VBUSENPEN

PHYPEN

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 DMPUPEN 0 RW DMPU Pin Enable

When set, the USB_DMPU pin is enabled.

1 VBUSENPEN 0 RW VBUSEN Pin Enable

When set, the USB_VBUSEN pin is enabled.

0 PHYPEN 0 RW USB PHY Pin Enable

When set, the USB PHY and USB pins are enabled. The USB_DP and USB_DM are changed from regular GPIO pins to USB pins.

15.6.8 USB_GOTGCTL - OTG Control and Status Register

The OTG Control and Status register controls the behavior and reflects the status of the OTG function

of the core.

Offset Bit Position

0x3C000

Reset

Access

Name

OTGVER

BSESVLD

ASESVLD

DBNCTIME

CONIDSTS

DEVHNPEN

HSTSETHNPEN

HNPREQ

HSTNEGSCS

AVALIDOVVAL

AVALIDOVEN

BVALIDOVVAL

BVALIDOVEN

VBVALIDOVVAL

VBVALIDOVEN

SESREQ

SESREQSCS

Bit Name Reset Access Description

31:21 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

20 OTGVER 0 RW OTG Version

Indicates the OTG revision.

Value Mode Description

0 OTG13 OTG Version 1.3. In this version the core supports data line pulsing and VBus pulsing

for SRP.

1 OTG20 OTG Version 2.0. In this version the core supports only data line pulsing for SRP.

19 BSESVLD 0 R B-Session Valid device only

Indicates the Device mode transceiver status for B-session valid. In OTG mode, you can use this bit to determine if the device is

connected or disconnected.

18 ASESVLD 0 R A-Session Valid host only

Indicates the Host mode transceiver status for A-session valid.

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Bit Name Reset Access Description

17 DBNCTIME 0 R Long/Short Debounce Time host only

Indicates the debounce time of a detected connection.

Value Mode Description

0 LONG Long debounce time, used for physical connections (100 ms + 2.5 us).

1 SHORT Short debounce time, used for soft connections (2.5 us).

16 CONIDSTS 1 R Connector ID Status host and device

Indicates the connector ID status on a connect event.

Value Mode Description

0 A The core is in A-Device mode.

1 B The core is in B-Device mode.

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 DEVHNPEN 0 RW Device HNP Enabled device only

The application sets this bit when it successfully receives a SetFeature.SetHNPEnable command from the connected USB host.

10 HSTSETHNPEN 0 RW Host Set HNP Enable host only

The application sets this bit when it has successfully enabled HNP (using the SetFeature.SetHNPEnable command) on the connected

device.

9 HNPREQ 0 RW HNP Request device only

The application sets this bit to initiate an HNP request to the connected USB host. The application can clear this bit by writing a 0

when the Host Negotiation Success Status Change bit in the OTG Interrupt register (USB_GOTGINT.HSTNEGSUCSTSCHNG) is

set. The core clears this bit when the HSTNEGSUCSTSCHNG bit is cleared.

8 HSTNEGSCS 0 R Host Negotiation Success device only

The core sets this bit when host negotiation is successful. The core clears this bit when the HNP Request (HNPREQ) bit in this

7 AVALIDOVVAL 0 RW Avalid Override Value

This bit is used to set Override value for Avalid signal when USB_GOTGCTL.AVALIDOVEN is set.

6 AVALIDOVEN 0 RW AValid Override Enable

This bit is used to enable/disable the software to override the Avalid signal using the USB_GOTGCTL.AVALIDOVVAL. When set

Avalid received from the PHY is overridden with USB_GOTGCTL.AVALIDOVVAL.

5 BVALIDOVVAL 0 RW Bvalid Override Value

This bit is used to set Override value for Bvalid signal when USB_GOTGCTL.BVALIDOVEN is set.

4 BVALIDOVEN 0 RW BValid Override Enable

This bit is used to enable/disable the software to override the Bvalid signal using the USB_GOTGCTL.BVALIDOVVAL. When set

Bvalid received from the PHY is overridden with USB_GOTGCTL.BVALIDOVVAL.

3 VBVALIDOVVAL 0 RW VBUS Valid Override Value

This bit is used to set Override value for vbusvalid signal when USB_GOTGCTL.VBVALIDOVEN is set.

2 VBVALIDOVEN 0 RW VBUS-Valid Override Enable

This bit is used to enable/disable the software to override the vbusvalid signal using the USB_GOTGCTL.VBVALIDOVVAL. When

set, vbusvalid received from the PHY is overridden with USB_GOTGCTL.VBVALIDOVVAL.

1 SESREQ 0 RW Session Request device only

The application sets this bit to initiate a session request on the USB. The application can clear this bit by writing a 0 when the Host

Negotiation Success Status Change bit in the OTG Interrupt register (USB_GOTGINT.HSTNEGSUCSTSCHNG) is set. The core

clears this bit when the HSTNEGSUCSTSCHNG bit is cleared. The application must wait until the VBUS discharges to 0.2 V, after the

B-Session Valid bit in this register (USB_GOTGCTL.BSESVLD) is cleared. This discharge time can be obtained from the datasheet.

0 SESREQSCS 0 R Session Request Success device only

The core sets this bit when a session request initiation is successful.

15.6.9 USB_GOTGINT - OTG Interrupt Register

The application reads this register whenever there is an OTG interrupt and clears the bits in this register

to clear the OTG interrupt.

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Offset Bit Position

0x3C004

Reset

Access

RW1H

Name

DBNCEDONE

ADEVTOUTCHG

HSTNEGDET

HSTNEGSUCSTSCHNG

SESREQSUCSTSCHNG

SESENDDET

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19 DBNCEDONE 0 RW1H Debounce Done host only

The core sets this bit when the debounce is completed after the device connect. The application can start driving USB reset after

seeing this interrupt. This bit is only valid when the HNP Capable or SRP Capable bit is set in the Core USB Configuration register

(USB_GUSBCFG.HNPCAP or USB_GUSBCFG.SRPCAP, respectively). This bit can be set only by the core and the application

should write 1 to clear it.

18 ADEVTOUTCHG 0 RW1H A-Device Timeout Change host and device

The core sets this bit to indicate that the A-device has timed out while waiting for the B-device to connect. This bit can be set only

by the core and the application should write 1 to clear it.

17 HSTNEGDET 0 RW1H Host Negotiation Detected host and device

The core sets this bit when it detects a host negotiation request on the USB. This bit can be set only by the core and the application

should write 1 to clear it.

16:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 HSTNEGSUCSTSCHNG 0 RW1H Host Negotiation Success Status Change host and device

The core sets this bit on the success or failure of a USB host negotiation request. The application must read the Host Negotiation

Success bit of the OTG Control and Status register (USB_GOTGCTL.HSTNEGSCS) to check for success or failure. This bit can be

set only by the core and the application should write 1 to clear it.

8 SESREQSUCSTSCHNG 0 RW1H Session Request Success Status Change host and device

The core sets this bit on the success or failure of a session request. The application must read the Session Request Success bit

in the OTG Control and Status register (USB_GOTGCTL.SESREQSCS) to check for success or failure. This bit can be set only by

the core and the application should write 1 to clear it.

7:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 SESENDDET 0 RW1H Session End Detected host and device

The core sets this bit when VBUS is in the range 0.8V - 2.0V. This bit can be set only by the core and the application should write

1 to clear it.

1:0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15.6.10 USB_GAHBCFG - AHB Configuration Register

This register can be used to configure the core after power-on or a change in mode. This register

mainly contains AHB system-related configuration parameters. Do not change this register after the

initial programming. The application must program this register before starting any transactions on either

the AHB or the USB.

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Offset Bit Position

0x3C008

Reset

0x0

Access

Name

NOTIALLDMAWRIT

REMMEMSUPP

PTXFEMPLVL

NPTXFEMPLVL

DMAEN

HBSTLEN

GLBLINTRMSK

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 NOTIALLDMAWRIT 0 RW Notify All DMA Writes

This bit is programmed to enable the System DMA Done functionality for all the DMA write Transactions corresponding to the Channel/

Endpoint. This bit is valid only when USB_GAHBCFG.REMMEMSUPP is set to 1. When set, the core asserts int_dma_req for all the

DMA write transactions on the AHB interface along with int_dma_done, chep_last_transact and chep_number signal informations.

The core waits for sys_dma_done signal for all the DMA write transactions in order to complete the transfer of a particular Channel/

Endpoint. When cleared, the core asserts int_dma_req signal only for the last transaction of DMA write transfer corresponding to a

particular Channel/Endpoint. Similarly, the core waits for sys_dma_done signal only for that transaction of DMA write to complete

the transfer of a particular Channel/Endpoint.

21 REMMEMSUPP 0 RW Remote Memory Support

This bit is programmed to enable the functionality to wait for the system DMA Done Signal for the DMA Write Transfers. When set, the

int_dma_req output signal is asserted when HSOTG DMA starts write transfer to the external memory. When the core is done with the

Transfers it asserts int_dma_done signal to flag the completion of DMA writes from HSOTG. The core then waits for sys_dma_done

signal from the system to proceed further and complete the Data Transfer corresponding to a particular Channel/Endpoint. When

cleared, the int_dma_req and int_dma_done signals are not asserted and the core proceeds with the assertion of the XferComp

interrupt as soon as the DMA write transfer is done at the HSOTG Core Boundary and it doesn't wait for the sys_dma_done signal

to complete the DATA.

20:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 PTXFEMPLVL 0 RW Periodic TxFIFO Empty Level host only

Indicates when the Periodic TxFIFO Empty Interrupt bit in the Core Interrupt register (USB_GINTSTS.PTXFEMP) is triggered. This

bit is used only in Slave mode.

Value Mode Description

0 HALFEMPTY USB_GINTSTS.PTXFEMP interrupt indicates that the Periodic TxFIFO is half empty.

1 EMPTY USB_GINTSTS.PTXFEMP interrupt indicates that the Periodic TxFIFO is completely

empty.

7 NPTXFEMPLVL 0 RW Non-Periodic TxFIFO Empty Level host and device

This bit is used only in Slave mode. In host mode this bit indicates when the Non-Periodic TxFIFO Empty Interrupt bit in the Core

Interrupt register (USB_GINTSTS.NPTXFEMP) is triggered. In device mode, this bit indicates when IN endpoint Transmit FIFO empty

interrupt (USB_DIEP0INT/USB_DIEPx_INT.TXFEMP) is triggered.

Value Mode Description

0 HALFEMPTY Host Mode: USB_GINTSTS.NPTXFEMP interrupt indicates that the Non-Periodic

TxFIFO is half empty.

Device Mode: USB_DIEP0INT/USB_DIEPx_INT.TXFEMP interrupt indicates that the

IN Endpoint TxFIFO is half empty.

1 EMPTY Host Mode: USB_GINTSTS.NPTXFEMP interrupt indicates that the Non-Periodic

TxFIFO is completely empty.

Device Mode: USB_DIEP0INT/USB_DIEPx_INT.TXFEMP interrupt indicates that the

IN Endpoint TxFIFO is completely empty.

6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DMAEN 0 RW DMA Enable host and device

When set to 0 the core operates in Slave mode. When set to 1 the core operates in a DMA mode.

4:1 HBSTLEN 0x0 RW Burst Length/Type host and device

This field is used in DMA mode.

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Bit Name Reset Access Description

Value Mode Description

0 SINGLE Single transfer.

1 INCR Incrementing burst of unspecified length.

3 INCR4 4-beat incrementing burst.

5 INCR8 8-beat incrementing burst.

7 INCR16 16-beat incrementing burst.

0 GLBLINTRMSK 0 RW Global Interrupt Mask host and device

The application uses this bit to mask or unmask the interrupt line assertion to itself. Irrespective of this bit's setting, the interrupt status

registers are updated by the core. Set to unmask.

15.6.11 USB_GUSBCFG - USB Configuration Register

This register can be used to configure the core after power-on or a changing to Host mode or Device

mode. It contains USB and USB-PHY related configuration parameters. The application must program

this register before starting any transactions on either the AHB or the USB. Do not make changes to

this register after the initial programming.

Offset Bit Position

0x3C00C

Reset

0x5

0x0

Access

Name

CORRUPTTXPKT

FORCEDEVMODE

FORCEHSTMODE

TXENDDELAY

TERMSELDLPULSE

USBTRDTIM

HNPCAP

SRPCAP

FSINTF

TOUTCAL

Bit Name Reset Access Description

31 CORRUPTTXPKT 0 W1 Corrupt Tx packet host and device

This bit is for debug purposes only. Never Set this bit to 1. The application should always write 0 to this bit.

30 FORCEDEVMODE 0 RW Force Device Mode host and device

Writing a 1 to this bit forces the core to device mode irrespective of the state of the ID pin. After setting the force bit, the application

must wait at least 25 ms before the change to take effect.

29 FORCEHSTMODE 0 RW Force Host Mode host and device

Writing a 1 to this bit forces the core to host mode irrespective of the state of the ID pin. After setting the force bit, the application

must wait at least 65 ms before the change to take effect.

28 TXENDDELAY 0 RW Tx End Delay device only

Writing 1 to this bit enables the core to follow the TxEndDelay timings as per UTMI+ specification 1.05 section 4.1.5 for opmode

signal during remote wakeup.

27:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 TERMSELDLPULSE 0 RW TermSel DLine Pulsing Selection device only

This bit selects utmi_termselect to drive data line pulse during SRP.

Value Mode Description

0 TXVALID Data line pulsing using utmi_txvalid.

1 TERMSEL Data line pulsing using utmi_termsel.

21:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:10 USBTRDTIM 0x5 RW USB Turnaround Time device only

Sets the turnaround time in PHY clocks. Specifies the response time For a MAC request to the Packet FIFO Controller (PFC) to fetch

data from the DFIFO (SPRAM). Always write this field to 5.

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Bit Name Reset Access Description

9 HNPCAP 0 RW HNP-Capable host and device

The application uses this bit to control the core's HNP capabilities. Set to enable HNP capability.

8 SRPCAP 0 RW SRP-Capable host and device

The application uses this bit to control the core's SRP capabilities. If the core operates as a non-SRP-capable B-device, it cannot

request the connected A-device (host) to activate VBUS and start a session. Set to enable SRP capability.

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 FSINTF 0 RW Full-Speed Serial Interface Select host and device

Always write this bit to 0.

4:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 TOUTCAL 0x0 RW Timeout Calibration host and device

Always write this field to 0.

15.6.12 USB_GRSTCTL - Reset Register

The application uses this register to reset various hardware features inside the core.

Offset Bit Position

0x3C010

Reset

0x00

Access

RW1H

Name

AHBIDLE

DMAREQ

TXFNUM

TXFFLSH

RXFFLSH

FRMCNTRRST

CSFTRST

Bit Name Reset Access Description

31 AHBIDLE 1 R AHB Master Idle host and device

Indicates that the AHB Master State Machine is in the IDLE condition.

30 DMAREQ 0 R DMA Request Signal host and device

Indicates that the DMA request is in progress. Used for debug.

29:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:6 TXFNUM 0x00 RW TxFIFO Number host and device

This is the FIFO number that must be flushed using the TxFIFO Flush bit. This field must not be changed until the core clears the

TxFIFO Flush bit.

Value Mode Description

0 F0 Host mode: Non-periodic TxFIFO flush.

Device: Tx FIFO 0 flush

1 F1 Host mode: Periodic TxFIFO flush.

Device: TXFIFO 1 flush.

2 F2 Device mode: TXFIFO 2 flush.

3 F3 Device mode: TXFIFO 3 flush.

4 F4 Device mode: TXFIFO 4 flush.

5 F5 Device mode: TXFIFO 5 flush.

6 F6 Device mode: TXFIFO 6 flush.

16 FALL Flush all the transmit FIFOs in device or host mode.

5 TXFFLSH 0 RW1H TxFIFO Flush host and device

This bit selectively flushes a single or all transmit FIFOs, but cannot do so if the core is in the midst of a transaction. The application

must write this bit only after checking that the core is neither writing to the TxFIFO nor reading from the TxFIFO. NAK Effective

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Bit Name Reset Access Description

Interrupt ensures the core is not reading from the FIFO. USB_GRSTCTL.AHBIDLE ensures the core is not writing anything to the

FIFO. Flushing is normally recommended when FIFOs are reconfigured. FIFO flushing is also recommended during device endpoint

disable. The application must wait until the core clears this bit before performing any operations. This bit takes eight clocks to clear.

4 RXFFLSH 0 RW1H RxFIFO Flush host and device

The application can flush the entire RxFIFO using this bit, but must first ensure that the core is not in the middle of a transaction. The

application must only write to this bit after checking that the core is neither reading from the RxFIFO nor writing to the RxFIFO. The

application must wait until the bit is cleared before performing any other operations. This bit requires 8 clocks to clear.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 FRMCNTRRST 0 RW1H Host Frame Counter Reset host only

The application writes this bit to reset the frame number counter inside the core. When the frame counter is reset, the subsequent

SOF sent out by the core has a frame number of 0. When application writes 1 to the bit, it might not be able to read back the value

as it will get cleared by the core in a few clock cycles.

1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 CSFTRST 0 RW1H Core Soft Reset host and device

Resets the core by clearing the interrupts and all the CSR registers except the following register bits:

USB_PCGCCTL.RSTPDWNMODULE, USB_PCGCCTL.GATEHCLK, USB_PCGCCTL.PWRCLMP, USB_GUSBCFG.FSINTF,

USB_HCFG.FSLSPCLKSEL, USB_DCFG.DEVSPD.

All module state machines (except the AHB Slave Unit) are reset to the IDLE state, and all the transmit FIFOs and the receive FIFO

are flushed. Any transactions on the AHB Master are terminated as soon as possible, after gracefully completing the last data phase

of an AHB transfer. Any transactions on the USB are terminated immediately. The application can write to this bit any time it wants

to reset the core. This is a self-clearing bit and the core clears this bit after all the necessary logic is reset in the core, which can

take several clocks, depending on the current state of the core. Once this bit is cleared software must wait at least 3 clock cycles

before doing any access to the core. Software must also must check that bit 31 of this register is 1 (AHB Master is IDLE) before

starting any operation.

15.6.13 USB_GINTSTS - Interrupt Register

This register interrupts the application for system-level events in the current mode (Device mode or Host

mode). Some of the bits in this register are valid only in Host mode, while others are valid in Device

mode only. This register also indicates the current mode. To clear the interrupt status bits of type RW1H,

the application must write 1 into the bit.

The FIFO status interrupts are read only; once software reads from or writes to the FIFO while servicing

these interrupts, FIFO interrupt conditions are cleared automatically.

The application must clear the USB_GINTSTS register at initialization before unmasking the interrupt

bit to avoid any interrupts generated prior to initialization.

Offset Bit Position

0x3C014

Reset

Access

RW1H

Name

WKUPINT

SESSREQINT

DISCONNINT

CONIDSTSCHNG

PTXFEMP

HCHINT

PRTINT

RESETDET

FETSUSP

INCOMPLP

INCOMPISOIN

OEPINT

IEPINT

EOPF

ISOOUTDROP

ENUMDONE

USBRST

USBSUSP

ERLYSUSP

GOUTNAKEFF

GINNAKEFF

NPTXFEMP

RXFLVL

SOF

OTGINT

MODEMIS

CURMOD

Bit Name Reset Access Description

31 WKUPINT 0 RW1H Resume/Remote Wakeup Detected Interrupt host and device

Wakeup Interrupt during Suspend state. In Device mode this interrupt is asserted only when Host Initiated Resume is detected on

USB. In Host mode this interrupt is asserted only when Device Initiated Remote Wakeup is detected on USB. This bit can be set

only by the core and the application should write 1 to clear.

30 SESSREQINT 0 RW1H Session Request/New Session Detected Interrupt host and

device

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Bit Name Reset Access Description

In Host mode, this interrupt is asserted when a session request is detected from the device. In Device mode, this interrupt is asserted

when the VBUS voltage reaches the session-valid level. This bit can be set only by the core and the application should write 1 to clear.

29 DISCONNINT 0 RW1H Disconnect Detected Interrupt host only

Asserted when a device disconnect is detected. This bit can be set only by the core and the application should write 1 to clear it.

28 CONIDSTSCHNG 1 RW1H Connector ID Status Change host and device

The core sets this bit when there is a change in connector ID status. This bit can be set only by the core and the application should

write 1 to clear it.

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 PTXFEMP 1 R Periodic TxFIFO Empty host only

This interrupt is asserted when the Periodic Transmit FIFO is either half or completely empty and there is space for at least one entry

to be written in the Periodic Request Queue. The half or completely empty status is determined by the Periodic TxFIFO Empty Level

bit in the Core AHB Configuration register (USB_GAHBCFG.PTXFEMPLVL).

25 HCHINT 0 R Host Channels Interrupt host only

The core sets this bit to indicate that an interrupt is pending on one of the channels of the core (in Host mode). The application must

read the Host All Channels Interrupt (USB_HAINT) register to determine the exact number of the channel on which the interrupt

occurred, and then read the corresponding Host Channel-x Interrupt (USB_HCx_INT) register to determine the exact cause of the

interrupt. The application must clear the appropriate status bit in the USB_HCx_INT register to clear this bit.

24 PRTINT 0 R Host Port Interrupt host only

The core sets this bit to indicate a change in port status in Host mode. The application must read the Host Port Control and Status

(USB_HPRT) register to determine the exact event that caused this interrupt. The application must clear the appropriate status bit

in the Host Port Control and Status register to clear this bit.

23 RESETDET 0 RW1H Reset detected Interrupt device only

In Device mode, this interrupt is asserted when a reset is detected on the USB in EM2 when the device is in Suspend.

In Host mode, this interrupt is not asserted.

22 FETSUSP 0 RW1H Data Fetch Suspended device only

This interrupt is valid only in DMA mode. This interrupt indicates that the core has stopped fetching data for IN endpoints due to the

unavailability of TxFIFO space or Request Queue space. This interrupt is used by the application for an endpoint mismatch algorithm.

For example, after detecting an endpoint mismatch, the application: Sets a Global non-periodic IN NAK handshake, Disables In

endpoints, Flushes the FIFO, Determines the token sequence from the IN Token Sequence, Re-enables the endpoints, Clears the

Global non-periodic IN NAK handshake.

If the Global non-periodic IN NAK is cleared, the core has not yet fetched data for the IN endpoint, and the IN token is received: the

core generates an IN Token Received when FIFO Empty interrupt. The OTG then sends the host a NAK response. To avoid this

scenario, the application can check the USB_GINTSTS.FETSUSP interrupt, which ensures that the FIFO is full before clearing a

Global NAK handshake. Alternatively, the application can mask the IN Token Received when FIFO Empty interrupt when clearing

a Global IN NAK handshake.

21 INCOMPLP 0 RW1H Incomplete Periodic Transfer host and device

In Host mode, the core sets this interrupt bit when there are incomplete periodic transactions still pending which are scheduled for the

current frame. In Device mode, the core sets this interrupt to indicate that there is at least one isochronous OUT endpoint on which

the transfer is not completed in the current frame. This bit can be set only by the core and the application should write 1 to clear it.

20 INCOMPISOIN 0 RW1H Incomplete Isochronous IN Transfer device only

The core sets this interrupt to indicate that there is at least one isochronous IN endpoint on which the transfer is not completed in

the current frame.

19 OEPINT 0 R OUT Endpoints Interrupt device only

The core sets this bit to indicate that an interrupt is pending on one of the OUT endpoints of the core (in Device mode). The application

must read the Device All Endpoints Interrupt (USB_DAINT) register to determine the exact number of the OUT endpoint on which

the interrupt occurred, and then read the corresponding Device OUT Endpoint-x Interrupt (USB_DOEP0INT/USB_DOEPx_INT)

register to determine the exact cause of the interrupt. The application must clear the appropriate status bit in the corresponding

USB_DOEP0INT/USB_DOEPx_INT register to clear this bit.

18 IEPINT 0 R IN Endpoints Interrupt device only

The core sets this bit to indicate that an interrupt is pending on one of the IN endpoints of the core (in Device mode). The application

must read the Device All Endpoints Interrupt (USB_DAINT) register to determine the exact number of the IN endpoint on Device IN

Endpoint-x Interrupt (USB_DIEP0INT/USB_DIEPx_INT) register to determine the exact cause of the interrupt. The application must

clear the appropriate status bit in the corresponding USB_DIEP0INT/USB_DIEPx_INT register to clear this bit.

17:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 EOPF 0 RW End of Periodic Frame Interrupt

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Bit Name Reset Access Description

Indicates that the period specified in the Periodic Frame Interval field of the Device Configuration register (DCFG_PERFRINT) has

been reached in the current microframe.

14 ISOOUTDROP 0 RW1H Isochronous OUT Packet Dropped Interrupt device only

The core sets this bit when it fails to write an isochronous OUT packet into the RxFIFO because the RxFIFO does not have enough

space to accommodate a maximum packet size packet for the isochronous OUT endpoint.

13 ENUMDONE 0 RW1H Enumeration Done device only

The core sets this bit to indicate that speed enumeration is complete. The application must read the Device Status (USB_DSTS)

12 USBRST 0 RW1H USB Reset device only

The core sets this bit to indicate that a reset is detected on the USB.

11 USBSUSP 0 RW1H USB Suspend device only

The core sets this bit to indicate that a suspend was detected on the USB. The core enters the Suspended state when there is no

activity on the bus for an extended period of time.

10 ERLYSUSP 0 RW1H Early Suspend device only

The core sets this bit to indicate that an Idle state has been detected on the USB for 3 ms.

9:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 GOUTNAKEFF 0 R Global OUT NAK Effective device only

Indicates that the Set Global OUT NAK bit in the Device Control register (USB_DCTL.SGOUTNAK), set by the application,

has taken effect in the core. This bit can be cleared by writing the Clear Global OUT NAK bit in the Device Control register

(USB_DCTL.CGOUTNAK).

6 GINNAKEFF 0 R Global IN Non-periodic NAK Effective device only

Indicates that the Set Global Non-periodic IN NAK bit in the Device Control register (USB_DCTL.SGNPINNAK), set by the application,

has taken effect in the core. That is, the core has sampled the Global IN NAK bit set by the application. This bit can be cleared by

clearing the Clear Global Non-periodic IN NAK bit in the Device Control register (USB_DCTL.CGNPINNAK). This interrupt does not

necessarily mean that a NAK handshake is sent out on the USB. The STALL bit takes precedence over the NAK bit.

5 NPTXFEMP 1 R Non-Periodic TxFIFO Empty host only

This interrupt is asserted when the Non-periodic TxFIFO is either half or completely empty, and there is space for at least one entry

to be written to the Non-periodic Transmit Request Queue. The half or completely empty status is determined by the Non-periodic

TxFIFO Empty Level bit in the Core AHB Configuration register (USB_GAHBCFG.NPTXFEMPLVL).

4 RXFLVL 0 R RxFIFO Non-Empty host and device

Indicates that there is at least one packet pending to be read from the RxFIFO.

3 SOF 0 RW1H Start of Frame host and device

In Host mode, the core sets this bit to indicate that an SOF (FS) or Keep-Alive (LS) is transmitted on the USB. The application must

write a 1 to this bit to clear the interrupt.

In Device mode, in the core sets this bit to indicate that an SOF token has been received on the USB. The application can read the

Device Status register to get the current frame number. This interrupt is seen only when the core is operating at full-speed (FS). This

bit can be set only by the core and the application should write 1 to clear it.

2 OTGINT 0 R OTG Interrupt host and device

The core sets this bit to indicate an OTG protocol event. The application must read the OTG Interrupt Status (USB_GOTGINT) register

to determine the exact event that caused this interrupt. The application must clear the appropriate status bit in the USB_GOTGINT

1 MODEMIS 0 RW1H Mode Mismatch Interrupt host and device

The core sets this bit when the application is trying to access a Host mode register, when the core is operating in Device mode or when

the application accesses a Device mode register, when the core is operating in Host mode. The register access is ignored by the core

internally and does not affect the operation of the core. This bit can be set only by the core and the application should write 1 to clear it.

0 CURMOD 0 R Current Mode of Operation host and device

Indicates the current mode.

Value Mode Description

0 DEVICE Device mode.

1 HOST Host mode.

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15.6.14 USB_GINTMSK - Interrupt Mask Register

This register works with the Interrupt Register (USB_GINTSTS) to interrupt the application. When an

interrupt bit is masked (bit is 0), the interrupt associated with that bit is not generated. However, the

USB_GINTSTS register bit corresponding to that interrupt is still set.

Offset Bit Position

0x3C018

Reset

Access

Name

WKUPINTMSK

SESSREQINTMSK

DISCONNINTMSK

CONIDSTSCHNGMSK

PTXFEMPMSK

HCHINTMSK

PRTINTMSK

RESETDETMSK

FETSUSPMSK

INCOMPLPMSK

INCOMPISOINMSK

OEPINTMSK

IEPINTMSK

EOPFMSK

ISOOUTDROPMSK

ENUMDONEMSK

USBRSTMSK

USBSUSPMSK

ERLYSUSPMSK

GOUTNAKEFFMSK

GINNAKEFFMSK

NPTXFEMPMSK

RXFLVLMSK

SOFMSK

OTGINTMSK

MODEMISMSK

Bit Name Reset Access Description

31 WKUPINTMSK 0 RW Resume/Remote Wakeup Detected Interrupt Mask host and

device

Set to 1 to unmask WKUPINT interrupt.

30 SESSREQINTMSK 0 RW Session Request/New Session Detected Interrupt Mask host and

device

Set to 1 to unmask SESSREQINT interrupt.

29 DISCONNINTMSK 0 RW Disconnect Detected Interrupt Mask host and device

Set to 1 to unmask DISCONNINT interrupt.

28 CONIDSTSCHNGMSK 0 RW Connector ID Status Change Mask host and device

Set to 1 to unmask CONIDSTSCHNG interrupt.

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 PTXFEMPMSK 0 RW Periodic TxFIFO Empty Mask host only

Set to 1 to unmask PTXFEMP interrupt.

25 HCHINTMSK 0 RW Host Channels Interrupt Mask host only

Set to 1 to unmask HCHINT interrupt.

24 PRTINTMSK 0 RW Host Port Interrupt Mask host only

Set to 1 to unmask PRTINT interrupt.

23 RESETDETMSK 0 RW Reset detected Interrupt Mask device only

Set to 1 to unmask RESETDET interrupt.

22 FETSUSPMSK 0 RW Data Fetch Suspended Mask device only

Set to 1 to unmask FETSUSP interrupt.

21 INCOMPLPMSK 0 RW Incomplete Periodic Transfer Mask host and device

Set to 1 to unmask INCOMPLP interrupt.

20 INCOMPISOINMSK 0 RW Incomplete Isochronous IN Transfer Mask device only

Set to 1 to unmask INCOMPISOIN interrupt.

19 OEPINTMSK 0 RW OUT Endpoints Interrupt Mask device only

Set to 1 to unmask OEPINT interrupt.

18 IEPINTMSK 0 RW IN Endpoints Interrupt Mask device only

Set to 1 to unmask IEPINT interrupt.

17:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

15 EOPFMSK 0 RW End of Periodic Frame Interrupt Mask device only

Set to 1 to unmask EOPF interrupt.

14 ISOOUTDROPMSK 0 RW Isochronous OUT Packet Dropped Interrupt Mask device only

Set to 1 to unmask ISOOUTDROP interrupt.

13 ENUMDONEMSK 0 RW Enumeration Done Mask device only

Set to 1 to unmask ENUMDONE interrupt.

12 USBRSTMSK 0 RW USB Reset Mask device only

Set to 1 to unmask USBRST interrupt.

11 USBSUSPMSK 0 RW USB Suspend Mask device only

Set to 1 to unmask USBSUSP interrupt.

10 ERLYSUSPMSK 0 RW Early Suspend Mask device only

Set to 1 to unmask ERLYSUSP interrupt.

9:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 GOUTNAKEFFMSK 0 RW Global OUT NAK Effective Mask device only

Set to 1 to unmask GOUTNAKEFF interrupt.

6 GINNAKEFFMSK 0 RW Global Non-periodic IN NAK Effective Mask device only

Set to 1 to unmask GINNAKEFF interrupt.

5 NPTXFEMPMSK 0 RW Non-Periodic TxFIFO Empty Mask host only

Set to 1 to unmask NPTXFEMP interrupt.

4 RXFLVLMSK 0 RW Receive FIFO Non-Empty Mask host and device

Set to 1 to unmask RXFLVL interrupt.

3 SOFMSK 0 RW Start of Frame Mask host and device

Set to 1 to unmask SOF interrupt.

2 OTGINTMSK 0 RW OTG Interrupt Mask host and device

Set to 1 to unmask OTGINT interrupt.

1 MODEMISMSK 0 RW Mode Mismatch Interrupt Mask host and device

Set to 1 to unmask MODEMIS interrupt.

0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15.6.15 USB_GRXSTSR - Receive Status Debug Read Register

A read to the Receive Status Debug Read register returns the contents of the top of the Receive FIFO.

The receive status contents must be interpreted differently in Host and Device modes. The core ignores

the receive status pop/read when the receive FIFO is empty and returns a value of 0x00000000. The

application must only pop the Receive Status FIFO when the Receive FIFO Non-Empty bit of the Core

Interrupt register (USB_GINTSTS.RXFLVL) is asserted.

Offset Bit Position

0x3C01C

Reset

0x0

0x000

0x0

Access

Name

PKTSTS

DPID

BCNT

CHEPNUM

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Bit Name Reset Access Description

31:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24:21 FN 0x0 R Frame Number device only

This is the least significant 4 bits of the Frame number in which the packet is received on the USB.

20:17 PKTSTS 0x0 R Packet Status (host or device)

Indicates the status of the received packet.

Value Mode Description

1 GOUTNAK Device mode: Global OUT NAK (triggers an interrupt).

2 PKTRCV Host mode: IN data packet received.

Device mode: OUT data packet received.

3 XFERCOMPL Host mode: IN transfer completed (triggers an interrupt).

Device mode: OUT transfer completed (triggers an interrupt).

4 SETUPCOMPL Device mode: SETUP transaction completed (triggers an interrupt).

5 TGLERR Host mode: Data toggle error (triggers an interrupt).

6 SETUPRCV Device mode: SETUP data packet received.

7 CHLT Host mode: Channel halted (triggers an interrupt).

16:15 DPID 0x0 R Data PID (host or device)

Host mode: Indicates the Data PID of the received packet. Device mode: Indicates the Data PID of the received OUT data packet.

Value Mode Description

0 DATA0 DATA0 PID.

1 DATA1 DATA1 PID.

2 DATA2 DATA2 PID.

3 MDATA MDATA PID.

14:4 BCNT 0x000 R Byte Count (host or device)

Host mode: Indicates the byte count of the received IN data packet.

Device mode: Indicates the byte count of the received data packet.

3:0 CHEPNUM 0x0 R Channel Number host only / Endpoint Number device only

Host mode: Indicates the channel number to which the current received packet belongs.

Device mode: Indicates the endpoint number to which the current received packet belongs.

15.6.16 USB_GRXSTSP - Receive Status Read and Pop Register

A read to the Receive Status Read and Pop register returns the contents of the top of the Receive FIFO

and pops the top data entry out of the RxFIFO. The receive status contents must be interpreted differently

in Host and Device modes. The core ignores the receive status pop/read when the receive FIFO is empty

and returns a value of 0x00000000. The application must only pop the Receive Status FIFO when the

Receive FIFO Non-Empty bit of the Core Interrupt register (USB_GINTSTS.RXFLVL) is asserted.

Offset Bit Position

0x3C020

Reset

0x0

0x000

0x0

Access

Name

PKTSTS

DPID

BCNT

CHEPNUM

Bit Name Reset Access Description

31:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

24:21 FN 0x0 R Frame Number device only

This is the least significant 4 bits of the Frame number in which the packet is received on the USB.

20:17 PKTSTS 0x0 R Packet Status (host or device)

Indicates the status of the received packet.

Value Mode Description

1 GOUTNAK Device mode: Global OUT NAK (triggers an interrupt).

2 PKTRCV Host mode: IN data packet received.

Device mode: OUT data packet received.

3 XFERCOMPL Host mode: IN transfer completed (triggers an interrupt).

Device mode: OUT transfer completed (triggers an interrupt).

4 SETUPCOMPL Device mode: SETUP transaction completed (triggers an interrupt).

5 TGLERR Host mode: Data toggle error (triggers an interrupt).

6 SETUPRCV Device mode: SETUP data packet received.

7 CHLT Host mode: Channel halted (triggers an interrupt).

16:15 DPID 0x0 R Data PID (host or device)

Host mode: Indicates the Data PID of the received packet.

Device mode: Indicates the Data PID of the received OUT data packet.

Value Mode Description

0 DATA0 DATA0 PID.

1 DATA1 DATA1 PID.

2 DATA2 DATA2 PID.

3 MDATA MDATA PID.

14:4 BCNT 0x000 R Byte Count (host or device)

Host mode: Indicates the byte count of the received IN data packet.

Device mode: Indicates the byte count of the received data packet.

3:0 CHEPNUM 0x0 R Channel Number host only / Endpoint Number device only

Host mode: Indicates the channel number to which the current received packet belongs.

Device mode: Indicates the endpoint number to which the current received packet belongs.

15.6.17 USB_GRXFSIZ - Receive FIFO Size Register

The application can program the RAM size that must be allocated to the RxFIFO.

Offset Bit Position

0x3C024

Reset

0x200

Access

Name

RXFDEP

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:0 RXFDEP 0x200 RW RxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

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15.6.18 USB_GNPTXFSIZ - Non-periodic Transmit FIFO Size Register

The application can program the RAM size and the memory start address for the Non-periodic TxFIFO.

Offset Bit Position

0x3C028

Reset

0x0200

0x200

Access

Name

NPTXFINEPTXF0DEP

NPTXFSTADDR

Bit Name Reset Access Description

31:16 NPTXFINEPTXF0DEP 0x0200 RW Non-periodic TxFIFO Depth host only / IN Endpoint TxFIFO 0

Depth device only

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:0 NPTXFSTADDR 0x200 RW Non-periodic Transmit RAM Start Address host only

This field contains the memory start address for Non-periodic Transmit FIFO RAM. Programmed values must not exceed the reset

value.

15.6.19 USB_GNPTXSTS - Non-periodic Transmit FIFO/Queue Status

This register is used in host mode only. This read-only register contains the free space information for

the Non-periodic TxFIFO and the Nonperiodic Transmit Request Queue.

Offset Bit Position

0x3C02C

Reset

0x00

0x08

0x0200

Access

Name

NPTXQTOP

NPTXQSPCAVAIL

NPTXFSPCAVAIL

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:24 NPTXQTOP 0x00 R Top of the Non-periodic Transmit Request Queue

Entry in the Non-periodic Tx Request Queue that is currently being processed by the MAC.

Bits [6:3]: Channel/endpoint number.

Bits [2:1]: 00: IN/OUT token, 01: Zero-length transmit packet (device IN/host OUT), 10: Unused, 11: Channel halt command.

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Bit Name Reset Access Description

Bit [0]: Terminate (last Entry for selected channel/endpoint).

23:16 NPTXQSPCAVAIL 0x08 R Non-periodic Transmit Request Queue Space Available

Indicates the amount of free space (locations) available in the Non-periodic Transmit Request Queue. This queue holds both IN and

OUT requests in Host mode. Device mode has only IN requests.

15:0 NPTXFSPCAVAIL 0x0200 R Non-periodic TxFIFO Space Available

Indicates the amount of free space available in the Non-periodic TxFIFO. Values are in terms of 32-bit words.

15.6.20 USB_GDFIFOCFG - Global DFIFO Configuration Register

Offset Bit Position

0x3C05C

Reset

0x01F2

0x0200

Access

Name

EPINFOBASEADDR

GDFIFOCFG

Bit Name Reset Access Description

31:16 EPINFOBASEADDR 0x01F2 RW Endpoint Info Base Address

This field provides the start address of the EP info controller.

15:0 GDFIFOCFG 0x0200 RW DFIFO Config

This field is for dynamic programming of the DFIFO Size. This value takes effect only when the application programs a non zero

value to this register. The core does not have any corrective logic if the FIFO sizes are programmed incorrectly.

15.6.21 USB_HPTXFSIZ - Host Periodic Transmit FIFO Size Register

This register holds the size and the memory start address of the Periodic TxFIFO.

Offset Bit Position

0x3C100

Reset

0x200

0x400

Access

Name

PTXFSIZE

PTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 PTXFSIZE 0x200 RW Host Periodic TxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:0 PTXFSTADDR 0x400 RW Host Periodic TxFIFO Start Address

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Bit Name Reset Access Description

This field contains the memory start address for Host Periodic TxFIFO.

15.6.22 USB_DIEPTXF1 - Device IN Endpoint Transmit FIFO 1 Size Register

This register holds the size and memory start address of IN endpoint TxFIFO 1 in Device mode. For IN

endpoint FIFO 0 use USB_GNPTXFSIZ register for programming the size and memory start address.

Offset Bit Position

0x3C104

Reset

0x200

0x400

Access

Name

INEPNTXFDEP

INEPNTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 INEPNTXFDEP 0x200 RW IN Endpoint TxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:0 INEPNTXFSTADDR 0x400 RW IN Endpoint FIFO 1 Transmit RAM Start Address

This field contains the memory start address for IN endpoint Transmit FIFO 1.

15.6.23 USB_DIEPTXF2 - Device IN Endpoint Transmit FIFO 2 Size Register

This register holds the size and memory start address of IN endpoint TxFIFO 2 in Device mode. For IN

endpoint FIFO 0 use USB_GNPTXFSIZ register for programming the size and memory start address.

Offset Bit Position

0x3C108

Reset

0x200

0x600

Access

Name

INEPNTXFDEP

INEPNTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 INEPNTXFDEP 0x200 RW IN Endpoint TxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

10:0 INEPNTXFSTADDR 0x600 RW IN Endpoint FIFO 2 Transmit RAM Start Address

This field contains the memory start address for IN endpoint Transmit FIFO 2.

15.6.24 USB_DIEPTXF3 - Device IN Endpoint Transmit FIFO 3 Size Register

This register holds the size and memory start address of IN endpoint TxFIFO 3 in Device mode. For IN

endpoint FIFO 0 use USB_GNPTXFSIZ register for programming the size and memory start address.

Offset Bit Position

0x3C10C

Reset

0x200

0x800

Access

Name

INEPNTXFDEP

INEPNTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 INEPNTXFDEP 0x200 RW IN Endpoint TxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 INEPNTXFSTADDR 0x800 RW IN Endpoint FIFO 3 Transmit RAM Start Address

This field contains the memory start address for IN endpoint Transmit FIFO 3.

15.6.25 USB_DIEPTXF4 - Device IN Endpoint Transmit FIFO 4 Size Register

This register holds the size and memory start address of IN endpoint TxFIFO 4 in Device mode. For IN

endpoint FIFO 0 use USB_GNPTXFSIZ register for programming the size and memory start address.

Offset Bit Position

0x3C110

Reset

0x200

0xA00

Access

Name

INEPNTXFDEP

INEPNTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 INEPNTXFDEP 0x200 RW IN Endpoint TxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

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Bit Name Reset Access Description

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 INEPNTXFSTADDR 0xA00 RW IN Endpoint FIFO 4 Transmit RAM Start Address

This field contains the memory start address for IN endpoint Transmit FIFO 4.

15.6.26 USB_DIEPTXF5 - Device IN Endpoint Transmit FIFO 5 Size Register

This register holds the size and memory start address of IN endpoint TxFIFO 5 in Device mode. For IN

endpoint FIFO 0 use USB_GNPTXFSIZ register for programming the size and memory start address.

Offset Bit Position

0x3C114

Reset

0x200

0xC00

Access

Name

INEPNTXFDEP

INEPNTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 INEPNTXFDEP 0x200 RW IN Endpoint TxFIFO Depth

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 INEPNTXFSTADDR 0xC00 RW IN Endpoint FIFO 5 Transmit RAM Start Address

This field contains the memory start address for IN endpoint Transmit FIFO 5.

15.6.27 USB_DIEPTXF6 - Device IN Endpoint Transmit FIFO 6 Size Register

This register holds the size and memory start address of IN endpoint TxFIFO 6 in Device mode. For IN

endpoint FIFO 0 use USB_GNPTXFSIZ register for programming the size and memory start address.

Offset Bit Position

0x3C118

Reset

0x200

0xE00

Access

Name

INEPNTXFDEP

INEPNTXFSTADDR

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:16 INEPNTXFDEP 0x200 RW IN Endpoint TxFIFO Depth

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Bit Name Reset Access Description

This value is in terms of 32-bit words. Minimum value is 16. Maximum value is 512.

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 INEPNTXFSTADDR 0xE00 RW IN Endpoint FIFO 6 Transmit RAM Start Address

This field contains the memory start address for IN endpoint Transmit FIFO 6.

15.6.28 USB_HCFG - Host Configuration Register

This register configures the core after power-on. Do not make changes to this register after initializing

the host.

Offset Bit Position

0x3C400

Reset

0x00

0x0

Access

Name

MODECHTIMEN

RESVALID

ENA32KHZS

FSLSSUPP

FSLSPCLKSEL

Bit Name Reset Access Description

31 MODECHTIMEN 0 RW Mode Change Time

This bit is used to enable/disable the Host core to wait 200 clock cycles at the end of Resume before changing the PHY opmode to

normal operation. When set to 0 the Host core waits for either 200 PHY clock cycles or a linestate of SE0 at the end of resume to

the change the PHY opmode to normal operation. When set to 1 the Host core waits only for a linstate of SE0 at the end of resume

to change the PHY opmode to normal operation.

30:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:8 RESVALID 0x00 RW Resume Validation Period

This field is effective only when USB_HCFG.ENA32KHZS is set. It will control the resume period when the core resumes from

suspend. The core counts for RESVALID number of clock cycles to detect a valid resume when USB_HCFG.ENA32KHZS is set.

7 ENA32KHZS 0 RW Enable 32 KHz Suspend mode

When this bit is set the core expects that the clock to the core during Suspend is switched from 48 MHz to 32 KHz.

6:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 FSLSSUPP 0 RW FS- and LS-Only Support

The application uses this bit to control the core's enumeration speed. Using this bit, the application can make the core enumerate as

a FS host, even If the connected device supports HS traffic. Do not make changes to this field after initial programming.

Value Mode Description

0 HSFSLS HS/FS/LS, based on the maximum speed supported by the connected device.

1 FSLS FS/LS-only, even If the connected device can support HS.

1:0 FSLSPCLKSEL 0x0 RW FS/LS PHY Clock Select

Use this field to set the internal PHY clock frequency. Set to 48 MHz in FS Host mode and 6 MHz in LS Host mode. When you select

a 6 MHz clock during LS mode, you must do a soft reset.

Value Mode Description

1 DIV1 Internal PHY clock is running at 48 MHz (undivided).

2 DIV8 Internal PHY clock is running at 6 MHz (48 MHz divided by 8).

15.6.29 USB_HFIR - Host Frame Interval Register

This register stores the frame interval information for the current speed to which the core has

enumerated.

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Offset Bit Position

0x3C404

Reset

0x17D7

Access

Name

HFIRRLDCTRL

FRINT

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 HFIRRLDCTRL 0 RW Reload Control

This bit allows dynamic reloading of the HFIR register during run time. This bit needs to be programmed during initial configuration

and its value should not be changed during runtime.

Value Mode Description

0 STATIC The HFIR cannot be reloaded dynamically.

1 DYNAMIC The HFIR can be dynamically reloaded during runtime.

15:0 FRINT 0x17D7 RW Frame Interval

The value that the application programs to this field specifies the interval between two consecutive SOFs (FS) or Keep-Alive tokens

(LS). This field contains the number of PHY clocks that constitute the required frame interval. The application can write a value to

this register only after the Port Enable bit of the Host Port Control and Status register (USB_HPRT.PRTENA) has been set. If no

value is programmed, the core calculates the value based on the PHY clock specified in the FS/LS PHY Clock Select field of the

Host Configuration register (USB_HCFG.FSLSPCLKSEL). Do not change the value of this field after the initial configuration. Set to

48000 (1 ms at 48 MHz) for FS and 6000 (1 ms at 6 MHz) for LS.

15.6.30 USB_HFNUM - Host Frame Number/Frame Time Remaining

This register indicates the current frame number. It also indicates the time remaining (in terms of the

number of PHY clocks) in the current frame.

Offset Bit Position

0x3C408

Reset

0x0000

0x3FFF

Access

Name

FRREM

FRNUM

Bit Name Reset Access Description

31:16 FRREM 0x0000 R Frame Time Remaining

Indicates the amount of time remaining in the current Frame, in terms of PHY clocks. This field decrements on each PHY clock. When

it reaches zero, this field is reloaded with the value in the Frame Interval register and a new SOF is transmitted on the USB.

15:0 FRNUM 0x3FFF R Frame Number

This field increments when a new SOF is transmitted on the USB, and is reset to 0 when it reaches 0x3FFF.

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15.6.31 USB_HPTXSTS - Host Periodic Transmit FIFO/Queue Status

This read-only register contains the free space information for the Periodic TxFIFO and the Periodic

Transmit Request Queue.

Offset Bit Position

0x3C410

Reset

0x00

0x08

0x0200

Access

Name

PTXQTOP

PTXQSPCAVAIL

PTXFSPCAVAIL

Bit Name Reset Access Description

31:24 PTXQTOP 0x00 R Top of the Periodic Transmit Request Queue

This indicates the Entry in the Periodic Tx Request Queue that is currently being processes by the MAC. This register is used for

debugging.

Bit [7]: Odd/Even Frame. 0: send in even Frame, 1: send in odd Frame.

Bits [6:3]: Channel/endpoint number.

Bits [2:1]: Type. 00: IN/OUT, 01: Zero-length packet, 10: Unused, 11: Disable channel command.

Bit [0]: Terminate (last Entry for the selected channel/endpoint).

23:16 PTXQSPCAVAIL 0x08 R Periodic Transmit Request Queue Space Available

Indicates the number of free locations available to be written in the Periodic Transmit Request Queue. This queue holds both IN

and OUT requests.

15:0 PTXFSPCAVAIL 0x0200 R Periodic Transmit Data FIFO Space Available

Indicates the number of free locations available to be written to in the Periodic TxFIFO. Values are in terms of 32-bit words.

15.6.32 USB_HAINT - Host All Channels Interrupt Register

When a significant event occurs on a channel, the Host All Channels Interrupt register interrupts the

application using the Host Channels Interrupt bit of the Core Interrupt register (USB_GINTSTS.HCHINT).

There is one interrupt bit per channel. Bits in this register are set and cleared when the application sets

and clears bits in the corresponding Host Channel x Interrupt register.

Offset Bit Position

0x3C414

Reset

0x0000

Access

Name

HAINT

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Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:0 HAINT 0x0000 R Channel Interrupt for channel 0 - 13.

When the interrupt bit for a channel x set, one or more of the interrupt flags in the USB_HCx_INT are set.

15.6.33 USB_HAINTMSK - Host All Channels Interrupt Mask Register

The Host All Channel Interrupt Mask register works with the Host All Channel Interrupt register to interrupt

the application when an event occurs on a channel. There is one interrupt mask bit per channel. Set

bits to unmask.

Offset Bit Position

0x3C418

Reset

0x0000

Access

Name

HAINTMSK

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:0 HAINTMSK 0x0000 RW Channel Interrupt Mask for channel 0 - 13

Set bit n to unmask channel n interrupts.

15.6.34 USB_HPRT - Host Port Control and Status Register

This register is available only in Host mode. This register holds USB port-related information such as USB

reset, enable, suspend, resume, connect status, and test mode for the port. Some bits in this register

can trigger an interrupt to the application through the Host Port Interrupt bit of the Core Interrupt register

(USB_GINTSTS.PRTINT). On a Port Interrupt, the application must read this register and clear the bit

that caused the interrupt. For the RW1H bits, the application must write a 1 to the bit to clear the interrupt.

Offset Bit Position

0x3C440

Reset

0x0

Access

RW1H

Name

PRTSPD

PRTTSTCTL

PRTPWR

PRTLNSTS

PRTRST

PRTSUSP

PRTRES

PRTOVRCURRCHNG

PRTOVRCURRACT

PRTENCHNG

PRTENA

PRTCONNDET

PRTCONNSTS

Bit Name Reset Access Description

31:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:17 PRTSPD 0x0 R Port Speed

Indicates the speed of the device attached to this port.

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Bit Name Reset Access Description

Value Mode Description

0 HS High speed.

1 FS Full speed.

2 LS Low speed.

16:13 PRTTSTCTL 0x0 RW Port Test Control

The application writes a nonzero value to this field to put the port into a Test mode, and the corresponding pattern is signaled on

the port.

Value Mode Description

0 DISABLE Test mode disabled.

1 J Test_J mode.

2 K Test_K mode.

3 SE0NAK Test_SE0_NAK mode.

4 PACKET Test_Packet mode.

5 FORCE Test_Force_Enable.

12 PRTPWR 0 RW Port Power

The application uses this field to control power to this port. The core can clear this bit on an over current condition.

Value Mode Description

0 OFF Power off.

1 ON Power on.

11:10 PRTLNSTS 0x0 R Port Line Status

Indicates the current logic level USB data lines. Bit [0]: Logic level of D+. Bit [1]: Logic level of D-.

9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 PRTRST 0 RW Port Reset

When the application sets this bit, a reset sequence is started on this port. The application must time the reset period and clear this

bit after the reset sequence is complete. The application must leave this bit set for at least 10 ms to start a reset on the port. The

application can leave it set for another 10 ms in addition to the required minimum duration, before clearing the bit, even though there

is no maximum limit set by the USB standard.

7 PRTSUSP 0 RW1H Port Suspend

The application sets this bit to put this port in Suspend mode. The core only stops sending SOFs when this is set. To stop the PHY

clock, the application must set USB_PCGCCTL.STOPPCLK, which puts the PHY into suspend mode. The read value of this bit

reflects the current suspend status of the port. This bit is cleared by the core after a remote wakeup signal is detected or the application

sets the Port Reset bit or Port Resume bit in this register or the Resume/Remote Wakeup Detected Interrupt bit or Disconnect

Detected Interrupt bit in the Core Interrupt register (USB_GINTSTS.WKUPINT or USB_GINTSTS.DISCONNINT respectively). This

bit is cleared by the core even if there is no device connected to the Host.

6 PRTRES 0 RW Port Resume

The application sets this bit to drive resume signaling on the port. The core continues to drive the resume signal until the application

clears this bit. If the core detects a USB remote wakeup sequence, as indicated by the Port Resume/Remote Wakeup Detected

Interrupt bit of the Core Interrupt register (USB_GINTSTS.WKUPINT), the core starts driving resume signaling without application

intervention and clears this bit when it detects a disconnect condition. The read value of this bit indicates whether the core is currently

driving resume signaling.

5 PRTOVRCURRCHNG 0 RW1H Port Overcurrent Change

The core sets this bit when the status of the Port Overcurrent Active bit (bit 4) in this register changes. This bit can be set only by

the core and the application should write 1 to clear it.

4 PRTOVRCURRACT 0 R Port Overcurrent Active

Indicates the overcurrent condition of the port. When there is an overcurrent condition this bit is 1.

3 PRTENCHNG 0 RW1H Port Enable/Disable Change

The core sets this bit when the status of the Port Enable bit[2] of this register changes. This bit can be set only by the core and the

application should write 1 to clear it.

2 PRTENA 0 RW1H Port Enable

A port is enabled only by the core after a reset sequence, and is disabled by an overcurrent condition, a disconnect condition, or by

the application clearing this bit. The application cannot set this bit by a register write. It can only clear it to disable the port by writing

1. This bit does not trigger any interrupt to the application.

1 PRTCONNDET 0 RW1H Port Connect Detected

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Bit Name Reset Access Description

The core sets this bit when a device connection is detected to trigger an interrupt to the application using the Host Port Interrupt bit of

the Core Interrupt register (USB_GINTSTS.PRTINT). This bit can be set only by the core and the application should write 1 to clear

it. The application must write a 1 to this bit to clear the interrupt.

0 PRTCONNSTS 0 R Port Connect Status

When this bit is 1 a device is attached to the port.

15.6.35 USB_HCx_CHAR - Host Channel x Characteristics Register

Offset Bit Position

0x3C500

Reset

0x00

0x0

0x000

Access

RW1H

Name

CHENA

CHDIS

ODDFRM

DEVADDR

EPTYPE

LSPDDEV

EPDIR

EPNUM

MPS

Bit Name Reset Access Description

31 CHENA 0 RW1H Channel Enable

This field is set by the application and cleared by the core. The state of this bit reflects the channel enable status.

30 CHDIS 0 RW1H Channel Disable

The application sets this bit to stop transmitting/receiving data on a channel, even before the transfer for that channel is complete.

The application must wait for the Channel Disabled interrupt before treating the channel as disabled.

29 ODDFRM 0 RW Odd Frame

This field is set (reset) by the application to indicate that the OTG host must perform a transfer in an odd frame. This field is applicable

for only periodic (isochronous and interrupt) transactions.

28:22 DEVADDR 0x00 RW Device Address

This field selects the specific device serving as the data source or sink.

21:20 MC 0x0 RW Multi Count

For periodic transfers this field indicates to the host the number of transactions that must be executed per frame for this periodic

endpoint. For non-periodic transfers, this field is used only in DMA mode, and specifies the number packets to be fetched for this

channel before the internal DMA engine changes arbitration.

19:18 EPTYPE 0x0 RW Endpoint Type

Indicates the transfer type selected.

Value Mode Description

0 CONTROL Control endpoint.

1 ISO Isochronous endpoint.

2 BULK Bulk endpoint.

3 INT Interrupt endpoint.

17 LSPDDEV 0 RW Low-Speed Device

This field is set by the application to indicate that this channel is communicating to a low-speed device.

16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 EPDIR 0 RW Endpoint Direction

Indicates whether the transaction is IN or OUT.

Value Mode Description

0 OUT Direction is OUT.

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Bit Name Reset Access Description

Value Mode Description

1 IN Direction is IN.

14:11 EPNUM 0x0 RW Endpoint Number

Indicates the endpoint number on the device serving as the data source or sink.

10:0 MPS 0x000 RW Maximum Packet Size

Indicates the maximum packet size of the associated endpoint.

15.6.36 USB_HCx_INT - Host Channel x Interrupt Register

This register indicates the status of a channel with respect to USB- and AHB-related events. The

application must read this register when the Host Channels Interrupt bit of the Core Interrupt register

(USB_GINTSTS.HCHINT) is set. Before the application can read this register, it must first read the Host

All Channels Interrupt (USB_HAINT) register to get the exact channel number for the Host Channel x

Interrupt register. The application must clear the appropriate bit in this register to clear the corresponding

bits in the USB_HAINT and USB_GINTSTS registers.

Offset Bit Position

0x3C508

Reset

Access

RW1H

Name

DATATGLERR

FRMOVRUN

BBLERR

XACTERR

ACK

NAK

STALL

AHBERR

CHHLTD

XFERCOMPL

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 DATATGLERR 0 RW1H Data Toggle Error

This bit can be set only by the core and the application should write 1 to clear it.

9 FRMOVRUN 0 RW1H Frame Overrun

This bit can be set only by the core and the application should write 1 to clear it.

8 BBLERR 0 RW1H Babble Error

This bit can be set only by the core and the application should write 1 to clear it.

7 XACTERR 0 RW1H Transaction Error

Indicates one of the following errors occurred on the USB: CRC check failure, Timeout, Bit stuff error or False EOP. This bit can be

set only by the core and the application should write 1 to clear it.

6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 ACK 0 RW1H ACK Response Received/Transmitted Interrupt

This bit can be set only by the core and the application should write 1 to clear it.

4 NAK 0 RW1H NAK Response Received Interrupt

This bit can be set only by the core and the application should write 1 to clear it.

3 STALL 0 RW1H STALL Response Received Interrupt

This bit can be set only by the core and the application should write 1 to clear it.

2 AHBERR 0 RW1H AHB Error

This is generated only in DMA mode when there is an AHB error during AHB read/write. The application can read the corresponding

channel's DMA address register to get the error address.

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Bit Name Reset Access Description

1 CHHLTD 0 RW1H Channel Halted

In DMA mode this bit indicates the transfer completed abnormally either because of any USB transaction error or in response to

disable request by the application or because of a completed transfer.

0 XFERCOMPL 0 RW1H Transfer Completed

Transfer completed normally without any errors. This bit can be set only by the core and the application should write 1 to clear it.

15.6.37 USB_HCx_INTMSK - Host Channel x Interrupt Mask Register

This register reflects the mask for each channel status described in the USB_CHx_INT.

Offset Bit Position

0x3C50C

Reset

Access

Name

DATATGLERRMSK

FRMOVRUNMSK

BBLERRMSK

XACTERRMSK

ACKMSK

NAKMSK

STALLMSK

AHBERRMSK

CHHLTDMSK

XFERCOMPLMSK

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 DATATGLERRMSK 0 RW Data Toggle Error Mask

Set to unmask DATATGLERR interrupt.

9 FRMOVRUNMSK 0 RW Frame Overrun Mask

Set to unmask FRMOVRUN interrupt.

8 BBLERRMSK 0 RW Babble Error Mask

Set to unmask BBLERR interrupt.

7 XACTERRMSK 0 RW Transaction Error Mask

Set to unmask XACTERR interrupt.

6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 ACKMSK 0 RW ACK Response Received/Transmitted Interrupt Mask

Set to unmask ACK interrupt.

4 NAKMSK 0 RW NAK Response Received Interrupt Mask

Set to unmask NAK interrupt.

3 STALLMSK 0 RW STALL Response Received Interrupt Mask

Set to unmask STALL interrupt.

2 AHBERRMSK 0 RW AHB Error Mask

Set to unmask AHBERR interrupt.

1 CHHLTDMSK 0 RW Channel Halted Mask

Set to unmask CHHLTD interrupt.

0 XFERCOMPLMSK 0 RW Transfer Completed Mask

Set to unmask XFERCOMPL interrupt.

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15.6.38 USB_HCx_TSIZ - Host Channel x Transfer Size Register

Offset Bit Position

0x3C510

Reset

0x0

0x000

0x00000

Access

Name

PID

PKTCNT

XFERSIZE

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:29 PID 0x0 RW Packet ID

The application programs this field with the packet ID type to use for the initial transaction. The host maintains this field for the rest

of the transfer.

Value Mode Description

0 DATA0 DATA0 PID.

1 DATA2 DATA2 PID.

2 DATA1 DATA1 PID.

3 MDATA MDATA (non-control) / SETUP (control) PID.

28:19 PKTCNT 0x000 RW Packet Count

This field is programmed by the application with the expected number of packets to be transmitted (OUT) or received (IN). The

host decrements this count on every successful transmission or reception of an OUT/IN packet. Once this count reaches zero, the

application is interrupted to indicate normal completion.

18:0 XFERSIZE 0x00000 RW Transfer Size

For an OUT, this field is the number of data bytes the host sends during the transfer. For an IN, this field is the buffer size that the

application has reserved for the transfer. The application is expected to program this field as an integer multiple of the maximum

packet size for IN transactions (periodic and non-periodic).

15.6.39 USB_HCx_DMAADDR - Host Channel x DMA Address Register

This register is used by the OTG host in the internal DMA mode to maintain the current buffer pointer

for IN/OUT transactions. The starting DMA address must be DWORD-aligned.

Offset Bit Position

0x3C514

Reset

0xXXXXXXXX

Access

Name

DMAADDR

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Bit Name Reset Access Description

31:0 DMAADDR 0xXXXXXXXX RW DMA Address

This field holds the start address in the external memory from which the data for the endpoint must be fetched or to which it must

be stored. This register is incremented on every AHB transaction. The data for this register field is stored in RAM. Thus, the reset

value is undefined (X).

15.6.40 USB_DCFG - Device Configuration Register

This register configures the core in Device mode after power-on or after certain control commands or

enumeration. Do not make changes to this register after initial programming.

Offset Bit Position

0x3C800

Reset

0x02

0x0

0x00

0x0

Access

Name

RESVALID

PERFRINT

DEVADDR

ENA32KHZSUSP

NZSTSOUTHSHK

DEVSPD

Bit Name Reset Access Description

31:26 RESVALID 0x02 RW Resume Validation Period

This field is effective only when USB_DCFG.ENA32KHZSUSP is set. It will control the resume period when the core resumes from

suspend. The core counts for RESVALID number of clock cycles to detect a valid resume when USB_DCFG.ENA32KHZSUSP is set.

25:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12:11 PERFRINT 0x0 RW Periodic Frame Interval

Indicates the time within a frame at which the application must be notified using the End Of Periodic Frame Interrupt. This can be

used to determine if all the isochronous traffic for that frame is complete.

Value Mode Description

0 80PCNT 80% of the frame interval.

1 85PCNT 85% of the frame interval.

2 90PCNT 90% of the frame interval.

3 95PCNT 95% of the frame interval.

10:4 DEVADDR 0x00 RW Device Address

The application must program this field after every SetAddress control command.

3 ENA32KHZSUSP 0 RW Enable 32 KHz Suspend mode

When this bit is set, the core expects that the PHY clock during Suspend is switched from 48 MHz to 32 KHz.

2 NZSTSOUTHSHK 0 RW Non-Zero-Length Status OUT Handshake

The application can use this field to select the handshake the core sends on receiving a nonzero-length data packet during the OUT

transaction of a control transfer's Status stage. When set to 1 send a STALL handshake on a nonzero-length status OUT transaction

and do not send the received OUT packet to the application. When set to 0 send the received OUT packet to the application (zerolength

or nonzero-length) and send a handshake based on the NAK and STALL bits for the endpoint in the Device Endpoint Control register.

1:0 DEVSPD 0x0 RW Device Speed

Indicates the speed at which the application requires the core to enumerate, or the maximum speed the application can support.

However, the actual bus speed is determined only after the chirp sequence is completed, and is based on the speed of the USB

host to which the core is connected.

Value Mode Description

2 LS Low speed (PHY clock is 6 MHz). If you select 6 MHz LS mode, you must do a soft

reset.

3 FS Full speed (PHY clock is 48 MHz).

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15.6.41 USB_DCTL - Device Control Register

Offset Bit Position

0x3C804

Reset

0x0

Access

Name

NAKONBBLE

IGNRFRMNUM

PWRONPRGDONE

CGOUTNAK

SGOUTNAK

CGNPINNAK

SGNPINNAK

TSTCTL

GOUTNAKSTS

GNPINNAKSTS

SFTDISCON

RMTWKUPSIG

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 NAKONBBLE 0 RW NAK on Babble Error

Set NAK automatically on babble. The core sets NAK automatically for the endpoint on which babble is received.

15 IGNRFRMNUM 0 RW Ignore Frame number For Isochronous End points

When set to 0 the core transmits the packets only in the frame number in which they are intended to be transmitted. When set to 1

the core ignores the frame number, sending packets immediately as the packets are ready.

14:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 PWRONPRGDONE 0 RW Power-On Programming Done

The application uses this bit to indicate that register programming is completed after a wake-up from Power Down mode.

10 CGOUTNAK 0 W1 Clear Global OUT NAK

A write to this field clears the Global OUT NAK.

9 SGOUTNAK 0 W1 Set Global OUT NAK

A write to this field sets the Global OUT NAK. The application uses this bit to send a NAK handshake on all OUT endpoints.

The application must set this bit only after making sure that the Global OUT NAK Effective bit in the Core Interrupt Register

(USB_GINTSTS.GOUTNAKEFF) is cleared.

8 CGNPINNAK 0 W1 Clear Global Non-periodic IN NAK

A write to this field clears the Global Non-periodic IN NAK.

7 SGNPINNAK 0 W1 Set Global Non-periodic IN NAK

A write to this field sets the Global Non-periodic IN NAK. The application uses this bit to send a NAK handshake on all non-periodic IN

endpoints. The application must set this bit only after making sure that the Global IN NAK Effective bit in the Core Interrupt Register

(USB_GINTSTS.GINNAKEFF) is cleared.

6:4 TSTCTL 0x0 RW Test Control

Set to a non-zero value to enable test control.

Value Mode Description

0 DISABLE Test mode disabled.

1 J Test_J mode.

2 K Test_K mode.

3 SE0NAK Test_SE0_NAK mode.

4 PACKET Test_Packet mode.

5 FORCE Test_Force_Enable.

3 GOUTNAKSTS 0 R Global OUT NAK Status

When this bit is 0 a handshake is sent based on the FIFO Status and the NAK and STALL bit settings. When this bit is 1 no data

is written to the RxFIFO, irrespective of space availability. Sends a NAK handshake on all packets, except on SETUP transactions.

All isochronous OUT packets are dropped.

2 GNPINNAKSTS 0 R Global Non-periodic IN NAK Status

When this bit is 0 a handshake is sent out based on the data availability in the transmit FIFO. When this bit is 1 a NAK handshake

is sent out on all non-periodic IN endpoints, irrespective of the data availability in the transmit FIFO.

1 SFTDISCON 0 RW Soft Disconnect

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Bit Name Reset Access Description

The application uses this bit to signal the core to do a soft disconnect. As long as this bit is set, the host does not see that the device is

connected, and the device does not receive signals on the USB. The core stays in the disconnected state until the application clears

this bit. When suspended, the minimum duration for which the core must keep this bit set is 1 ms + 2.5 us. When IDLE or performing

transactions, the minimum duration for which the core must keep this bit set is 2.5 us.

0 RMTWKUPSIG 0 RW Remote Wakeup Signaling

When the application sets this bit, the core initiates remote signaling to wake up the USB host. The application must set this bit

to instruct the core to exit the Suspend state. As specified in the USB 2.0 specification, the application must clear this bit 1-15 ms

after setting it.

15.6.42 USB_DSTS - Device Status Register

This register indicates the status of the core with respect to USB-related events. It must be read on

interrupts from Device All Interrupts (USB_DAINT) register.

Offset Bit Position

0x3C808

Reset

0x0000

0x1

Access

Name

SOFFN

ERRTICERR

ENUMSPD

SUSPSTS

Bit Name Reset Access Description

31:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:8 SOFFN 0x0000 R Frame Number of the Received SOF

This field contains a Frame number. This field may return a non zero value if read immediately after power on reset. In case the

register bits reads non zero immediately after power on reset it does not indicate that SOF has been received from the host. The

read value of this interrupt is valid only after a valid connection between host and device is established.

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 ERRTICERR 0 R Erratic Error

The core sets this bit to report any erratic errors (PHY error) Due to erratic errors, the core goes into Suspended state and an interrupt

is generated to the application with Early Suspend bit of the Core Interrupt register (USB_GINTSTS.ERLYSUSP). If the early suspend

is asserted due to an erratic error, the application can only perform a soft disconnect recover.

2:1 ENUMSPD 0x1 R Enumerated Speed

Indicates the speed at which the core has come up after speed detection through a chirp sequence.

Value Mode Description

2 LS Low speed (PHY clock is running at 6 MHz).

3 FS Full speed (PHY clock is running at 48 MHz).

0 SUSPSTS 0 R Suspend Status

In Device mode, this bit is set as long as a Suspend condition is detected on the USB. The core enters the Suspended state when

there is no activity on the bus for an extended period of time. The core comes out of the suspend when there is any activity on the

bus or when the application writes to the Remote Wakeup Signaling bit in the Device Control register (USB_DCTL.RMTWKUPSIG).

15.6.43 USB_DIEPMSK - Device IN Endpoint Common Interrupt Mask

This register works with each of the Device IN Endpoint Interrupt (USB_DIEP0INT/USB_DIEPx_INT)

registers for all endpoints to generate an interrupt per IN endpoint. The IN endpoint interrupt for a specific

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status in the USB_DIEP0INT/USB_DIEPx_INT register can be masked by writing to the corresponding

bit in this register. Status bits are masked by default.

Offset Bit Position

0x3C810

Reset

Access

Name

NAKMSK

TXFIFOUNDRNMSK

INEPNAKEFFMSK

INTKNTXFEMPMSK

TIMEOUTMSK

AHBERRMSK

EPDISBLDMSK

XFERCOMPLMSK

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 NAKMSK 0 RW NAK interrupt Mask

Set to 1 to unmask NAK Interrupt.

12:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 TXFIFOUNDRNMSK 0 RW Fifo Underrun Mask

Set to 1 to unmask TXFIFOUNDRN Interrupt.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 INEPNAKEFFMSK 0 RW IN Endpoint NAK Effective Mask

Set to 1 to unmask INEPNAKEFF Interrupt.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 INTKNTXFEMPMSK 0 RW IN Token Received When TxFIFO Empty Mask

Set to 1 to unmask INTKNTXFEMP Interrupt.

3 TIMEOUTMSK 0 RW Timeout Condition Mask

Set to 1 to unmask Interrupt TIMEOUT. Applies to Non-isochronous endpoints.

2 AHBERRMSK 0 RW AHB Error Mask

Set to 1 to unmask AHBERR Interrupt.

1 EPDISBLDMSK 0 RW Endpoint Disabled Interrupt Mask

Set to 1 to unmask EPDISBLD Interrupt.

0 XFERCOMPLMSK 0 RW Transfer Completed Interrupt Mask

Set to 1 to unmask XFERCOMPL Interrupt.

15.6.44 USB_DOEPMSK - Device OUT Endpoint Common Interrupt Mask

This register works with each of the Device OUT Endpoint Interrupt (USB_DOEP0INT/

USB_DOEPx_INT) registers for all endpoints to generate an interrupt per OUT endpoint. The OUT

endpoint interrupt for a specific status in the USB_DOEP0INT/USB_DOEPx_INT register can be masked

by writing into the corresponding bit in this register. Status bits are masked by default.

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Offset Bit Position

0x3C814

Reset

Access

Name

NAKMSK

BBLEERRMSK

OUTPKTERRMSK

BACK2BACKSETUP

OUTTKNEPDISMSK

SETUPMSK

AHBERRMSK

EPDISBLDMSK

XFERCOMPLMSK

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 NAKMSK 0 RW NAK interrupt Mask

Set to 1 to unmask NAK Interrupt.

12 BBLEERRMSK 0 RW Babble Error interrupt Mask

Set to 1 to unmask BBLEERR Interrupt.

11:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 OUTPKTERRMSK 0 RW OUT Packet Error Mask

Set to 1 to unmask OUTPKTERR Interrupt.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 BACK2BACKSETUP 0 RW Back-to-Back SETUP Packets Received Mask

Set to 1 to unmask BACK2BACKSETUP Interrupt. Applies to control OUT endpoints only.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 OUTTKNEPDISMSK 0 RW OUT Token Received when Endpoint Disabled Mask

Set to 1 to unmask OUTTKNEPDIS Interrupt. Applies to control OUT endpoints only.

3 SETUPMSK 0 RW SETUP Phase Done Mask

Set to 1 to unmask SETUP Interrupt. Applies to control endpoints only.

2 AHBERRMSK 0 RW AHB Error

Set to 1 to unmask AHBERR Interrupt.

1 EPDISBLDMSK 0 RW Endpoint Disabled Interrupt Mask

Set to 1 to unmask EPDISBLD Interrupt.

0 XFERCOMPLMSK 0 RW Transfer Completed Interrupt Mask

Set to 1 to unmask XFERCOMPL Interrupt.

15.6.45 USB_DAINT - Device All Endpoints Interrupt Register

When a significant event occurs on an endpoint, a Device All Endpoints Interrupt register interrupts

the application using the Device OUT Endpoints Interrupt bit or Device IN Endpoints Interrupt bit of

the Core Interrupt register (USB_GINTSTS.OEPINT or USB_GINTSTS.IEPINT, respectively). There is

one interrupt bit per endpoint. For a bidirectional endpoint, the corresponding IN and OUT interrupt

bits are used. Bits in this register are set and cleared when the application sets and clears bits in the

corresponding Device Endpoint Interrupt register (USB_DIEP0INT/USB_DIEPx_INT, USB_DOEP0INT/

USB_DOEPx_INT).

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Offset Bit Position

0x3C818

Reset

Access

Name

OUTEPINT6

OUTEPINT5

OUTEPINT4

OUTEPINT3

OUTEPINT2

OUTEPINT1

OUTEPINT0

INEPINT6

INEPINT5

INEPINT4

INEPINT3

INEPINT2

INEPINT1

INEPINT0

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 OUTEPINT6 0 R OUT Endpoint 6 Interrupt Bit

This bit is set when on or more of the interrupt flags in USB_DOEP5_INT are set.

21 OUTEPINT5 0 R OUT Endpoint 5 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DOEP4_INT are set.

20 OUTEPINT4 0 R OUT Endpoint 4 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DOEP3_INT are set.

19 OUTEPINT3 0 R OUT Endpoint 3 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DOEP2_INT are set.

18 OUTEPINT2 0 R OUT Endpoint 2 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DOEP1_INT are set.

17 OUTEPINT1 0 R OUT Endpoint 1 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DOEP0_INT are set.

16 OUTEPINT0 0 R OUT Endpoint 0 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DOEP0INT are set.

15:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 INEPINT6 0 R IN Endpoint 6 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP5_INT are set.

5 INEPINT5 0 R IN Endpoint 5 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP4_INT are set.

4 INEPINT4 0 R IN Endpoint 4 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP3_INT are set.

3 INEPINT3 0 R IN Endpoint 3 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP2_INT are set.

2 INEPINT2 0 R IN Endpoint 2 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP1_INT are set.

1 INEPINT1 0 R IN Endpoint 1 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP0_INT are set.

0 INEPINT0 0 R IN Endpoint 0 Interrupt Bit

This bit is set when one or more of the interrupt flags in USB_DIEP0INT are set.

15.6.46 USB_DAINTMSK - Device All Endpoints Interrupt Mask Register

The Device Endpoint Interrupt Mask register works with the Device Endpoint Interrupt register to interrupt

the application when an event occurs on a device endpoint. However, the Device All Endpoints Interrupt

(USB_DAINT) register bit corresponding to that interrupt is still set.

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Offset Bit Position

0x3C81C

Reset

Access

Name

OUTEPMSK6

OUTEPMSK5

OUTEPMSK4

OUTEPMSK3

OUTEPMSK2

OUTEPMSK1

OUTEPMSK0

INEPMSK6

INEPMSK5

INEPMSK4

INEPMSK3

INEPMSK2

INEPMSK1

INEPMSK0

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 OUTEPMSK6 0 RW OUT Endpoint 6 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT6.

21 OUTEPMSK5 0 RW OUT Endpoint 5 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT5.

20 OUTEPMSK4 0 RW OUT Endpoint 4 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT4.

19 OUTEPMSK3 0 RW OUT Endpoint 3 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT3.

18 OUTEPMSK2 0 RW OUT Endpoint 2 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT2.

17 OUTEPMSK1 0 RW OUT Endpoint 1 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT1.

16 OUTEPMSK0 0 RW OUT Endpoint 0 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.OUTEPINT0.

15:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 INEPMSK6 0 RW IN Endpoint 6 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT6.

5 INEPMSK5 0 RW IN Endpoint 5 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT5.

4 INEPMSK4 0 RW IN Endpoint 4 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT4.

3 INEPMSK3 0 RW IN Endpoint 3 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT3.

2 INEPMSK2 0 RW IN Endpoint 2 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT2.

1 INEPMSK1 0 RW IN Endpoint 1 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT1.

0 INEPMSK0 0 RW IN Endpoint 0 Interrupt mask Bit

Set to 1 to unmask USB_DAINT.INEPINT0.

15.6.47 USB_DVBUSDIS - Device VBUS Discharge Time Register

This register specifies the VBUS discharge time after VBUS pulsing during SRP.

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Offset Bit Position

0x3C828

Reset

0x17D7

Access

Name

DVBUSDIS

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DVBUSDIS 0x17D7 RW Device VBUS Discharge Time

Specifies the VBUS discharge time after VBUS pulsing during SRP. This value equals VBUS discharge time in PHY clocks / 1024.

Depending on your VBUS load, this value can need adjustment.

15.6.48 USB_DVBUSPULSE - Device VBUS Pulsing Time Register

This register specifies the VBUS pulsing time during SRP.

Offset Bit Position

0x3C82C

Reset

0x5B8

Access

Name

DVBUSPULSE

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 DVBUSPULSE 0x5B8 RW Device VBUS Pulsing Time

Specifies the VBUS pulsing time during SRP. This value equals VBUS pulsing time in PHY clocks / 1024.

15.6.49 USB_DIEPEMPMSK - Device IN Endpoint FIFO Empty Interrupt

Mask Register

This register is used to control the IN endpoint FIFO empty interrupt generation (USB_DIEP0INT/

USB_DIEPx_INT.TXFEMP).

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Offset Bit Position

0x3C834

Reset

0x0000

Access

Name

DIEPEMPMSK

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DIEPEMPMSK 0x0000 RW IN EP Tx FIFO Empty Interrupt Mask Bits

These bits acts as mask bits for USB_DIEP0INT.TXFEMP/USB_DIEPx_INT.TXFEMP interrupt. One bit per IN Endpoint: Bit 0 for

IN EP 0, bit 6 for IN EP 6.

15.6.50 USB_DIEP0CTL - Device IN Endpoint 0 Control Register

This section describes the Control IN Endpoint 0 Control register. Nonzero control endpoints use

registers for endpoints 1 - 6.

Offset Bit Position

0x3C900

Reset

0x0

Access

RW1H

Name

EPENA

EPDIS

SNAK

CNAK

TXFNUM

STALL

EPTYPE

NAKSTS

USBACTEP

MPS

Bit Name Reset Access Description

31 EPENA 0 RW1H Endpoint Enable

In DMA mode this bit indicates that data is ready to be transmitted on the endpoint. The core clears this bit before setting the following

interrupts on this endpoint: Endpoint Disabled, Transfer Completed.

30 EPDIS 0 RW1H Endpoint Disable

The application sets this bit to stop transmitting data on an endpoint, even before the transfer for that endpoint is complete. The

application must wait for the Endpoint Disabled interrupt before treating the endpoint as disabled. The core clears this bit before

setting the Endpoint Disabled Interrupt. The application must set this bit only if Endpoint Enable is already set for this endpoint.

29:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27 SNAK 0 W1 Set NAK

A write to this bit sets the NAK bit for the endpoint. Using this bit, the application can control the transmission of NAK handshakes

on an endpoint. The core can also set this bit for an endpoint after a SETUP packet is received on that endpoint.

26 CNAK 0 W1 Clear NAK

A write to this bit clears the NAK bit for the endpoint.

25:22 TXFNUM 0x0 RW TxFIFO Number

This value is set to the FIFO number that is assigned to IN Endpoint 0.

21 STALL 0 RW1H Handshake

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Bit Name Reset Access Description

The application can only set this bit, and the core clears it, when a SETUP token is received for this endpoint. If a NAK bit, Global

Nonperiodic IN NAK, or Global OUT NAK is set along with this bit, the STALL bit takes priority.

20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:18 EPTYPE 0x0 R Endpoint Type

Hardcoded to 0. Endpoint 0 is always a control endpoint.

17 NAKSTS 0 R NAK Status

When this bit is 0 the core is transmitting non-NAK handshakes based on the FIFO status. When this bit is 1 the core is transmitting

NAK handshakes on this endpoint. When this bit is set, either by the application or core, the core stops transmitting data, even if

there is data available in the TxFIFO. Irrespective of this bit's setting, the core always responds to SETUP data packets with an

ACK handshake.

16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 USBACTEP 1 R USB Active Endpoint

This bit is always 1, indicating that control endpoint 0 is always active in all configurations and interfaces.

14:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 MPS 0x0 RW Maximum Packet Size

The application must program this field with the maximum packet size for the current logical endpoint.

Value Mode Description

0 64B 64 bytes.

1 32B 32 bytes.

2 16B 16 bytes.

3 8B 8 bytes.

15.6.51 USB_DIEP0INT - Device IN Endpoint 0 Interrupt Register

This register indicates the status of endpoint 0 with respect to USB- and AHB-related events. The

application must read this register when the IN Endpoints Interrupt bit of the Core Interrupt register

(USB_GINTSTS.IEPINT) is set. Before the application can read this register, it must first read the Device

All Endpoints Interrupt (USB_DAINT) register to get the exact endpoint number for the Device Endpoint

Interrupt register. The application must clear the appropriate bit in this register to clear the corresponding

bits in the USB_DAINT and USB_GINTSTS registers.

Offset Bit Position

0x3C908

Reset

Access

RW1H

Name

NAKINTRPT

BBLEERR

PKTDRPSTS

TXFEMP

INEPNAKEFF

INTKNTXFEMP

TIMEOUT

AHBERR

EPDISBLD

XFERCOMPL

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 NAKINTRPT 0 RW1H NAK Interrupt

The core generates this interrupt when a NAK is transmitted or received by the device. In case of isochronous IN endpoints the

interrupt gets generated when a zero length packet is transmitted due to un-availability of data in the TXFifo.

12 BBLEERR 0 RW1H NAK Interrupt

The core generates this interrupt when babble is received for the endpoint.

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Bit Name Reset Access Description

11 PKTDRPSTS 0 RW1H Packet Drop Status

This bit indicates to the application that an ISO OUT packet has been dropped. This bit does not have an associated mask bit and

does not generate an interrupt.

10:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 TXFEMP 1 R Transmit FIFO Empty

This interrupt is asserted when the TxFIFO for this endpoint is either half or completely empty. The half or completely empty status

is determined by the TxFIFO Empty Level bit in the Core AHB Configuration register (USB_GAHBCFG.NPTXFEMPLVL).

6 INEPNAKEFF 0 RW1H IN Endpoint NAK Effective

Applies to periodic IN endpoints only. This bit can be cleared when the application clears the IN endpoint NAK by writing to

USB_DIEP0CTL.CNAK. This interrupt indicates that the core has sampled the NAK bit set (either by the application or by the core).

The interrupt indicates that the IN endpoint NAK bit set by the application has taken effect in the core. This interrupt does not guarantee

that a NAK handshake is sent on the USB. A STALL bit takes priority over a NAK bit.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 INTKNTXFEMP 0 RW1H IN Token Received When TxFIFO is Empty

Indicates that an IN token was received when the associated TxFIFO (periodic/non-periodic) was empty. This interrupt is asserted

on the endpoint for which the IN token was received.

3 TIMEOUT 0 RW1H Timeout Condition

Indicates that the core has detected a timeout condition on the USB for the last IN token on this endpoint.

2 AHBERR 0 RW1H AHB Error

This is generated in DMA mode when there is an AHB error during an AHB read/write. The application can read the corresponding

endpoint DMA address register to get the error address.

1 EPDISBLD 0 RW1H Endpoint Disabled Interrupt

This bit indicates that the endpoint is disabled per the application's request.

0 XFERCOMPL 0 RW1H Transfer Completed Interrupt

This field indicates that the programmed transfer is complete on the AHB as well as on the USB, for this endpoint.

15.6.52 USB_DIEP0TSIZ - Device IN Endpoint 0 Transfer Size Register

The application must modify this register before enabling endpoint 0. Once endpoint 0 is enabled using

Endpoint Enable bit of the Device Control Endpoint 0 Control register (USB_DIEP0CTL.EPENA), the

core modifies this register. The application can only read this register once the core has cleared the

Endpoint Enable bit. Nonzero endpoints use the registers for endpoints 1-6.

Offset Bit Position

0x3C910

Reset

0x0

0x00

Access

Name

PKTCNT

XFERSIZE

Bit Name Reset Access Description

31:21 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

20:19 PKTCNT 0x0 RW Packet Count

Indicates the total number of USB packets that constitute the Transfer Size amount of data for endpoint 0. This field is decremented

every time a packet (maximum size or short packet) is read from the TxFIFO.

18:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:0 XFERSIZE 0x00 RW Transfer Size

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Bit Name Reset Access Description

Indicates the transfer size in bytes for endpoint 0. The core interrupts the application only after it has exhausted the transfer size

amount of data. The transfer size can be set to the maximum packet size of the endpoint, to be interrupted at the end of each packet.

The core decrements this field every time a packet from the external memory is written to the TxFIFO.

15.6.53 USB_DIEP0DMAADDR - Device IN Endpoint 0 DMA Address

Offset Bit Position

0x3C914

Reset

0xXXXXXXXX

Access

Name

DIEP0DMAADDR

Bit Name Reset Access Description

31:0 DIEP0DMAADDR 0xXXXXXXXX RW DMA Address

Holds the start address of the external memory for fetching endpoint data. For control endpoints, this field stores control OUT data

packets as well as SETUP transaction data packets. When more than three SETUP packets are received back-to-back, the SETUP

data packet in the memory is overwritten. This register is incremented on every AHB transaction. The application can give only a

DWORD-aligned address. The data for this register field is stored in RAM. Thus, the reset value is undefined (X).

15.6.54 USB_DIEP0TXFSTS - Device IN Endpoint 0 Transmit FIFO Status

This read-only register contains the free space information for the Device IN endpoint 0 TxFIFO.

Offset Bit Position

0x3C918

Reset

0x0200

Access

Name

SPCAVAIL

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 SPCAVAIL 0x0200 R TxFIFO Space Available

Indicates the amount of free space available in the Endpoint TxFIFO. Values are in terms of 32-bit words.

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15.6.55 USB_DIEPx_CTL - Device IN Endpoint x+1 Control Register

The application uses this register to control the behavior of each logical endpoint other than endpoint 0.

Offset Bit Position

0x3C920

Reset

0x0

0x000

Access

RW1H

Name

EPENA

EPDIS

SETD1PIDOF

SETD0PIDEF

SNAK

CNAK

TXFNUM

STALL

EPTYPE

NAKSTS

DPIDEOF

USBACTEP

MPS

Bit Name Reset Access Description

31 EPENA 0 RW1H Endpoint Enable

In DMA mode for IN endpoints, this bit indicates that data is ready to be transmitted on the endpoint. The core clears this bit before

setting any of the following interrupts on this endpoint: SETUP Phase Done, Endpoint Disabled, Transfer Completed. For control

endpoints in DMA mode, this bit must be set to be able to transfer SETUP data packets in memory.

30 EPDIS 0 RW1H Endpoint Disable

The application sets this bit to stop transmitting/receiving data on an endpoint, even before the transfer for that endpoint is complete.

The application must wait for the Endpoint Disabled interrupt before treating the endpoint as disabled. The core clears this bit before

setting the Endpoint Disabled interrupt. The application must set this bit only if Endpoint Enable is already set for this endpoint.

29 SETD1PIDOF 0 W1 Set DATA1 PID / Odd Frame

For bulk and interrupt endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field in this register

to DATA1ODD.

For isochronous endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field to odd (DATA1ODD).

28 SETD0PIDEF 0 W1 Set DATA0 PID / Even Frame

For bulk and interrupt endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field in this register

to DATA0EVEN.

For isochronous endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field to odd (DATA0EVEN).

27 SNAK 0 W1 Set NAK

A write to this bit sets the NAK bit for the endpoint. Using this bit, the application can control the transmission of NAK handshakes

on an endpoint. The core can also set this bit for an endpoint after a SETUP packet is received on that endpoint.

26 CNAK 0 W1 Clear NAK

A write to this bit clears the NAK bit for the endpoint.

25:22 TXFNUM 0x0 RW TxFIFO Number

These bits specify the FIFO number associated with this endpoint. Each active IN endpoint must be programmed to a separate FIFO

number. This field is valid only for IN endpoints.

21 STALL 0 RW1H Handshake

For bulk and interrupt endpoints: The application sets this bit to stall all tokens from the USB host to this endpoint. If a NAK bit, Global

Non-periodic IN NAK, or Global OUT NAK is set along with this bit, the STALL bit takes priority. In this case only the application

can clear this bit, never the core.

When control endpoint: The application can only set this bit, and the core clears it, when a SETUP token is received for this endpoint.

If a NAK bit, Global Non-periodic IN NAK, or Global OUT NAK is set along with this bit, the STALL bit takes priority. Irrespective of

this bit's setting, the core always responds to SETUP data packets with an ACK handshake.

20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:18 EPTYPE 0x0 RW Endpoint Type

This is the transfer type supported by this logical endpoint.

Value Mode Description

0 CONTROL Control Endpoint.

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Bit Name Reset Access Description

Value Mode Description

1 ISO Isochronous Endpoint.

2 BULK Bulk Endpoint.

3 INT Interrupt Endpoint.

17 NAKSTS 0 R NAK Status

When this bit is 0 the core is transmitting non-NAK handshakes based on the FIFO status. When this bit is 1 the core is transmitting

NAK handshakes on this endpoint. When either the application or the core sets this bit the core stops receiving any data on an OUT

endpoint, even if there is space in the RxFIFO to accommodate the incoming packet. For non-isochronous IN endpoints the core

stops transmitting any data on an IN endpoint, even if there data is available in the TxFIFO. For isochronous IN endpoints the core

sends out a zero-length data packet, even if there data is available in the TxFIFO. Irrespective of this bit's setting, the core always

responds to SETUP data packets with an ACK handshake.

16 DPIDEOF 0 R Endpoint Data PID / Even or Odd Frame

For interrupt/bulk endpoints this field contains the PID of the packet to be received or transmitted on this endpoint. The application

must program the PID of the first packet to be received or transmitted on this endpoint, after the endpoint is activated. The applications

use the SETD1PIDOF and SETD0PIDEF fields of this register to program either DATA0 or DATA1 PID. For isochronous endpoints,

this field indicates the frame number in which the core transmits/receives isochronous data for this endpoint. The application must

program the even/odd frame number in which it intends to transmit/receive isochronous data for this endpoint using the SETD0PIDEF

and SETD1PIDOF fields in this register.

Value Mode Description

0 DATA0EVEN DATA0 PID / Even Frame.

1 DATA1ODD DATA1 PID / Odd Frame.

15 USBACTEP 0 RW USB Active Endpoint

Indicates whether this endpoint is active in the current configuration and interface. The core clears this bit for all endpoints after

detecting a USB reset. After receiving the SetConfiguration and SetInterface commands, the application must program endpoint

registers accordingly and set this bit.

14:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:0 MPS 0x000 RW Maximum Packet Size

The application must program this field with the maximum packet size for the current logical endpoint. This value is in bytes.

15.6.56 USB_DIEPx_INT - Device IN Endpoint x+1 Interrupt Register

This register indicates the status of an endpoint with respect to USB- and AHB-related events. The

application must read this register when the IN Endpoints Interrupt bit of the Core Interrupt register

(USB_GINTSTS.IEPINT) is set. Before the application can read this register, it must first read the

Device All Endpoints Interrupt (USB_DAINT) register to get the exact endpoint number for the Device

Endpoint x+1 Interrupt register. The application must clear the appropriate bit in this register to clear the

corresponding bits in the USB_DAINT and USB_GINTSTS registers.

Offset Bit Position

0x3C928

Reset

Access

RW1H

Name

NAKINTRPT

BBLEERR

PKTDRPSTS

TXFEMP

INEPNAKEFF

INTKNTXFEMP

TIMEOUT

AHBERR

EPDISBLD

XFERCOMPL

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 NAKINTRPT 0 RW1H NAK Interrupt

The core generates this interrupt when a NAK is transmitted or received by the device. In case of isochronous IN endpoints the

interrupt gets generated when a zero length packet is transmitted due to un-availability of data in the TXFifo.

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Bit Name Reset Access Description

12 BBLEERR 0 RW1H NAK Interrupt

The core generates this interrupt when babble is received for the endpoint.

11 PKTDRPSTS 0 RW1H Packet Drop Status

This bit indicates to the application that an ISO OUT packet has been dropped. This bit does not have an associated mask bit and

does not generate an interrupt.

10:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 TXFEMP 1 R Transmit FIFO Empty

This interrupt is asserted when the TxFIFO for this endpoint is either half or completely empty. The half or completely empty status

is determined by the TxFIFO Empty Level bit in the Core AHB Configuration register (USB_GAHBCFG.NPTXFEMPLVL).

6 INEPNAKEFF 0 RW1H IN Endpoint NAK Effective

Applies to periodic IN endpoints only. This bit can be cleared when the application clears the IN endpoint NAK by writing to

USB_DIEPx_CTL.CNAK. This interrupt indicates that the core has sampled the NAK bit set (either by the application or by the

core). The interrupt indicates that the IN endpoint NAK bit set by the application has taken effect in the core. This interrupt does not

guarantee that a NAK handshake is sent on the USB. A STALL bit takes priority over a NAK bit.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 INTKNTXFEMP 0 RW1H IN Token Received When TxFIFO is Empty

Applies to non-periodic IN endpoints only. Indicates that an IN token was received when the associated TxFIFO (periodic/non-

periodic) was empty. This interrupt is asserted on the endpoint for which the IN token was received.

3 TIMEOUT 0 RW1H Timeout Condition

Applies only to Control IN endpoints. Indicates that the core has detected a timeout condition on the USB for the last IN token on

this endpoint.

2 AHBERR 0 RW1H AHB Error

This is generated only in DMA mode when there is an AHB error during an AHB read/write. The application can read the corresponding

endpoint DMA address register to get the error address.

1 EPDISBLD 0 RW1H Endpoint Disabled Interrupt

This bit indicates that the endpoint is disabled per the application's request.

0 XFERCOMPL 0 RW1H Transfer Completed Interrupt

This field indicates that the programmed transfer is complete on the AHB as well as on the USB, for this endpoint.

15.6.57 USB_DIEPx_TSIZ - Device IN Endpoint x+1 Transfer Size Register

The application must modify this register before enabling the endpoint. Once the endpoint is enabled

using Endpoint Enable bit of the Device Endpoint x+1 Control register (USB_DIEPx_CTL.EPENA), the

core modifies this register. The application can only read this register once the core has cleared the

Endpoint Enable bit.

Offset Bit Position

0x3C930

Reset

0x0

0x000

0x00000

Access

Name

PKTCNT

XFERSIZE

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

30:29 MC 0x0 RW Multi Count

For periodic IN endpoints, this field indicates the number of packets that must be transmitted per frame on the USB. The core uses

this field to calculate the data PID for isochronous IN endpoints.

28:19 PKTCNT 0x000 RW Packet Count

Indicates the total number of USB packets that constitute the Transfer Size amount of data. This field is decremented every time a

packet (maximum size or short packet) is read from the TxFIFO.

18:0 XFERSIZE 0x00000 RW Transfer Size

Indicates the transfer size in bytes. The core interrupts the application only after it has exhausted the transfer size amount of data.

The transfer size can be set to the maximum packet size of the endpoint, to be interrupted at the end of each packet. The core

decrements this field every time a packet from the external memory is written to the TxFIFO.

15.6.58 USB_DIEPx_DMAADDR - Device IN Endpoint x+1 DMA Address

Offset Bit Position

0x3C934

Reset

0xXXXXXXXX

Access

Name

DMAADDR

Bit Name Reset Access Description

31:0 DMAADDR 0xXXXXXXXX RW DMA Address

Holds the start address of the external memory for fetching endpoint data. For control endpoints, this field stores control OUT data

packets as well as SETUP transaction data packets. When more than three SETUP packets are received back-to-back, the SETUP

data packet in the memory is overwritten. This register is incremented on every AHB transaction. The application can give only a

DWORD-aligned address. The data for this register field is stored in RAM. Thus, the reset value is undefined (X).

15.6.59 USB_DIEPx_TXFSTS - Device IN Endpoint x+1 Transmit FIFO

Status Register

This read-only register contains the free space information for the Device IN endpoint TxFIFO.

Offset Bit Position

0x3C938

Reset

0x0200

Access

Name

SPCAVAIL

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Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 SPCAVAIL 0x0200 R TxFIFO Space Available

Indicates the amount of free space available in the Endpoint TxFIFO. Values are in terms of 32-bit words.

15.6.60 USB_DOEP0CTL - Device OUT Endpoint 0 Control Register

The application uses this register to control the behavior of each logical endpoint other than endpoint 0.

Offset Bit Position

0x3CB00

Reset

0x0

Access

RW1H

Name

EPENA

EPDIS

SNAK

CNAK

STALL

SNP

EPTYPE

NAKSTS

USBACTEP

MPS

Bit Name Reset Access Description

31 EPENA 0 RW1H Endpoint Enable

In DMA mode this bit indicates that the application has allocated the memory to start receiving data from the USB. The core clears

this bit before setting any of the following interrupts on this endpoint: SETUP Phase Done, Endpoint Disabled, Transfer Completed.

In DMA mode, this bit must be set for the core to transfer SETUP data packets into memory.

30 EPDIS 0 R Endpoint Disable

This bit is always 0. The application cannot disable control OUT endpoint 0.

29:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27 SNAK 0 W1 Set NAK

A write to this bit sets the NAK bit for the endpoint. Using this bit, the application can control the transmission of NAK handshakes

on an endpoint. The core can also set bit on a Transfer Completed interrupt, or after a SETUP is received on the endpoint.

26 CNAK 0 W1 Clear NAK

A write to this bit clears the NAK bit for the endpoint.

25:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21 STALL 0 RW1H Handshake

The application can only set this bit, and the core clears it, when a SETUP token is received for this endpoint. If a NAK bit or Global

OUT NAK is set along with this bit, the STALL bit takes priority. Irrespective of this bit's setting, the core always responds to SETUP

data packets with an ACK handshake.

20 SNP 0 RW Snoop Mode

This bit configures the endpoint to Snoop mode. In Snoop mode, the core does not check the correctness of OUT packets before

transferring them to application memory.

19:18 EPTYPE 0x0 R Endpoint Type

Hardcoded to 0. Endpoint 0 is always a control endpoint.

17 NAKSTS 0 R NAK Status

When this bit is 0 the core is transmitting non-NAK handshakes based on the FIFO status. When this bit is 1 the core is transmitting

NAK handshakes on this endpoint. When either the application or the core sets this bit, the core stops receiving data, even if there

is space in the RxFIFO to accommodate the incoming packet. Irrespective of this bit's setting, the core always responds to SETUP

data packets with an ACK handshake.

16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 USBACTEP 1 R USB Active Endpoint

This bit is always 1, indicating that a control endpoint 0 is always active in all configurations and interfaces.

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Bit Name Reset Access Description

14:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 MPS 0x0 R Maximum Packet Size

The maximum packet size for control OUT endpoint 0 is the same as what is programmed in control IN Endpoint 0.

Value Mode Description

0 64B 64 bytes.

1 32B 32 bytes.

2 16B 16 bytes.

3 8B 8 bytes.

15.6.61 USB_DOEP0INT - Device OUT Endpoint 0 Interrupt Register

This register indicates the status of endpoint 0 with respect to USB- and AHB-related events. The

application must read this register when the OUT Endpoints Interrupt bit of the Core Interrupt register

(USB_GINTSTS.OEPINT) is set. Before the application can read this register, it must first read the

Device All Endpoints Interrupt (USB_DAINT) register to get the exact endpoint number for the Device

Endpoint Interrupt register. The application must clear the appropriate bit in this register to clear the

corresponding bits in the USB_DAINT and USB_GINTSTS registers.

Offset Bit Position

0x3CB08

Reset

Access

RW1H

Name

NAKINTRPT

BBLEERR

PKTDRPSTS

BACK2BACKSETUP

OUTTKNEPDIS

SETUP

AHBERR

EPDISBLD

XFERCOMPL

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 NAKINTRPT 0 RW1H NAK Interrupt

The core generates this interrupt when a NAK is transmitted or received by the device. In case of isochronous IN endpoints the

interrupt gets generated when a zero length packet is transmitted due to un-availability of data in the TXFifo.

12 BBLEERR 0 RW1H NAK Interrupt

The core generates this interrupt when babble is received for the endpoint.

11 PKTDRPSTS 0 RW1H Packet Drop Status

This bit indicates to the application that an ISO OUT packet has been dropped. This bit does not have an associated mask bit and

does not generate an interrupt.

10:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 BACK2BACKSETUP 0 RW1H Back-to-Back SETUP Packets Received

This bit indicates that the core has received more than three back-to-back SETUP packets for this particular endpoint.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 OUTTKNEPDIS 0 RW1H OUT Token Received When Endpoint Disabled

Indicates that an OUT token was received when the endpoint was not yet enabled. This interrupt is asserted on the endpoint for

which the OUT token was received.

3 SETUP 0 RW1H Setup Phase Done

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Bit Name Reset Access Description

Indicates that the SETUP phase for the control endpoint is complete and no more back-to-back SETUP packets were received for

the current control transfer. On this interrupt, the application can decode the received SETUP data packet.

2 AHBERR 0 RW1H AHB Error

This is generated only in DMA mode when there is an AHB error during an AHB read/write. The application can read the corresponding

endpoint DMA address register to get the error address.

1 EPDISBLD 0 RW1H Endpoint Disabled Interrupt

This bit indicates that the endpoint is disabled per the application's request.

0 XFERCOMPL 0 RW1H Transfer Completed Interrupt

This field indicates that the programmed transfer is complete on the AHB as well as on the USB, for this endpoint.

15.6.62 USB_DOEP0TSIZ - Device OUT Endpoint 0 Transfer Size Register

The application must modify this register before enabling the endpoint. Once the endpoint is enabled

using Endpoint Enable bit of the Device Endpoint x+1 Control register (USB_DOEPx_CTL.EPENA), the

core modifies this register. The application can only read this register once the core has cleared the

Endpoint Enable bit.

Offset Bit Position

0x3CB10

Reset

0x0

0x00

Access

Name

SUPCNT

PKTCNT

XFERSIZE

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:29 SUPCNT 0x0 RW SETUP Packet Count

This field specifies the number of back-to-back SETUP data packets the endpoint can receive.

28:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19 PKTCNT 0 RW Packet Count

This field is decremented to zero after a packet is written into the RxFIFO.

18:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:0 XFERSIZE 0x00 RW Transfer Size

Indicates the transfer size in bytes for endpoint 0. The core interrupts the application only after it has exhausted the transfer size

amount of data. The transfer size can be set to the maximum packet size of the endpoint, to be interrupted at the end of each packet.

The core decrements this field every time a packet is read from the RxFIFO and written to the external memory.

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15.6.63 USB_DOEP0DMAADDR - Device OUT Endpoint 0 DMA Address

Offset Bit Position

0x3CB14

Reset

0xXXXXXXXX

Access

Name

DOEP0DMAADDR

Bit Name Reset Access Description

31:0 DOEP0DMAADDR 0xXXXXXXXX RW DMA Address

Holds the start address of the external memory for storing endpoint data. For control endpoints, this field stores control OUT data

packets as well as SETUP transaction data packets. When more than three SETUP packets are received back-to-back, the SETUP

data packet in the memory is overwritten. This register is incremented on every AHB transaction. The application can give only a

DWORD-aligned address. The data for this register field is stored in RAM. Thus, the reset value is undefined (X).

15.6.64 USB_DOEPx_CTL - Device OUT Endpoint x+1 Control Register

The application uses this register to control the behavior of each logical endpoint other than endpoint 0.

Offset Bit Position

0x3CB20

Reset

0x0

0x000

Access

RW1H

Name

EPENA

EPDIS

SETD1PIDOF

SETD0PIDEF

SNAK

CNAK

STALL

SNP

EPTYPE

NAKSTS

DPIDEOF

USBACTEP

MPS

Bit Name Reset Access Description

31 EPENA 0 RW1H Endpoint Enable

In DMA mode this bit indicates that the application has allocated the memory to start receiving data from the USB. The core clears

this bit before setting any of the following interrupts on this endpoint: SETUP Phase Done, Endpoint Disabled, Transfer Completed.

For control endpoints in DMA mode, this bit must be set to be able to transfer SETUP data packets in memory.

30 EPDIS 0 RW1H Endpoint Disable

The application sets this bit to stop transmitting/receiving data on an endpoint, even before the transfer for that endpoint is complete.

The application must wait for the Endpoint Disabled interrupt before treating the endpoint as disabled. The core clears this bit before

setting the Endpoint Disabled interrupt. The application must set this bit only if Endpoint Enable is already set for this endpoint.

29 SETD1PIDOF 0 W1 Set DATA1 PID / Odd Frame

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Bit Name Reset Access Description

For bulk and interrupt endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field in this register

to DATA1ODD. For isochronous endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field to

odd (DATA1ODD).

28 SETD0PIDEF 0 W1 Set DATA0 PID / Even Frame

For bulk and interrupt endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field in this register

to DATA0EVEN. For isochronous endpoints writing this field sets the Endpoint Data PID / Even or Odd Frame (DPIDEOF) field to

odd (DATA0EVEN).

27 SNAK 0 W1 Set NAK

A write to this bit sets the NAK bit for the endpoint. Using this bit, the application can control the transmission of NAK handshakes

on an endpoint. The core can also set this bit for an endpoint after a SETUP packet is received on that endpoint.

26 CNAK 0 W1 Clear NAK

A write to this bit clears the NAK bit for the endpoint.

25:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21 STALL 0 RW1H STALL Handshake

For non-control, non-isochronous endpoints: The application sets this bit to stall all tokens from the USB host to this endpoint. If a

NAK bit, Global Non-periodic IN NAK, or Global OUT NAK is set along with this bit, the STALL bit takes priority. Only the application

can clear this bit, never the core.

For control endpoints: The application can only set this bit, and the core clears it, when a SETUP token is received for this endpoint.

If a NAK bit, Global Non-periodic IN NAK, or Global OUT NAK is set along with this bit, the STALL bit takes priority. Irrespective of

this bit's setting, the core always responds to SETUP data packets with an ACK handshake.

20 SNP 0 RW Snoop Mode

This bit configures the endpoint to Snoop mode. In Snoop mode, the core does not check the correctness of OUT packets before

transferring them to application memory.

19:18 EPTYPE 0x0 RW Endpoint Type

This is the transfer type supported by this logical endpoint.

Value Mode Description

0 CONTROL Control Endpoint.

1 ISO Isochronous Endpoint.

2 BULK Bulk Endpoint.

3 INT Interrupt Endpoint.

17 NAKSTS 0 R NAK Status

When this bit is 0 the core is transmitting non-NAK handshakes based on the FIFO status. When this bit is 1 the core is transmitting

NAK handshakes on this endpoint. When either the application or the core sets this bit the core stops receiving any data on an OUT

endpoint, even if there is space in the RxFIFO to accommodate the incoming packet. Irrespective of this bit's setting, the core always

responds to SETUP data packets with an ACK handshake.

16 DPIDEOF 0 R Endpoint Data PID / Even-odd Frame

For interrupt/bulk endpoints: Contains the PID of the packet to be received or transmitted on this endpoint. The application must

program the PID of the first packet to be received or transmitted on this endpoint, after the endpoint is activated. The application use

the SETD1PIDOF and SETD0PIDEF fields of this register to program either DATA0 or DATA1 PID.

For isochronous endpoints: Indicates the frame number in which the core transmits/receives isochronous data for this endpoint. The

application must program the even/odd frame number in which it intends to transmit/receive isochronous data for this endpoint using

the SETD1PIDOF and SETD0PIDEF fields in this register.

Value Mode Description

0 DATA0EVEN DATA0 PID / Even Frame.

1 DATA1ODD DATA1 PID / Odd Frame.

15 USBACTEP 0 RW USB Active Endpoint

Indicates whether this endpoint is active in the current configuration and interface. The core clears this bit for all endpoints after

detecting a USB reset. After receiving the SetConfiguration and SetInterface commands, the application must program endpoint

registers accordingly and set this bit.

14:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:0 MPS 0x000 RW Maximum Packet Size

The application must program this field with the maximum packet size for the current logical endpoint. This value is in bytes.

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15.6.65 USB_DOEPx_INT - Device OUT Endpoint x+1 Interrupt Register

This register indicates the status of an endpoint with respect to USB- and AHB-related events. The

application must read this register when the OUT Endpoints Interrupt bit of the Core Interrupt register

(USB_GINTSTS.OEPINT) is set. Before the application can read this register, it must first read the

Device All Endpoints Interrupt (USB_DAINT) register to get the exact endpoint number for the Device

Endpoint Interrupt register. The application must clear the appropriate bit in this register to clear the

corresponding bits in the USB_DAINT and USB_GINTSTS registers.

Offset Bit Position

0x3CB28

Reset

Access

RW1H

Name

NAKINTRPT

BBLEERR

PKTDRPSTS

BACK2BACKSETUP

OUTTKNEPDIS

SETUP

AHBERR

EPDISBLD

XFERCOMPL

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 NAKINTRPT 0 RW1H NAK Interrupt

The core generates this interrupt when a NAK is transmitted or received by the device.

12 BBLEERR 0 RW1H Babble Error

The core generates this interrupt when babble is received for the endpoint.

11 PKTDRPSTS 0 RW1H Packet Drop Status

This bit indicates to the application that an ISO OUT packet has been dropped. This bit does not have an associated mask bit and

does not generate an interrupt.

10:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 BACK2BACKSETUP 0 RW1H Back-to-Back SETUP Packets Received

Applies to Control OUT endpoints only. This bit indicates that the core has received more than three back-to-back SETUP packets

for this particular endpoint.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 OUTTKNEPDIS 0 RW1H OUT Token Received When Endpoint Disabled

Applies only to control OUT endpoints. Indicates that an OUT token was received when the endpoint was not yet enabled. This

interrupt is asserted on the endpoint for which the OUT token was received.

3 SETUP 0 RW1H Setup Phase Done

Applies to control OUT endpoints only. Indicates that the SETUP phase for the control endpoint is complete and no more back-

to-back SETUP packets were received for the current control transfer. On this interrupt, the application can decode the received

SETUP data packet.

2 AHBERR 0 RW1H AHB Error

This is generated only in DMA mode when there is an AHB error during an AHB read/write. The application can read the corresponding

endpoint DMA address register to get the error address.

1 EPDISBLD 0 RW1H Endpoint Disabled Interrupt

This bit indicates that the endpoint is disabled per the application's request.

0 XFERCOMPL 0 RW1H Transfer Completed Interrupt

This field indicates that the programmed transfer is complete on the AHB as well as on the USB, for this endpoint.

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15.6.66 USB_DOEPx_TSIZ - Device OUT Endpoint x+1 Transfer Size

The application must modify this register before enabling the endpoint. Once the endpoint is enabled

using Endpoint Enable bit of the Device Endpoint x+1 Control register (USB_DOEPx_CTL.EPENA), the

core modifies this register. The application can only read this register once the core has cleared the

Endpoint Enable bit.

Offset Bit Position

0x3CB30

Reset

0x0

0x000

0x00000

Access

Name

RXDPIDSUPCNT

PKTCNT

XFERSIZE

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:29 RXDPIDSUPCNT 0x0 R Receive Data PID / SETUP Packet Count

For isochronous OUT endpoints: This is the data PID received in the last packet for this endpoint.

For control OUT Endpoints: This field specifies the number of back-to-back SETUP data packets the endpoint can receive.

Value Mode Description

0 DATA0 DATA0 PID.

1 DATA2 DATA2 PID / 1 Packet.

2 DATA1 DATA1 PID / 2 Packets.

3 MDATA MDATA PID / 3 Packets.

28:19 PKTCNT 0x000 RW Packet Count

This field is decremented to zero after a packet is written into the RxFIFO.

18:0 XFERSIZE 0x00000 RW Transfer Size

Indicates the transfer size in bytes. The core interrupts the application only after it has exhausted the transfer size amount of data.

The transfer size can be set to the maximum packet size of the endpoint, to be interrupted at the end of each packet. The core

decrements this field every time a packet is read from the RxFIFO and written to the external memory.

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15.6.67 USB_DOEPx_DMAADDR - Device OUT Endpoint x+1 DMA Address

Offset Bit Position

0x3CB34

Reset

0xXXXXXXXX

Access

Name

DMAADDR

Bit Name Reset Access Description

31:0 DMAADDR 0xXXXXXXXX RW DMA Address

Holds the start address of the external memory for storing endpoint data. For control endpoints, this field stores control OUT data

packets as well as SETUP transaction data packets. When more than three SETUP packets are received back-to-back, the SETUP

data packet in the memory is overwritten. This register is incremented on every AHB transaction. The application can give only a

DWORD-aligned address. The data for this register field is stored in RAM. Thus, the reset value is undefined (X).

15.6.68 USB_PCGCCTL - Power and Clock Gating Control Register

This register is available in Host and Device modes. The application use this register to control the core's

power-down and clock gating features.

Offset Bit Position

0x3CE00

Reset

Access

Name

RESETAFTERSUSP

PHYSLEEP

RSTPDWNMODULE

PWRCLMP

GATEHCLK

STOPPCLK

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 RESETAFTERSUSP 0 R Reset after suspend

When exiting EM2, this bit needs to be set in host mode before clamp is removed if the host needs to issue reset after suspend. If

this bit is not set, then the host issues resume after suspend. This bit is not applicable in device mode and when EM2 is not used.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 PHYSLEEP 0 R PHY In Sleep

Indicates that the PHY is in Sleep State.

5:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 RSTPDWNMODULE 0 RW Reset Power-Down Modules

The application sets this bit to reset the part of the USB that is powered down during EM2. The application clears this bit to release

reset after an waking up from EM2 when the PHY clock is back at 48/6 MHz. Accessing core registers is possible only when this

bit is set to 0.

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Bit Name Reset Access Description

2 PWRCLMP 0 RW Power Clamp

The application sets this bit before the power is turned off to clamp the signals between the power-on modules and the power-off

modules of the USB core. The application clears the bit to disable the clamping.

1 GATEHCLK 0 RW Gate HCLK

The application sets this bit to gate the clock (HCLK) to modules other than the AHB Slave and Master and wakeup logic when the

USB is suspended or the session is not valid. The application clears this bit when the USB is resumed or a new session starts.

0 STOPPCLK 0 RW Stop PHY clock

The application sets this bit to stop the PHY clock when the USB is suspended, the session is not valid, or the device is disconnected.

The application clears this bit when the USB is resumed or a new session starts.

15.6.69 USB_FIFO0Dx - Device EP 0/Host Channel 0 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 0 or channel 0, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x3D000

Reset

0xXXXXXXXX

Access

Name

FIFO0D

Bit Name Reset Access Description

31:0 FIFO0D 0xXXXXXXXX RW Device EP 0/Host Channel 0 FIFO

FIFO 0 push/pop region. Used in slave mode.

15.6.70 USB_FIFO1Dx - Device EP 1/Host Channel 1 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 1 or channel 1, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x3E000

Reset

0xXXXXXXXX

Access

Name

FIFO1D

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Bit Name Reset Access Description

31:0 FIFO1D 0xXXXXXXXX RW Device EP 1/Host Channel 1 FIFO

FIFO 1 push/pop region. Used in slave mode.

15.6.71 USB_FIFO2Dx - Device EP 2/Host Channel 2 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 2 or channel 2, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x3F000

Reset

0xXXXXXXXX

Access

Name

FIFO2D

Bit Name Reset Access Description

31:0 FIFO2D 0xXXXXXXXX RW Device EP 2/Host Channel 2 FIFO

FIFO 2 push/pop region. Used in slave mode.

15.6.72 USB_FIFO3Dx - Device EP 3/Host Channel 3 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 3 or channel 3, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x40000

Reset

0xXXXXXXXX

Access

Name

FIFO3D

Bit Name Reset Access Description

31:0 FIFO3D 0xXXXXXXXX RW Device EP 3/Host Channel 3 FIFO

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Bit Name Reset Access Description

FIFO 3 push/pop region. Used in slave mode.

15.6.73 USB_FIFO4Dx - Device EP 4/Host Channel 4 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 4 or channel 4, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x41000

Reset

0xXXXXXXXX

Access

Name

FIFO4D

Bit Name Reset Access Description

31:0 FIFO4D 0xXXXXXXXX RW Device EP 4/Host Channel 4 FIFO

FIFO 4 push/pop region. Used in slave mode.

15.6.74 USB_FIFO5Dx - Device EP 5/Host Channel 5 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 5 or channel 5, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x42000

Reset

0xXXXXXXXX

Access

Name

FIFO5D

Bit Name Reset Access Description

31:0 FIFO5D 0xXXXXXXXX RW Device EP 5/Host Channel 5 FIFO

FIFO 5 push/pop region. Used in slave mode.

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15.6.75 USB_FIFO6Dx - Device EP 6/Host Channel 6 FIFO

This register, available in both Host and Device modes, is used to read or write the FIFO space for

endpoint 6 or channel 6, in a given direction. If a host channel is of type IN, the FIFO can only be read

on the channel. Similarly, if a host channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x43000

Reset

0xXXXXXXXX

Access

Name

FIFO6D

Bit Name Reset Access Description

31:0 FIFO6D 0xXXXXXXXX RW Device EP 6/Host Channel 6 FIFO

FIFO 6 push/pop region. Used in slave mode.

15.6.76 USB_FIFO7Dx - Host Channel 7 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 7, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x44000

Reset

0xXXXXXXXX

Access

Name

FIFO7D

Bit Name Reset Access Description

31:0 FIFO7D 0xXXXXXXXX RW Host Channel 7 FIFO

FIFO 7 push/pop region. Used in slave mode.

15.6.77 USB_FIFO8Dx - Host Channel 8 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 8, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

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Offset Bit Position

0x45000

Reset

0xXXXXXXXX

Access

Name

FIFO8D

Bit Name Reset Access Description

31:0 FIFO8D 0xXXXXXXXX RW Host Channel 8 FIFO

FIFO 8 push/pop region. Used in slave mode.

15.6.78 USB_FIFO9Dx - Host Channel 9 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 9, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x46000

Reset

0xXXXXXXXX

Access

Name

FIFO9D

Bit Name Reset Access Description

31:0 FIFO9D 0xXXXXXXXX RW Host Channel 9 FIFO

FIFO 9 push/pop region. Used in slave mode.

15.6.79 USB_FIFO10Dx - Host Channel 10 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 10, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

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Offset Bit Position

0x47000

Reset

0xXXXXXXXX

Access

Name

FIFO10D

Bit Name Reset Access Description

31:0 FIFO10D 0xXXXXXXXX RW Host Channel 10 FIFO

FIFO 10 push/pop region. Used in slave mode.

15.6.80 USB_FIFO11Dx - Host Channel 11 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 11, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x48000

Reset

0xXXXXXXXX

Access

Name

FIFO11D

Bit Name Reset Access Description

31:0 FIFO11D 0xXXXXXXXX RW Host Channel 11 FIFO

FIFO 11 push/pop region. Used in slave mode.

15.6.81 USB_FIFO12Dx - Host Channel 12 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 12, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

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Offset Bit Position

0x49000

Reset

0xXXXXXXXX

Access

Name

FIFO12D

Bit Name Reset Access Description

31:0 FIFO12D 0xXXXXXXXX RW Host Channel 12 FIFO

FIFO 12 push/pop region. Used in slave mode.

15.6.82 USB_FIFO13Dx - Host Channel 13 FIFO

This register, available in Host mode, is used to read or write the FIFO space for channel 13, in a given

direction. If a host channel is of type IN, the FIFO can only be read on the channel. Similarly, if a host

channel is of type OUT, the FIFO can only be written on the channel.

Offset Bit Position

0x4A000

Reset

0xXXXXXXXX

Access

Name

FIFO13D

Bit Name Reset Access Description

31:0 FIFO13D 0xXXXXXXXX RW Host Channel 13 FIFO

FIFO 13 push/pop region. Used in slave mode.

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15.6.83 USB_FIFORAMx - Direct Access to Data FIFO RAM for Debugging

(2 KB)

Offset Bit Position

0x5C000

Reset

0xXXXXXXXX

Access

Name

FIFORAM

Bit Name Reset Access Description

31:0 FIFORAM 0xXXXXXXXX RW FIFO RAM

Direct Access to Data FIFO RAM for Debugging (2 KB)

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16 I2C - Inter-Integrated Circuit Interface

01 2 3 4

MCU

I2C master/slave

Other I2C

master Other I2C

slave

VDD

I2C

EEPROM

SDA

SCL

Quick Facts

What?

The I2C interface allows communication

on I2C-buses with the lowest energy

consumption possible.

Why?

I2C is a popular serial bus that enables

communication with a number of external

devices using only two I/O pins.

How?

With the help of DMA, the I2C interface

allows I2C communication with minimal CPU

intervention. Address recognition is available

in all energy modes (except EM4), allowing

the MCU to wait for data on the I2C-bus with

sub-µA current consumption.

16.1 Introduction

The I2C module provides an interface between the MCU and a serial I2C-bus. It is capable of acting

as both master and slave, and supports multi-master buses. Standard-mode, fast-mode and fast-mode

plus speeds are supported, allowing transmission rates all the way from 10 kbit/s up to 1 Mbit/s. Slave

arbitration and timeouts are also provided to allow implementation of an SMBus compliant system. The

interface provided to software by the I2C module allows both fine-grained control of the transmission

process and close to automatic transfers. Automatic recognition of slave addresses is provided in all

energy modes (except EM4).

16.2 Features

• True multi-master capability

• Support for different bus speeds

• Standard-mode (Sm) bit rate up to 100 kbit/s

• Fast-mode (Fm) bit rate up to 400 kbit/s

• Fast-mode Plus (Fm+) bit rate up to 1 Mbit/s

• Arbitration for both master and slave (allows SMBus ARP)

• Clock synchronization and clock stretching

• Hardware address recognition

• 7-bit masked address

• General call address

• Active in all energy modes (except EM4)

• 10-bit address support

• Error handling

• Clock low timeout

• Clock high timeout

• Arbitration lost

• Bus error detection

• Double buffered data

• Full DMA support

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16.3 Functional Description

An overview of the I2C module is shown in Figure 16.1 (p. 414) .

Figure 16.1. I2C Overview

Transmit Buffer

Transmit

Shift Register

I2Cn_SDA

Receive Buffer

Receive

Shift Register

I2C Control and

Status

Peripheral Bus

I2Cn_SCL

ctrl

Symbol

Generator

Receive

Controller Clock generator

Address

Recognizer

16.3.1 I2C-Bus Overview

The I2C-bus uses two wires for communication; a serial data line (SDA) and a serial clock line (SCL) as

shown in Figure 16.2 (p. 414) . As a true multi-master bus it includes collision detection and arbitration

to resolve situations where multiple masters transmit data at the same time without data loss.

Figure 16.2. I2C-Bus Example

I2C master

#1 I2C master

#2 I2C slave

#1 I2C slave

#2 I2C slave

SDA

SCL

VDD

Each device on the bus is addressable by a unique address, and an I2C master can address all the

devices on the bus, including other masters.

Both the bus lines are open-drain. The maximum value of the pull-up resistor can be calculated as a

function of the maximal rise-time tr for the given bus speed, and the estimated bus capacitance Cb as

shown in Equation 16.1 (p. 414) .

I2C Pull-up Resistor Equation

Rp(max) = (tr/0.8473) x Cb. (16.1)

The maximal rise times for 100 kHz, 400 kHz and 1 MHz I2C are 1 µs, 300 ns and 120 ns respectively.

Note The GPIO drive strength can be used to control slew rate.

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Note If Vdd drops below the voltage on SCL and SDA lines, the MCU could become back

powered and pull the SCL and SDA lines low.

16.3.1.1 START and STOP Conditions

START and STOP conditions are used to initiate and stop transactions on the I2C-bus. All transactions on

the bus begin with a START condition (S) and end with a STOP condition (P). As shown in Figure 16.3 (p.

415) , a START condition is generated by pulling the SDA line low while SCL is high, and a STOP

condition is generated by pulling the SDA line high while SCL is high.

Figure 16.3. I2C START and STOP Conditions

SCL

SDA

S P

START condition STOP condition

The START and STOP conditions are easily identifiable bus events as they are the only conditions on

the bus where a transition is allowed on SDA while SCL is high. During the actual data transmission, SDA

is only allowed to change while SCL is low, and must be stable while SCL is high. One bit is transferred

per clock pulse on the I2C-bus as shown in Figure 16.2 (p. 414) .

Figure 16.4. I2C Bit Transfer on I2C-Bus

SCL

SDA

Data stable Data change

allowed

Data change

allowed

16.3.1.2 Bus Transfer

When a master wants to initiate a transfer on the bus, it waits until the bus is idle and transmits a START

condition on the bus. The master then transmits the address of the slave it wishes to interact with and

a single R/W bit telling whether it wishes to read from the slave (R/W bit set to 1) or write to the slave

(R/W bit set to 0).

After the 7-bit address and the R/W bit, the master releases the bus, allowing the slave to acknowledge

the request. During the next bit-period, the slave pulls SDA low (ACK) if it acknowledges the request,

or keeps it high if it does not acknowledge it (NACK).

Following the address acknowledge, either the slave or master transmits data, depending on the value

of the R/W bit. After every 8 bits (one byte) transmitted on the SDA line, the transmitter releases the

line to allow the receiver to transmit an ACK or a NACK. Both the data and the address are transmitted

with the most significant bit first.

The number of bytes in a bus transfer is unrestricted. The master ends the transmission after a (N)ACK

by sending a STOP condition on the bus. After a STOP condition, any master wishing to initiate a transfer

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on the bus can try to gain control of it. If the current master wishes to make another transfer immediately

after the current, it can start a new transfer directly by transmitting a repeated START condition (Sr)

instead of a STOP followed by a START.

Examples of I2C transfers are shown in Figure 16.5 (p. 416) , Figure 16.6 (p. 416) , and Figure 16.7 (p.

416) . The identifiers used are:

• ADDR - Address

• DATA - Data

• S - Start bit

• Sr - Repeated start bit

• P - Stop bit

• W/R - Read(1)/Write(0)

• A - ACK

• N - NACK

Figure 16.5. I2C Single Byte Write to Slave

WS ADDR DATA AA P

Figure 16.6. I2C Double Byte Read from Slave

RS ADDR DATAA DATA NA P

Figure 16.7. I2C Single Byte Write, then Repeated Start and Single Byte Read

RSr ADDR DATAA N PWS ADDR DATAA A

16.3.1.3 Addresses

I2C supports both 7-bit and 10-bit addresses. When using 7-bit addresses, the first byte transmitted after

the START-condition contains the address of the slave that the master wants to contact. In the 7-bit

address space, several addresses are reserved. These addresses are summarized in Table 16.1 (p.

416) , and include a General Call address which can be used to broadcast a message to all slaves

on the I2C-bus.

Table 16.1. I2C Reserved I2C Addresses

I2C Address R/W Description

0000-000 0 General Call address

0000-000 1 START byte

0000-001 X Reserved for the C-Bus format

0000-010 X Reserved for a different bus format

0000-011 X Reserved for future purposes

0000-1XX X Reserved for future purposes

1111-1XX X Reserved for future purposes

1111-0XX X 10 Bit slave addressing mode

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16.3.1.4 10-bit Addressing

To address a slave using a 10-bit address, two bytes are required to specify the address instead of

one. The seven first bits of the first byte must then be 1111 0XX, where XX are the two most significant

bits of the 10-bit address. As with 7-bit addresses, the eight bit of the first byte determines whether the

master wishes to read from or write to the slave. The second byte contains the eight least significant

bits of the slave address.

When a slave receives a 10-bit address, it must acknowledge both the address bytes if they match the

address of the slave.

When performing a master transmitter operation, the master transmits the two address bytes and then

the remaining data, as shown in Figure 16.8 (p. 417) .

Figure 16.8. I2C Master Transmitter/Slave Receiver with 10-bit Address

WS A A DATA A PAddr (2nd byte)ADDR (1st 7 bits)

When performing a master receiver operation however, the master first transmits the two address bytes

in a master transmitter operation, then sends a repeated START followed by the first address byte and

then receives data from the addressed slave. The slave addressed by the 10-bit address in the first two

address bytes must remember that it was addressed, and respond with data if the address transmitted

after the repeated start matches its own address. An example of this (with one byte transmitted) is shown

in Figure 16.9 (p. 417) .

Figure 16.9. I2C Master Receiver/Slave Transmitter with 10-bit Address

RSr DATAA N PWS A AADDR (1st 7 bits) Addr (2nd byte) ADDR (1st 7 bits)

16.3.1.5 Arbitration, Clock Synchronization, Clock Stretching

Arbitration and clock synchronization are features aimed at allowing multi-master buses. Arbitration

occurs when two devices try to drive the bus at the same time. If one device drives it low, while the

other drives it high, the one attempting to drive it high will not be able to do so due to the open-drain

bus configuration. Both devices sample the bus, and the one that was unable to drive the bus in the

desired direction detects the collision and backs off, letting the other device continue communication

on the bus undisturbed.

Clock synchronization is a means of synchronizing the clock outputs from several masters driving the

bus at once, and is a requirement for effective arbitration.

Slaves on the bus are allowed to force the clock output on the bus low in order to pause the

communication on the bus and give themselves time to process data or perform any real-time tasks they

might have. This is called clock stretching.

Arbitration is supported by the I2C module for both masters and slaves. Clock synchronization and clock

stretching is also supported.

16.3.2 Enable and Reset

The I2C is enabled by setting the EN bit in the I2Cn_CTRL register. Whenever this bit is cleared, the

internal state of the I2C is reset, terminating any ongoing transfers.

Note

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When enabling the I2C, the ABORT command or the Bus Idle Timeout feature must be

applied prior to use even if the BUSY flag is not set.

16.3.3 Safely Disabling and Changing Slave Configuration

The I2C slave is partially asynchronous, and some precautions are necessary to always ensure a safe

slave disable or slave configuration change. These measures should be taken, if (while the slave is

enabled) the user cannot guarantee that an address match will not occur at the exact time of slave

disable or slave configuration change.

Worst case consequences for an address match while disabling slave or changing configuration is that

the slave may end up in an undefined state. To reset the slave back to a known state, the EN bit in

I2Cn_CTRL must be reset. This should be done regardless of whether the slave is going to be re-enabled

or not.

16.3.4 Clock Generation

The SCL signal generated by the I2C master determines the maximum transmission rate on the bus.

The clock is generated as a division of the peripheral clock, and is given by Equation 16.2 (p. 418) :

I2C Maximum Transmission Rate

fSCL = 1/(Tlow + Thigh), (16.2)

where

Tlow and Thigh is the low and high periods of the clock signal respectively, given below. When the clock

is not streched, the low and high periods of the clock signal are:

I2C High and Low Cycles Equations

Thigh = (Nhigh × (CLKDIV + 1))/fHFPERCLK,

Tlow = (Nlow × (CLKDIV + 1))/fHFPERCLK.(16.3)

Equation 16.3 (p. 418) and Equation 16.2 (p. 418) does not apply for low clock division factors (0,

1 and 2) because of synchronization. For these clock division factors, the formulas for computing high

and low periods of the clock signal are given in Table 16.2 (p. 418) .

Table 16.2. I2C High and Low Periods for Low CLKDIV

CLKDIV Standard (4:4) Asymmetric (6:3) Fast (11:6)

Tlow Thigh Tlow Thigh Tlow Thigh

0 7/fHFPERCLK 7/fHFPERCLK 9/fHFPERCLK 6/fHFPERCLK 14/fHFPERCLK 9/fHFPERCLK

1 10/fHFPERCLK 10/fHFPERCLK 14/fHFPERCLK 8/fHFPERCLK 24/fHFPERCLK 14/fHFPERCLK

2 15/fHFPERCLK 15/fHFPERCLK 21/fHFPERCLK 12/fHFPERCLK 36/fHFPERCLK 21/fHFPERCLK

The values of Nlow and Nhigh and thus the ratio between the high and low parts of the clock signal is

controlled by CLHR in the I2Cn_CTRL register. The available modes are summarized in Table 16.3 (p.

419) along with the highest I2C-bus frequencies in the given modes that can be achieved without

violating the timing specifications of the I2C-bus. The maximum data hold time is dependent on the DIV

and is given by:

Maximum Data Hold Time

tHD,DAT-max = (4+DIV)/fHFPERCLK. (16.4)

Note DIV must be set to 1 or higher during slave mode operation.

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Table 16.3. I2C Clock Mode

HFPERCLK

frequency (MHz) Clock Low High

Ratio (CLHR) Sm max frequency

(kHz) Fm max frequency

(kHz) Fm+ max frequency

(kHz)

0 92 400 1000

1 82 400 1000

2 72 400 842

0 92 400 1000

1 81 400 848

2 71 400 736

0 90 400 1000

1 80 400 954

2 72 368 552

0 92 400 1000

1 81 400 636

2 68 368 608

0 91 400 785

1 81 333 733

2 71 289 478

0 91 400 471

1 81 299 439

6.6

2 64 286 286

0 59 85 85

1 54 79 79

1.2

2 52 52 52

16.3.5 Arbitration

Arbitration is enabled by default, but can be disabled by setting the ARBDIS bit in I2Cn_CTRL. When

arbitration is enabled, the value on SDA is sensed every time the I2C module attempts to change its

value. If the sensed value is different than the value the I2C module tried to output, it is interpreted as a

simultaneous transmission by another device, and that the I2C module has lost arbitration.

Whenever arbitration is lost, the ARBLOST interrupt flag in I2Cn_IF is set, any lines held are released,

and the I2C device goes idle. If an I2C master loses arbitration during the transmission of an address,

another master may be trying to address it. The master therefore receives the rest of the address, and

if the address matches the slave address of the master, the master goes into either slave transmitter

or slave receiver mode.

Note Arbitration can be lost both when operating as a master and when operating as a slave.

16.3.6 Buffers

16.3.6.1 Transmit Buffer and Shift Register

The I2C transmitter is double buffered through the transmit buffer and transmit shift register as shown in

Figure 16.1 (p. 414) . A byte is loaded into the transmit buffer by writing to I2Cn_TXDATA. When the

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transmit shift register is empty and ready for new data, the byte from the transmit buffer is then loaded

into the shift register. The byte is then kept in the shift register until it is transmitted. When a byte has

been transmitted, a new byte is loaded into the shift register (if available in the transmit buffer). If the

transmit buffer is empty, then the shift register also remains empty. The TXC flag in I2Cn_STATUS and

the TXC interrupt flags in I2Cn_IF are then set, signaling that the transmit shift register is out of data. TXC

is cleared when new data becomes available, but the TXC interrupt flag must be cleared by software.

Whenever a byte is loaded from the transmit buffer to the transmit shift register, the TXBL flag in

I2Cn_STATUS and the TXBL interrupt flag in I2Cn_IF are set. This indicates that there is room in the

buffer for more data. TXBL is cleared automatically when data is written to the buffer.

If a write is attempted to the transmit buffer while it is not empty, the TXOF interrupt flag in I2Cn_IF is set,

indicating the overflow. The data already in the buffer remains preserved, and no new data is written.

The transmit buffer and the transmit shift register can be cleared by setting command bit CLEARTX in

I2Cn_CMD. This will prevent the I2C module from transmitting the data in the buffer and the shift register,

and will make them available for new data. Any byte currently being transmitted will not be aborted.

Transmission of this byte will be completed.

16.3.6.2 Receive Buffer and Shift Register

Like the transmitter, the I2C receiver is double buffered. The receiver uses the receive buffer and receive

shift register as shown in Figure 16.1 (p. 414) . When a byte has been fully received by the receive

shift register, it is loaded into the receive buffer if there is room for it. Otherwise, the byte waits in the

shift register until space becomes available in the buffer.

When a byte becomes available in the receive buffer, the RXDATAV in I2Cn_STATUS and RXDATAV

interrupt flag in I2Cn_IF are set. The data can now be fetched from the buffer using I2Cn_RXDATA.

Reading from this register will pull a byte out of the buffer, making room for a new byte and clearing

RXDATAV in I2Cn_STATUS and RXDATAV in I2Cn_IF in the process.

If a read from the receive buffer is attempted through I2Cn_RXDATA while the buffer is empty, the RXUF

interrupt flag in I2Cn_IF is set, and the data read from the buffer is undefined.

I2Cn_RXDATAP can be used to read data from the receive buffer without removing it from the buffer.

The RXUF interrupt flag in I2Cn_IF will never be set as a result of reading from I2Cn_RXDATAP, but

the data read through I2Cn_RXDATAP when the receive buffer is empty is still undefined.

Once a transaction is complete (STOP sent or received), the receive buffer needs to be flushed (all

received data must be picked up) before starting a new transaction.

16.3.7 Master Operation

A bus transaction is initiated by transmitting a START condition (S) on the bus. This is done by setting

the START bit in I2Cn_CMD. The command schedules a START condition, and makes the I2C module

generate a start condition whenever the bus becomes free.

The I2C-bus is considered busy whenever another device on the bus transmits a START condition. Until

a STOP condition is detected, the bus is owned by the master issuing the START condition. The bus is

considered free when a STOP condition is transmitted on the bus. After a STOP is detected, all masters

that have data to transmit send a START condition and begin transmitting data. Arbitration ensures that

collisions are avoided.

When the START condition has been transmitted, the master must transmit a slave address (ADDR)

with an R/W bit on the bus. If this address is available in the transmit buffer, the master transmits it

immediately, but if the buffer is empty, the master holds the I2C-bus while waiting for software to write

the address to the transmit buffer.

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After the address has been transmitted, a sequence of bytes can be read from or written to the slave,

depending on the value of the R/W bit (bit 0 in the address byte). If the bit was cleared, the master

has entered a master transmitter role, where it now transmits data to the slave. If the bit was set, it

has entered a master receiver role, where it now should receive data from the slave. In either case, an

unlimited number of bytes can be transferred in one direction during the transmission.

At the end of the transmission, the master either transmits a repeated START condition (Sr) if it wishes

to continue with another transfer, or transmits a STOP condition (P) if it wishes to release the bus.

16.3.7.1 Master State Machine

The master state machine is shown in Figure 16.10 (p. 421) . A master operation starts in the far

left of the state machine, and follows the solid lines through the state machine, ending the operation or

continuing with a new operation when arriving at the right side of the state machine.

Branches in the path through the state machine are the results of bus events and choices made by

software, either directly or indirectly. The dotted lines show where I2C-specific interrupt flags are set

along the path and the full-drawn circles show places where interaction may be required by software

to let the transmission proceed.

Figure 16.10. I2C Master State Machine

Waiting

for idle

Idle/busy

ADDR R A

ADDR W

DATA P

XArb. lost 1

97 D7

DATA P

Arb. lost

ADDR R Arb. lost, ADDR match

ADDR W Arb. lost, ADDR match

ADDR X Arb. lost, no match 1

Master receiver

Master transmitter

Arbitration lost

Slave transmitter

Slave receiver

0/1

Bus state/event

Transmitted by self

Received from slave

START

condition

Interrupt flag set

Interaction required. Wait-

states inserted until manual

or automatic interaction has

been performed

Go to state

S P

ACK

STOP

condition

NACK

Repeated START condition

ADDR R

ADDR W

Slave address + read

(R/W bit set)

Slave address + write

(R/W bit cleared)

Bus state (STATE)

Bus reset

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16.3.7.2 Interactions

Whenever the I2C module is waiting for interaction from software, it holds the bus clock SCL low, freezing

all bus activities, and the BUSHOLD interrupt flag in I2Cn_IF is set. The action(s) required by software

depends on the current state the of the I2C module. This state can be read from the I2Cn_STATE register.

As an example, Table 16.5 (p. 424) shows the different states the I2C goes through when operating

as a Master Transmitter, i.e. a master that transmits data to a slave. As seen in the table, when a start

condition has been transmitted, a requirement is that there is an address and an R/W bit in the transmit

buffer. If the transmit buffer is empty, then the BUSHOLD interrupt flag is set, and the bus is held until

data becomes available in the buffer. While waiting for the address, I2Cn_STATE has a value 0x57,

which can be used to identify exactly what the I2C module is waiting for.

Note The bus would never stop at state 0x57 if the address was available in the transmit buffer.

The different interactions used by the I2C module are listed in Table 16.4 (p. 422) in prioritized order. If

a set of different courses of action are possible from a given state, the course of action using the highest

priority interactions, that first has everything it is waiting for is the one that is taken.

Table 16.4. I2C Interactions in Prioritized Order

Interaction Priority Software action Automatically continues if

STOP* 1 Set the STOP command bit

in I2Cn_CMD PSTOP is set (STOP

pending) in I2Cn_STATUS

ABORT 2 Set the ABORT command bit

in I2Cn_CMD Never, the transmission is

aborted

CONT* 3 Set the CONT command bit

in I2Cn_CMD PCONT is set in

I2Cn_STATUS (CONT

pending)

NACK* 4 Set the NACK command bit

in I2Cn_CMD PNACK is set in

I2Cn_STATUS (NACK

pending)

ACK* 5 Set the ACK command bit in

I2Cn_CMD AUTOACK is set in

I2Cn_CTRL or PACK is

set in I2Cn_STATUS (ACK

pending)

ADDR+W -> TXDATA 6 Write an address to the

transmit buffer with the R/W

bit set

Address is available in

transmit buffer with R/W bit

set

ADDR+R -> TXDATA 7 Write an address to the

transmit buffer with the R/W

bit cleared

Address is available in

transmit buffer with R/W bit

cleared

START* 8 Set the START command bit

in I2Cn_CMD PSTART is set in

I2Cn_STATUS (START

pending)

TXDATA 9 Write data to the transmit

buffer Data is available in transmit

buffer

RXDATA 10 Read data from receive

buffer Space is available in receive

buffer

None 11 No interaction is required

The commands marked with a * in Table 16.4 (p. 422) can be issued before an interaction is required.

When such a command is issued before it can be used/consumed by the I2C module, the command is

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set in a pending state, which can be read from the STATUS register. A pending START command can

for instance be identified by PSTART having a high value.

Whenever the I2C module requires an interaction, it checks the pending commands. If one or a

combination of these can fulfill an interaction, they are consumed by the module and the transmission

continues without setting the BUSHOLD interrupt flag in I2Cn_IF to get an interaction from software.

The pending status of a command goes low when it is consumed.

When several interactions are possible from a set of pending commands, the interaction with the highest

priority, i.e. the interaction closest to the top of Table 16.4 (p. 422) is applied to the bus.

Pending commands can be cleared by setting the CLEARPC command bit in I2Cn_CMD.

16.3.7.2.1 Automatic ACK Interaction

When receiving addresses and data, an ACK command in I2Cn_CMD is normally required after each

received byte. When AUTOACK is set in I2Cn_CTRL, an ACK is always pending, and the ACK-pending

bit PACK in I2Cn_STATUS is thus always set, even after an ACK has been consumed. This can be used

to reduce the amount of software interaction required during a transfer.

16.3.7.3 Reset State

After a reset, the state of the I2C-bus is unknown. To avoid interrupting transfers on the I2C-bus after

a reset of the I2C module or the entire MCU, the I2C-bus is assumed to be busy when coming out of a

reset, and the BUSY flag in I2Cn_STATUS is thus set. To be able to carry through master operations

on the I2C-bus, the bus must be idle.

The bus goes idle when a STOP condition is detected on the bus, but on buses with little activity, the

time before the I2C module detects that the bus is idle can be significant. There are two ways of assuring

that the I2C module gets out of the busy state.

• Use the ABORT command in I2Cn_CMD. When the ABORT command is issued, the I2C module is

instructed that the bus is idle. The I2C module can then initiate master operations.

• Use the Bus Idle Timeout. When SCL has been high for a long period of time, it is very likely that the

bus is idle. Set BITO in I2Cn_CTRL to an appropriate timeout period and set GIBITO in I2Cn_CTRL.

If activity has not been detected on the bus within the timeout period, the bus is then automatically

assumed idle, and master operations can be initiated.

Note If operating in slave mode, the above approach is not necessary.

16.3.7.4 Master Transmitter

To transmit data to a slave, the master must operate as a master transmitter. Table 16.5 (p. 424)

shows the states the I2C module goes through while acting as a master transmitter. Every state where

an interaction is required has the possible interactions listed, along with the result of the interactions.

The table also shows which interrupt flags are set in the different states. The interrupt flags enclosed

in parenthesis may be set. If the BUSHOLD interrupt in I2Cn_IF is set, the module is waiting for an

interaction, and the bus is frozen. The value of I2Cn_STATE will be equal to the values given in the table

when the BUSHOLD interrupt flag is set, and can be used to determine which interaction is required to

make the transmission continue.

The interrupt flag START in I2Cn_IF is set when the I2C module transmits the START.

A master operation is started by issuing a START command by setting START in I2Cn_CMD. ADDR

+W, i.e. the address of the slave to address + the R/W bit is then required by the I2C module. If this

is not available in the transmit buffer, then the bus is held and the BUSHOLD interrupt flag is set. The

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value of I2Cn_STATE will then be 0x57. As seen in the table, the I2C module also stops in this state if

the address is not available after a repeated start condition.

To continue, write a byte to I2Cn_TXDATA with the address of the slave in the 7 most significant bits

and the least significant bit cleared (ADDR+W). This address will then be transmitted, and the slave will

reply with an ACK or a NACK. If no slave replies to the address, the response will also be NACK. If the

address was acknowledged, the master now has four choices. It can send a data byte by placing it in

I2Cn_TXDATA (the master should check the TXBL interrupt flag before writing to I2Cn_TXDATA), this

byte is then transmitted. The master can also stop the transmission by sending a STOP, it can send a

repeated start by sending START, or it can send a STOP and then a START as soon as possible.

If a NACK was received, the master has to issue a CONT command in addition to providing data in order

to continue transmission. This is not standard I2C, but is provided for flexibility. The rest of the options

are similar to when an ACK was received.

If a new byte was transmitted, an ACK or NACK is received after the transmission of the byte, and the

master has the same options as for when the address was sent.

The master may lose arbitration at any time during transmission. In this case, the ARBLOST interrupt flag

in I2Cn_IF is set. If the arbitration was lost during the transfer of an address, and SLAVE in I2Cn_CTRL

is set, the master then checks which address was transmitted. If it was the address of the master, then

the master goes to slave mode.

After a master has transmitted a START and won any arbitration, it owns the bus until it transmits a

STOP. After a STOP, the bus is released, and arbitration decides which bus master gains the bus next.

The MSTOP interrupt flag in I2Cn_IF is set when a STOP condition is transmitted by the master.

Table 16.5. I2C Master Transmitter

I2Cn_STATEDescription I2Cn_IF Required

interaction Response

ADDR

+W ->

TXDATA

ADDR+W will be sent

STOP STOP will be sent and bus released.

0x57 Start transmitted START interrupt flag

(BUSHOLD interrupt

flag)

STOP +

START STOP will be sent and bus released. Then a

START will be sent when bus becomes idle.

ADDR

+W ->

TXDATA

ADDR+W will be sent

STOP STOP will be sent and bus released.

0x57 Repeated start

transmitted START interrupt flag

(BUSHOLD interrupt

flag)

STOP +

START STOP will be sent and bus released. Then a

START will be sent when bus becomes idle.

- ADDR+W transmitted TXBL interrupt flag

(TXC interrupt flag) None

TXDATA DATA will be sent

STOP STOP will be sent. Bus will be released

START Repeated start condition will be sent

0x97 ADDR+W transmitted,

ACK received ACK interrupt flag

(BUSHOLD interrupt

flag)

STOP +

START STOP will be sent and the bus released. Then

a START will be sent when the bus becomes

idle

CONT +

TXDATA DATA will be sent0x9F ADDR+W

transmitted,NACK

received

NACK (BUSHOLD

interrupt flag)

STOP STOP will be sent. Bus will be released

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I2Cn_STATEDescription I2Cn_IF Required

interaction Response

START Repeated start condition will be sent

STOP +

START STOP will be sent and the bus released. Then

a START will be sent when the bus becomes

idle

- Data transmitted TXBL interrupt flag

(TXC interrupt flag) None

TXDATA DATA will be sent

STOP STOP will be sent. Bus will be released

START Repeated start condition will be sent

0xD7 Data transmitted,ACK

received ACK interrupt flag

(BUSHOLD interrupt

flag)

STOP +

START STOP will be sent and the bus released. Then

a START will be sent when the bus becomes

idle

CONT +

TXDATA DATA will be sent

STOP STOP will be sent. Bus will be released

START Repeated start condition will be sent

0xDF Data

transmitted,NACK

received

NACK(BUSHOLD

interrupt flag)

STOP +

START STOP will be sent and the bus released. Then

a START will be sent when the bus becomes

idle

None - Stop transmitted MSTOP interrupt flag

START START will be sent when bus becomes idle

None - Arbitration lost ARBLOST interrupt

flag START START will be sent when bus becomes idle

16.3.7.5 Master Receiver

To receive data from a slave, the master must operate as a master receiver, see Table 16.6 (p. 426) .

This is done by transmitting ADDR+R as the address byte instead of ADDR+W, which is transmitted to

become a master transmitter. The address byte loaded into the data register thus has to contain the 7-

bit slave address in the 7 most significant bits of the byte, and have the least significant bit set.

When the address has been transmitted, the master receives an ACK or a NACK. If an ACK is received,

the ACK interrupt flag in I2Cn_IF is set, and if space is available in the receive shift register, reception

of a byte from the slave begins. If the receive buffer and shift register is full however, the bus is held

until data is read from the receive buffer or another interaction is made. Note that the STOP and START

interactions have a higher priority than the data-available interaction, so if a STOP or START command

is pending, the highest priority interaction will be performed, and data will not be received from the slave.

If a NACK was received, the CONT command in I2Cn_CMD has to be issued in order to continue

receiving data, even if there is space available in the receive buffer and/or shift register.

After a data byte has been received the master must ACK or NACK the received byte. If an ACK is

pending or AUTOACK in I2Cn_CTRL is set, an ACK is sent automatically and reception continues if

space is available in the receive buffer.

If a NACK is sent, the CONT command must be used in order to continue transmission. If an ACK

or NACK is issued along with a START or STOP or both, then the ACK/NACK is transmitted and the

reception is ended. If START in I2Cn_CMD is set alone, a repeated start condition is transmitted after

the ACK/NACK. If STOP in I2Cn_CMD is set, a stop condition is sent regardless of whether START is

set. If START is set in this case, it is set as pending.

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As when operating as a master transmitter, arbitration can be lost as a master receiver. When this

happens the ARBLOST interrupt flag in I2Cn_IF is set, and the master has a possibility of being selected

as a slave given the correct conditions.

Table 16.6. I2C Master Receiver

I2Cn_STATEDescription I2Cn_IF Required

interaction Response

ADDR

+R ->

TXDATA

ADDR+R will be sent

STOP STOP will be sent and bus released.

0x57 START transmitted START interrupt flag

(BUSHOLD interrupt

flag)

STOP +

START STOP will be sent and bus released. Then a

START will be sent when bus becomes idle.

ADDR

+R ->

TXDATA

ADDR+R will be sent

STOP STOP will be sent and bus released.

0x57 Repeated START

transmitted START interrupt

flag(BUSHOLD

interrupt flag)

STOP +

START STOP will be sent and bus released. Then a

START will be sent when bus becomes idle.

- ADDR+R transmitted TXBL interrupt flag

(TXC interrupt flag) None

RXDATA Start receiving

STOP STOP will be sent and the bus released

START Repeated START will be sent

0x93 ADDR+R transmitted,

ACK received ACK interrupt

flag(BUSHOLD)

STOP +

START STOP will be sent and the bus released. Then

a START will be sent when the bus becomes

idle

CONT +

RXDATA Continue, start receiving

STOP STOP will be sent and the bus released

START Repeated START will be sent

0x9B ADDR+R

transmitted,NACK

received

NACK(BUSHOLD)

STOP +

START STOP will be sent and the bus released. Then

a START will be sent when the bus becomes

idle

ACK +

RXDATA ACK will be transmitted, reception continues

NACK +

CONT +

RXDATA

NACK will be transmitted, reception continues

ACK/

NACK +

STOP

ACK/NACK will be sent and the bus will be

released.

ACK/

NACK +

START

ACK/NACK will be sent, and then a repeated

start condition.

0xB3 Data received RXDATA interrupt

flag(BUSHOLD

interrupt flag)

ACK/

NACK +

STOP +

START

ACK/NACK will be sent and the bus will be

released. Then a START will be sent when the

bus becomes idle

- Stop received MSTOP interrupt flag None

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I2Cn_STATEDescription I2Cn_IF Required

interaction Response

START START will be sent when bus becomes idle

None - Arbitration lost ARBLOST interrupt

flag START START will be sent when bus becomes idle

16.3.8 Bus States

The I2Cn_STATE register can be used to determine which state the I2C module and the I2C bus are in

at a given time. The register consists of the STATE bit-field, which shows which state the I2C module is

at in any ongoing transmission, and a set of single-bits, which reveal the transmission mode, whether

the bus is busy or idle, and whether the bus is held by this I2C module waiting for a software response.

The possible values of the STATE field are summarized in Table 16.7 (p. 427) . When this field is

cleared, the I2C module is not a part of any ongoing transmission. The remaining status bits in the

I2Cn_STATE register are listed in Table 16.8 (p. 427) .

Table 16.7. I2C STATE Values

Mode Value Description

IDLE 0 No transmission is being performed by this module.

WAIT 1 Waiting for idle. Will send a start condition as soon as the bus is idle.

START 2 Start being transmitted

ADDR 3 Address being transmitted or has been received

ADDRACK 4 Address ACK/NACK being transmitted or received

DATA 5 Data being transmitted or received

DATAACK 6 Data ACK/NACK being transmitted or received

Table 16.8. I2C Transmission Status

Bit Description

BUSY Set whenever there is activity on the bus. Whether or not this module is

responsible for the activity cannot be determined by this byte.

MASTER Set when operating as a master. Cleared at all other times.

TRANSMITTER Set when operating as a transmitter; either a master transmitter or a slave

transmitter. Cleared at all other times

BUSHOLD Set when the bus is held by this I2C module because an action is required by

software.

NACK Only valid when bus is held and STATE is ADDRACK or DATAACK. In that case

it is set if a NACK was received. In all other cases, the bit is cleared.

Note I2Cn_STATE reflects the internal state of the I2C module, and therefore only held constant

as long as the bus is held, i.e. as long as BUSHOLD in I2Cn_STATUS is set.

16.3.9 Slave Operation

The I2C module operates in master mode by default. To enable slave operation, i.e. to allow the device to

be addressed as an I2C slave, the SLAVE bit in I2Cn_CTRL must be set. In this case the slave operates

in a mixed mode, both capable of starting transmissions as a master, and being addressed as a slave.

When operating in the slave mode, HFPERCLK frequency must be higher than 4.2 MHz for Standard-

mode, 11 MHz for Fast-mode, and 24.4 MHz for Fast-mode Plus.

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16.3.9.1 Slave State Machine

The slave state machine is shown in Figure 16.11 (p. 428) . The dotted lines show where I2C-specific

interrupt flags are set. The full-drawn circles show places where interaction may be required by software

to let the transmission proceed.

Figure 16.11. I2C Slave State Machine

73 D5

S ADDR R A

ADDR W

DATA P

Arb. lost 1

71 B1

DATA P

Slave transmitter

Slave receiver

XArb. lost 1

Idle/busy

0/1

Bus state/event

Transmitted by self

Received from master

Bus state (STATE)

Interrupt flag set

Interaction required. Clock-

stretching applied until

manual or automatic

interaction has been

performed

Go to state

16.3.9.2 Address Recognition

The I2C module provides automatic address recognition for 7-bit addresses. 10-bit address recognition is

not fully automatic, but can be assisted by the 7-bit address comparator as shown in Section 16.3.11 (p.

432) . Address recognition is supported in all energy modes (except EM4).

The slave address, i.e. the address which the I2C module should be addressed with, is defined in

the I2Cn_SADDR register. In addition to the address, a mask must be specified, telling the address

comparator which bits of an incoming address to compare with the address defined in I2Cn_SADDR.

The mask is defined in I2Cn_SADDRMASK, and for every zero in the mask, the corresponding bit in

the slave address is treated as a don’t-care.

An incoming address that fails address recognition is automatically replied to with a NACK. Since only

the bits defined by the mask are checked, a mask with a value 0x00 will result in all addresses being

accepted. A mask with a value 0x7F will only match the exact address defined in I2Cn_SADDR, while

a mask 0x70 will match all addresses where the three most significant bits in I2Cn_SADDR and the

incoming address are equal.

If GCAMEN in I2Cn_CTRL is set, the general call address is always accepted regardless of the result

of the address recognition. The start-byte, i.e. the general call address with the R/W bit set is ignored

unless it is included in the defined slave address.

When an address is accepted by the address comparator, the decision of whether to ACK or NACK the

address is passed to software.

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16.3.9.3 Slave Transmitter

When SLAVE in I2Cn_CTRL is set, the RSTART interrupt flag in I2Cn_IF will be set when repeated

START conditions are detected. After a START or repeated START condition, the bus master will

transmit an address along with an R/W bit. If there is no room in the receive shift register for the address,

the bus will be held by the slave until room is available in the shift register. Transmission then continues

and the address is loaded into the shift register. If this address does not pass address recognition, it is

automatically NACK’ed by the slave, and the slave goes to an idle state. The address byte is in this case

discarded, making the shift register ready for a new address. It is not loaded into the receive buffer.

If the address was accepted and the R/W bit was set (R), indicating that the master wishes to read from

the slave, the slave now goes into the slave transmitter mode. Software interaction is now required to

decide whether the slave wants to acknowledge the request or not. The accepted address byte is loaded

into the receive buffer like a regular data byte. If no valid interaction is pending, the bus is held until the

slave responds with a command. The slave can reject the request with a single NACK command.

The slave will in that case go to an idle state, and wait for the next start condition. To continue the

transmission, the slave must make sure data is loaded into the transmit buffer and send an ACK. The

loaded data will then be transmitted to the master, and an ACK or NACK will be received from the master.

Data transmission can also continue after a NACK if a CONT command is issued along with the NACK.

This is not standard I2C however.

If the master responds with an ACK, it may expect another byte of data, and data should be made

available in the transmit buffer. If data is not available, the bus is held until data is available.

If the response is a NACK however, this is an indication of that the master has received enough bytes

and wishes to end the transmission. The slave now automatically goes idle, unless CONT in I2Cn_CMD

is set and data is available for transmission. The latter is not standard I2C.

The master ends the transmission by sending a STOP or a repeated START. The SSTOP interrupt

flag in I2Cn_IF is set when the master transmits a STOP condition. If the transmission is ended with a

repeated START, then the SSTOP interrupt flag is not set.

Note The SSTOP interrupt flag in I2Cn_IF will be set regardless of whether the slave is

participating in the transmission or not, as long as SLAVE in I2Cn_CTRL is set and a STOP

condition is detected

If arbitration is lost at any time during transmission, the ARBLOST interrupt flag in I2Cn_IF is set, the

bus is released and the slave goes idle.

See Table 16.9 (p. 430) for more information.

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Table 16.9. I2C Slave Transmitter

I2Cn_STATEDescription I2Cn_IF Required

interaction Response

0x41 Repeated START

received RSTART interrupt flag

(BUSHOLD interrupt

flag)

RXDATA Receive and compare address

ADDR interrupt flag ACK +

TXDATA ACK will be sent, then DATA

RXDATA interrupt flag NACK NACK will be sent, slave goes idle

0x75 ADDR + R received

(BUSHOLD interrupt

flag) NACK +

CONT +

TXDATA

NACK will be sent, then DATA.

- Data transmitted TXBL interrupt flag

(TXC interrupt flag) None

0xD5 Data transmitted, ACK

received ACK interrupt flag

(BUSHOLD interrupt

flag)

TXDATA DATA will be transmitted

NACK interrupt flag None The slave goes idle0xDD Data transmitted,

NACK received (BUSHOLD interrupt

flag) CONT +

TXDATA DATA will be transmitted

None The slave goes idle- Stop received SSTOP interrupt flag

START START will be sent when bus becomes idle

None The slave goes idle- Arbitration lost ARBLOST interrupt

flag START START will be sent when the bus becomes idle

16.3.9.4 Slave Receiver

A slave receiver operation is started in the same way as a slave transmitter operation, with the exception

that the address transmitted by the master has the R/W bit cleared (W), indicating that the master wishes

to write to the slave. The slave then goes into slave receiver mode.

To receive data from the master, the slave should respond to the address with an ACK and make sure

space is available in the receive buffer. Transmission will then continue, and the slave will receive a

byte from the master.

If a NACK is sent without a CONT, the transmission is ended for the slave, and it goes idle. If the slave

issues both the NACK and CONT commands and has space available in the receive buffer, it will be

open for continuing reception from the master.

When a byte has been received from the master, the slave must ACK or NACK the byte. The responses

here are the same as for the reception of the address byte.

The master ends the transmission by sending a STOP or a repeated START. The SSTOP interrupt flag

is set when the master transmits a STOP condition. If the transmission is ended with a repeated START,

then the SSTOP interrupt flag in I2Cn_IF is not set.

Note The SSTOP interrupt flag in I2Cn_IF will be set regardless of whether the slave is

participating in the transmission or not, as long as SLAVE in I2Cn_CTRL is set and a STOP

condition is detected

If arbitration is lost at any time during transmission, the ARBLOST interrupt flag in I2Cn_IF is set, the

bus is released and the slave goes idle.

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See Table 16.10 (p. 431) for more information.

Table 16.10. I2C - Slave Receiver

I2Cn_STATEDescription I2Cn_IF Required

interaction Response

- Repeated START

received RSTART interrupt flag

(BUSHOLD interrupt

flag)

RXDATA Receive and compare address

ACK +

RXDATA ACK will be sent and data will be received

NACK NACK will be sent, slave goes idle

0x71 ADDR + W received ADDR interrupt flag

RXDATA interrupt flag

(BUSHOLD interrupt

flag)

NACK +

CONT +

RXDATA

NACK will be sent and DATA will be received.

ACK +

RXDATA ACK will be sent and data will be received

NACK NACK will be sent and slave will go idle

0xB1 Data received RXDATA interrupt flag

(BUSHOLD interrupt

flag)

NACK +

CONT +

RXDATA

NACK will be sent and data will be received

None The slave goes idle- Stop received SSTOP interrupt flag

START START will be sent when bus becomes idle

None The slave goes idle- Arbitration lost ARBLOST interrupt

flag START START will be sent when the bus becomes idle

16.3.10 Transfer Automation

The I2C can be set up to complete transfers with a minimal amount of interaction.

16.3.10.1 DMA

DMA can be used to automatically load data into the transmit buffer and load data out from the receive

buffer. When using DMA, software is thus relieved of moving data to and from memory after each

transferred byte.

16.3.10.2 Automatic ACK

When AUTOACK in I2Cn_CTRL is set, an ACK is sent automatically whenever an ACK interaction is

possible and no higher priority interactions are pending.

16.3.10.3 Automatic STOP

A STOP can be generated automatically on two conditions. These apply only to the master transmitter.

If AUTOSN in I2Cn_CTRL is set, the I2C module ends a transmission by transmitting a STOP condition

when operating as a master transmitter and a NACK is received.

If AUTOSE in I2Cn_CTRL is set, the I2C module always ends a transmission when there is no more

data in the transmit buffer. If data has been transmitted on the bus, the transmission is ended after the

(N)ACK has been received by the slave. If a START is sent when no data is available in the transmit

buffer and AUTOSE is set, then the STOP condition is sent immediately following the START. Software

must thus make sure data is available in the transmit buffer before the START condition has been fully

transmitted if data is to be transferred.

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16.3.11 Using 10-bit Addresses

When using 10-bit addresses in slave mode, set the I2Cn_SADDR register to 1111 0XX where XX

are the two most significant bits of the 10-bit address, and set I2Cn_SADDRMASK to 0xFF. Address

matches will now be given on all 10-bit addresses where the two most significant bits are correct.

When receiving an address match, the slave must acknowledge the address and receive the first data

byte. This byte contains the second part of the 10-bit address. If it matches the address of the slave,

the slave should ACK the byte to continue the transmission, and if it does not match, the slave should

NACK it.

When the master is operating as a master transmitter, the data bytes will follow after the second address

byte. When the master is operating as a master receiver however, a repeated START condition is sent

after the second address byte. The address sent after this repeated START is equal to the first of the

address bytes transmitted previously, but now with the R/W byte set, and only the slave that found a

match on the entire 10-bit address in the previous message should ACK this address. The repeated

start should take the master into a master receiver mode, and after the single address byte sent this

time around, the slave begins transmission to the master.

16.3.12 Error Handling

16.3.12.1 ABORT Command

Some bus errors may require software intervention to be resolved. The I2C module provides an ABORT

command, which can be set in I2Cn_CMD, to help resolve bus errors.

When the bus for some reason is locked up and the I2C module is in the middle of a transmission it

cannot get out of, or for some other reason the I2C wants to abort a transmission, the ABORT command

can be used.

Setting the ABORT command will make the I2C module discard any data currently being transmitted

or received, release the SDA and SCL lines and go to an idle mode. ABORT effectively makes the I2C

module forget about any ongoing transfers.

16.3.12.2 Bus Reset

A bus reset can be performed by setting the START and STOP commands in I2Cn_CMD while the

transmit buffer is empty. A START condition will then be transmitted, immediately followed by a STOP

condition. A bus reset can also be performed by transmitting a START command with the transmit buffer

empty and AUTOSE set.

16.3.12.3 I2C-Bus Errors

An I2C-bus error occurs when a START or STOP condition is misplaced, which happens when the value

on SDA changes while SCL is high during bit-transmission on the I2C-bus. If the I2C module is part of

the current transmission when a bus error occurs, any data currently being transmitted or received is

discarded, SDA and SCL are released, the BUSERR interrupt flag in I2Cn_IF is set to indicate the error,

and the module automatically takes a course of action as defined in Table 16.11 (p. 432) .

Table 16.11. I2C Bus Error Response

Misplaced START Misplaced STOP

In a master/slave operation Treated as START. Receive address. Go idle. Perform any pending actions.

16.3.12.4 Bus Lockup

A lockup occurs when a master or slave on the I2C-bus has locked the SDA or SCL at a low value,

preventing other devices from putting high values on the bus, and thus making communication on the

bus impossible.

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Many slave-only devices operating on an I2C-bus are not capable of driving SCL low, but in the rare

case that SCL is stuck LOW, the advice is to apply a hardware reset signal to the slaves on the bus. If

this does not work, cycle the power to the devices in order to make them release SCL.

When SDA is stuck low and SCL is free, a master should send 9 clock pulses on SCL while tristating

the SDA. This procedure is performed in the GPIO module after clearing the I2C_ROUTE register and

disabling the I2C module. The device that held the bus low should release it sometime within those 9

clocks. If not, use the same approach as for when SCL is stuck, resetting and possibly cycling power

to the slaves.

Lockup of SDA can be detected by keeping count of the number of continuous arbitration losses during

address transmission. If arbitration is also lost during the transmission of a general call address, i.e.

during the transmission of the STOP condition, which should never happen during normal operation,

this is a good indication of SDA lockup.

Detection of SCL lockups can be done using the timeout functionality defined in Section 16.3.12.6 (p.

433)

16.3.12.5 Bus Idle Timeout

When SCL has been high for a significant amount of time, this is a good indication of that the bus is

idle. On an SMBus system, the bus is only allowed to be in this state for a maximum of 50 µs before

the bus is considered idle.

The bus idle timeout BITO in I2Cn_CTRL can be used to detect situations where the bus goes idle in the

middle of a transmission. The timeout can be configured in BITO, and when the bus has been idle for the

given amount of time, the BITO interrupt flag in I2Cn_IF is set. The bus can also be set idle automatically

on a bus idle timeout. This is enabled by setting GIBITO in I2Cn_CTRL.

When the bus idle timer times out, it wraps around and continues counting as long as its condition is

true. If the bus is not set idle using GIBITO or the ABORT command in I2Cn_CMD, this will result in

periodic timeouts.

Note This timeout will be generated even if SDA is held low.

The bus idle timeout is active as long as the bus is busy, i.e. BUSY in I2Cn_STATUS is set. The timeout

can be used to get the I2C module out of the busy-state it enters when reset, see Section 16.3.7.3 (p.

423) .

16.3.12.6 Clock Low Timeout

The clock timeout, which can be configured in CLTO in I2Cn_CTRL, starts counting whenever SCL goes

low, and times out if SCL does not go high within the configured timeout. A clock low timeout results in

CLTOIF in I2Cn_IF being set, allowing software to take action.

When the timer times out, it wraps around and continues counting as long as SCL is low. An SCL lockup

will thus result in periodic clock low timeouts as long as SCL is low.

16.3.13 DMA Support

The I2C module has full DMA support. The DMA controller can write to the transmit buffer using the

I2Cn_TXDATA register, and it can read from the receive buffer using the RXDATA register. A request

for the DMA controller to read from the I2C receive buffer can come from the following source:

• Data available in the receive buffer

A write request can come from one of the following sources:

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• Transmit buffer and shift register empty. No data to send

• Transmit buffer empty

16.3.14 Interrupts

The interrupts generated by the I2C module are combined into one interrupt vector, I2C_INT. If I2C

interrupts are enabled, an interrupt will be made if one or more of the interrupt flags in I2Cn_IF and their

corresponding bits in I2Cn_IEN are set.

16.3.15 Wake-up

The I2C receive section can be active all the way down to energy mode EM3, and can wake up the CPU

on address interrupt. All address match modes are supported.

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16.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 I2Cn_CTRL RW Control Register

0x004 I2Cn_CMD W1 Command Register

0x008 I2Cn_STATE R State Register

0x00C I2Cn_STATUS R Status Register

0x010 I2Cn_CLKDIV RW Clock Division Register

0x014 I2Cn_SADDR RW Slave Address Register

0x018 I2Cn_SADDRMASK RW Slave Address Mask Register

0x01C I2Cn_RXDATA R Receive Buffer Data Register

0x020 I2Cn_RXDATAP R Receive Buffer Data Peek Register

0x024 I2Cn_TXDATA W Transmit Buffer Data Register

0x028 I2Cn_IF R Interrupt Flag Register

0x02C I2Cn_IFS W1 Interrupt Flag Set Register

0x030 I2Cn_IFC W1 Interrupt Flag Clear Register

0x034 I2Cn_IEN RW Interrupt Enable Register

0x038 I2Cn_ROUTE RW I/O Routing Register

16.5 Register Description

16.5.1 I2Cn_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

CLTO

GIBITO

BITO

CLHR

GCAMEN

ARBDIS

AUTOSN

AUTOSE

AUTOACK

SLAVE

Bit Name Reset Access Description

31:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 CLTO 0x0 RW Clock Low Timeout

Use to generate a timeout when CLK has been low for the given amount of time. Wraps around and continues counting when the

timeout is reached.

Value Mode Description

0 OFF Timeout disabled

1 40PCC Timeout after 40 prescaled clock cycles. In standard mode at 100 kHz, this results in

a 50us timeout.

2 80PCC Timeout after 80 prescaled clock cycles. In standard mode at 100 kHz, this results in

a 100us timeout.

3 160PCC Timeout after 160 prescaled clock cycles. In standard mode at 100 kHz, this results

in a 200us timeout.

4 320PPC Timeout after 320 prescaled clock cycles. In standard mode at 100 kHz, this results

in a 400us timeout.

5 1024PPC Timeout after 1024 prescaled clock cycles. In standard mode at 100 kHz, this results

in a 1280us timeout.

15 GIBITO 0 RW Go Idle on Bus Idle Timeout

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Bit Name Reset Access Description

When set, the bus automatically goes idle on a bus idle timeout, allowing new transfers to be initiated.

Value Description

0 A bus idle timeout has no effect on the bus state.

1 A bus idle timeout tells the I2C module that the bus is idle, allowing new transfers to be initiated.

14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:12 BITO 0x0 RW Bus Idle Timeout

Use to generate a timeout when SCL has been high for a given amount time between a START and STOP condition. When in a

bus transaction, i.e. the BUSY flag is set, a timer is started whenever SCL goes high. When the timer reaches the value defined

by BITO, it sets the BITO interrupt flag. The BITO interrupt flag will then be set periodically as long as SCL remains high. The bus

idle timeout is active as long as BUSY is set. It is thus stopped automatically on a timeout if GIBITO is set. It is also stopped a

STOP condition is detected and when the ABORT command is issued. The timeout is activated whenever the bus goes BUSY, i.e.

a START condition is detected.

Value Mode Description

0 OFF Timeout disabled

1 40PCC Timeout after 40 prescaled clock cycles. In standard mode at 100 kHz, this results in

a 50us timeout.

2 80PCC Timeout after 80 prescaled clock cycles. In standard mode at 100 kHz, this results in

a 100us timeout.

3 160PCC Timeout after 160 prescaled clock cycles. In standard mode at 100 kHz, this results

in a 200us timeout.

11:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 CLHR 0x0 RW Clock Low High Ratio

Determines the ratio between the low and high parts of the clock signal generated on SCL as master.

Value Mode Description

0 STANDARD The ratio between low period and high period counters (Nlow:Nhigh) is 4:4

1 ASYMMETRIC The ratio between low period and high period counters (Nlow:Nhigh) is 6:3

2 FAST The ratio between low period and high period counters (Nlow:Nhigh) is 11:6

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 GCAMEN 0 RW General Call Address Match Enable

Set to enable address match on general call in addition to the programmed slave address.

Value Description

0 General call address will be NACK'ed if it is not included by the slave address and address mask.

1 When a general call address is received, a software response is required.

5 ARBDIS 0 RW Arbitration Disable

A master or slave will not release the bus upon losing arbitration.

Value Description

0 When a device loses arbitration, the ARB interrupt flag is set and the bus is released.

1 When a device loses arbitration, the ARB interrupt flag is set, but communication proceeds.

4 AUTOSN 0 RW Automatic STOP on NACK

Write to 1 to make a master transmitter send a STOP when a NACK is received from a slave.

Value Description

0 Stop is not automatically sent if a NACK is received from a slave.

1 The master automatically sends a STOP if a NACK is received from a slave.

3 AUTOSE 0 RW Automatic STOP when Empty

Write to 1 to make a master transmitter send a STOP when no more data is available for transmission.

Value Description

0 A stop must be sent manually when no more data is to be transmitted.

1 The master automatically sends a STOP when no more data is available for transmission.

2 AUTOACK 0 RW Automatic Acknowledge

Set to enable automatic acknowledges.

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Bit Name Reset Access Description

Value Description

0 Software must give one ACK command for each ACK transmitted on the I2C bus.

1 Addresses that are not automatically NACK'ed, and all data is automatically acknowledged.

1 SLAVE 0 RW Addressable as Slave

Set this bit to allow the device to be selected as an I2C slave.

Value Description

0 All addresses will be responded to with a NACK

1 Addresses matching the programmed slave address or the general call address (if enabled) require a response from

software. Other addresses are automatically responded to with a NACK.

0 EN 0 RW I2C Enable

Use this bit to enable or disable the I2C module.

Value Description

0 The I2C module is disabled. And its internal state is cleared

1 The I2C module is enabled.

16.5.2 I2Cn_CMD - Command Register

Offset Bit Position

0x004

Reset

Access

Name

CLEARPC

CLEARTX

ABORT

CONT

NACK

ACK

STOP

START

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 CLEARPC 0 W1 Clear Pending Commands

Set to clear pending commands.

6 CLEARTX 0 W1 Clear TX

Set to clear transmit buffer and shift register. Will not abort ongoing transfer.

5 ABORT 0 W1 Abort transmission

Abort the current transmission making the bus go idle. When used in combination with STOP, a STOP condition is sent as soon as

possible before aborting the transmission. The stop condition is subject to clock synchronization.

4 CONT 0 W1 Continue transmission

Set to continue transmission after a NACK has been received.

3 NACK 0 W1 Send NACK

Set to transmit a NACK the next time an acknowledge is required.

2 ACK 0 W1 Send ACK

Set to transmit an ACK the next time an acknowledge is required.

1 STOP 0 W1 Send stop condition

Set to send stop condition as soon as possible.

0 START 0 W1 Send start condition

Set to send start condition as soon as possible. If a transmission is ongoing and not owned, the start condition will be sent as soon

as the bus is idle. If the current transmission is owned by this module, a repeated start condition will be sent. Use in combination with

a STOP command to automatically send a STOP, then a START when the bus becomes idle.

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16.5.3 I2Cn_STATE - State Register

Offset Bit Position

0x008

Reset

0x0

Access

Name

STATE

BUSHOLD

NACKED

TRANSMITTER

MASTER

BUSY

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:5 STATE 0x0 R Transmission State

The state of any current transmission. Cleared if the I2C module is idle.

Value Mode Description

0 IDLE No transmission is being performed.

1 WAIT Waiting for idle. Will send a start condition as soon as the bus is idle.

2 START Start transmitted or received

3 ADDR Address transmitted or received

4 ADDRACK Address ack/nack transmitted or received

5 DATA Data transmitted or received

6 DATAACK Data ack/nack transmitted or received

4 BUSHOLD 0 R Bus Held

Set if the bus is currently being held by this I2C module.

3 NACKED 0 R Nack Received

Set if a NACK was received and STATE is ADDRACK or DATAACK.

2 TRANSMITTER 0 R Transmitter

Set when operating as a master transmitter or a slave transmitter. When cleared, the system may be operating as a master receiver,

a slave receiver or the current mode is not known.

1 MASTER 0 R Master

Set when operating as an I2C master. When cleared, the system may be operating as an I2C slave.

0 BUSY 1 R Bus Busy

Set when the bus is busy. Whether the I2C module is in control of the bus or not has no effect on the value of this bit. When the

MCU comes out of reset, the state of the bus is not known, and thus BUSY is set. Use the ABORT command or a bus idle timeout

to force the I2C module out of the BUSY state.

16.5.4 I2Cn_STATUS - Status Register

Offset Bit Position

0x00C

Reset

Access

Name

RXDATAV

TXBL

TXC

PABORT

PCONT

PNACK

PACK

PSTOP

PSTART

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

8 RXDATAV 0 R RX Data Valid

Set when data is available in the receive buffer. Cleared when the receive buffer is empty.

7 TXBL 1 R TX Buffer Level

Indicates the level of the transmit buffer. Set when the transmit buffer is empty, and cleared when it is full.

6 TXC 0 R TX Complete

Set when a transmission has completed and no more data is available in the transmit buffer. Cleared when a new transmission starts.

5 PABORT 0 R Pending abort

An abort is pending and will be transmitted as soon as possible.

4 PCONT 0 R Pending continue

A continue is pending and will be transmitted as soon as possible.

3 PNACK 0 R Pending NACK

A not-acknowledge is pending and will be transmitted as soon as possible.

2 PACK 0 R Pending ACK

An acknowledge is pending and will be transmitted as soon as possible.

1 PSTOP 0 R Pending STOP

A stop condition is pending and will be transmitted as soon as possible.

0 PSTART 0 R Pending START

A start condition is pending and will be transmitted as soon as possible.

16.5.5 I2Cn_CLKDIV - Clock Division Register

Offset Bit Position

0x010

Reset

0x000

Access

Name

DIV

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 DIV 0x000 RW Clock Divider

Specifies the clock divider for the I2C. Note that DIV must be 1 or higher when slave is enabled.

16.5.6 I2Cn_SADDR - Slave Address Register

Offset Bit Position

0x014

Reset

0x00

Access

Name

ADDR

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Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:1 ADDR 0x00 RW Slave address

Specifies the slave address of the device.

0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16.5.7 I2Cn_SADDRMASK - Slave Address Mask Register

Offset Bit Position

0x018

Reset

0x00

Access

Name

MASK

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:1 MASK 0x00 RW Slave Address Mask

Specifies the significant bits of the slave address. Setting the mask to 0x00 will match all addresses, while setting it to 0x7F will only

match the exact address specified by ADDR.

0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16.5.8 I2Cn_RXDATA - Receive Buffer Data Register

Offset Bit Position

0x01C

Reset

0x00

Access

Name

RXDATA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 RXDATA 0x00 R RX Data

Use this register to read from the receive buffer. Buffer is emptied on read access.

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16.5.9 I2Cn_RXDATAP - Receive Buffer Data Peek Register

Offset Bit Position

0x020

Reset

0x00

Access

Name

RXDATAP

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 RXDATAP 0x00 R RX Data Peek

Use this register to read from the receive buffer. Buffer is not emptied on read access.

16.5.10 I2Cn_TXDATA - Transmit Buffer Data Register

Offset Bit Position

0x024

Reset

0x00

Access

Name

TXDATA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 TXDATA 0x00 W TX Data

Use this register to write a byte to the transmit buffer.

16.5.11 I2Cn_IF - Interrupt Flag Register

Offset Bit Position

0x028

Reset

Access

Name

SSTOP

CLTO

BITO

RXUF

TXOF

BUSHOLD

BUSERR

ARBLOST

MSTOP

NACK

ACK

RXDATAV

TXBL

TXC

ADDR

RSTART

START

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 SSTOP 0 R Slave STOP condition Interrupt Flag

Set when a STOP condition has been received. Will be set regardless of the EFM32 being involved in the transaction or not.

15 CLTO 0 R Clock Low Timeout Interrupt Flag

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Bit Name Reset Access Description

Set on each clock low timeout. The timeout value can be set in CLTO bit field in the I2Cn_CTRL register.

14 BITO 0 R Bus Idle Timeout Interrupt Flag

Set on each bus idle timeout. The timeout value can be set in the BITO bit field in the I2Cn_CTRL register.

13 RXUF 0 R Receive Buffer Underflow Interrupt Flag

Set when data is read from the receive buffer through the I2Cn_RXDATA register while the receive buffer is empty.

12 TXOF 0 R Transmit Buffer Overflow Interrupt Flag

Set when data is written to the transmit buffer while the transmit buffer is full.

11 BUSHOLD 0 R Bus Held Interrupt Flag

Set when the bus becomes held by the I2C module.

10 BUSERR 0 R Bus Error Interrupt Flag

Set when a bus error is detected. The bus error is resolved automatically, but the current transfer is aborted.

9 ARBLOST 0 R Arbitration Lost Interrupt Flag

Set when arbitration is lost.

8 MSTOP 0 R Master STOP Condition Interrupt Flag

Set when a STOP condition has been successfully transmitted. If arbitration is lost during the transmission of the STOP condition,

then the MSTOP interrupt flag is not set.

7 NACK 0 R Not Acknowledge Received Interrupt Flag

Set when a NACK has been received.

6 ACK 0 R Acknowledge Received Interrupt Flag

Set when an ACK has been received.

5 RXDATAV 0 R Receive Data Valid Interrupt Flag

Set when data is available in the receive buffer. Cleared automatically when the receive buffer is read.

4 TXBL 1 R Transmit Buffer Level Interrupt Flag

Set when the transmit buffer becomes empty. Cleared automatically when new data is written to the transmit buffer.

3 TXC 0 R Transfer Completed Interrupt Flag

Set when the transmit shift register becomes empty and there is no more data in the transmit buffer.

2 ADDR 0 R Address Interrupt Flag

Set when incoming address is accepted, i.e. own address or general call address is received.

1 RSTART 0 R Repeated START condition Interrupt Flag

Set when a repeated start condition is detected.

0 START 0 R START condition Interrupt Flag

Set when a start condition is successfully transmitted.

16.5.12 I2Cn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x02C

Reset

Access

Name

SSTOP

CLTO

BITO

RXUF

TXOF

BUSHOLD

BUSERR

ARBLOST

MSTOP

NACK

ACK

TXC

ADDR

RSTART

START

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

16 SSTOP 0 W1 Set SSTOP Interrupt Flag

Write to 1 to set the SSTOP interrupt flag.

15 CLTO 0 W1 Set Clock Low Interrupt Flag

Write to 1 to set the CLTO interrupt flag.

14 BITO 0 W1 Set Bus Idle Timeout Interrupt Flag

Write to 1 to set the BITO interrupt flag.

13 RXUF 0 W1 Set Receive Buffer Underflow Interrupt Flag

Write to 1 to set the RXUF interrupt flag.

12 TXOF 0 W1 Set Transmit Buffer Overflow Interrupt Flag

Write to 1 to set the TXOF interrupt flag.

11 BUSHOLD 0 W1 Set Bus Held Interrupt Flag

Write to 1 to set the BUSHOLD interrupt flag.

10 BUSERR 0 W1 Set Bus Error Interrupt Flag

Write to 1 to set the BUSERR interrupt flag.

9 ARBLOST 0 W1 Set Arbitration Lost Interrupt Flag

Write to 1 to set the ARBLOST interrupt flag.

8 MSTOP 0 W1 Set MSTOP Interrupt Flag

Write to 1 to set the MSTOP interrupt flag.

7 NACK 0 W1 Set Not Acknowledge Received Interrupt Flag

Write to 1 to set the NACK interrupt flag.

6 ACK 0 W1 Set Acknowledge Received Interrupt Flag

Write to 1 to set the ACK interrupt flag.

5:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 TXC 0 W1 Set Transfer Completed Interrupt Flag

Write to 1 to set the TXC interrupt flag.

2 ADDR 0 W1 Set Address Interrupt Flag

Write to 1 to set the ADDR interrupt flag.

1 RSTART 0 W1 Set Repeated START Interrupt Flag

Write to 1 to set the RSTART interrupt flag.

0 START 0 W1 Set START Interrupt Flag

Write to 1 to set the START interrupt flag.

16.5.13 I2Cn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x030

Reset

Access

Name

SSTOP

CLTO

BITO

RXUF

TXOF

BUSHOLD

BUSERR

ARBLOST

MSTOP

NACK

ACK

TXC

ADDR

RSTART

START

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 SSTOP 0 W1 Clear SSTOP Interrupt Flag

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Bit Name Reset Access Description

Write to 1 to clear the SSTOP interrupt flag.

15 CLTO 0 W1 Clear Clock Low Interrupt Flag

Write to 1 to clear the CLTO interrupt flag.

14 BITO 0 W1 Clear Bus Idle Timeout Interrupt Flag

Write to 1 to clear the BITO interrupt flag.

13 RXUF 0 W1 Clear Receive Buffer Underflow Interrupt Flag

Write to 1 to clear the RXUF interrupt flag.

12 TXOF 0 W1 Clear Transmit Buffer Overflow Interrupt Flag

Write to 1 to clear the TXOF interrupt flag.

11 BUSHOLD 0 W1 Clear Bus Held Interrupt Flag

Write to 1 to clear the BUSHOLD interrupt flag.

10 BUSERR 0 W1 Clear Bus Error Interrupt Flag

Write to 1 to clear the BUSERR interrupt flag.

9 ARBLOST 0 W1 Clear Arbitration Lost Interrupt Flag

Write to 1 to clear the ARBLOST interrupt flag.

8 MSTOP 0 W1 Clear MSTOP Interrupt Flag

Write to 1 to clear the MSTOP interrupt flag.

7 NACK 0 W1 Clear Not Acknowledge Received Interrupt Flag

Write to 1 to clear the NACK interrupt flag.

6 ACK 0 W1 Clear Acknowledge Received Interrupt Flag

Write to 1 to clear the ACK interrupt flag.

5:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 TXC 0 W1 Clear Transfer Completed Interrupt Flag

Write to 1 to clear the TXC interrupt flag.

2 ADDR 0 W1 Clear Address Interrupt Flag

Write to 1 to clear the ADDR interrupt flag.

1 RSTART 0 W1 Clear Repeated START Interrupt Flag

Write to 1 to clear the RSTART interrupt flag.

0 START 0 W1 Clear START Interrupt Flag

Write to 1 to clear the START interrupt flag.

16.5.14 I2Cn_IEN - Interrupt Enable Register

Offset Bit Position

0x034

Reset

Access

Name

SSTOP

CLTO

BITO

RXUF

TXOF

BUSHOLD

BUSERR

ARBLOST

MSTOP

NACK

ACK

RXDATAV

TXBL

TXC

ADDR

RSTART

START

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 SSTOP 0 RW SSTOP Interrupt Enable

Enable interrupt on SSTOP.

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Bit Name Reset Access Description

15 CLTO 0 RW Clock Low Interrupt Enable

Enable interrupt on clock low timeout.

14 BITO 0 RW Bus Idle Timeout Interrupt Enable

Enable interrupt on bus idle timeout.

13 RXUF 0 RW Receive Buffer Underflow Interrupt Enable

Enable interrupt on receive buffer underflow.

12 TXOF 0 RW Transmit Buffer Overflow Interrupt Enable

Enable interrupt on transmit buffer overflow.

11 BUSHOLD 0 RW Bus Held Interrupt Enable

Enable interrupt on bus-held.

10 BUSERR 0 RW Bus Error Interrupt Enable

Enable interrupt on bus error.

9 ARBLOST 0 RW Arbitration Lost Interrupt Enable

Enable interrupt on loss of arbitration.

8 MSTOP 0 RW MSTOP Interrupt Enable

Enable interrupt on MSTOP.

7 NACK 0 RW Not Acknowledge Received Interrupt Enable

Enable interrupt when not-acknowledge is received.

6 ACK 0 RW Acknowledge Received Interrupt Enable

Enable interrupt on acknowledge received.

5 RXDATAV 0 RW Receive Data Valid Interrupt Enable

Enable interrupt on receive buffer full.

4 TXBL 0 RW Transmit Buffer level Interrupt Enable

Enable interrupt on transmit buffer level.

3 TXC 0 RW Transfer Completed Interrupt Enable

Enable interrupt on transfer completed.

2 ADDR 0 RW Address Interrupt Enable

Enable interrupt on recognized address.

1 RSTART 0 RW Repeated START condition Interrupt Enable

Enable interrupt on transmitted or received repeated START condition.

0 START 0 RW START Condition Interrupt Enable

Enable interrupt on transmitted or received START condition.

16.5.15 I2Cn_ROUTE - I/O Routing Register

Offset Bit Position

0x038

Reset

0x0

Access

Name

LOCATION

SCLPEN

SDAPEN

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

10:8 LOCATION 0x0 RW I/O Location

Decides the location of the I2C I/O pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

4 LOC4 Location 4

5 LOC5 Location 5

6 LOC6 Location 6

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SCLPEN 0 RW SCL Pin Enable

When set, the SCL pin of the I2C is enabled.

0 SDAPEN 0 RW SDA Pin Enable

When set, the SDA pin of the I2C is enabled.

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17 USART - Universal Synchronous Asynchronous

Receiver/Transmitter

01 2 3 4

USARTRX/

MISO

TX/

MOSI

DMA

controller RAM

CLK

EFM32

SPI

USART

SmartCards

IrDA

Quick Facts

What?

The USART handles high-speed UART, SPI-

bus, SmartCards, and IrDA communication.

Why?

Serial communication is frequently used in

embedded systems and the USART allows

efficient communication with a wide range of

external devices.

How?

The USART has a wide selection of operating

modes, frame formats and baud rates. The

multi-processor mode allows the USART

to remain idle when not addressed. Triple

buffering and DMA support makes high data-

rates possible with minimal CPU intervention

and it is possible to transmit and receive large

frames while the MCU remains in EM1.

17.1 Introduction

The Universal Synchronous Asynchronous serial Receiver and Transmitter (USART) is a very flexible

serial I/O module. It supports full duplex asynchronous UART communication as well as RS-485, SPI,

MicroWire and 3-wire. It can also interface with ISO7816 SmartCards, and IrDA devices.

17.2 Features

• Asynchronous and synchronous (SPI) communication

• Full duplex and half duplex

• Separate TX/RX enable

• Separate receive / transmit 2-level buffers, with additional separate shift registers

• Programmable baud rate, generated as an fractional division from the peripheral clock

(HFPERCLKUSARTn)

• Max bit-rate

• SPI master mode, peripheral clock rate/2

• SPI slave mode, peripheral clock rate/8

• UART mode, peripheral clock rate/16, 8, 6, or 4

• Asynchronous mode supports

• Majority vote baud-reception

• False start-bit detection

• Break generation/detection

• Multi-processor mode

• Synchronous mode supports

• All 4 SPI clock polarity/phase configurations

• Master and slave mode

• Data can be transmitted LSB first or MSB first

• Configurable number of data bits, 4-16 (plus the parity bit, if enabled)

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• HW parity bit generation and check

• Configurable number of stop bits in asynchronous mode: 0.5, 1, 1.5, 2

• HW collision detection

• Multi-processor mode

• IrDA modulator on USART0

• SmartCard (ISO7816) mode

• I2S mode

• Separate interrupt vectors for receive and transmit interrupts

• Loopback mode

• Half duplex communication

• Communication debugging

• PRS RX input

17.3 Functional Description

An overview of the USART module is shown in Figure 17.1 (p. 448) .

Figure 17.1. USART Overview

TX Buffer

(2-level FIFO)

TX Shift Register

U(S)n_TX

RX Buffer

(2-level FIFO)

RX Shift Register

UART Control

and status

Peripheral Bus

Baud rate

generator

USn_CLK Pin

ctrl

USn_CS

U(S)n_RX

IrDA

modulator

IrDA

demodulator

!RXBLOCK

PRS inputs

17.3.1 Modes of Operation

The USART operates in either asynchronous or synchronous mode.

In synchronous mode, a separate clock signal is transmitted with the data. This clock signal is generated

by the bus master, and both the master and slave sample and transmit data according to this clock.

Both master and slave modes are supported by the USART. The synchronous communication mode is

compatible with the Serial Peripheral Interface Bus (SPI) standard.

In asynchronous mode, no separate clock signal is transmitted with the data on the bus. The USART

receiver thus has to determine where to sample the data on the bus from the actual data. To make this

possible, additional synchronization bits are added to the data when operating in asynchronous mode,

resulting in a slight overhead.

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Asynchronous or synchronous mode can be selected by configuring SYNC in USARTn_CTRL. The

options are listed with supported protocols in Table 17.1 (p. 449) . Full duplex and half duplex

communication is supported in both asynchronous and synchronous mode.

Table 17.1. USART Asynchronous vs. Synchronous Mode

SYNC Communication Mode Supported Protocols

0 Asynchronous RS-232, RS-485 (w/external driver), IrDA, ISO 7816

1 Synchronous SPI, MicroWire, 3-wire

Table 17.2 (p. 449) explains the functionality of the different USART pins when the USART operates

in different modes. Pin functionality enclosed in square brackets is optional, and depends on additional

configuration parameters. LOOPBK and MASTER are discussed in Section 17.3.2.5 (p. 457) and

Section 17.3.3.3 (p. 465) respectively.

Table 17.2. USART Pin Usage

Pin functionality

SYNC LOOPBK MASTER U(S)n_TX

(MOSI) U(S)n_RX (MISO) USn_CLK USn_CS

0 0 x Data out Data in - [Driver enable]

1 1 x Data out/in - - [Driver enable]

1 0 0 Data in Data out Clock in Slave select

1 0 1 Data out Data in Clock out [Auto slave select]

1 1 0 Data out/in - Clock in Slave select

1 1 1 Data out/in - Clock out [Auto slave select]

17.3.2 Asynchronous Operation

17.3.2.1 Frame Format

The frame format used in asynchronous mode consists of a set of data bits in addition to bits for

synchronization and optionally a parity bit for error checking. A frame starts with one start-bit (S), where

the line is driven low for one bit-period. This signals the start of a frame, and is used for synchronization.

Following the start bit are 4 to 16 data bits and an optional parity bit. Finally, a number of stop-bits, where

the line is driven high, end the frame. An example frame is shown in Figure 17.2 (p. 449) .

Figure 17.2. USART Asynchronous Frame Format

S 0 1 2 34 [5] [6] [7] [8] [P] Stop

Start or idleStop or idle

Frame

The number of data bits in a frame is set by DATABITS in USARTn_FRAME, see Table 17.3 (p. 450)

, and the number of stop-bits is set by STOPBITS in USARTn_FRAME, see Table 17.4 (p. 450) .

Whether or not a parity bit should be included, and whether it should be even or odd is defined by

PARITY, also in USARTn_FRAME. For communication to be possible, all parties of an asynchronous

transfer must agree on the frame format being used.

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Table 17.3. USART Data Bits

DATA BITS [3:0] Number of Data bits

0001 4

0010 5

0011 6

0100 7

0101 8 (Default)

0110 9

0111 10

1000 11

1001 12

1010 13

1011 14

1100 15

1101 16

Table 17.4. USART Stop Bits

STOP BITS [1:0] Number of Stop bits

00 0.5

01 1 (Default)

10 1.5

11 2

The order in which the data bits are transmitted and received is defined by MSBF in USARTn_CTRL.

When MSBF is cleared, data in a frame is sent and received with the least significant bit first. When it

is set, the most significant bit comes first.

The frame format used by the transmitter can be inverted by setting TXINV in USARTn_CTRL, and the

format expected by the receiver can be inverted by setting RXINV in USARTn_CTRL. These bits affect

the entire frame, not only the data bits. An inverted frame has a low idle state, a high start-bit, inverted

data and parity bits, and low stop-bits.

17.3.2.1.1 Parity bit Calculation and Handling

When parity bits are enabled, hardware automatically calculates and inserts any parity bits into outgoing

frames, and verifies the received parity bits in incoming frames. This is true for both asynchronous and

synchronous modes, even though it is mostly used in asynchronous communication. The possible parity

modes are defined in Table 17.5 (p. 451) . When even parity is chosen, a parity bit is inserted to make

the number of high bits (data + parity) even. If odd parity is chosen, the parity bit makes the total number

of high bits odd.

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Table 17.5. USART Parity Bits

STOP BITS [1:0] Description

00 No parity bit (Default)

01 Reserved

10 Even parity

11 Odd parity

17.3.2.2 Clock Generation

The USART clock defines the transmission and reception data rate. When operating in asynchronous

mode, the baud rate (bit-rate) is given by Equation 17.1 (p. 451)

USART Baud Rate

br = fHFPERCLK/(oversample x (1 + USARTn_CLKDIV/256)) (17.1)

where fHFPERCLK is the peripheral clock (HFPERCLKUSARTn) frequency and oversample is the

oversampling rate as defined by OVS in USARTn_CTRL, see Table 17.6 (p. 451) .

Table 17.6. USART Oversampling

OVS [1:0] oversample

00 16

01 8

10 6

11 4

The USART has a fractional clock divider to allow the USART clock to be controlled more accurately

than what is possible with a standard integral divider.

The clock divider used in the USART is a 15-bit value, with a 13-bit integral part and a 2-bit fractional

part. The fractional part is configured in the two LSBs of DIV in USART_CLKDIV. The lowest achievable

baud rate at 32 MHz is about 244 bauds/sec.

Fractional clock division is implemented by distributing the selected fraction over four baud periods. The

fractional part of the divider tells how many of these periods should be extended by one peripheral clock

cycle.

Given a desired baud rate brdesired, the clock divider USARTn_CLKDIV can be calculated by using

Equation 17.2 (p. 451) :

USART Desired Baud Rate

USARTn_CLKDIV = 256 x (fHFPERCLK/(oversample x brdesired) - 1) (17.2)

Table 17.7 (p. 452) shows a set of desired baud rates and how accurately the USART is able to

generate these baud rates when running at a 4 MHz peripheral clock, using 16x or 8x oversampling.

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Table 17.7. USART Baud Rates @ 4MHz Peripheral Clock

USARTn_OVS =00 USARTn_OVS =01

Desired

baud rate

[baud/s] USARTn_CLKDIV/256 Actual baud

rate [baud/s] Error % USARTn_CLKDIV/256 Actual baud

rate [baud/s] Error %

600 415,75 599,88 -0,02 832,25 600,06 0,01

1200 207,25 1200,48 0,04 415,75 1199,76 -0,02

2400 103,25 2398,082 -0,08 207,25 2400,96 0,04

4800 51 4807,692 0,16 103,25 4796,163 -0,08

9600 25 9615,385 0,16 51 9615,385 0,16

14400 16,25 14492,75 0,64 33,75 14388,49 -0,08

19200 12 19230,77 0,16 25 19230,77 0,16

28800 7,75 28571,43 -0,79 16,25 28985,51 0,64

38400 5,5 38461,54 0,16 12 38461,54 0,16

57600 3,25 58823,53 2,12 7,75 57142,86 -0,79

76800 2,25 76923,08 0,16 5,5 76923,08 0,16

115200 1,25 111111,1 -3,55 3,25 117647,1 2,12

230400 0 250000 8,51 1,25 222222,2 -3,55

17.3.2.3 Data Transmission

Asynchronous data transmission is initiated by writing data to the transmit buffer using one of the

methods described in Section 17.3.2.3.1 (p. 452) . When the transmission shift register is empty and

ready for new data, a frame from the transmit buffer is loaded into the shift register, and if the transmitter

is enabled, transmission begins. When the frame has been transmitted, a new frame is loaded into the

shift register if available, and transmission continues. If the transmit buffer is empty, the transmitter goes

to an idle state, waiting for a new frame to become available.

Transmission is enabled through the command register USARTn_CMD by setting TXEN, and disabled

by setting TXDIS in the same command register. When the transmitter is disabled using TXDIS, any

ongoing transmission is aborted, and any frame currently being transmitted is discarded. When disabled,

the TX output goes to an idle state, which by default is a high value. Whether or not the transmitter is

enabled at a given time can be read from TXENS in USARTn_STATUS.

When the USART transmitter is enabled and there is no data in the transmit shift register or transmit

buffer, the TXC flag in USARTn_STATUS and the TXC interrupt flag in USARTn_IF are set, signaling

that the transmitter is idle. The TXC status flag is cleared when a new frame becomes available for

transmission, but the TXC interrupt flag must be cleared by software.

17.3.2.3.1 Transmit Buffer Operation

The transmit-buffer is a 2-level FIFO buffer. A frame can be loaded into the buffer by writing

to USARTn_TXDATA, USARTn_TXDATAX, USARTn_TXDOUBLE or USARTn_TXDOUBLEX. Using

USARTn_TXDATA allows 8 bits to be written to the buffer, while using USARTn_TXDOUBLE will write

2 frames of 8 bits to the buffer. If 9-bit frames are used, the 9th bit of the frames will in these cases be

set to the value of BIT8DV in USARTn_CTRL.

To set the 9th bit directly and/or use transmission control, USARTn_TXDATAX and

USARTn_TXDOUBLEX must be used. USARTn_TXDATAX allows 9 data bits to be written, as well

as a set of control bits regarding the transmission of the written frame. Every frame in the buffer is

stored with 9 data bits and additional transmission control bits. USARTn_TXDOUBLEX allows two

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frames, complete with control bits to be written at once. When data is written to the transmit buffer

using USARTn_TXDATAX and USARTn_TXDOUBLEX, the 9th bit(s) written to these registers override

the value in BIT8DV in USARTn_CTRL, and alone define the 9th bits that are transmitted if 9-bit

frames are used. Figure 17.3 (p. 453) shows the basics of the transmit buffer when DATABITS in

USARTn_FRAME is configured to less than 10 bits.

Figure 17.3. USART Transmit Buffer Operation

Write CTRL

TX buffer element 1

TX buffer element 0

Shift register

Peripheral Bus

Write CTRL

TXDOUBLE,

TXDOUBLEX TXDATA,

TXDATAX

When writing more frames to the transmit buffer than there is free space for, the TXOF interrupt flag in

USARTn_IF will be set, indicating the overflow. The data already in the transmit buffer is preserved in

this case, and no data is written.

In addition to the interrupt flag TXC in USARTn_IF and status flag TXC in USARTn_STATUS which are

set when the transmitter is idle, TXBL in USARTn_STATUS and the TXBL interrupt flag in USARTn_IF

are used to indicate the level of the transmit buffer. TXBIL in USARTn_CTRL controls the level at which

these bits are set. If TXBIL is cleared, they are set whenever the transmit buffer becomes empty, and if

TXBIL is set, they are set whenever the transmit buffer goes from full to half-full or empty. Both the TXBL

status flag and the TXBL interrupt flag are cleared automatically when their condition becomes false

The transmit buffer, including the transmit shift register can be cleared by setting CLEARTX in

USARTn_CMD. This will prevent the USART from transmitting the data in the buffer and shift register,

and will make them available for new data. Any frame currently being transmitted will not be aborted.

Transmission of this frame will be completed.

17.3.2.3.2 Frame Transmission Control

The transmission control bits, which can be written using USARTn_TXDATAX and

USARTn_TXDOUBLEX, affect the transmission of the written frame. The following options are available:

• Generate break: By setting TXBREAK, the output will be held low during the stop-bit period to generate

a framing error. A receiver that supports break detection detects this state, allowing it to be used e.g.

for framing of larger data packets. The line is driven high before the next frame is transmitted so the

next start condition can be identified correctly by the recipient. Continuous breaks lasting longer than

a USART frame are thus not supported by the USART. GPIO can be used for this.

• Disable transmitter after transmission: If TXDISAT is set, the transmitter is disabled after the frame

has been fully transmitted.

• Enable receiver after transmission: If RXENAT is set, the receiver is enabled after the frame has

been fully transmitted. It is enabled in time to detect a start-bit directly after the last stop-bit has been

transmitted.

• Unblock receiver after transmission: If UBRXAT is set, the receiver is unblocked and RXBLOCK is

cleared after the frame has been fully transmitted.

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• Tristate transmitter after transmission: If TXTRIAT is set, TXTRI is set after the frame has been

fully transmitted, tristating the transmitter output. Tristating of the output can also be performed

automatically by setting AUTOTRI. If AUTOTRI is set TXTRI is always read as 0.

Note When in SmartCard mode with repeat enabled, none of the actions, except generate break,

will be performed until the frame is transmitted without failure. Generation of a break in

SmartCard mode with repeat enabled will cause the USART to detect a NACK on every

frame.

17.3.2.4 Data Reception

Data reception is enabled by setting RXEN in USARTn_CMD. When the receiver is enabled, it actively

samples the input looking for a transition from high to low indicating the start baud of a new frame. When

a start baud is found, reception of the new frame begins if the receive shift register is empty and ready

for new data. When the frame has been received, it is pushed into the receive buffer, making the shift

receive buffer is full, the received frame remains in the shift register until more space in the receive

buffer is available. If an incoming frame is detected while both the receive buffer and the receive shift

is set to indicate the buffer overflow.

The receiver can be disabled by setting the command bit RXDIS in USARTn_CMD. Any frame currently

being received when the receiver is disabled is discarded. Whether or not the receiver is enabled at a

given time can be read out from RXENS in USARTn_STATUS.

17.3.2.4.1 Receive Buffer Operation

When data becomes available in the receive buffer, the RXDATAV flag in USARTn_STATUS, and

the RXDATAV interrupt flag in USARTn_IF are set, and when the buffer becomes full, RXFULL in

USARTn_STATUS and the RXFULL interrupt flag in USARTn_IF are set. The status flags RXDATAV

and RXFULL are automatically cleared by hardware when their condition is no longer true. This also

goes for the RXDATAV interrupt flag, but the RXFULL interrupt flag must be cleared by software. When

the RXFULL flag is set, notifying that the buffer is full, space is still available in the receive shift register

for one more frame.

Data can be read from the receive buffer in a number of ways. USARTn_RXDATA gives access to the

8 least significant bits of the received frame, and USARTn_RXDOUBLE makes it possible to read the 8

least significant bits of two frames at once, pulling two frames from the buffer. To get access to the 9th,

most significant bit, USARTn_RXDATAX must be used. This register also contains status information

regarding the frame. USARTn_RXDOUBLEX can be used to get two frames complete with the 9th bits

and status bits.

When a frame is read from the receive buffer using USARTn_RXDATA or USARTn_RXDATAX,

the frame is pulled out of the buffer, making room for a new frame. USARTn_RXDOUBLE and

USARTn_RXDOUBLEX pull two frames out of the buffer. If an attempt is done to read more frames from

the buffer than what is available, the RXUF interrupt flag in USARTn_IF is set to signal the underflow,

and the data read from the buffer is undefined.

Frames can be read from the receive buffer without removing the data by using USARTn_RXDATAXP

and USARTn_RXDOUBLEXP. USARTn_RXDATAXP gives access the first frame in the buffer with

status bits, while USARTn_RXDOUBLEXP gives access to both frames with status bits. The data read

from these registers when the receive buffer is empty is undefined. If the receive buffer contains one

valid frame, the first frame in USARTn_RXDOUBLEXP will be valid. No underflow interrupt is generated

by a read using these registers, i.e. RXUF in USARTn_IF is never set as a result of reading from

USARTn_RXDATAXP or USARTn_RXDOUBLEXP.

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The basic operation of the receive buffer when DATABITS in USARTn_FRAME is configured to less

than 10 bits is shown in Figure 17.4 (p. 455) .

Figure 17.4. USART Receive Buffer Operation

Status

RX buffer element 0

RX buffer element 1

Shift register

Peripheral Bus

Status

RXDOUBLE

RXDOUBLEX

RXDOUBLEXP

RXDATA,

RXDATAX,

RXDATAXP

The receive buffer, including the receive shift register can be cleared by setting CLEARRX in

USARTn_CMD. Any frame currently being received will not be discarded.

17.3.2.4.2 Blocking Incoming Data

When using hardware frame recognition, as detailed in Section 17.3.2.8 (p. 461) and

Section 17.3.2.9 (p. 462) , it is necessary to be able to let the receiver sample incoming frames without

passing the frames to software by loading them into the receive buffer. This is accomplished by blocking

incoming data.

Incoming data is blocked as long as RXBLOCK in USARTn_STATUS is set. When blocked, frames

received by the receiver will not be loaded into the receive buffer, and software is not notified by the

RXDATAV flag in USARTn_STATUS or the RXDATAV interrupt flag in USARTn_IF at their arrival. For

data to be loaded into the receive buffer, RXBLOCK must be cleared in the instant a frame is fully

received by the receiver. RXBLOCK is set by setting RXBLOCKEN in USARTn_CMD and disabled by

setting RXBLOCKDIS also in USARTn_CMD. There is one exception where data is loaded into the

receive buffer even when RXBLOCK is set. This is when an address frame is received when operating

in multi-processor mode. See Section 17.3.2.8 (p. 461) for more information.

Frames received containing framing or parity errors will not result in the FERR and PERR interrupt

flags in USARTn_IF being set while RXBLOCK in USARTn_STATUS is set. Hardware recognition is not

applied to these erroneous frames, and they are silently discarded.

Note If a frame is received while RXBLOCK in USARTn_STATUS is cleared, but stays in the

receive shift register because the receive buffer is full, the received frame will be loaded into

the receive buffer when space becomes available even if RXBLOCK is set at that time.

The overflow interrupt flag RXOF in USARTn_IF will be set if a frame in the receive shift

even though RXBLOCK in USARTn_STATUS is set.

17.3.2.4.3 Clock Recovery and Filtering

The receiver samples the incoming signal at a rate 16, 8, 6 or 4 times higher than the given baud rate,

depending on the oversampling mode given by OVS in USARTn_CTRL. Lower oversampling rates make

higher baud rates possible, but give less room for errors.

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When a high-to-low transition is registered on the input while the receiver is idle, this is recognized as a

start-bit, and the baud rate generator is synchronized with the incoming frame.

For oversampling modes 16, 8 and 6, every bit in the incoming frame is sampled three times to gain

a level of noise immunity. These samples are aimed at the middle of the bit-periods, as visualized in

Figure 17.5 (p. 456) . With OVS=0 in USARTn_CTRL, the start and data bits are thus sampled at

locations 8, 9 and 10 in the figure, locations 4, 5 and 6 for OVS=1 and locations 3, 4, and 5 for OVS=2.

The value of a sampled bit is determined by majority vote. If two or more of the three bit-samples are

high, the resulting bit value is high. If the majority is low, the resulting bit value is low.

Majority vote is used for all oversampling modes except 4x oversampling. In this mode, a single sample

is taken at position 3 as shown in Figure 17.5 (p. 456) .

Majority vote can be disabled by setting MVDIS in USARTn_CTRL.

If the value of the start bit is found to be high, the reception of the frame is aborted, filtering out false

start bits possibly generated by noise on the input.

Figure 17.5. USART Sampling of Start and Data Bits

0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11

Idle Start bit Bit 0

0 1 2 3 4 5 6 7 8 1 2 3 4 5 6

OVS = 0OVS = 1

1 2 3 4 5 6 1

OVS = 2

1 2 3 4 1 2 3 4

OVS = 3

2 3 4 50

If the baud rate of the transmitter and receiver differ, the location each bit is sampled will be shifted

towards the previous or next bit in the frame. This is acceptable for small errors in the baud rate, but for

larger errors, it will result in transmission errors.

When the number of stop bits is 1 or more, stop bits are sampled like the start and data bits as seen in

Figure 17.6 (p. 457) . When a stop bit has been detected by sampling at positions 8, 9 and 10 for normal

mode, or 4, 5 and 6 for smart mode, the USART is ready for a new start bit. As seen in Figure 17.6 (p.

457) , a stop-bit of length 1 normally ends at c, but the next frame will be received correctly as long as

the start-bit comes after position a for OVS=0 and OVS=3, and b for OVS=1 and OVS=2.

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Figure 17.6. USART Sampling of Stop Bits when Number of Stop Bits are 1 or More

13 14 15 16 1 2 3 4 5 6 7 8 9 10 0/1

1 stop bit

7 8 1 2 3 4 5 6

0/1

OVS = 0OVS = 1

X X X

n’th bit

a b c

Idle or start bit

0/1

OVS = 2

4 1 2 3 0/1

OVS = 3

2 3 46 1 1

When working with stop bit lengths of half a baud period, the above sampling scheme no longer suffices.

In this case, the stop-bit is not sampled, and no framing error is generated in the receiver if the stop-

bit is not generated. The line must still be driven high before the next start bit however for the USART

to successfully identify the start bit.

17.3.2.4.4 Parity Error

When parity bits are enabled, a parity check is automatically performed on incoming frames. When a

parity error is detected in an incoming frame, the data parity error bit PERR in the frame is set, as well

as the interrupt flag PERR in USARTn_IF. Frames with parity errors are loaded into the receive buffer

like regular frames.

PERR can be accessed by reading the frame from the receive buffer using the USARTn_RXDATAX,

USARTn_RXDATAXP, USARTn_RXDOUBLEX or USARTn_RXDOUBLEXP registers.

If ERRSTX in USARTn_CTRL is set, the transmitter is disabled on received parity and framing errors. If

ERRSRX in USARTn_CTRL is set, the receiver is disabled on parity and framing errors.

17.3.2.4.5 Framing Error and Break Detection

A framing error is the result of an asynchronous frame where the stop bit was sampled to a value of 0.

This can be the result of noise and baud rate errors, but can also be the result of a break generated

by the transmitter on purpose.

When a framing error is detected in an incoming frame, the framing error bit FERR in the frame is set.

The interrupt flag FERR in USARTn_IF is also set. Frames with framing errors are loaded into the receive

buffer like regular frames.

FERR can be accessed by reading the frame from the receive buffer using the USARTn_RXDATAX,

USARTn_RXDATAXP, USARTn_RXDOUBLEX or USARTn_RXDOUBLEXP registers.

If ERRSTX in USARTn_CTRL is set, the transmitter is disabled on parity and framing errors. If ERRSRX

in USARTn_CTRL is set, the receiver is disabled on parity and framing errors.

17.3.2.5 Local Loopback

The USART receiver samples U(S)n_RX by default, and the transmitter drives U(S)n_TX by default.

This is not the only option however. When LOOPBK in USARTn_CTRL is set, the receiver is connected

to the U(S)n_TX pin as shown in Figure 17.7 (p. 458) . This is useful for debugging, as the USART

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can receive the data it transmits, but it is also used to allow the USART to read and write to the same

pin, which is required for some half duplex communication modes. In this mode, the U(S)n_TX pin must

be enabled as an output in the GPIO.

Figure 17.7. USART Local Loopback

USART

RX U(S)n_RX

TX U(S)n_TX

LOOBPK = 0

µC

USART

RX U(S)n_RX

TX U(S)n_TX

LOOBPK = 1

µC

17.3.2.6 Asynchronous Half Duplex Communication

When doing full duplex communication, two data links are provided, making it possible for data to be

sent and received at the same time. In half duplex mode, data is only sent in one direction at a time.

There are several possible half duplex setups, as described in the following sections.

17.3.2.6.1 Single Data-link

In this setup, the USART both receives and transmits data on the same pin. This is enabled by setting

LOOPBK in USARTn_CTRL, which connects the receiver to the transmitter output. Because they are

both connected to the same line, it is important that the USART transmitter does not drive the line when

receiving data, as this would corrupt the data on the line.

When communicating over a single data-link, the transmitter must thus be tristated whenever not

transmitting data. This is done by setting the command bit TXTRIEN in USARTn_CMD, which tristates

the transmitter. Before transmitting data, the command bit TXTRIDIS, also in USARTn_CMD, must be

set to enable transmitter output again. Whether or not the output is tristated at a given time can be read

from TXTRI in USARTn_STATUS. If TXTRI is set when transmitting data, the data is shifted out of the

shift register, but is not put out on U(S)n_TX.

When operating a half duplex data bus, it is common to have a bus master, which first transmits a request

to one of the bus slaves, then receives a reply. In this case, the frame transmission control bits, which

can be set by writing to USARTn_TXDATAX, can be used to make the USART automatically disable

transmission, tristate the transmitter and enable reception when the request has been transmitted,

making it ready to receive a response from the slave.

Tristating the transmitter can also be performed automatically by the USART by using AUTOTRI in

USARTn_CTRL. When AUTOTRI is set, the USART automatically tristates U(S)n_TX whenever the

transmitter is idle, and enables transmitter output when the transmitter goes active. If AUTOTRI is set

TXTRI is always read as 0.

Note Another way to tristate the transmitter is to enable wired-and or wired-or mode in GPIO.

For wired-and mode, outputting a 1 will be the same as tristating the output, and for wired-

or mode, outputting a 0 will be the same as tristating the output. This can only be done on

buses with a pull-up or pull-down resistor respectively.

17.3.2.6.2 Single Data-link with External Driver

Some communication schemes, such as RS-485 rely on an external driver. Here, the driver has an extra

input which enables it, and instead of tristating the transmitter when receiving data, the external driver

must be disabled.

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This can be done manually by assigning a GPIO to turn the driver on or off, or it can be handled

automatically by the USART. If AUTOCS in USARTn_CTRL is set, the USn_CS output is automatically

activated one baud period before the transmitter starts transmitting data, and deactivated when the last

bit has been transmitted and there is no more data in the transmit buffer to transmit, or the transmitter

becomes disabled. This feature can be used to turn the external driver on when transmitting data, and

turn it off when the data has been transmitted.

Figure 17.8 (p. 459) shows an example configuration where USn_CS is used to automatically enable

and disable an external driver.

Figure 17.8. USART Half Duplex Communication with External Driver

USART

µC

The USn_CS output is active low by default, but its polarity can be changed with CSINV in

USARTn_CTRL. AUTOCS works regardless of which mode the USART is in, so this functionality can

also be used for automatic chip/slave select when in synchronous mode (e.g. SPI).

17.3.2.6.3 Two Data-links

Some limited devices only support half duplex communication even though two data links are available.

In this case software is responsible for making sure data is not transmitted when incoming data is

expected.

17.3.2.7 Large Frames

As each frame in the transmit and receive buffers holds a maximum of 9 bits, both the elements in the

buffers are combined when working with USART-frames of 10 or more data bits.

To transmit such a frame, at least two elements must be available in the transmit buffer. If only one

element is available, the USART will wait for the second element before transmitting the combined frame.

Both the elements making up the frame are consumed when transmitting such a frame.

When using large frames, the 9th bits in the buffers are unused. For an 11 bit frame, the 8 least significant

bits are thus taken from the first element in the buffer, and the 3 remaining bits are taken from the second

element as shown in Figure 17.9 (p. 460) . The first element in the transmit buffer, i.e. element 0 in

Figure 17.9 (p. 460) is the first element written to the FIFO, or the least significant byte when writing

two bytes at a time using USARTn_TXDOUBLE.

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Figure 17.9. USART Transmission of Large Frames

Write CTRL

TX buffer element 1

TX buffer element 0

Shift register

Peripheral Bus

0 1 2 3 4 5 6 7 0 1 2

0 1 2

0 1 2 3 4 5 6 7

As shown in Figure 17.9 (p. 460) , frame transmission control bits are taken from the second element

in FIFO.

The two buffer elements can be written at the same time using the USARTn_TXDOUBLE or

USARTn_TXDOUBLEX register. The TXDATAX0 bitfield then refers to buffer element 0, and

TXDATAX1 refers to buffer element 1.

Figure 17.10. USART Transmission of Large Frames, MSBF

TX buffer element 1

TX buffer element 0

Shift register

Peripheral Bus

2 1 0 7 6 5 4 3 2 1 0

0 1 2 3 4 5 6 7

0 1 2

Figure 17.10 (p. 460) illustrates the order of the transmitted bits when an 11 bit frame is transmitted

with MSBF set. If MSBF is set and the frame is smaller than 10 bits, only the contents of transmit buffer

0 will be transmitted.

When receiving a large frame, BYTESWAP in USARTn_CTRL determines the order the way the large

frame is split into the two buffer elements. If BYTESWAP is cleared, the least significant 8 bits of the

received frame are loaded into the first element of the receive buffer, and the remaining bits are loaded

into the second element, as shown in Figure 17.11 (p. 461) . The first byte read from the buffer thus

contains the 8 least significant bits. Set BYTESWAP to reverse the order.

The status bits are loaded into both elements of the receive buffer. The frame is not moved from the

receive shift register before there are two free spaces in the receive buffer.

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Figure 17.11. USART Reception of Large Frames

Status

RX buffer element 0

RX buffer element 1

Shift register

Peripheral Bus

Status

0 1 2 3 4 5 6 7 0 1 2

0 1 2

0 1 2 3 4 5 6 7

The two buffer elements can be read at the same time using the USARTn_RXDOUBLE or

USARTn_RXDOUBLEX register. RXDATA0 then refers to buffer element 0 and RXDATA1 refers to

buffer element 1.

Large frames can be used in both asynchronous and synchronous modes.

17.3.2.8 Multi-Processor Mode

To simplify communication between multiple processors, the USART supports a special multi-processor

mode. In this mode the 9th data bit in each frame is used to indicate whether the content of the remaining

8 bits is data or an address.

When multi-processor mode is enabled, an incoming 9-bit frame with the 9th bit equal to the value of

MPAB in USARTn_CTRL is identified as an address frame. When an address frame is detected, the

MPAF interrupt flag in USARTn_IF is set, and the address frame is loaded into the receive register. This

happens regardless of the value of RXBLOCK in USARTn_STATUS.

Multi-processor mode is enabled by setting MPM in USARTn_CTRL, and the value of the 9th bit in

address frames can be set in MPAB. Note that the receiver must be enabled for address frames to be

detected. The receiver can be blocked however, preventing data from being loaded into the receive

buffer while looking for address frames.

Example 17.1 (p. 461) explains basic usage of the multi-processor mode:

Example 17.1. USART Multi-processor Mode Example

1. All slaves enable multi-processor mode and, enable and block the receiver. They will now not receive

data unless it is an address frame. MPAB in USARTn_CTRL is set to identify frames with the 9th bit

high as address frames.

2. The master sends a frame containing the address of a slave and with the 9th bit set.

3. All slaves receive the address frame and get an interrupt. They can read the address from the receive

buffer. The selected slave unblocks the receiver to start receiving data from the master.

4. The master sends data with the 9th bit cleared.

5. Only the slave with RX enabled receives the data. When transmission is complete, the slave blocks

the receiver and waits for a new address frame.

When a slave has received an address frame and wants to receive the following data, it must make

sure the receiver is unblocked before the next frame has been completely received in order to prevent

data loss.

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BIT8DV in USARTn_CTRL can be used to specify the value of the 9th bit without writing to the transmit

buffer with USARTn_TXDATAX or USARTn_TXDOUBLEX, giving higher efficiency in multi-processor

mode, as the 9th bit is only set when writing address frames, and 8-bit writes to the USART can be used

when writing the data frames.

17.3.2.9 Collision Detection

The USART supports a basic form of collision detection. When the receiver is connected to the output

of the transmitter, either by using the LOOPBK bit in USARTn_CTRL or through an external connection,

this feature can be used to detect whether data transmitted on the bus by the USART did get corrupted

by a simultaneous transmission by another device on the bus.

For collision detection to be enabled, CCEN in USARTn_CTRL must be set, and the receiver enabled.

The data sampled by the receiver is then continuously compared with the data output by the transmitter.

If they differ, the CCF interrupt flag in USARTn_IF is set. The collision check includes all bits of the

transmitted frames. The CCF interrupt flag is set once for each bit sampled by the receiver that differs

from the bit output by the transmitter. When the transmitter output is disabled, i.e. the transmitter is

tristated, collisions are not registered.

17.3.2.10 SmartCard Mode

In SmartCard mode, the USART supports the ISO 7816 I/O line T0 mode. With exception of the stop-

bits (guard time), the 7816 data frame is equal to the regular asynchronous frame. In this mode, the

receiver pulls the line low for one baud, half a baud into the guard time to indicate a parity error. This

NAK can for instance be used by the transmitter to re-transmit the frame. SmartCard mode is a half

duplex asynchronous mode, so the transmitter must be tristated whenever not transmitting data.

To enable SmartCard mode, set SCMODE in USARTn_CTRL, set the number of databits in a frame to

8, and configure the number of stopbits to 1.5 by writing to STOPBITS in USARTn_FRAME.

The SmartCard mode relies on half duplex communication on a single line, so for it to work, both the

receiver and transmitter must work on the same line. This can be achieved by setting LOOPBK in

USARTn_CTRL or through an external connection. The TX output should be configured as open-drain

in the GPIO module.

When no parity error is identified by the receiver, the data frame is as shown in Figure 17.12 (p. 462)

. The frame consists of 8 data bits, a parity bit, and 2 stop bits. The transmitter does not drive the output

line during the guard time.

Figure 17.12. USART ISO 7816 Data Frame Without Error

S 0 1 2 34 5 6 7 PStop

Start or idleStop or idle

ISO 7816 Frame without error

If a parity error is detected by the receiver, it pulls the line I/O line low after half a stop bit, see

Figure 17.13 (p. 463) . It holds the line low for one bit-period before it releases the line. In this case,

the guard time is extended by one bit period before a new transmission can start, resulting in a total

of 3 stop bits.

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Figure 17.13. USART ISO 7816 Data Frame With Error

S 0 1 2 34 5 6 7 PStop

Start or idle

Stop or idle

ISO 7816 Frame with error

Stop

NAK

On a parity error, the NAK is generated by hardware. The NAK generated by the receiver is sampled

as the stop-bit of the frame. Because of this, parity errors when in SmartCard mode are reported with

both a parity error and a framing error.

When transmitting a T0 frame, the USART receiver on the transmitting side samples position 16, 17 and

18 in the stop-bit to detect the error signal when in 16x oversampling mode as shown in Figure 17.14 (p.

463) . Sampling at this location places the stop-bit sample in the middle of the bit-period used for the

error signal (NAK).

If a NAK is transmitted by the receiver, it will thus appear as a framing error at the transmitter, and the

FERR interrupt flag in USARTn_IF will be set. If SCRETRANS USARTn_CTRL is set, the transmitter

will automatically retransmit a NACK’ed frame. The transmitter will retransmit the frame until it is ACK’ed

by the receiver. This only works when the number of databits in a frame is configured to 8.

Set SKIPPERRF in USARTn_CTRL to make the receiver discard frames with parity errors. The PERR

interrupt flag in USARTn_IF is set when a frame is discarded because of a parity error.

Figure 17.14. USART SmartCard Stop Bit Sampling

13 14 15 16 1 2 3 4 5 6 7 8 9 10 11

1/2 stop bit

7 8 1 2 3 4 5 6

OVS = 0OVS = 1

14 15 16

PNAK or stop

17 18 X

9 10

X X X X

Stop

1 2 3 4 5 6 7

OVS = 2

1 2 3 4 5 x

OVS = 3

8 x6

For communication with a SmartCard, a clock signal needs to be generated for the card. This clock

output can be generated using one of the timers. See the ISO 7816 specification for more info on this

clock signal.

SmartCard T1 mode is also supported. The T1 frame format used is the same as the asynchronous

frame format with parity bit enabled and one stop bit. The USART must then be configured to operate

in asynchronous half duplex mode.

17.3.3 Synchronous Operation

Most of the features in asynchronous mode are available in synchronous mode. Multi-processor mode

can be enabled for 9-bit frames, loopback is available and collision detection can be performed.

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17.3.3.1 Frame Format

The frames used in synchronous mode need no start and stop bits since a single clock is available to

all parts participating in the communication. Parity bits cannot be used in synchronous mode.

The USART supports frame lengths of 4 to 16 bits per frame. Larger frames can be simulated by

transmitting multiple smaller frames, i.e. a 22 bit frame can be sent using two 11-bit frames, and a 21

bit frame can be generated by transmitting three 7-bit frames. The number of bits in a frame is set using

DATABITS in USARTn_FRAME.

The frames in synchronous mode are by default transmitted with the least significant bit first like in

asynchronous mode. The bit-order can be reversed by setting MSBF in USARTn_CTRL.

The frame format used by the transmitter can be inverted by setting TXINV in USARTn_CTRL, and the

format expected by the receiver can be inverted by setting RXINV, also in USARTn_CTRL.

17.3.3.2 Clock Generation

The bit-rate in synchronous mode is given by Equation 17.3 (p. 464) . As in the case of asynchronous

operation, the clock division factor have a 13-bit integral part and a 2-bit fractional part.

USART Synchronous Mode Bit Rate

br = fHFPERCLK/(2 x (1 + USARTn_CLKDIV/256)) (17.3)

Given a desired baud rate brdesired, the clock divider USARTn_CLKDIV can be calculated using

Equation 17.4 (p. 464)

USART Synchronous Mode Clock Division Factor

USARTn_CLKDIV = 256 x (fHFPERCLK/(2 x brdesired) - 1) (17.4)

When the USART operates in master mode, the highest possible bit rate is half the peripheral clock rate.

When operating in slave mode however, the highest bit rate is an eighth of the peripheral clock:

• Master mode: brmax = fHFPERCLK/2

• Slave mode: brmax = fHFPERCLK/8

On every clock edge data on the data lines, MOSI and MISO, is either set up or sampled. When CLKPHA

in USARTn_CTRL is cleared, data is sampled on the leading clock edge and set-up is done on the

trailing edge. If CLKPHA is set however, data is set-up on the leading clock edge, and sampled on the

trailing edge. In addition to this, the polarity of the clock signal can be changed by setting CLKPOL in

USARTn_CTRL, which also defines the idle state of the clock. This results in four different modes which

are summarized in Table 17.8 (p. 464) . Figure 17.15 (p. 465) shows the resulting timing of data

set-up and sampling relative to the bus clock.

Table 17.8. USART SPI Modes

SPI mode CLKPOL CLKPHA Leading edge Trailing edge

0 0 0 Rising, sample Falling, set-up

1 0 1 Rising, set-up Falling, sample

2 1 0 Falling, sample Rising, set-up

3 1 1 Falling, set-up Rising, sample

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Figure 17.15. USART SPI Timing

0 1 2 3 4 5 6 7

USn_CLK

USn_CS

USn_TX/

USn_RX

CLKPOL = 0

CLKPOL = 1

CLKPHA = 0

CLKPHA = 1 X

X X

If CPHA=1, the TX underflow flag, TXUF, will be set on the first setup clock edge of a frame in slave

mode if TX data is not available. If CPHA=0, TXUF is set if data is not available in the transmit buffer

three HFPERCLK cycles prior to the first sample clock edge. The RXDATAV flag is updated on the last

sample clock edge of a transfer, while the RX overflow interrupt flag, RXOF, is set on the first sample

clock edge if the receive buffer overflows. When a transfer has been performed, interrupt flags TXBL

and TXC are updated on the first setup clock edge of the succeeding frame, or when CS is deasserted.

17.3.3.3 Master Mode

When in master mode, the USART is in full control of the data flow on the synchronous bus. When

operating in full duplex mode, the slave cannot transmit data to the master without the master transmitting

to the slave. The master outputs the bus clock on USn_CLK.

Communication starts whenever there is data in the transmit buffer and the transmitter is enabled. The

USART clock then starts, and the master shifts bits out from the transmit shift register using the internal

clock.

When there are no more frames in the transmit buffer and the transmit shift register is empty, the clock

stops, and communication ends. When the receiver is enabled, it samples data using the internal clock

when the transmitter transmits data. Operation of the RX and TX buffers is as in asynchronous mode.

17.3.3.3.1 Operation of USn_CS Pin

When operating in master mode, the USn_CS pin can have one of two functions, or it can be disabled.

If USn_CS is configured as an output, it can be used to automatically generate a chip select for a slave

by setting AUTOCS in USARTn_CTRL. If AUTOCS is set, USn_CS is activated when a transmission

begins, and deactivated directly after the last bit has been transmitted and there is no more data in the

transmit buffer. By default, USn_CS is active low, but its polarity can be inverted by setting CSINV in

USARTn_CTRL.

When USn_CS is configured as an input, it can be used by another master that wants control of the bus

to make the USART release it. When USn_CS is driven low, or high if CSINV is set, the interrupt flag

SSM in USARTn_IF is set, and if CSMA in USARTn_CTRL is set, the USART goes to slave mode.

17.3.3.3.2 AUTOTX

A synchronous master is required to transmit data to a slave in order to receive data from the slave. In

some cases, only a few words are transmitted and a lot of data is then received from the slave. In that

case, one solution is to keep feeding the TX with data to transmit, but that consumes system bandwidth.

Instead AUTOTX can be used.

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When AUTOTX in USARTn_CTRL is set, the USART transmits data as long as there is available space

in the RX shift register for the chosen frame size. This happens even though there is no data in the TX

buffer. The TX underflow interrupt flag TXUF in USARTn_IF is set on the first word that is transmitted

which does not contain valid data.

During AUTOTX the USART will always send the previous sent bit, thus reducing the number of

transitions on the TX output. So if the last bit sent was a 0, 0's will be sent during AUTOTX and if the

last bit sent was a 1, 1's will be sent during AUTOTX.

17.3.3.3.3 Synchronous Master Sample Delay

To improve speed in certain conditions by reducing the setup-time requirements for the SPI slave, the

master can be configured to sample the data one half SCLK-cycle later, i.e. on the next setup edge,

which, in SPI mode 0, is the rising edge. This is enabled by setting SMSDELAY in USARTn_CTRL and

can be used together with all SPI slaves that does not set up new data before the next setup edge, as

the propagation delay of SCLK will ensure sufficient hold time.

Note If used together with another Silicon Laboratories chip utilizing SSSEARLY, a very thorough

understanding of the timing is required.

Figure 17.16. USART SPI timing with SMSDELAY

01 2 3 4 5 6 7

USn_CLK

USn_CS

USn_TX

(MOSI) X X

01 2 3 4 5 6 7

USn_RX

(MISO) X X

Ordinary Sample Edge Sample Edge with SMSDELAY

17.3.3.4 Slave Mode

When the USART is in slave mode, data transmission is not controlled by the USART, but by an external

master. The USART is therefore not able to initiate a transmission, and has no control over the number

of bytes written to the master.

The output and input to the USART are also swapped when in slave mode, making the receiver take its

input from USn_TX (MOSI) and the transmitter drive USn_RX (MISO).

To transmit data when in slave mode, the slave must load data into the transmit buffer and enable the

transmitter. The data will remain in the USART until the master starts a transmission by pulling the

USn_CS input of the slave low and transmitting data. For every frame the master transmits to the slave,

a frame is transferred from the slave to the master. After a transmission, MISO remains in the same

state as the last bit transmitted. This also applies if the master transmits to the slave and the slave TX

buffer is empty.

If the transmitter is enabled in synchronous slave mode and the master starts transmission of a frame,

the underflow interrupt flag TXUF in USARTn_IF will be set if no data is available for transmission to

the master.

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If the slave needs to control its own chip select signal, this can be achieved by clearing CSPEN in the

ROUTE register. The internal chip select signal can then be controlled through CSINV in the CTRL

and vice versa.

17.3.3.4.1 Synchronous Slave Setup Early

To improve speed in certain conditions by improving the setup time when running in slave mode, the

slave can be configured to set up data one half SCLK-cycle earlier, i.e. on the previous sample edge,

which, for SPI mode 0, is the falling edge. This is enabled by setting SSSEARLY in USARTn_CTRL and

can be used with all SPI masters that samples the data on the sample edge, as the SCLK propagation

delay will ensure sufficient hold time.

Note If used together with another Silicon Laboratories chip utilizing SMSDELAY, a very

thorough understanding of the timing is required.

Figure 17.17. USART SPI Slave Timing with SSSEARLY

01 2 3 4 5 6 7

USn_CLK

USn_CS

USn_TX

(MOSI) X X

012 3 4 5 6 7

USn_RX

(MISO) XX

17.3.3.5 Synchronous Half Duplex Communication

Half duplex communication in synchronous mode is very similar to half duplex communication in

asynchronous mode as detailed in Section 17.3.2.6 (p. 458) . The main difference is that in this mode,

the master must generate the bus clock even when it is not transmitting data, i.e. it must provide the

slave with a clock to receive data. To generate the bus clock, the master should transmit data with the

transmitter tristated, i.e. TXTRI in USARTn_STATUS set, when receiving data. If 2 bytes are expected

from the slave, then transmit 2 bytes with the transmitter tristated, and the slave uses the generated

bus clock to transmit data to the master. TXTRI can be set by setting the TXTRIEN command bit in

USARTn_CMD.

Note When operating as SPI slave in half duplex mode, TX has to be tristated (not disabled)

during data reception if the slave is to transmit data in the current transfer.

17.3.3.6 I2S

I2S is a synchronous format for transmission of audio data. The frame format is 32-bit, but since data is

always transmitted with MSB first, an I2S device operating with 16-bit audio may choose to only process

the 16 msb of the frame, and only transmit data in the 16 msb of the frame.

In addition to the bit clock used for regular synchronous transfers, I2S mode uses a separate word clock.

When operating in mono mode, with only one channel of data, the word clock pulses once at the start of

each new word. In stereo mode, the word clock toggles at the start of new words, and also gives away

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whether the transmitted word is for the left or right audio channel; A word transmitted while the word

clock is low is for the left channel, and a word transmitted while the word clock is high is for the right.

When operating in I2S mode, the CS pin is used as a the word clock. In master mode, this is automatically

driven by the USART, and in slave mode, the word clock is expected from an external master.

17.3.3.6.1 Word Format

The general I2S word format is 32 bits wide, but the USART also supports 16-bit and 8-bit words. In

addition to this, it can be specified how many bits of the word should actually be used by the USART.

These parameters are given by FORMAT in USARTn_I2SCTRL.

As an example, configuring FORMAT to using a 32-bit word with 16-bit data will make each word on the

I2S bus 32-bits wide, but when receiving data through the USART, only the 16 most significant bits of

each word can be read out of the USART. Similarly, only the 16 most significant bits have to be written

to the USART when transmitting. The rest of the bits will be transmitted as zeroes.

17.3.3.6.2 Major Modes

The USART supports a set of different I2S formats as shown in Table 17.9 (p. 468) , but it is not limited

to these modes. MONO, JUSTIFY and DELAY in USARTn_I2SCTRL can be mixed and matched to

create an appropriate format. MONO enables mono mode, i.e. one data stream instead of two which is

the default. JUSTIFY aligns data within a word on the I2S bus, either left or right which can bee seen in

figures Figure 17.20 (p. 469) and Figure 17.21 (p. 469) . Finally, DELAY specifies whether a new I2S

word should be started directly on the edge of the word-select signal, or one bit-period after the edge.

Table 17.9. USART I2S Modes

Mode MONO JUSTIFY DELAY CLKPOL

Regular I2S 0 0 1 0

Left-Justified 0 0 0 1

Right-Justified 0 1 0 1

Mono 1 0 0 0

The regular I2S waveform is shown in Figure 17.18 (p. 468) and Figure 17.19 (p. 469) . The first

figure shows a waveform transmitted with full accuracy. The wordlength can be configured to 32-bit,

16-bit or 8-bit using FORMAT in USARTn_I2SCTRL. In the second figure, I2S data is transmitted with

reduced accuracy, i.e. the data transmitted has less bits than what is possible in the bus format.

Note that the msb of a word transmitted in regular I2S mode is delayed by one cycle with respect to

word select

Figure 17.18. USART Standard I2S waveform

USn_CLK

USn_CS

(word select)

USn_TX/

USn_RX MSB

Left channelRight channel Right channel

LSB MSBLSB

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Figure 17.19. USART Standard I2S waveform (reduced accuracy)

USn_CLK

USn_CS

(word select)

USn_TX/

USn_RX MSB

Left channelRight channel Right channel

LSB MSB

A left-justified stream is shown in Figure 17.20 (p. 469) . Note that the MSB comes directly after the

edge on the word-select signal in contradiction to the regular I2S waveform where it comes one bit-

period after.

Figure 17.20. USART Left-justified I2S waveform

USn_CLK

USn_CS

(word select)

USn_TX/

USn_RX MSB

Left channelRight channel Right channel

LSB MSB

A right-justified stream is shown in Figure 17.21 (p. 469) . The left and right justified streams are equal

when the data-size is equal to the word-width.

Figure 17.21. USART Right-justified I2S waveform

USn_CLK

USn_TX/

USn_RX MSB

Left channelRight channel Right channel

LSBLSB

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In mono-mode, the word-select signal pulses at the beginning of each word instead of toggling for each

word. Mono I2S waveform is shown in Figure 17.22 (p. 470) .

Figure 17.22. USART Mono I2S waveform

USn_CLK

USn_CS

(word select)

USn_TX/

USn_RX MSB

Left channelRight channel Right channel

LSB MSB

17.3.3.6.3 Using I2S Mode

When using the USART in I2S mode, DATABITS in USARTn_FRAME must be set to 8 or 16 data-bits.

8 databits can be used in all modes, and 16 can be used in the modes where the number of bytes in the

I2S word is even. In addition to this, MSBF in USARTn_CTRL should be set, and CLKPOL and CLKPHA

in USARTn_CTRL should be cleared.

The USART does not have separate TX and RX buffers for left and right data, so when using I2S in stereo

mode, the application must keep track of whether the buffers contain left or right data. This can be done

by observing TXBLRIGHT, RXDATAVRIGHT and RXFULLRIGHT in USARTn_STATUS. TXBLRIGHT

tells whether TX is expecting data for the left or right channel. It will be set with TXBL if right data is

expected. The receiver will set RXDATAVRIGHT if there is at least one right element in the buffer, and

RXFULLRIGHT if the buffer is full of right elements.

When using I2S with DMA, separate DMA requests can be used for left and right data by setting

DMASPLIT in USARTn_I2SCTRL.

In both master and slave mode the USART always starts transmitting on the LEFT channel after being

enabled. In master mode, the transmission will stop if TX becomes empty. In that case, TXC is set.

Continuing the transmission in this case will make the data-stream continue where it left off. To make

the USART start on the LEFT channel after going empty, disable and re-enable TX.

17.3.4 PRS-triggered Transmissions

If a transmission must be started on an event with very little delay, the PRS system can be used

to trigger the transmission. The PRS channel to use as a trigger can be selected using TSEL in

USARTn_TRIGCTRL. When a positive edge is detected on this signal, the receiver is enabled if RXTEN

in USARTn_TRIGCTRL is set, and the transmitter is enabled if TXTEN in USARTn_TRIGCTRL is set.

Only one signal input is supported by the USART.

The AUTOTX feature can also be enabled via PRS. If an external SPI device sets a pin high when there is

data to be read from the device, this signal can be routed to the USART through the PRS system and be

used to make the USART clock data out of the external device. If AUTOTXTEN in USARTn_TRIGCTRL

is set, the USART will transmit data whenever the PRS signal selected by TSEL is high given that there

is enough room in the RX buffer for the chosen frame size. Note that if there is no data in the TX buffer

when using AUTOTX, the TX underflow interrupt will be set.

AUTOTXTEN can also be combined with TXTEN to make the USART transmit a command to the

external device prior to clocking out data. To do this, disable TX using the TXDIS command, load the

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TX buffer with the command and enable AUTOTXTEN and TXTEN. When the selected PRS input goes

high, the USART will now transmit the loaded command, and then continue clocking out while both the

PRS input is high and there is room in the RX buffer

17.3.5 PRS RX Input

The USART can be configured to receive data directly from a PRS channel by setting RXPRS in

USARTn_INPUT. The PRS channel used is selected using RXPRSSEL in USARTn_INPUT. This way,

for example, a differential RX signal can be input to the ACMP and the output routed via PRS to the

USART.

17.3.6 DMA Support

The USART has full DMA support. The DMA controller can write to the transmit buffer using the

registers USARTn_TXDATA, USARTn_TXDATAX, USARTn_TXDOUBLE and USARTn_TXDOUBLEX,

and it can read from the receive buffer using the registers USARTn_RXDATA, USARTn_RXDATAX,

USARTn_RXDOUBLE and USARTn_RXDOUBLEX. This enables single byte transfers, 9 bit data +

control/status bits, double byte and double byte + control/status transfers both to and from the USART.

A request for the DMA controller to read from the USART receive buffer can come from the following

source:

• Data available in the receive buffer.

• Data available in the receive buffer and data is for the RIGHT I2S channel. Only used in I2S mode.

A write request can come from one of the following sources:

• Transmit buffer and shift register empty. No data to send.

• Transmit buffer has room for more data.

• Transmit buffer has room for RIGHT I2S data. Only used in I2S mode.

Even though there are two sources for write requests to the DMA, only one should be used at a time,

since the requests from both sources are cleared even though only one of the requests are used.

In some cases, it may be sensible to temporarily stop DMA access to the USART when an error such

as a framing error has occurred. This is enabled by setting ERRSDMA in USARTn_CTRL.

17.3.7 Transmission Delay

By configuring TXDELAY in USARTn_CTRL, the transmitter can be forced to wait a number of bit-

periods from it is ready to transmit data, to it actually transmits the data. This delay is only applied to the

first frame transmitted after the transmitter has been idle. When transmitting frames back-to-back the

delay is not introduced between the transmitted frames.

This is useful on half duplex buses, because the receiver always returns received frames to software

during the first stop-bit. The bus may still be driven for up to 3 baud periods, depending on the current

frame format. Using the transmission delay, a transmission can be started when a frame is received,

and it is possible to make sure that the transmitter does not begin driving the output before the frame

on the bus is completely transmitted.

TXDELAY in USARTn_CTRL only applies to asynchronous transmission.

17.3.8 Interrupts

The interrupts generated by the USART are combined into two interrupt vectors. Interrupts related to

reception are assigned to one interrupt vector, and interrupts related to transmission are assigned to

the other. Separating the interrupts in this way allows different priorities to be set for transmission and

reception interrupts.

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The transmission interrupt vector groups the transmission-related interrupts generated by the following

interrupt flags:

• TXC

• TXBL

• TXOF

• CCF

The reception interrupt on the other hand groups the reception-related interrupts, triggered by the

following interrupt flags:

• RXDATAV

• RXFULL

• RXOF

• RXUF

• PERR

• FERR

• MPAF

• SSM

If USART interrupts are enabled, an interrupt will be made if one or more of the interrupt flags in

USART_IF and their corresponding bits in USART_IEN are set.

17.3.9 IrDA Modulator/Demodulator

The IrDA modulator onUSART0 implements the physical layer of the IrDA specification, which is

necessary for communication over IrDA. The modulator takes the signal output from the USART module,

and modulates it before it leaves USART0 . In the same way, the input signal is demodulated before

it enters the actual USART module. The modulator is only available on USART0 , and implements the

original Rev. 1.0 physical layer and one high speed extension which supports speeds from 2.4 kbps

to 1.152 Mbps.

The data from and to the USART is represented in a NRZ (Non Return to Zero) format, where the signal

value is at the same level through the entire bit period. For IrDA, the required format is RZI (Return to

Zero Inverted), a format where a “1” is signalled by holding the line low, and a “0” is signalled by a short

high pulse. An example is given in Figure 17.23 (p. 472) .

Figure 17.23. USART Example RZI Signal for a given Asynchronous USART Frame

S 0 1 2 34 5 6 7 PStop

IdleIdle

USART

(NRZ)

IrDA

(RZI)

The IrDA module is enabled by setting IREN. The USART transmitter output and receiver input is then

routed through the IrDA modulator.

The width of the pulses generated by the IrDA modulator is set by configuring IRPW in

USARTn_IRCTRL. Four pulse widths are available, each defined relative to the configured bit period

as listed in Table 17.10 (p. 473) .

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Table 17.10. USART IrDA Pulse Widths

IRPW Pulse width OVS=0 Pulse width OVS=1 Pulse width OVS=2 Pulse width OVS=3

00 1/16 1/8 1/6 1/4

01 2/16 2/8 2/6 N/A

10 3/16 3/8 N/A N/A

11 4/16 N/A N/A N/A

By default, no filter is enabled in the IrDA demodulator. A filter can be enabled by setting IRFILT in

USARTn_IRCTRL. When the filter is enabled, an incoming pulse has to last for 4 consecutive clock

cycles to be detected by the IrDA demodulator.

Note that by default, the idle value of the USART data signal is high. This means that the IrDA modulator

generates negative pulses, and the IrDA demodulator expects negative pulses. To make the IrDA module

use RZI signalling, both TXINV and RXINV in USARTn_CTRL must be set.

The IrDA module can also modulate a signal from the PRS system, and transmit a modulated signal to

the PRS system. To use a PRS channel as transmitter source instead of the USART, set IRPRSEN in

USARTn_IRCTRL high. The channel is selected by configuring IRPRSSEL in USARTn_IRCTRL.

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17.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 USARTn_CTRL RW Control Register

0x004 USARTn_FRAME RW USART Frame Format Register

0x008 USARTn_TRIGCTRL RW USART Trigger Control register

0x00C USARTn_CMD W1 Command Register

0x010 USARTn_STATUS R USART Status Register

0x014 USARTn_CLKDIV RW Clock Control Register

0x018 USARTn_RXDATAX R RX Buffer Data Extended Register

0x01C USARTn_RXDATA R RX Buffer Data Register

0x020 USARTn_RXDOUBLEX R RX Buffer Double Data Extended Register

0x024 USARTn_RXDOUBLE R RX FIFO Double Data Register

0x028 USARTn_RXDATAXP R RX Buffer Data Extended Peek Register

0x02C USARTn_RXDOUBLEXP R RX Buffer Double Data Extended Peek Register

0x030 USARTn_TXDATAX W TX Buffer Data Extended Register

0x034 USARTn_TXDATA W TX Buffer Data Register

0x038 USARTn_TXDOUBLEX W TX Buffer Double Data Extended Register

0x03C USARTn_TXDOUBLE W TX Buffer Double Data Register

0x040 USARTn_IF R Interrupt Flag Register

0x044 USARTn_IFS W1 Interrupt Flag Set Register

0x048 USARTn_IFC W1 Interrupt Flag Clear Register

0x04C USARTn_IEN RW Interrupt Enable Register

0x050 USARTn_IRCTRL RW IrDA Control Register

0x054 USARTn_ROUTE RW I/O Routing Register

0x058 USARTn_INPUT RW USART Input Register

0x05C USARTn_I2SCTRL RW I2S Control Register

17.5 Register Description

17.5.1 USARTn_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

SMSDELAY

MVDIS

AUTOTX

BYTESWAP

TXDELAY

SSSEARLY

ERRSTX

ERRSRX

ERRSDMA

BIT8DV

SKIPPERRF

SCRETRANS

SCMODE

AUTOTRI

AUTOCS

CSINV

TXINV

RXINV

TXBIL

CSMA

MSBF

CLKPHA

CLKPOL

OVS

MPAB

MPM

CCEN

LOOPBK

SYNC

Bit Name Reset Access Description

31 SMSDELAY 0 RW Synchronous Master Sample Delay

Delay Synchronous Master sample point to the next setup edge to improve timing and allow communication at higher speeds.

30 MVDIS 0 RW Majority Vote Disable

Disable majority vote for 16x, 8x and 6x oversampling modes.

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Bit Name Reset Access Description

29 AUTOTX 0 RW Always Transmit When RX Not Full

Transmits as long as RX is not full. If TX is empty, underflows are generated.

28 BYTESWAP 0 RW Byteswap In Double Accesses

Set to switch the order of the bytes in double accesses.

Value Description

0 Normal byte order

1 Byte order swapped

27:26 TXDELAY 0x0 RW TX Delay Transmission

Configurable delay before new transfers. Frames sent back-to-back are not delayed.

Value Mode Description

0 NONE Frames are transmitted immediately

1 SINGLE Transmission of new frames are delayed by a single baud period

2 DOUBLE Transmission of new frames are delayed by two baud periods

3 TRIPLE Transmission of new frames are delayed by three baud periods

25 SSSEARLY 0 RW Synchronous Slave Setup Early

Setup data on sample edge in synchronous slave mode to improve MOSI setup time.

24 ERRSTX 0 RW Disable TX On Error

When set, the transmitter is disabled on framing and parity errors (asynchronous mode only) in the receiver.

Value Description

0 Received framing and parity errors have no effect on transmitter

1 Received framing and parity errors disable the transmitter

23 ERRSRX 0 RW Disable RX On Error

When set, the receiver is disabled on framing and parity errors (asynchronous mode only).

Value Description

0 Framing and parity errors have no effect on receiver

1 Framing and parity errors disable the receiver

22 ERRSDMA 0 RW Halt DMA On Error

When set, DMA requests will be cleared on framing and parity errors (asynchronous mode only).

Value Description

0 Framing and parity errors have no effect on DMA requests from the USART

1 DMA requests from the USART are blocked while the PERR or FERR interrupt flags are set

21 BIT8DV 0 RW Bit 8 Default Value

The default value of the 9th bit. If 9-bit frames are used, and an 8-bit write operation is done, leaving the 9th bit unspecified, the

9th bit is set to the value of BIT8DV.

20 SKIPPERRF 0 RW Skip Parity Error Frames

When set, the receiver discards frames with parity errors (asynchronous mode only). The PERR interrupt flag is still set.

19 SCRETRANS 0 RW SmartCard Retransmit

When in SmartCard mode, a NACK'ed frame will be kept in the shift register and retransmitted if the transmitter is still enabled.

18 SCMODE 0 RW SmartCard Mode

Use this bit to enable or disable SmartCard mode.

17 AUTOTRI 0 RW Automatic TX Tristate

When enabled, TXTRI is set by hardware whenever the transmitter is idle, and TXTRI is cleared by hardware when transmission starts.

Value Description

0 The output on U(S)n_TX when the transmitter is idle is defined by TXINV

1 U(S)n_TX is tristated whenever the transmitter is idle

16 AUTOCS 0 RW Automatic Chip Select

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Bit Name Reset Access Description

When enabled, the output on USn_CS will be activated one baud-period before transmission starts, and deactivated when

transmission ends.

15 CSINV 0 RW Chip Select Invert

Default value is active low. This affects both the selection of external slaves, as well as the selection of the microcontroller as a slave.

Value Description

0 Chip select is active low

1 Chip select is active high

14 TXINV 0 RW Transmitter output Invert

The output from the USART transmitter can optionally be inverted by setting this bit.

Value Description

0 Output from the transmitter is passed unchanged to U(S)n_TX

1 Output from the transmitter is inverted before it is passed to U(S)n_TX

13 RXINV 0 RW Receiver Input Invert

Setting this bit will invert the input to the USART receiver.

Value Description

0 Input is passed directly to the receiver

1 Input is inverted before it is passed to the receiver

12 TXBIL 0 RW TX Buffer Interrupt Level

Determines the interrupt and status level of the transmit buffer.

Value Mode Description

0 EMPTY TXBL and the TXBL interrupt flag are set when the transmit buffer becomes empty.

TXBL is cleared when the buffer becomes nonempty.

1 HALFFULL TXBL and TXBLIF are set when the transmit buffer goes from full to half-full or empty.

TXBL is cleared when the buffer becomes full.

11 CSMA 0 RW Action On Slave-Select In Master Mode

This register determines the action to be performed when slave-select is configured as an input and driven low while in master mode.

Value Mode Description

0 NOACTION No action taken

1 GOTOSLAVEMODE Go to slave mode

10 MSBF 0 RW Most Significant Bit First

Decides whether data is sent with the least significant bit first, or the most significant bit first.

Value Description

0 Data is sent with the least significant bit first

1 Data is sent with the most significant bit first

9 CLKPHA 0 RW Clock Edge For Setup/Sample

Determines where data is set-up and sampled according to the bus clock when in synchronous mode.

Value Mode Description

0 SAMPLELEADING Data is sampled on the leading edge and set-up on the trailing edge of the bus clock

in synchronous mode

1 SAMPLETRAILING Data is set-up on the leading edge and sampled on the trailing edge of the bus clock

in synchronous mode

8 CLKPOL 0 RW Clock Polarity

Determines the clock polarity of the bus clock used in synchronous mode.

Value Mode Description

0 IDLELOW The bus clock used in synchronous mode has a low base value

1 IDLEHIGH The bus clock used in synchronous mode has a high base value

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:5 OVS 0x0 RW Oversampling

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Bit Name Reset Access Description

Sets the number of clock periods in a UART bit-period. More clock cycles gives better robustness, while less clock cycles gives

better performance.

Value Mode Description

0 X16 Regular UART mode with 16X oversampling in asynchronous mode

1 X8 Double speed with 8X oversampling in asynchronous mode

2 X6 6X oversampling in asynchronous mode

3 X4 Quadruple speed with 4X oversampling in asynchronous mode

4 MPAB 0 RW Multi-Processor Address-Bit

Defines the value of the multi-processor address bit. An incoming frame with its 9th bit equal to the value of this bit marks the frame

as a multi-processor address frame.

3 MPM 0 RW Multi-Processor Mode

Multi-processor mode uses the 9th bit of the USART frames to tell whether the frame is an address frame or a data frame.

Value Description

0 The 9th bit of incoming frames has no special function

1 An incoming frame with the 9th bit equal to MPAB will be loaded into the receive buffer regardless of RXBLOCK and

will result in the MPAB interrupt flag being set

2 CCEN 0 RW Collision Check Enable

Enables collision checking on data when operating in half duplex modus.

Value Description

0 Collision check is disabled

1 Collision check is enabled. The receiver must be enabled for the check to be performed

1 LOOPBK 0 RW Loopback Enable

Allows the receiver to be connected directly to the USART transmitter for loopback and half duplex communication.

Value Description

0 The receiver is connected to and receives data from U(S)n_RX

1 The receiver is connected to and receives data from U(S)n_TX

0 SYNC 0 RW USART Synchronous Mode

Determines whether the USART is operating in asynchronous or synchronous mode.

Value Description

0 The USART operates in asynchronous mode

1 The USART operates in synchronous mode

17.5.2 USARTn_FRAME - USART Frame Format Register

Offset Bit Position

0x004

Reset

0x1

0x0

0x5

Access

Name

STOPBITS

PARITY

DATABITS

Bit Name Reset Access Description

31:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:12 STOPBITS 0x1 RW Stop-Bit Mode

Determines the number of stop-bits used.

Value Mode Description

0 HALF The transmitter generates a half stop bit. Stop-bits are not verified by receiver

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Bit Name Reset Access Description

Value Mode Description

1 ONE One stop bit is generated and verified

2 ONEANDAHALF The transmitter generates one and a half stop bit. The receiver verifies the first stop bit

3 TWO The transmitter generates two stop bits. The receiver checks the first stop-bit only

11:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 PARITY 0x0 RW Parity-Bit Mode

Determines whether parity bits are enabled, and whether even or odd parity should be used. Only available in asynchronous mode.

Value Mode Description

0 NONE Parity bits are not used

2 EVEN Even parity are used. Parity bits are automatically generated and checked by hardware.

3 ODD Odd parity is used. Parity bits are automatically generated and checked by hardware.

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 DATABITS 0x5 RW Data-Bit Mode

This register sets the number of data bits in a USART frame.

Value Mode Description

1 FOUR Each frame contains 4 data bits

2 FIVE Each frame contains 5 data bits

3 SIX Each frame contains 6 data bits

4 SEVEN Each frame contains 7 data bits

5 EIGHT Each frame contains 8 data bits

6 NINE Each frame contains 9 data bits

7 TEN Each frame contains 10 data bits

8 ELEVEN Each frame contains 11 data bits

9 TWELVE Each frame contains 12 data bits

10 THIRTEEN Each frame contains 13 data bits

11 FOURTEEN Each frame contains 14 data bits

12 FIFTEEN Each frame contains 15 data bits

13 SIXTEEN Each frame contains 16 data bits

17.5.3 USARTn_TRIGCTRL - USART Trigger Control register

Offset Bit Position

0x008

Reset

0x0

Access

Name

AUTOTXTEN

TXTEN

RXTEN

TSEL

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 AUTOTXTEN 0 RW AUTOTX Trigger Enable

When set, AUTOTX is enabled as long as the PRS channel selected by TSEL has a high value.

5 TXTEN 0 RW Transmit Trigger Enable

When set, the PRS channel selected by TSEL sets TXEN, enabling the transmitter on positive trigger edges.

4 RXTEN 0 RW Receive Trigger Enable

When set, the PRS channel selected by TSEL sets RXEN, enabling the receiver on positive trigger edges.

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Bit Name Reset Access Description

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 TSEL 0x0 RW Trigger PRS Channel Select

Select USART PRS trigger channel. The PRS signal can enable RX and/or TX, depending on the setting of RXTEN and TXTEN.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected

1 PRSCH1 PRS Channel 1 selected

2 PRSCH2 PRS Channel 2 selected

3 PRSCH3 PRS Channel 3 selected

4 PRSCH4 PRS Channel 4 selected

5 PRSCH5 PRS Channel 5 selected

6 PRSCH6 PRS Channel 6 selected

7 PRSCH7 PRS Channel 7 selected

17.5.4 USARTn_CMD - Command Register

Offset Bit Position

0x00C

Reset

Access

Name

CLEARRX

CLEARTX

TXTRIDIS

TXTRIEN

RXBLOCKDIS

RXBLOCKEN

MASTERDIS

MASTEREN

TXDIS

TXEN

RXDIS

RXEN

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 CLEARRX 0 W1 Clear RX

Set to clear receive buffer and the RX shift register.

10 CLEARTX 0 W1 Clear TX

Set to clear transmit buffer and the TX shift register.

9 TXTRIDIS 0 W1 Transmitter Tristate Disable

Disables tristating of the transmitter output.

8 TXTRIEN 0 W1 Transmitter Tristate Enable

Tristates the transmitter output.

7 RXBLOCKDIS 0 W1 Receiver Block Disable

Set to clear RXBLOCK, resulting in all incoming frames being loaded into the receive buffer.

6 RXBLOCKEN 0 W1 Receiver Block Enable

Set to set RXBLOCK, resulting in all incoming frames being discarded.

5 MASTERDIS 0 W1 Master Disable

Set to disable master mode, clearing the MASTER status bit and putting the USART in slave mode.

4 MASTEREN 0 W1 Master Enable

Set to enable master mode, setting the MASTER status bit. Master mode should not be enabled while TXENS is set to 1. To enable

both master and TX mode, write MASTEREN before TXEN, or enable them both in the same write operation.

3 TXDIS 0 W1 Transmitter Disable

Set to disable transmission.

2 TXEN 0 W1 Transmitter Enable

Set to enable data transmission.

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Bit Name Reset Access Description

1 RXDIS 0 W1 Receiver Disable

Set to disable data reception. If a frame is under reception when the receiver is disabled, the incoming frame is discarded.

0 RXEN 0 W1 Receiver Enable

Set to activate data reception on U(S)n_RX.

17.5.5 USARTn_STATUS - USART Status Register

Offset Bit Position

0x010

Reset

Access

Name

RXFULLRIGHT

RXDATAVRIGHT

TXBSRIGHT

TXBDRIGHT

RXFULL

RXDATAV

TXBL

TXC

TXTRI

RXBLOCK

MASTER

TXENS

RXENS

Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 RXFULLRIGHT 0 R RX Full of Right Data

When set, the entire RX buffer contains right data. Only used in I2S mode.

11 RXDATAVRIGHT 0 R RX Data Right

When set, reading RXDATA or RXDATAX gives right data. Else left data is read. Only used in I2S mode.

10 TXBSRIGHT 0 R TX Buffer Expects Single Right Data

When set, the TX buffer expects at least a single right data. Else it expects left data. Only used in I2S mode.

9 TXBDRIGHT 0 R TX Buffer Expects Double Right Data

When set, the TX buffer expects double right data. Else it may expect a single right data or left data. Only used in I2S mode.

8 RXFULL 0 R RX FIFO Full

Set when the RXFIFO is full. Cleared when the receive buffer is no longer full. When this bit is set, there is still room for one more

frame in the receive shift register.

7 RXDATAV 0 R RX Data Valid

Set when data is available in the receive buffer. Cleared when the receive buffer is empty.

6 TXBL 1 R TX Buffer Level

Indicates the level of the transmit buffer. If TXBIL is cleared, TXBL is set whenever the transmit buffer is empty, and if TXBIL is set,

TXBL is set whenever the transmit buffer is half-full or empty.

5 TXC 0 R TX Complete

Set when a transmission has completed and no more data is available in the transmit buffer and shift register. Cleared when data

is written to the transmit buffer.

4 TXTRI 0 R Transmitter Tristated

Set when the transmitter is tristated, and cleared when transmitter output is enabled. If AUTOTRI in USARTn_CTRL is set this bit

is always read as 0.

3 RXBLOCK 0 R Block Incoming Data

When set, the receiver discards incoming frames. An incoming frame will not be loaded into the receive buffer if this bit is set at the

instant the frame has been completely received.

2 MASTER 0 R SPI Master Mode

Set when the USART operates as a master. Set using the MASTEREN command and clear using the MASTERDIS command.

1 TXENS 0 R Transmitter Enable Status

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Bit Name Reset Access Description

Set when the transmitter is enabled.

0 RXENS 0 R Receiver Enable Status

Set when the receiver is enabled.

17.5.6 USARTn_CLKDIV - Clock Control Register

Offset Bit Position

0x014

Reset

0x0000

Access

Name

DIV

Bit Name Reset Access Description

31:21 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

20:6 DIV 0x0000 RW Fractional Clock Divider

Specifies the fractional clock divider for the USART.

5:0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17.5.7 USARTn_RXDATAX - RX Buffer Data Extended Register

Offset Bit Position

0x018

Reset

0x000

Access

Name

FERR

PERR

RXDATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 FERR 0 R Data Framing Error

Set if data in buffer has a framing error. Can be the result of a break condition.

14 PERR 0 R Data Parity Error

Set if data in buffer has a parity error (asynchronous mode only).

13:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 RXDATA 0x000 R RX Data

Use this register to access data read from the USART. Buffer is cleared on read access.

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17.5.8 USARTn_RXDATA - RX Buffer Data Register

Offset Bit Position

0x01C

Reset

0x00

Access

Name

RXDATA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 RXDATA 0x00 R RX Data

Use this register to access data read from USART. Buffer is cleared on read access. Only the 8 LSB can be read using this register.

17.5.9 USARTn_RXDOUBLEX - RX Buffer Double Data Extended Register

Offset Bit Position

0x020

Reset

0x000

Access

Name

FERR1

PERR1

RXDATA1

FERR0

PERR0

RXDATA0

Bit Name Reset Access Description

31 FERR1 0 R Data Framing Error 1

Set if data in buffer has a framing error. Can be the result of a break condition.

30 PERR1 0 R Data Parity Error 1

Set if data in buffer has a parity error (asynchronous mode only).

29:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24:16 RXDATA1 0x000 R RX Data 1

Second frame read from buffer.

15 FERR0 0 R Data Framing Error 0

Set if data in buffer has a framing error. Can be the result of a break condition.

14 PERR0 0 R Data Parity Error 0

Set if data in buffer has a parity error (asynchronous mode only).

13:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 RXDATA0 0x000 R RX Data 0

First frame read from buffer.

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17.5.10 USARTn_RXDOUBLE - RX FIFO Double Data Register

Offset Bit Position

0x024

Reset

0x00

Access

Name

RXDATA1

RXDATA0

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:8 RXDATA1 0x00 R RX Data 1

Second frame read from buffer.

7:0 RXDATA0 0x00 R RX Data 0

First frame read from buffer.

17.5.11 USARTn_RXDATAXP - RX Buffer Data Extended Peek Register

Offset Bit Position

0x028

Reset

0x000

Access

Name

FERRP

PERRP

RXDATAP

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 FERRP 0 R Data Framing Error Peek

Set if data in buffer has a framing error. Can be the result of a break condition.

14 PERRP 0 R Data Parity Error Peek

Set if data in buffer has a parity error (asynchronous mode only).

13:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 RXDATAP 0x000 R RX Data Peek

Use this register to access data read from the USART.

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17.5.12 USARTn_RXDOUBLEXP - RX Buffer Double Data Extended Peek

Offset Bit Position

0x02C

Reset

0x000

Access

Name

FERRP1

PERRP1

RXDATAP1

FERRP0

PERRP0

RXDATAP0

Bit Name Reset Access Description

31 FERRP1 0 R Data Framing Error 1 Peek

Set if data in buffer has a framing error. Can be the result of a break condition.

30 PERRP1 0 R Data Parity Error 1 Peek

Set if data in buffer has a parity error (asynchronous mode only).

29:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24:16 RXDATAP1 0x000 R RX Data 1 Peek

Second frame read from FIFO.

15 FERRP0 0 R Data Framing Error 0 Peek

Set if data in buffer has a framing error. Can be the result of a break condition.

14 PERRP0 0 R Data Parity Error 0 Peek

Set if data in buffer has a parity error (asynchronous mode only).

13:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 RXDATAP0 0x000 R RX Data 0 Peek

First frame read from FIFO.

17.5.13 USARTn_TXDATAX - TX Buffer Data Extended Register

Offset Bit Position

0x030

Reset

0x000

Access

Name

RXENAT

TXDISAT

TXBREAK

TXTRIAT

UBRXAT

TXDATAX

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 RXENAT 0 W Enable RX After Transmission

Set to enable reception after transmission.

14 TXDISAT 0 W Clear TXEN After Transmission

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Bit Name Reset Access Description

Set to disable transmitter and release data bus directly after transmission.

13 TXBREAK 0 W Transmit Data As Break

Set to send data as a break. Recipient will see a framing error or a break condition depending on its configuration and the value

of TXDATA.

12 TXTRIAT 0 W Set TXTRI After Transmission

Set to tristate transmitter by setting TXTRI after transmission.

11 UBRXAT 0 W Unblock RX After Transmission

Set clear RXBLOCK after transmission, unblocking the receiver.

10:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 TXDATAX 0x000 W TX Data

Use this register to write data to the USART. If TXEN is set, a transfer will be initiated at the first opportunity.

17.5.14 USARTn_TXDATA - TX Buffer Data Register

Offset Bit Position

0x034

Reset

0x00

Access

Name

TXDATA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 TXDATA 0x00 W TX Data

This frame will be added to TX buffer. Only 8 LSB can be written using this register. 9th bit and control bits will be cleared.

17.5.15 USARTn_TXDOUBLEX - TX Buffer Double Data Extended Register

Offset Bit Position

0x038

Reset

0x000

Access

Name

RXENAT1

TXDISAT1

TXBREAK1

TXTRIAT1

UBRXAT1

TXDATA1

RXENAT0

TXDISAT0

TXBREAK0

TXTRIAT0

UBRXAT0

TXDATA0

Bit Name Reset Access Description

31 RXENAT1 0 W Enable RX After Transmission

Set to enable reception after transmission.

30 TXDISAT1 0 W Clear TXEN After Transmission

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Bit Name Reset Access Description

Set to disable transmitter and release data bus directly after transmission.

29 TXBREAK1 0 W Transmit Data As Break

Set to send data as a break. Recipient will see a framing error or a break condition depending on its configuration and the value

of USARTn_TXDATA.

28 TXTRIAT1 0 W Set TXTRI After Transmission

Set to tristate transmitter by setting TXTRI after transmission.

27 UBRXAT1 0 W Unblock RX After Transmission

Set clear RXBLOCK after transmission, unblocking the receiver.

26:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24:16 TXDATA1 0x000 W TX Data

Second frame to write to FIFO.

15 RXENAT0 0 W Enable RX After Transmission

Set to enable reception after transmission.

14 TXDISAT0 0 W Clear TXEN After Transmission

Set to disable transmitter and release data bus directly after transmission.

13 TXBREAK0 0 W Transmit Data As Break

Set to send data as a break. Recipient will see a framing error or a break condition depending on its configuration and the value

of TXDATA.

12 TXTRIAT0 0 W Set TXTRI After Transmission

Set to tristate transmitter by setting TXTRI after transmission.

11 UBRXAT0 0 W Unblock RX After Transmission

Set clear RXBLOCK after transmission, unblocking the receiver.

10:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 TXDATA0 0x000 W TX Data

First frame to write to buffer.

17.5.16 USARTn_TXDOUBLE - TX Buffer Double Data Register

Offset Bit Position

0x03C

Reset

0x00

Access

Name

TXDATA1

TXDATA0

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:8 TXDATA1 0x00 W TX Data

Second frame to write to buffer.

7:0 TXDATA0 0x00 W TX Data

First frame to write to buffer.

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17.5.17 USARTn_IF - Interrupt Flag Register

Offset Bit Position

0x040

Reset

Access

Name

CCF

SSM

MPAF

FERR

PERR

TXUF

TXOF

RXUF

RXOF

RXFULL

RXDATAV

TXBL

TXC

Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 CCF 0 R Collision Check Fail Interrupt Flag

Set when a collision check notices an error in the transmitted data.

11 SSM 0 R Slave-Select In Master Mode Interrupt Flag

Set when the device is selected as a slave when in master mode.

10 MPAF 0 R Multi-Processor Address Frame Interrupt Flag

Set when a multi-processor address frame is detected.

9 FERR 0 R Framing Error Interrupt Flag

Set when a frame with a framing error is received while RXBLOCK is cleared.

8 PERR 0 R Parity Error Interrupt Flag

Set when a frame with a parity error (asynchronous mode only) is received while RXBLOCK is cleared.

7 TXUF 0 R TX Underflow Interrupt Flag

Set when operating as a synchronous slave, no data is available in the transmit buffer when the master starts transmission of a

new frame.

6 TXOF 0 R TX Overflow Interrupt Flag

Set when a write is done to the transmit buffer while it is full. The data already in the transmit buffer is preserved.

5 RXUF 0 R RX Underflow Interrupt Flag

Set when trying to read from the receive buffer when it is empty.

4 RXOF 0 R RX Overflow Interrupt Flag

Set when data is incoming while the receive shift register is full. The data previously in the shift register is lost.

3 RXFULL 0 R RX Buffer Full Interrupt Flag

Set when the receive buffer becomes full.

2 RXDATAV 0 R RX Data Valid Interrupt Flag

Set when data becomes available in the receive buffer.

1 TXBL 1 R TX Buffer Level Interrupt Flag

Set when the buffer becomes empty if TXBIL is cleared, and is set whenever the transmit buffer goes from full to half-full or empty

if TXBIL is set.

0 TXC 0 R TX Complete Interrupt Flag

This interrupt is used after a transmission when both the TX buffer and shift register are empty.

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17.5.18 USARTn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x044

Reset

Access

Name

CCF

SSM

MPAF

FERR

PERR

TXUF

TXOF

RXUF

RXOF

RXFULL

TXC

Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 CCF 0 W1 Set Collision Check Fail Interrupt Flag

Write to 1 to set the CCF interrupt flag.

11 SSM 0 W1 Set Slave-Select in Master mode Interrupt Flag

Write to 1 to set the SSM interrupt flag.

10 MPAF 0 W1 Set Multi-Processor Address Frame Interrupt Flag

Write to 1 to set the MPAF interrupt flag.

9 FERR 0 W1 Set Framing Error Interrupt Flag

Write to 1 to set the FERR interrupt flag.

8 PERR 0 W1 Set Parity Error Interrupt Flag

Write to 1 to set the PERR interrupt flag.

7 TXUF 0 W1 Set TX Underflow Interrupt Flag

Write to 1 to set the TXUF interrupt flag.

6 TXOF 0 W1 Set TX Overflow Interrupt Flag

Write to 1 to set the TXOF interrupt flag.

5 RXUF 0 W1 Set RX Underflow Interrupt Flag

Write to 1 to set the RXUF interrupt flag.

4 RXOF 0 W1 Set RX Overflow Interrupt Flag

Write to 1 to set the RXOF interrupt flag.

3 RXFULL 0 W1 Set RX Buffer Full Interrupt Flag

Write to 1 to set the RXFULL interrupt flag.

2:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 TXC 0 W1 Set TX Complete Interrupt Flag

Write to 1 to set the TXC interrupt flag.

17.5.19 USARTn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x048

Reset

Access

Name

CCF

SSM

MPAF

FERR

PERR

TXUF

TXOF

RXUF

RXOF

RXFULL

TXC

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Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 CCF 0 W1 Clear Collision Check Fail Interrupt Flag

Write to 1 to clear the CCF interrupt flag.

11 SSM 0 W1 Clear Slave-Select In Master Mode Interrupt Flag

Write to 1 to clear the SSM interrupt flag.

10 MPAF 0 W1 Clear Multi-Processor Address Frame Interrupt Flag

Write to 1 to clear the MPAF interrupt flag.

9 FERR 0 W1 Clear Framing Error Interrupt Flag

Write to 1 to clear the FERR interrupt flag.

8 PERR 0 W1 Clear Parity Error Interrupt Flag

Write to 1 to clear the PERR interrupt flag.

7 TXUF 0 W1 Clear TX Underflow Interrupt Flag

Write to 1 to clear the TXUF interrupt flag.

6 TXOF 0 W1 Clear TX Overflow Interrupt Flag

Write to 1 to clear the TXOF interrupt flag.

5 RXUF 0 W1 Clear RX Underflow Interrupt Flag

Write to 1 to clear the RXUF interrupt flag.

4 RXOF 0 W1 Clear RX Overflow Interrupt Flag

Write to 1 to clear the RXOF interrupt flag.

3 RXFULL 0 W1 Clear RX Buffer Full Interrupt Flag

Write to 1 to clear the RXFULL interrupt flag.

2:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 TXC 0 W1 Clear TX Complete Interrupt Flag

Write to 1 to clear the TXC interrupt flag.

17.5.20 USARTn_IEN - Interrupt Enable Register

Offset Bit Position

0x04C

Reset

Access

Name

CCF

SSM

MPAF

FERR

PERR

TXUF

TXOF

RXUF

RXOF

RXFULL

RXDATAV

TXBL

TXC

Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 CCF 0 RW Collision Check Fail Interrupt Enable

Enable interrupt on collision check error detected.

11 SSM 0 RW Slave-Select In Master Mode Interrupt Enable

Enable interrupt on slave-select in master mode.

10 MPAF 0 RW Multi-Processor Address Frame Interrupt Enable

Enable interrupt on multi-processor address frame.

9 FERR 0 RW Framing Error Interrupt Enable

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Bit Name Reset Access Description

Enable interrupt on framing error.

8 PERR 0 RW Parity Error Interrupt Enable

Enable interrupt on parity error (asynchronous mode only).

7 TXUF 0 RW TX Underflow Interrupt Enable

Enable interrupt on TX underflow.

6 TXOF 0 RW TX Overflow Interrupt Enable

Enable interrupt on TX overflow.

5 RXUF 0 RW RX Underflow Interrupt Enable

Enable interrupt on RX underflow.

4 RXOF 0 RW RX Overflow Interrupt Enable

Enable interrupt on RX overflow.

3 RXFULL 0 RW RX Buffer Full Interrupt Enable

Enable interrupt on RX Buffer full.

2 RXDATAV 0 RW RX Data Valid Interrupt Enable

Enable interrupt on RX data.

1 TXBL 0 RW TX Buffer Level Interrupt Enable

Enable interrupt on TX buffer level.

0 TXC 0 RW TX Complete Interrupt Enable

Enable interrupt on TX complete.

17.5.21 USARTn_IRCTRL - IrDA Control Register

Offset Bit Position

0x050

Reset

0x0

Access

Name

IRPRSEN

IRPRSSEL

IRFILT

IRPW

IREN

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 IRPRSEN 0 RW IrDA PRS Channel Enable

Enable the PRS channel selected by IRPRSSEL as input to IrDA module instead of TX.

6:4 IRPRSSEL 0x0 RW IrDA PRS Channel Select

A PRS can be used as input to the pulse modulator instead of TX. This value selects the channel to use.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected

1 PRSCH1 PRS Channel 1 selected

2 PRSCH2 PRS Channel 2 selected

3 PRSCH3 PRS Channel 3 selected

4 PRSCH4 PRS Channel 4 selected

5 PRSCH5 PRS Channel 5 selected

6 PRSCH6 PRS Channel 6 selected

7 PRSCH7 PRS Channel 7 selected

3 IRFILT 0 RW IrDA RX Filter

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Bit Name Reset Access Description

Set to enable filter on IrDA demodulator.

Value Description

0 No filter enabled

1 Filter enabled. IrDA pulse must be high for at least 4 consecutive clock cycles to be detected

2:1 IRPW 0x0 RW IrDA TX Pulse Width

Configure the pulse width generated by the IrDA modulator as a fraction of the configured USART bit period.

Value Mode Description

0 ONE IrDA pulse width is 1/16 for OVS=0 and 1/8 for OVS=1

1 TWO IrDA pulse width is 2/16 for OVS=0 and 2/8 for OVS=1

2 THREE IrDA pulse width is 3/16 for OVS=0 and 3/8 for OVS=1

3 FOUR IrDA pulse width is 4/16 for OVS=0 and 4/8 for OVS=1

0 IREN 0 RW Enable IrDA Module

Enable IrDA module and rout USART signals through it.

17.5.22 USARTn_ROUTE - I/O Routing Register

Offset Bit Position

0x054

Reset

0x0

Access

Name

LOCATION

CLKPEN

CSPEN

TXPEN

RXPEN

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 LOCATION 0x0 RW I/O Location

Decides the location of the USART I/O pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

4 LOC4 Location 4

5 LOC5 Location 5

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 CLKPEN 0 RW CLK Pin Enable

When set, the CLK pin of the USART is enabled.

Value Description

0 The USn_CLK pin is disabled

1 The USn_CLK pin is enabled

2 CSPEN 0 RW CS Pin Enable

When set, the CS pin of the USART is enabled.

Value Description

0 The USn_CS pin is disabled

1 The USn_CS pin is enabled

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Bit Name Reset Access Description

1 TXPEN 0 RW TX Pin Enable

When set, the TX/MOSI pin of the USART is enabled

Value Description

0 The U(S)n_TX (MOSI) pin is disabled

1 The U(S)n_TX (MOSI) pin is enabled

0 RXPEN 0 RW RX Pin Enable

When set, the RX/MISO pin of the USART is enabled.

Value Description

0 The U(S)n_RX (MISO) pin is disabled

1 The U(S)n_RX (MISO) pin is enabled

17.5.23 USARTn_INPUT - USART Input Register

Offset Bit Position

0x058

Reset

0x0

Access

Name

RXPRS

RXPRSSEL

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 RXPRS 0 RW PRS RX Enable

When set, the PRS channel selected as input to RX.

3:0 RXPRSSEL 0x0 RW RX PRS Channel Select

Select PRS channel as input to RX.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected

1 PRSCH1 PRS Channel 1 selected

2 PRSCH2 PRS Channel 2 selected

3 PRSCH3 PRS Channel 3 selected

4 PRSCH4 PRS Channel 4 selected

5 PRSCH5 PRS Channel 5 selected

6 PRSCH6 PRS Channel 6 selected

7 PRSCH7 PRS Channel 7 selected

8 PRSCH8 PRS Channel 8 selected

9 PRSCH9 PRS Channel 9 selected

10 PRSCH10 PRS Channel 10 selected

11 PRSCH11 PRS Channel 11 selected

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17.5.24 USARTn_I2SCTRL - I2S Control Register

Offset Bit Position

0x05C

Reset

0x0

Access

Name

FORMAT

DELAY

DMASPLIT

JUSTIFY

MONO

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 FORMAT 0x0 RW I2S Word Format

Configure the data-width used internally for I2S data

Value Mode Description

0 W32D32 32-bit word, 32-bit data

1 W32D24M 32-bit word, 32-bit data with 8 lsb masked

2 W32D24 32-bit word, 24-bit data

3 W32D16 32-bit word, 16-bit data

4 W32D8 32-bit word, 8-bit data

5 W16D16 16-bit word, 16-bit data

6 W16D8 16-bit word, 8-bit data

7 W8D8 8-bit word, 8-bit data

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 DELAY 0 RW Delay on I2S data

Set to add a one-cycle delay between a transition on the word-clock and the start of the I2S word. Should be set for standard I2S format

3 DMASPLIT 0 RW Separate DMA Request For Left/Right Data

When set DMA requests for right-channel data are put on the TXBLRIGHT and RXDATAVRIGHT DMA requests.

2 JUSTIFY 0 RW Justification of I2S Data

Determines whether the I2S data is left or right justified

Value Mode Description

0 LEFT Data is left-justified

1 RIGHT Data is right-justified

1 MONO 0 RW Stero or Mono

Switch between stereo and mono mode. Set for mono

0 EN 0 RW Enable I2S Mode

Set the U(S)ART in I2S mode.

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18 UART - Universal Asynchronous Receiver/

Transmitter

01 2 3 4

UART RX

DMA

controller RAM

EFM32

Quick Facts

What?

The UART is capable of high-speed

asynchronous serial communication.

Why?

Serial communication is frequently used in

embedded systems and the UART allows

efficient communication with a wide range of

external devices.

How?

The UART has a wide selection of operating

modes, frame formats and baud rates. The

multi-processor mode allows the UART

to remain idle when not addressed. Triple

buffering and DMA support makes high data-

rates possible with minimal CPU intervention

and it is possible to transmit and receive large

frames while the MCU remains in EM1.

18.1 Introduction

The Universal Asynchronous serial Receiver and Transmitter (UART) is a very flexible serial I/O module.

It supports full- and half-duplex asynchronous UART communication.

18.2 Features

• Full duplex and half duplex

• Separate TX / RX enable

• Separate receive / transmit 2-level buffers, with additional separate shift registers

• Programmable baud rate, generated as an fractional division from the peripheral clock (HFPERCLK)

• Max bit-rate

• UART standard mode, peripheral clock rate / 16

• UART FAST mode, peripheral clock rate / 8

• Asynchronous mode supports

• Majority vote baud-reception

• False start-bit detection

• Break generation/detection

• Multi-processor mode

• Configurable number of data bits, 4-16 (plus the parity bit, if enabled)

• HW parity bit generation and check

• Configurable number of stop bits in asynchronous mode: 0.5, 1, 1.5, 2

• HW collision detection

• Multi-processor mode

• Separate interrupt vectors for receive and transmit interrupts

• Loopback mode

• Half duplex communication

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• Communication debugging

• PRS can trigger transmissions

• Full DMA support

• PRS RX input

18.3 Functional Description

The UART is functionally equivalent to the USART with the exceptions defined in Table 18.1 (p. 495)

. The register map and register descriptions are equal to those of the USART. See the USART chapter

for detailed information on the operation of the UART.

Table 18.1. UART Limitations

Feature Limitations

Synchronous operation Not available. SYNC, CSMA, SMSDELAY, SSSEARLY, CSINV, CPOL and

CPHA in USARTn_CTRL, and MASTEREN in USARTn_STATUS are always 0.

Transmission direction Always LSB first. MSBF in USARTn_CTRL is always 0.

Chip-select Not available. AUTOCS in USARTn_CTRL is always 0.

SmartCard mode Not available. SCMODE in USARTn_CTRL is always 0.

Frame size Limited to 8-9 databits. Other configurations of DATABITS in USARTn_FRAME

are not possible.

IrDA Not available. IREN in USARTn_IRCTRL is always 0.

18.4 Register Description

The register description of the UART is equivalent to the register description of the USART except the

limitations mentioned in Table 18.1 (p. 495) . See the USART chapter for complete information.

18.5 Register Map

The register map of the UART is equivalent to the register map of the USART. See the USART chapter

for complete information.

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19 LEUART - Low Energy Universal Asynchronous

Receiver/Transmitter

01 2 3 4

LEUART

DMA

controller RAM

Quick Facts

What?

The LEUART provides full UART

communication using a low frequency 32.768

kHz clock, and has special features for

communication without CPU intervention.

Why?

It allows UART communication to be

performed in low energy modes, using only a

few µA during active communication and only

150 nA when waiting for incoming data.

How?

A low frequency clock signal allows

communication with less energy. Using

DMA, the LEUART can transmit and receive

data with minimal CPU intervention. Special

UART-frames can be configured to help

control the data flow, further automating data

transmission.

19.1 Introduction

The unique LEUARTTM, the Low Energy UART, is a UART that allows two-way UART communication

on a strict power budget. Only a 32.768 kHz clock is needed to allow UART communication at baud

rates up to 9600.

Even when the EFM is in low energy mode EM2 (with most core functionality turned off), the LEUART

can wait for an incoming UART frame while having an extremely low energy consumption. When a UART

frame is completely received, the CPU can quickly be woken up. Alternatively, multiple frames can be

transferred via the Direct Memory Access (DMA) module into RAM memory before waking up the CPU.

Received data can optionally be blocked until a configurable start frame is detected. A signal frame can

be configured to generate an interrupt to indicate e.g. the end of a data transmission. The start frame and

signal frame can be used in combination for instance to handle higher level communication protocols.

Similarly, data can be transmitted in EM2 either on a frame-by-frame basis with data from the CPU or

through use of the DMA.

The LEUART includes all necessary hardware support to make asynchronous serial communication

possible with minimum of software intervention and energy consumption.

19.2 Features

• Low energy asynchronous serial communications

• Full/half duplex communication

• Separate TX / RX enable

• Separate double buffered transmit buffer and receive buffer

• Programmable baud rate, generated as a fractional division of the LFBCLK

• Supports baud rates from 300 baud/s to 9600 baud/s

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• Can use a high frequency clock source for even higher baud rates

• Configurable number of data bits: 8 or 9 (plus parity bit, if enabled)

• Configurable parity: off, even or odd

• HW parity bit generation and check

• Configurable number of stop bits, 1 or 2

• Capable of sleep-mode wake-up on received frame

• Either wake-up on any received byte or

• Wake up only on specified start and signal frames

• Supports transmission and reception in EM0, EM1 and EM2 with

• Full DMA support

• Specified start-byte can start reception automatically

• IrDA modulator (pulse generator, pulse extender)

• Multi-processor mode

• Loopback mode

• Half duplex communication

• Communication debugging

• PRS RX input

19.3 Functional Description

An overview of the LEUART module is shown in Figure 19.1 (p. 497) .

Figure 19.1. LEUART Overview

TX Buffer

TX Shift Register

Signal frame interrupt

RX Buffer

RX Shift Register

LEUn_RX

UART Control

and status

Peripheral Bus

TX Baud rate

generator RX Baud rate

generator

Start frame

(STARTFRAME)

RX Wakeup

SYNC

Pulse

extend

Pulse

gen Signal frame

(SIGFRAME)

=Start frame interrupt

!RXBLOCK

LEUn_TX

PRS Input

19.3.1 Frame Format

The frame format used by the LEUART consists of a set of data bits in addition to bits for synchronization

and optionally a parity bit for error checking. A frame starts with one start-bit (S), where the line is driven

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low for one bit-period. This signals the start of a frame, and is used for synchronization. Following the

start bit are 8 or 9 data bits and an optional parity bit. The data is transmitted with the least significant

bit first. Finally, a number of stop-bits, where the line is driven high, end the frame. The frame format

is shown in Figure 19.2 (p. 498) .

Figure 19.2. LEUART Asynchronous Frame Format

S 0 1 2 34 5 6 7 [8] [P] Stop

Start or idleStop or idle

Frame

The number of data bits in a frame is set by DATABITS in LEUARTn_CTRL, and the number of stop-bits

is set by STOPBITS in LEUARTn_CTRL. Whether or not a parity bit should be included, and whether

it should be even or odd is defined by PARITY in LEUARTn_CTRL. For communication to be possible,

all parties of an asynchronous transfer must agree on the frame format being used.

The frame format used by the LEUART can be inverted by setting INV in LEUARTn_CTRL. This affects

the entire frame, resulting in a low idle state, a high start-bit, inverted data and parity bits, and low stop-

bits. INV should only be changed while the receiver is disabled.

19.3.1.1 Parity Bit Calculation and Handling

Hardware automatically inserts parity bits into outgoing frames and checks the parity bits of incoming

frames. The possible parity modes are defined in Table 19.1 (p. 498) . When even parity is chosen,

a parity bit is inserted to make the number of high bits (data + parity) even. If odd parity is chosen, the

parity bit makes the total number of high bits odd. When parity bits are disabled, which is the default

configuration, the parity bit is omitted.

Table 19.1. LEUART Parity Bit

PARITY [1:0] Description

00 No parity (default)

01 Reserved

10 Even parity

11 Odd parity

See Section 19.3.5.4 (p. 503) for more information on parity bit handling.

19.3.2 Clock Source

The LEUART clock source is selected by the LFB bit field the CMU_LFCLKSEL register. The clock is

prescaled by the LEUARTn bitfield in the CMU_LFBPRESC0 register and enabled by the LEUARTn bit

in the CMU_LFBCLKEN0.

To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0, in addition to

the module clock.

19.3.3 Clock Generation

The LEUART clock defines the transmission and reception data rate. The clock generator employs a

fractional clock divider to allow baud rates that are not attainable by integral division of the 32.768 kHz

clock that drives the LEUART.

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The clock divider used in the LEUART is a 12-bit value, with a 7-bit integral part and a 5-bit fractional

part. The baud rate of the LEUART is given by :

LEUART Baud Rate Equation

br = fLEUARTn/(1 + LEUARTn_CLKDIV/256) (19.1)

where fLEUARTn is the clock frequency supplied to the LEUART. The value of LEUARTn_CLKDIV thus

defines the baud rate of the LEUART. The integral part of the divider is right-aligned in the upper 24

bits of LEUARTn_CLKDIV and the fractional part is left-aligned in the lower 8 bits. The divider is thus a

256th of LEUARTn_CLKDIV as seen in the equation.

For a desired baud rate brDESIRED, LEUARTn_CLKDIV can be calculated by using:

LEUART CLKDIV Equation

LEUARTn_CLKDIV = 256 x (fLEUARTn/brDESIRED - 1) (19.2)

Table 19.2 (p. 499) lists a set of desired baud rates and the closest baud rates reachable by the

LEUART with a 32.768 kHz clock source. It also shows the average baud rate error.

Table 19.2. LEUART Baud Rates

Desired baud rate

[baud/s] LEUARTn_CLKDIV LEUARTn_CLKDIV/256 Actual baud rate

[baud/s] Error [%]

300 27704 108,21875 300,0217 0,01

600 13728 53,625 599,8719 -0,02

1200 6736 26,3125 1199,744 -0,02

2400 3240 12,65625 2399,487 -0,02

4800 1488 5,8125 4809,982 0,21

9600 616 2,40625 9619,963 0,21

19.3.4 Data Transmission

Data transmission is initiated by writing data to the transmit buffer using one of the methods described

in Section 19.3.4.1 (p. 499) . When the transmission shift register is empty and ready for new data,

a frame from the transmit buffer is loaded into the shift register, and if the transmitter is enabled,

transmission begins. When the frame has been transmitted, a new frame is loaded into the shift register

if available, and transmission continues. If the transmit buffer is empty, the transmitter goes to an idle

state, waiting for a new frame to become available. Transmission is enabled through the command

disabled using TXDIS, any ongoing transmission is aborted, and any frame currently being transmitted is

discarded. When disabled, the TX output goes to an idle state, which by default is a high value. Whether

or not the transmitter is enabled at a given time can be read from TXENS in LEUARTn_STATUS.

After a transmission, when there is no more data in the shift register or transmit buffer, the TXC flag in

LEUARTn_STATUS and the TXC interrupt flag in LEUARTn_IF are set, signaling that the transmitter is

idle. The TXC status flag is cleared when a new byte becomes available for transmission, but the TXC

interrupt flag must be cleared by software.

19.3.4.1 Transmit Buffer Operation

A frame can be loaded into the transmit buffer by writing to LEUARTn_TXDATA or LEUARTn_TXDATAX.

Using LEUARTn_TXDATA allows 8 bits to be written to the buffer. If 9 bit frames are used, the 9th bit

will in that case be set to the value of BIT8DV in LEUARTn_CTRL. To set the 9th bit directly and/or

use transmission control, LEUARTn_TXDATAX must be used. When writing data to the transmit buffer

using LEUARTn_TXDATAX, the 9th bit written to LEUARTn_TXDATAX overrides the value in BIT8DV,

and alone defines the 9th bit that is transmitted if 9-bit frames are used.

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If a write is attempted to the transmit buffer when it is not empty, the TXOF interrupt flag in LEUARTn_IF

is set, indicating the overflow. The data already in the buffer is in that case preserved, and no data is

written.

In addition to the interrupt flag TXC in LEUARTn_IF and the status flag TXC in LEUARTn_STATUS

which are set when the transmitter becomes idle, TXBL in LEUARTn_STATUS and the TXBL interrupt

flag in LEUARTn_IF are used to indicate the level of the transmit buffer. Whenever the transmit buffer

becomes empty, these flags are set high. Both the TXBL status flag and the TXBL interrupt flag are

cleared automatically when data is written to the transmit buffer.

The transmit buffer, including the TX shift register can be cleared by setting command bit CLEARTX in

LEUARTn_CMD. This will prevent the LEUART from transmitting the data in the buffer and shift register,

and will make them available for new data. Any frame currently being transmitted will not be aborted.

Transmission of this frame will be completed. An overview of the operation of the transmitter is shown

in Figure 19.3 (p. 500) .

Figure 19.3. LEUART Transmitter Overview

LEUn_TX Transmit shift register

TXENS

d0-d8 control d0 d2 d4 d6 d8d7d5d3d1 control

TXDATA

TXDATAX

BIT8DV

Transmit buffer

19.3.4.2 Frame Transmission Control

The transmission control bits, which can be written using LEUARTn_TXDATAX, affect the transmission

of the written frame. The following options are available:

• Generate break: By setting WBREAK, the output will be held low during the first stop-bit period to

generate a framing error. A receiver that supports break detection detects this state, allowing it to be

used e.g. for framing of larger data packets. The line is driven high for one baud period before the next

frame is transmitted so the next start condition can be identified correctly by the recipient. Continuous

breaks lasting longer than an UART frame are thus not supported by the LEUART. GPIO can be used

for this. Note that when AUTOTRI in LEUARTn_CTRL is used, the transmitter is not tristated before

the high-bit after the break has been transmitted.

• Disable transmitter after transmission: If TXDISAT is set, the transmitter is disabled after the frame

has been fully transmitted.

• Enable receiver after transmission: If RXENAT is set, the receiver is enabled after the frame has

been fully transmitted. It is enabled in time to detect a start-bit directly after the last stop-bit has been

transmitted.

The transmission control bits in the LEUART cannot tristate the transmitter. This is performed

automatically by hardware however, if AUTOTRI in LEUARTn_CTRL is set. See Section 19.3.7 (p. 505)

for more information on half duplex operation.

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19.3.4.3 Jitter in Transmitted Data

Internally the LEUART module uses only the positive edges of the 32.768 kHz clock (LFBCLK) for

transmission and reception. Transmitted data will thus have jitter equal to the difference between the

optimal data set-up location and the closest positive edge on the 32.768 kHz clock. The jitter in on the

location data is set up by the transmitter will thus be no more than half a clock period according to the

optimal set-up location. The jitter in the period of a single baud output by the transmitter will never be

more than one clock period.

19.3.5 Data Reception

Data reception is enabled by setting RXEN in LEUARTn_CMD. When the receiver is enabled, it actively

samples the input looking for a transition from high to low indicating the start baud of a new frame. When

a start baud is found, reception of the new frame begins if the receive shift register is empty and ready

for new data. When the frame has been received, it is pushed into the receive buffer, making the shift

receive buffer is full, the received frame remains in the shift register until more space in the receive

buffer is available.

If an incoming frame is detected while both the receive buffer and the receive shift register are full, the

data in the receive shift register is overwritten, and the RXOF interrupt flag in LEUARTn_IF is set to

indicate the buffer overflow.

The receiver can be disabled by setting the command bit RXDIS in LEUARTn_CMD. Any frame currently

being received when the receiver is disabled is discarded. Whether or not the receiver is enabled at a

given time can be read out from RXENS in LEUARTn_STATUS.

19.3.5.1 Receive Buffer Operation

When data becomes available in the receive buffer, the RXDATAV flag in LEUARTn_STATUS and the

RXDATAV interrupt flag in LEUARTn_IF are set. Both the RXDATAV status flag and the RXDATAV

interrupt flag are cleared by hardware when data is no longer available, i.e. when data has been read

out of the buffer.

Data can be read from receive buffer using either LEUARTn_RXDATA or LEUARTn_RXDATAX.

LEUARTn_RXDATA gives access to the 8 least significant bits of the received frame, while

LEUARTn_RXDATAX must be used to get access to the 9th, most significant bit. The latter register also

contains status information regarding the frame.

When a frame is read from the receive buffer using LEUARTn_RXDATA or LEUARTn_RXDATAX, the

frame is removed from the buffer, making room for a new one. If an attempt is done to read more

frames from the buffer than what is available, the RXUF interrupt flag in LEUARTn_IF is set to signal

the underflow, and the data read from the buffer is undefined.

Frames can also be read from the receive buffer without removing the data by using

LEUARTn_RXDATAXP, which gives access to the frame in the buffer including control bits. Data read

from this register when the receive buffer is empty is undefined. No underflow interrupt is generated

by a read using LEUARTn_RXDATAXP, i.e. the RXUF interrupt flag is never set as a result of reading

from LEUARTn_RXDATAXP.

An overview of the operation of the receiver is shown in Figure 19.4 (p. 502) .

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Figure 19.4. LEUART Receiver Overview

LEUn_RX Receive shift register

RXENS !RXBLOCK

d0-d8 status d0 d2 d4 d6 d8d7d5d3d1 status

RXDATA

RXDATAX

(RXDATAXP)

Receive buffer

19.3.5.2 Blocking Incoming Data

When using hardware frame recognition, as detailed in Section 19.3.5.6 (p. 503) , Section 19.3.5.7 (p.

504) , and Section 19.3.5.8 (p. 504) , it is necessary to be able to let the receiver sample

incoming frames without passing the frames to software by loading them into the receive buffer. This is

accomplished by blocking incoming data.

Incoming data is blocked as long as RXBLOCK in LEUARTn_STATUS is set. When blocked, frames

received by the receiver will not be loaded into the receive buffer, and software is not notified by the

RXDATAV bit in LEUARTn_STATUS or the RXDATAV interrupt flag in LEUARTn_IF at their arrival.

For data to be loaded into the receive buffer, RXBLOCK must be cleared in the instant a frame is fully

received by the receiver. RXBLOCK is set by setting RXBLOCKEN in LEUARTn_CMD and disabled

by setting RXBLOCKDIS also in LEUARTn_CMD. There are two exceptions where data is loaded into

the receive buffer even when RXBLOCK is set. The first is when an address frame is received when

in operating in multi-processor mode as shown in Section 19.3.5.8 (p. 504) . The other case is when

receiving a start-frame when SFUBRX in LEUARTn_CTRL is set; see Section 19.3.5.6 (p. 503)

Frames received containing framing or parity errors will not result in the FERR and PERR interrupt flags

in LEUARTn_IF being set while RXBLOCK is set. Hardware recognition is not applied to these erroneous

frames, and they are silently discarded.

Note If a frame is received while RXBLOCK in LEUARTn_STATUS is cleared, but stays in the

receive shift register because the receive buffer is full, the received frame will be loaded into

the receive buffer when space becomes available even if RXBLOCK is set at that time.

The overflow interrupt flag RXOF in LEUARTn_IF will be set if a frame in the receive shift

even though RXBLOCK is set.

19.3.5.3 Data Sampling

The receiver samples each incoming baud as close as possible to the middle of the baud-period. Except

for the start-bit, only a single sample is taken of each of the incoming bauds.

The length of a baud-period is given by 1 + LEUARTn_CLKDIV/256, as a number of 32.768 kHz clock

periods. Let the clock cycle where a start-bit is first detected be given the index 0. The optimal sampling

point for each baud in the UART frame is then given by the following equation:

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LEUART Optimal Sampling Point

Sopt(n) = n (1 + LEUARTn_CLKDIV/256) + CLKDIV/512 (19.3)

where n is the bit-index.

Since samples are only done on the positive edges of the 32.768 kHz clock, the actual samples are

performed on the closest positive edge, i.e. the edge given by the following equation:

LEUART Actual Sampling Point

S(n) = floor(n x (1 + LEUARTn_CLKDIV/256) + LEUARTn_CLKDIV/512) (19.4)

The sampling location will thus have jitter according to difference between Sopt and S. The start-bit is

found at n=0, then follows the data bits, any parity bit, and the stop bits.

If the value of the start-bit is found to be high, then the start-bit is discarded, and the receiver waits for

a new start-bit.

19.3.5.4 Parity Error

When the parity bit is enabled, a parity check is automatically performed on incoming frames. When

a parity error is detected in a frame, the data parity error bit PERR in the frame is set, as well as the

interrupt flag PERR. Frames with parity errors are loaded into the receive buffer like regular frames.

PERR can be accessed by reading the frame from the receive buffer using the LEUARTn_RXDATAX

19.3.5.5 Framing Error and Break Detection

A framing error is the result of a received frame where the stop bit was sampled to a value of 0. This

can be the result of noise and baud rate errors, but can also be the result of a break generated by the

transmitter on purpose.

When a framing error is detected, the framing error bit FERR in the received frame is set. The interrupt

flag FERR in LEUARTn_IF is also set. Frames with framing errors are loaded into the receive buffer

like regular frames.

FERR can be accessed by reading the frame from the receive buffer using the LEUARTn_RXDATAX

or LEUARTn_RXDATAXP registers.

19.3.5.6 Programmable Start Frame

The LEUART can be configured to start receiving data when a special start frame is detected on the input.

This can be useful when operating in low energy modes, allowing other devices to gain the attention of

the LEUART by transmitting a given frame.

When SFUBRX in LEUARTn_CTRL is set, an incoming frame matching the frame defined in

LEUARTn_STARTFRAME will result in RXBLOCK in LEUARTn_STATUS being cleared. This can be

used to enable reception when a specified start frame is detected. If the receiver is enabled and blocked,

i.e. RXENS and RXBLOCK in LEUARTn_STATUS are set, the receiver will receive all incoming frames,

but unless an incoming frame is a start frame it will be discarded and not loaded into the receive buffer.

When a start frame is detected, the block is cleared, and frames received from that point, including the

start frame, are loaded into the receive buffer.

An incoming start frame results in the STARTF interrupt flag in LEUARTn_IF being set, regardless of

the value of SFUBRX in LEUARTn_CTRL. This allows an interrupt to be made when the start frame

is detected.

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When 8 data-bit frame formats are used, only the 8 least significant bits of LEUARTn_STARTFRAME

are compared to incoming frames. The full length of LEUARTn_STARTFRAME is used when operating

with frames consisting of 9 data bits.

Note The receiver must be enabled for start frames to be detected. In addition, a start frame with

a parity error or framing error is not detected as a start frame.

19.3.5.7 Programmable Signal Frame

As well as the configurable start frame, a special signal frame can be specified. When a frame matching

the frame defined in LEUARTn_SIGFRAME is detected by the receiver, the SIGF interrupt flag in

LEUARTn_IF is set. As for start frame detection, the receiver must be enabled for signal frames to be

detected.

One use of the programmable signal frame is to signal the end of a multi-frame message transmitted to

the LEUART. An interrupt will then be triggered when the packet has been completely received, allowing

software to process it. Used in conjunction with the programmable start frame and DMA, this makes it

possible for the LEUART to automatically begin the reception of a packet on a specified start frame,

load the entire packet into memory, and give an interrupt when reception of a packet has completed.

The device can thus wait for data packets in EM2, and only be woken up when a packet has been

completely received.

A signal frame with a parity error or framing error is not detected as a signal frame.

19.3.5.8 Multi-Processor Mode

To simplify communication between multiple processors and maintain compatibility with the USART, the

LEUART supports a multi-processor mode. In this mode the 9th data bit in each frame is used to indicate

whether the content of the remaining 8 bits is data or an address.

When multi-processor mode is enabled, an incoming 9-bit frame with the 9th bit equal to the value of

MPAB in LEUARTn_CTRL is identified as an address frame. When an address frame is detected, the

MPAF interrupt flag in LEUARTn_IF is set, and the address frame is loaded into the receive register.

This happens regardless of the value of RXBLOCK in LEUARTn_STATUS.

Multi-processor mode is enabled by setting MPM in LEUARTn_CTRL. The mode can be used in buses

with multiple slaves, allowing the slaves to be addressed using the special address frames. An addressed

slave, which was previously blocking reception using RXBLOCK, would then unblock reception, receive

a message from the bus master, and then block reception again, waiting for the next message. See the

USART for a more detailed example.

Note The programmable start frame functionality can be used for automatic address matching,

enabling reception on a correctly configured incoming frame.

An address frame with a parity error or a framing error is not detected as an address frame.

19.3.6 Loopback

The LEUART receiver samples LEUn_RX by default, and the transmitter drives LEUn_TX by default.

This is not the only configuration however. When LOOPBK in LEUARTn_CTRL is set, the receiver is

connected to the LEUn_TX pin as shown in Figure 19.5 (p. 505) . This is useful for debugging, as the

LEUART can receive the data it transmits, but it is also used to allow the LEUART to read and write to

the same pin, which is required for some half duplex communication modes. In this mode, the LEUn_TX

pin must be enabled as an output in the GPIO.

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Figure 19.5. LEUART Local Loopback

LEUART

RX LEUn_RX

TX LEUn_TX

LOOPBK = 0

µC

LEUART

RX LEUn_RX

TX LEUn_TX

LOOPBK = 1

µC

19.3.7 Half Duplex Communication

When doing full duplex communication, two data links are provided, making it possible for data to be

sent and received at the same time. In half duplex mode, data is only sent in one direction at a time.

There are several possible half duplex setups, as described in the following sections.

19.3.7.1 Single Data-link

In this setup, the LEUART both receives and transmits data on the same pin. This is enabled by setting

LOOPBK in LEUARTn_CTRL, which connects the receiver to the transmitter output. Because they are

both connected to the same line, it is important that the LEUART transmitter does not drive the line when

receiving data, as this would corrupt the data on the line.

When communicating over a single data-link, the transmitter must thus be tristated whenever not

transmitting data. If AUTOTRI in LEUARTn_CTRL is set, the LEUART automatically tristates LEUn_TX

whenever the transmitter is inactive. It is then the responsibility of the software protocol to make sure

the transmitter is not transmitting data whenever incoming data is expected.

The transmitter can also be tristated from software by configuring the GPIO pin as an input and disabling

the LEUART output on LEUn_TX.

Note Another way to tristate the transmitter is to enable wired-and or wired-or mode in GPIO.

For wired-and mode, outputting a 1 will be the same as tristating the output, and for wired-

or mode, outputting a 0 will be the same as tristating the output. This can only be done on

buses with a pull-up or pull-down resistor respectively.

19.3.7.2 Single Data-link with External Driver

Some communication schemes, such as RS-485 rely on an external driver. Here, the driver has an extra

input which enables it, and instead of Tristating the transmitter when receiving data, the external driver

must be disabled. The USART has hardware support for automatically turning the driver on and off.

When using the LEUART in such a setup, the driver must be controlled by a GPIO. Figure 19.6 (p. 505)

shows an example configuration using an external driver.

Figure 19.6. LEUART Half Duplex Communication with External Driver

LEUART

µC GPIO

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19.3.7.3 Two Data-links

Some limited devices only support half duplex communication even though two data links are available.

In this case software is responsible for making sure data is not transmitted when incoming data is

expected.

19.3.8 Transmission Delay

By configuring TXDELAY in LEUARTn_CTRL, the transmitter can be forced to wait a number of bit-

periods from it is ready to transmit data, to it actually transmits the data. This delay is only applied to the

first frame transmitted after the transmitter has been idle. When transmitting frames back-to-back the

delay is not introduced between the transmitted frames.

This is useful on half duplex buses, because the receiver always returns received frames to software

during the first stop-bit. The bus may still be driven for up to 3 baud periods, depending on the current

frame format. Using the transmission delay, a transmission can be started when a frame is received,

and it is possible to make sure that the transmitter does not begin driving the output before the frame

on the bus is completely transmitted.

19.3.9 PRS RX Input

The LEUART can be configured to receive data directly from the PRS channel by setting RX_PRS in

LEUARTn_INPUT. The PRS channel used can be selected using RX_PRS_SEL in LEUARTn_INPUT.

19.3.10 DMA Support

The LEUART has full DMA support in energy modes EM0 – EM2. The DMA controller can write to the

transmit buffer using the registers LEUARTn_TXDATA and LEUARTn_TXDATAX, and it can read from

receive buffer using the registers LEUARTn_RXDATA and LEUARTn_RXDATAX. This enables single

byte transfers and 9 bit data + control/status bits transfers both to and from the LEUART. The DMA will

start up the HFRCO and run from this when it is waken by the LEUART in EM2. The HFRCO is disabled

once the transaction is done.

A request for the DMA controller to read from the receive buffer can come from one of the following

sources:

• Receive buffer full

A write request can come from one of the following sources:

• Transmit buffer and shift register empty. No data to send.

• Transmit buffer empty

In some cases, it may be sensible to temporarily stop DMA access to the LEUART when a parity or

framing error has occurred. This is enabled by setting ERRSDMA in LEUARTn_CTRL. When this bit is

set, the DMA controller will not get requests from the receive buffer if a framing error or parity error is

detected in the received byte. The ERRSDMA bit applies only to the RX DMA.

When operating in EM2, the DMA controller must be powered up in order to perform the transfer. This

is automatically performed for read operations if RXDMAWU in LEUARTn_CTRL is set and for write

operations if TXDMAWU in LEUARTn_CTRL is set. To make sure the DMA controller still transfers bits

to and from the LEUART in low energy modes, these bits must thus be configured accordingly.

Note When RXDMAWU or TXDMAWU is set, the system will not be able to go to EM2/EM3

before all related LEUART DMA requests have been processed. This means that if

RXDMAWU is set and the LEUART receives a frame, the system will not be able to go to

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EM2/EM3 before the frame has been read from the LEUART. In order for the system to go

to EM2 during the last byte transmission, LEUART_CTRL_TXDMAWU must be cleared in

the DMA interrupt service routine. This is because TXBL will be high during that last byte

transfer.

19.3.11 Pulse Generator/ Pulse Extender

The LEUART has an optional pulse generator for the transmitter output, and a pulse extender on the

receiver input. These are enabled by setting PULSEEN in LEUARTn_PULSECTRL, and with INV in

LEUARTn_CTRL set, they will change the output/input format of the LEUART from NRZ to RZI as shown

in Figure 19.7 (p. 507) .

Figure 19.7. LEUART - NRZ vs. RZI

S 0 1 2 34 5 6 7 PStop

IdleIdle

NRZ

RZI

If PULSEEN in LEUARTn_PULSECTRL is set while INV in LEUARTn_CTRL is cleared, the output

waveform will like RZI shown in Figure 19.7 (p. 507) , only inverted.

The width of the pulses from the pulse generator can be configured using PULSEW in

LEUARTn_PULSECTRL. The generated pulse width is PULSEW + 1 cycles of the 32.768 kHz clock,

which makes pulse width from 31.25µs to 500µs possible.

Since the incoming signal is only sampled on positive clock edges, the width of the incoming pulses

must be at least two 32.768 kHz clock periods wide for reliable detection by the LEUART receiver. They

must also be shorter than half a UART baud period.

At 2400 baud/s or lower, the pulse generator is able to generate RZI pulses compatible with the IrDA

physical layer specification. The external IrDA device must generate pulses of sufficient length for

successful two-way communication.

19.3.11.1 Interrupts

The interrupts generated by the LEUART are combined into one interrupt vector. If LEUART interrupts

are enabled, an interrupt will be made if one or more of the interrupt flags in LEUARTn_IF and their

corresponding bits in LEUART_IEN are set.

19.3.12 Register access

Since this module is a Low Energy Peripheral, and runs off a clock which is asynchronous to

the HFCORECLK, special considerations must be taken when accessing registers. Please refer to

Section 5.3 (p. 20) for a description on how to perform register accesses to Low Energy Peripherals.

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19.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 LEUARTn_CTRL RW Control Register

0x004 LEUARTn_CMD W1 Command Register

0x008 LEUARTn_STATUS R Status Register

0x00C LEUARTn_CLKDIV RW Clock Control Register

0x010 LEUARTn_STARTFRAME RW Start Frame Register

0x014 LEUARTn_SIGFRAME RW Signal Frame Register

0x018 LEUARTn_RXDATAX R Receive Buffer Data Extended Register

0x01C LEUARTn_RXDATA R Receive Buffer Data Register

0x020 LEUARTn_RXDATAXP R Receive Buffer Data Extended Peek Register

0x024 LEUARTn_TXDATAX W Transmit Buffer Data Extended Register

0x028 LEUARTn_TXDATA W Transmit Buffer Data Register

0x02C LEUARTn_IF R Interrupt Flag Register

0x030 LEUARTn_IFS W1 Interrupt Flag Set Register

0x034 LEUARTn_IFC W1 Interrupt Flag Clear Register

0x038 LEUARTn_IEN RW Interrupt Enable Register

0x03C LEUARTn_PULSECTRL RW Pulse Control Register

0x040 LEUARTn_FREEZE RW Freeze Register

0x044 LEUARTn_SYNCBUSY R Synchronization Busy Register

0x054 LEUARTn_ROUTE RW I/O Routing Register

0x0AC LEUARTn_INPUT RW LEUART Input Register

19.5 Register Description

19.5.1 LEUARTn_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x000

Reset

0x0

Access

Name

TXDELAY

TXDMAWU

RXDMAWU

BIT8DV

MPAB

MPM

SFUBRX

LOOPBK

ERRSDMA

INV

STOPBITS

PARITY

DATABITS

AUTOTRI

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:14 TXDELAY 0x0 RW TX Delay Transmission

Configurable delay before new transfers. Frames sent back-to-back are not delayed.

Value Mode Description

0 NONE Frames are transmitted immediately

1 SINGLE Transmission of new frames are delayed by a single baud period

2 DOUBLE Transmission of new frames are delayed by two baud periods

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Bit Name Reset Access Description

Value Mode Description

3 TRIPLE Transmission of new frames are delayed by three baud periods

13 TXDMAWU 0 RW TX DMA Wakeup

Set to wake the DMA controller up when in EM2 and space is available in the transmit buffer.

Value Description

0 While in EM2, the DMA controller will not get requests about space being available in the transmit buffer

1 DMA is available in EM2 for the request about space available in the transmit buffer

12 RXDMAWU 0 RW RX DMA Wakeup

Set to wake the DMA controller up when in EM2 and data is available in the receive buffer.

Value Description

0 While in EM2, the DMA controller will not get requests about data being available in the receive buffer

1 DMA is available in EM2 for the request about data in the receive buffer

11 BIT8DV 0 RW Bit 8 Default Value

When 9-bit frames are transmitted, the default value of the 9th bit is given by BIT8DV. If TXDATA is used to write a frame, then the

value of BIT8DV is assigned to the 9th bit of the outgoing frame. If a frame is written with TXDATAX however, the default value is

overridden by the written value.

10 MPAB 0 RW Multi-Processor Address-Bit

Defines the value of the multi-processor address bit. An incoming frame with its 9th bit equal to the value of this bit marks the frame

as a multi-processor address frame.

9 MPM 0 RW Multi-Processor Mode

Set to enable multi-processor mode.

Value Description

0 The 9th bit of incoming frames have no special function

1 An incoming frame with the 9th bit equal to MPAB will be loaded into the receive buffer regardless of RXBLOCK and

will result in the MPAB interrupt flag being set

8 SFUBRX 0 RW Start-Frame UnBlock RX

Clears RXBLOCK when the start-frame is found in the incoming data. The start-frame is loaded into the receive buffer.

Value Description

0 Detected start-frames have no effect on RXBLOCK

1 When a start-frame is detected, RXBLOCK is cleared and the start-frame is loaded into the receive buffer

7 LOOPBK 0 RW Loopback Enable

Set to connect receiver to LEUn_TX instead of LEUn_RX.

Value Description

0 The receiver is connected to and receives data from LEUn_RX

1 The receiver is connected to and receives data from LEUn_TX

6 ERRSDMA 0 RW Clear RX DMA On Error

When set,RX DMA requests will be cleared on framing and parity errors.

Value Description

0 Framing and parity errors have no effect on DMA requests from the LEUART

1 RX DMA requests from the LEUART are disabled if a framing error or parity error occurs.

5 INV 0 RW Invert Input And Output

Set to invert the output on LEUn_TX and input on LEUn_RX.

Value Description

0 A high value on the input/output is 1, and a low value is 0.

1 A low value on the input/output is 1, and a high value is 0.

4 STOPBITS 0 RW Stop-Bit Mode

Determines the number of stop-bits used. Only used when transmitting data. The receiver only verifies that one stop bit is present.

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Bit Name Reset Access Description

Value Mode Description

0 ONE One stop-bit is transmitted with every frame

1 TWO Two stop-bits are transmitted with every frame

3:2 PARITY 0x0 RW Parity-Bit Mode

Determines whether parity bits are enabled, and whether even or odd parity should be used.

Value Mode Description

0 NONE Parity bits are not used

2 EVEN Even parity are used. Parity bits are automatically generated and checked by hardware.

3 ODD Odd parity is used. Parity bits are automatically generated and checked by hardware.

1 DATABITS 0 RW Data-Bit Mode

This register sets the number of data bits.

Value Mode Description

0 EIGHT Each frame contains 8 data bits

1 NINE Each frame contains 9 data bits

0 AUTOTRI 0 RW Automatic Transmitter Tristate

When set, LEUn_TX is tristated whenever the transmitter is inactive.

Value Description

0 LEUn_TX is held high when the transmitter is inactive. INV inverts the inactive state.

1 LEUn_TX is tristated when the transmitter is inactive

19.5.2 LEUARTn_CMD - Command Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x004

Reset

Access

Name

CLEARRX

CLEARTX

RXBLOCKDIS

RXBLOCKEN

TXDIS

TXEN

RXDIS

RXEN

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 CLEARRX 0 W1 Clear RX

Set to clear receive buffer and the RX shift register.

6 CLEARTX 0 W1 Clear TX

Set to clear transmit buffer and the TX shift register.

5 RXBLOCKDIS 0 W1 Receiver Block Disable

Set to clear RXBLOCK, resulting in all incoming frames being loaded into the receive buffer.

4 RXBLOCKEN 0 W1 Receiver Block Enable

Set to set RXBLOCK, resulting in all incoming frames being discarded.

3 TXDIS 0 W1 Transmitter Disable

Set to disable transmission.

2 TXEN 0 W1 Transmitter Enable

Set to enable data transmission.

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Bit Name Reset Access Description

1 RXDIS 0 W1 Receiver Disable

Set to disable data reception. If a frame is under reception when the receiver is disabled, the incoming frame is discarded.

0 RXEN 0 W1 Receiver Enable

Set to activate data reception on LEUn_RX.

19.5.3 LEUARTn_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

RXDATAV

TXBL

TXC

RXBLOCK

TXENS

RXENS

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 RXDATAV 0 R RX Data Valid

Set when data is available in the receive buffer. Cleared when the receive buffer is empty.

4 TXBL 1 R TX Buffer Level

Indicates the level of the transmit buffer. Set when the transmit buffer is empty, and cleared when it is full.

3 TXC 0 R TX Complete

Set when a transmission has completed and no more data is available in the transmit buffer. Cleared when a new transmission starts.

2 RXBLOCK 0 R Block Incoming Data

When set, the receiver discards incoming frames. An incoming frame will not be loaded into the receive buffer if this bit is set at the

instant the frame has been completely received.

1 TXENS 0 R Transmitter Enable Status

Set when the transmitter is enabled.

0 RXENS 0 R Receiver Enable Status

Set when the receiver is enabled. The receiver must be enabled for start frames, signal frames, and multi-processor address bit

detection.

19.5.4 LEUARTn_CLKDIV - Clock Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x00C

Reset

0x000

Access

Name

DIV

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Bit Name Reset Access Description

31:15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:3 DIV 0x000 RW Fractional Clock Divider

Specifies the fractional clock divider for the LEUART.

2:0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19.5.5 LEUARTn_STARTFRAME - Start Frame Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x010

Reset

0x000

Access

Name

STARTFRAME

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 STARTFRAME 0x000 RW Start Frame

When a frame matching STARTFRAME is detected by the receiver, STARTF interrupt flag is set, and if SFUBRX is set, RXBLOCK

is cleared. The start-frame is be loaded into the RX buffer.

19.5.6 LEUARTn_SIGFRAME - Signal Frame Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x014

Reset

0x000

Access

Name

SIGFRAME

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 SIGFRAME 0x000 RW Signal Frame

When a frame matching SIGFRAME is detected by the receiver, SIGF interrupt flag is set.

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19.5.7 LEUARTn_RXDATAX - Receive Buffer Data Extended Register

Offset Bit Position

0x018

Reset

0x000

Access

Name

FERR

PERR

RXDATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 FERR 0 R Receive Data Framing Error

Set if data in buffer has a framing error. Can be the result of a break condition.

14 PERR 0 R Receive Data Parity Error

Set if data in buffer has a parity error.

13:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 RXDATA 0x000 R RX Data

Use this register to access data read from the LEUART. Buffer is cleared on read access.

19.5.8 LEUARTn_RXDATA - Receive Buffer Data Register

Offset Bit Position

0x01C

Reset

0x00

Access

Name

RXDATA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 RXDATA 0x00 R RX Data

Use this register to access data read from LEUART. Buffer is cleared on read access. Only the 8 LSB can be read using this register.

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19.5.9 LEUARTn_RXDATAXP - Receive Buffer Data Extended Peek

Offset Bit Position

0x020

Reset

0x000

Access

Name

FERRP

PERRP

RXDATAP

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 FERRP 0 R Receive Data Framing Error Peek

Set if data in buffer has a framing error. Can be the result of a break condition.

14 PERRP 0 R Receive Data Parity Error Peek

Set if data in buffer has a parity error.

13:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 RXDATAP 0x000 R RX Data Peek

Use this register to access data read from the LEUART.

19.5.10 LEUARTn_TXDATAX - Transmit Buffer Data Extended Register

(Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x024

Reset

0x000

Access

Name

RXENAT

TXDISAT

TXBREAK

TXDATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15 RXENAT 0 W Enable RX After Transmission

Set to enable reception after transmission.

Value Description

0 -

1 The receiver is enabled, setting RXENS after the frame has been transmitted

14 TXDISAT 0 W Disable TX After Transmission

Set to disable transmitter directly after transmission has competed.

Value Description

0 -

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Bit Name Reset Access Description

Value Description

1 The transmitter is disabled, clearing TXENS after the frame has been transmitted

13 TXBREAK 0 W Transmit Data As Break

Set to send data as a break. Recipient will see a framing error or a break condition depending on its configuration and the value

of TXDATA.

Value Description

0 The specified number of stop-bits are transmitted

1 Instead of the ordinary stop-bits, 0 is transmitted to generate a break. A single stop-bit is generated after the break to

allow the receiver to detect the start of the next frame

12:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:0 TXDATA 0x000 W TX Data

Use this register to write data to the LEUART. If the transmitter is enabled, a transfer will be initiated at the first opportunity.

19.5.11 LEUARTn_TXDATA - Transmit Buffer Data Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x028

Reset

0x00

Access

Name

TXDATA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 TXDATA 0x00 W TX Data

This frame will be added to the transmit buffer. Only 8 LSB can be written using this register. 9th bit and control bits will be cleared.

19.5.12 LEUARTn_IF - Interrupt Flag Register

Offset Bit Position

0x02C

Reset

Access

Name

SIGF

STARTF

MPAF

FERR

PERR

TXOF

RXUF

RXOF

RXDATAV

TXBL

TXC

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 SIGF 0 R Signal Frame Interrupt Flag

Set when a signal frame is detected.

9 STARTF 0 R Start Frame Interrupt Flag

Set when a start frame is detected.

8 MPAF 0 R Multi-Processor Address Frame Interrupt Flag

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Bit Name Reset Access Description

Set when a multi-processor address frame is detected.

7 FERR 0 R Framing Error Interrupt Flag

Set when a frame with a framing error is received while RXBLOCK is cleared.

6 PERR 0 R Parity Error Interrupt Flag

Set when a frame with a parity error is received while RXBLOCK is cleared.

5 TXOF 0 R TX Overflow Interrupt Flag

Set when a write is done to the transmit buffer while it is full. The data already in the transmit buffer is preserved.

4 RXUF 0 R RX Underflow Interrupt Flag

Set when trying to read from the receive buffer when it is empty.

3 RXOF 0 R RX Overflow Interrupt Flag

Set when data is incoming while the receive shift register is full. The data previously in shift register is overwritten by the new data.

2 RXDATAV 0 R RX Data Valid Interrupt Flag

Set when data becomes available in the receive buffer.

1 TXBL 1 R TX Buffer Level Interrupt Flag

Set when space becomes available in the transmit buffer for a new frame.

0 TXC 0 R TX Complete Interrupt Flag

Set after a transmission when both the TX buffer and shift register are empty.

19.5.13 LEUARTn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x030

Reset

Access

Name

SIGF

STARTF

MPAF

FERR

PERR

TXOF

RXUF

RXOF

TXC

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 SIGF 0 W1 Set Signal Frame Interrupt Flag

Write to 1 to set the SIGF interrupt flag.

9 STARTF 0 W1 Set Start Frame Interrupt Flag

Write to 1 to set the STARTF interrupt flag.

8 MPAF 0 W1 Set Multi-Processor Address Frame Interrupt Flag

Write to 1 to set the MPAF interrupt flag.

7 FERR 0 W1 Set Framing Error Interrupt Flag

Write to 1 to set the FERR interrupt flag.

6 PERR 0 W1 Set Parity Error Interrupt Flag

Write to 1 to set the PERR interrupt flag.

5 TXOF 0 W1 Set TX Overflow Interrupt Flag

Write to 1 to set the TXOF interrupt flag.

4 RXUF 0 W1 Set RX Underflow Interrupt Flag

Write to 1 to set the RXUF interrupt flag.

3 RXOF 0 W1 Set RX Overflow Interrupt Flag

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Bit Name Reset Access Description

Write to 1 to set the RXOF interrupt flag.

2:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 TXC 0 W1 Set TX Complete Interrupt Flag

Write to 1 to set the TXC interrupt flag.

19.5.14 LEUARTn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x034

Reset

Access

Name

SIGF

STARTF

MPAF

FERR

PERR

TXOF

RXUF

RXOF

TXC

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 SIGF 0 W1 Clear Signal-Frame Interrupt Flag

Write to 1 to clear the SIGF interrupt flag.

9 STARTF 0 W1 Clear Start-Frame Interrupt Flag

Write to 1 to clear the STARTF interrupt flag.

8 MPAF 0 W1 Clear Multi-Processor Address Frame Interrupt Flag

Write to 1 to clear the MPAF interrupt flag.

7 FERR 0 W1 Clear Framing Error Interrupt Flag

Write to 1 to clear the FERR interrupt flag.

6 PERR 0 W1 Clear Parity Error Interrupt Flag

Write to 1 to clear the PERR interrupt flag.

5 TXOF 0 W1 Clear TX Overflow Interrupt Flag

Write to 1 to clear the TXOF interrupt flag.

4 RXUF 0 W1 Clear RX Underflow Interrupt Flag

Write to 1 to clear the RXUF interrupt flag.

3 RXOF 0 W1 Clear RX Overflow Interrupt Flag

Write to 1 to clear the RXOF interrupt flag.

2:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 TXC 0 W1 Clear TX Complete Interrupt Flag

Write to 1 to clear the TXC interrupt flag.

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19.5.15 LEUARTn_IEN - Interrupt Enable Register

Offset Bit Position

0x038

Reset

Access

Name

SIGF

STARTF

MPAF

FERR

PERR

TXOF

RXUF

RXOF

RXDATAV

TXBL

TXC

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 SIGF 0 RW Signal Frame Interrupt Enable

Enable interrupt on signal frame.

9 STARTF 0 RW Start Frame Interrupt Enable

Enable interrupt on start frame.

8 MPAF 0 RW Multi-Processor Address Frame Interrupt Enable

Enable interrupt on multi-processor address frame.

7 FERR 0 RW Framing Error Interrupt Enable

Enable interrupt on framing error.

6 PERR 0 RW Parity Error Interrupt Enable

Enable interrupt on parity error.

5 TXOF 0 RW TX Overflow Interrupt Enable

Enable interrupt on TX overflow.

4 RXUF 0 RW RX Underflow Interrupt Enable

Enable interrupt on RX underflow.

3 RXOF 0 RW RX Overflow Interrupt Enable

Enable interrupt on RX overflow.

2 RXDATAV 0 RW RX Data Valid Interrupt Enable

Enable interrupt on RX data.

1 TXBL 0 RW TX Buffer Level Interrupt Enable

Enable interrupt on TX buffer level.

0 TXC 0 RW TX Complete Interrupt Enable

Enable interrupt on TX complete.

19.5.16 LEUARTn_PULSECTRL - Pulse Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x03C

Reset

0x0

Access

Name

PULSEFILT

PULSEEN

PULSEW

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Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 PULSEFILT 0 RW Pulse Filter

Enable a one-cycle pulse filter for pulse extender

Value Description

0 Filter is disabled. Pulses must be at least 2 cycles long for reliable detection.

1 Filter is enabled. Pulses must be at least 3 cycles long for reliable detection.

4 PULSEEN 0 RW Pulse Generator/Extender Enable

Filter LEUART output through pulse generator and the LEUART input through the pulse extender.

3:0 PULSEW 0x0 RW Pulse Width

Configure the pulse width of the pulse generator as a number of 32.768 kHz clock cycles.

19.5.17 LEUARTn_FREEZE - Freeze Register

Offset Bit Position

0x040

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

When set, the update of the LEUART is postponed until this bit is cleared. Use this bit to update several registers simultaneously.

Value Mode Description

0 UPDATE Each write access to a LEUART register is updated into the Low Frequency domain

as soon as possible.

1 FREEZE The LEUART is not updated with the new written value.

19.5.18 LEUARTn_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x044

Reset

Access

Name

PULSECTRL

TXDATA

TXDATAX

SIGFRAME

STARTFRAME

CLKDIV

CMD

CTRL

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7 PULSECTRL 0 R PULSECTRL Register Busy

Set when the value written to PULSECTRL is being synchronized.

6 TXDATA 0 R TXDATA Register Busy

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Bit Name Reset Access Description

Set when the value written to TXDATA is being synchronized.

5 TXDATAX 0 R TXDATAX Register Busy

Set when the value written to TXDATAX is being synchronized.

4 SIGFRAME 0 R SIGFRAME Register Busy

Set when the value written to SIGFRAME is being synchronized.

3 STARTFRAME 0 R STARTFRAME Register Busy

Set when the value written to STARTFRAME is being synchronized.

2 CLKDIV 0 R CLKDIV Register Busy

Set when the value written to CLKDIV is being synchronized.

1 CMD 0 R CMD Register Busy

Set when the value written to CMD is being synchronized.

0 CTRL 0 R CTRL Register Busy

Set when the value written to CTRL is being synchronized.

19.5.19 LEUARTn_ROUTE - I/O Routing Register

Offset Bit Position

0x054

Reset

0x0

Access

Name

LOCATION

TXPEN

RXPEN

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 LOCATION 0x0 RW I/O Location

Decides the location of the LEUART I/O pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

4 LOC4 Location 4

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 TXPEN 0 RW TX Pin Enable

When set, the TX pin of the LEUART is enabled.

Value Description

0 The LEUn_TX pin is disabled

1 The LEUn_TX pin is enabled

0 RXPEN 0 RW RX Pin Enable

When set, the RX pin of the LEUART is enabled.

Value Description

0 The LEUn_RX pin is disabled

1 The LEUn_RX pin is enabled

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19.5.20 LEUARTn_INPUT - LEUART Input Register

Offset Bit Position

0x0AC

Reset

0x0

Access

Name

RXPRS

RXPRSSEL

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 RXPRS 0 RW PRS RX Enable

When set, the PRS channel selected as input to RX.

3:0 RXPRSSEL 0x0 RW RX PRS Channel Select

Select PRS channel as input to RX.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected

1 PRSCH1 PRS Channel 1 selected

2 PRSCH2 PRS Channel 2 selected

3 PRSCH3 PRS Channel 3 selected

4 PRSCH4 PRS Channel 4 selected

5 PRSCH5 PRS Channel 5 selected

6 PRSCH6 PRS Channel 6 selected

7 PRSCH7 PRS Channel 7 selected

8 PRSCH8 PRS Channel 8 selected

9 PRSCH9 PRS Channel 9 selected

10 PRSCH10 PRS Channel 10 selected

11 PRSCH11 PRS Channel 11 selected

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20 TIMER - Timer/Counter

01 2 3 4

TIMER

Counter

Capture values

Compare values

PRS

ADC

Output compare/PWM

Input capture

USART

Clock

Quick Facts

What?

The TIMER (Timer/Counter) keeps track of

timing and counts events, generates output

waveforms and triggers timed actions in other

peripherals.

Why?

Most applications have activities that need

to be timed accurately with as little CPU

intervention and energy consumption as

possible.

How?

The flexible 16-bit TIMER can be configured

to provide PWM waveforms with optional

dead-time insertion for e.g. motor control, or

work as a frequency generator. The Timer

can also count events and control other

peripherals through the PRS, which offloads

the CPU and reduce energy consumption.

20.1 Introduction

The 16-bit general purpose Timer has 3 compare/capture channels for input capture and compare/Pulse-

Width Modulation (PWM) output. TIMER0 also includes a Dead-Time Insertion module suitable for motor

control applications.

20.2 Features

• 16-bit auto reload up/down counter

• Dedicated 16-bit reload register which serves as counter maximum

• 3 Compare/Capture channels

• Individual configurable as either input capture or output compare/PWM

• Multiple Counter modes

• Count up

• Count down

• Count up/down

• Quadrature Decoder

• Direction and count from external pins

• 2x Count Mode

• Counter control from PRS or external pin

• Start

• Stop

• Reload and start

• Inter-Timer connection

• Allows 32-bit counter mode

• Start/stop synchronization between several Timers

• Input Capture

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• Period measurement

• Pulse width measurement

• Two capture registers for each capture channel

• Capture on either positive or negative edge

• Capture on both edges

• Optional digital noise filtering on capture inputs

• Output Compare

• Compare output toggle/pulse on compare match

• Immediate update of compare registers

• PWM

• Up-count PWM

• Up/down-count PWM

• Predictable initial PWM output state (configured by SW)

• Buffered compare register to ensure glitch-free update of compare values

• Clock sources

• HFPERCLKTIMERn

• 10-bit Prescaler

• External pin

• Peripheral Reflex System

• Debug mode

• Configurable to either run or stop when processor is stopped (break)

• Interrupts, PRS output and/or DMA request

• Underflow

• Overflow

• Compare/Capture event

• Dead-Time Insertion Unit (TIMER0 only)

• Complementary PWM outputs with programmable dead-time

• Dead-time is specified independently for rising and falling edge

• 10-bit prescaler

• 6-bit time value

• Outputs have configurable polarity

• Outputs can be set inactive individually by software.

• Configurable action on fault

• Set outputs inactive

• Clear output

• Tristate output

• Individual fault sources

• One or two PRS signals

• Debugger

• Support for automatic restart

• Core lockup

• Configuration lock

20.3 Functional Description

An overview of the TIMER module is shown in Figure 20.1 (p. 524) . The Timer module consists of

a 16 bit up/down counter with 3 Compare/Capture channels connected to pins TIMn_CC0, TIMn_CC1,

and TIMn_CC2.

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Figure 20.1. TIMER Block Overview

==Compare and

PWM config

Compare and

PWM config

Compare and

PWM config

TnCCR0[15:0

]

TnCCR1[15:0

]

Compare Match x

TIMERn_TOPTIMERn_CNT

TIMERn_CCx

Input Capture

Update

condition

Note: For simplicity, all

TIMERn_CCx registers are

grouped together in the figure,

but they all have individual Input

Capture Registers

= 0

CNTCLK

Counter

control

Overflow

Underflow

TIMn_CC0 Input logic Edge

detect

Quadrature

Decoder

Input logic

Edge

detect

Edge

detect

PRS inputs

Prescaler

HFPERCLKTIMERn

TIMn_CC1

TIMn_CC2

TIMn_CC0

TIMn_CC1

TIMn_CC2

20.3.1 Counter Modes

The Timer consists of a counter that can be configured to the following modes:

1. Up-count: Counter counts up until it reaches the value in TIMERn_TOP, where it is reset to 0 before

counting up again.

2. Down-count: The counter starts at the value in TIMERn_TOP and counts down. When it reaches 0,

it is reloaded with the value in TIMERn_TOP.

3. Up/Down-count: The counter starts at 0 and counts up. When it reaches the value in TIMERn_TOP,

it counts down until it reaches 0 and starts counting up again.

4. Quadrature Decoder: Two input channels where one determines the count direction, while the other

pin triggers a clock event.

In addition, to the TIMER modes listed above, the TIMER also supports a 2x Count Mode. In this mode

the counter increments/decrements by 2. The 2x Count Mode intended use is to generate 2x PWM

frequency when the Compare/Capture channel is put in PWM mode. The 2x Count Mode can be enabled

by setting the X2CNT bitfield in the TIMERn_CTRL register.

The counter value can be read or written by software at any time by accessing the CNT field in

TIMERn_CNT.

20.3.1.1 Events

Overflow is set when the counter value shifts from TIMERn_TOP to the next value when counting up. In

up-count mode the next value is 0. In up/down-count mode, the next value is TIMERn_TOP-1.

Underflow is set when the counter value shifts from 0 to the next value when counting down. In down-

count mode, the next value is TIMERn_TOP. In up/down-count mode the next value is 1.

Update event is set on overflow in up-count mode and on underflow in down-count or up/down count

mode. This event is used to time updates of buffered values.

20.3.1.2 Operation

Figure 20.2 (p. 525) shows the hardware Timer/Counter control. Software can start or stop the counter

by writing a 1 to the START or STOP bits in TIMERn_CMD. The counter value (CNT in TIMERn_CNT)

can always be written by software to any 16-bit value.

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It is also possible to control the counter through either an external pin or PRS input. This is done through

the input logic for the Compare/Capture Channel 0. The Timer/Counter allows individual actions (start,

stop, reload) to be taken for rising and falling input edges. This is configured in the RISEA and FALLA

fields in TIMERn_CTRL. The reload value is 0 in up-count and up/down-count mode and TOP in down-

count mode.

The RUNNING bit in TIMERn_STATUS indicates if the Timer is running or not. If the SYNC bit in

TIMERn_CTRL is set, the Timer is started/stopped/reloaded (external pin or PRS) when any of the other

timers are started/stopped/reloaded.

The DIR bit in TIMERn_STATUS indicates the counting direction of the Timer at any given time. The

counter value can be read or written by software through the CNT field in TIMERn_CNT. In Up/Down-

Count mode the count direction will be set to up if the CNT value is written by software.

Figure 20.2. TIMER Hardware Timer/Counter Control

Counter

(Controlled by TIMERn_CTRL)

Compare/Capture channel 0

(Controlled by TIMERn_CC0_CTRL)

TIMn_CC0

PRS channels

PRSSEL

INSEL

Filter

FILT

ICEDGE

Input

Capture 0

Counter

RISEA FALLA

Start

Stop

Reload&Start

20.3.1.3 Clock Source

The counter can be clocked from several sources, which are all synchronized with the peripheral clock

(HFPERCLK). See Figure 20.3 (p. 525) .

Figure 20.3. TIMER Clock Selection

Counter

(Controlled by TIMERn_CTRL)

Compare/Capture channel 1

(Controlled by TIMERn_CC1_CTRL)

TIMn_CC1

PRS channels

PRSSEL

INSEL

Filter

FILT

ICEDGE

HFPERCLKTIMERn

CLKSEL

Prescaler

PRESC

Input

Capture 1

Counter

20.3.1.3.1 Peripheral Clock (HFPERCLK)

The peripheral clock (HFPERCLK) can be used as a source with a configurable prescale factor of

2^PRESC, where PRESC is an integer between 0 and 10, which is set in PRESC in TIMERn_CTRL.

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However, if 2x Count Mode is enabled and the Compare/Capture channels are put in PWM mode, the

CC output is updated on both clock edges so prescaling the peripheral clock will result in incorrect result.

The prescaler is stopped and reset when the timer is stopped.

20.3.1.3.2 Compare/ Capture Channel 1 Input

The Timer can also be clocked by positive and/or negative edges on the Compare/Capture channel 1

input. This input can either come from the TIMn_CC1 pin or one of the PRS channels. The input signal

must not have a higher frequency than fHFPERCLK/3 when running from a pin input or a PRS input with

FILT enabled in TIMERn_CCx_CTRL. When running from PRS without FILT, the frequency can be as

high as fHFPERCLK. Note that when clocking the Timer from the same pulse that triggers a start (through

RISEA/FALLA in TIMERn_CTRL), the starting pulse will not update the Counter Value.

20.3.1.3.3 Underflow/Overflow from Neighboring Timer

All Timers are linked together (see Figure 20.4 (p. 526) ), allowing timers to count on overflow/underflow

from the lower numbered neighbouring timers to form a 32-bit or 48-bit timer. Note that all timers must

be set to same count direction and less significant timer(s) can only be set to count up or down.

Figure 20.4. TIMER Connections

TIMER0TIMER1TIMER2 Overflow Overflow

Underflow Underflow

20.3.1.4 One-Shot Mode

By default, the counter counts continuously until it is stopped. If the OSMEN bit is set in the

TIMERn_CTRL register, however, the counter is disabled by hardware on the first update event. Note

that when the counter is running with CC1 as clock source (0b01 in CLKSEL in TIMERn_CTRL) and

OSMEN is set, a CC1 capture event will not take place on the update event (CC1 rising edge) that stops

the Timer.

20.3.1.5 Top Value Buffer

The TIMERn_TOP register can be altered either by writing it directly or by writing to the TIMER_TOPB

(buffer) register. When writing to the buffer register the TIMERn_TOPB register will be written to

TIMERn_TOP on the next update event. Buffering ensures that the TOP value is not set below the

actual count value. The TOPBV flag in TIMERn_STATUS indicates whether the TIMERn_TOPB register

contains data that have not yet been written to the TIMERn_TOP register (see Figure 20.5 (p. 526) .

Figure 20.5. TIMER TOP Value Update Functionality

TOP

APB Write (TOPB) TOPB

Load APB

TOPBV

Set

Clear

APB Write (TOP)

Update event

Load TOPB

APB Data

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20.3.1.6 Quadrature Decoder

Quadrature Decoding mode is used to track motion and determine both rotation direction and position.

The Quadrature Decoder uses two input channels that are 90 degrees out of phase (see Figure 20.6 (p.

527) ).

Figure 20.6. TIMER Quadrature Encoded Inputs

Channel A

Channel B

Forward rotation (Channel A leads Channel B)

90°

Channel A

Channel B

Backward rotation (Channel B leads Channel A)

90°

In the Timer these inputs are tapped from the Compare/Capture channel 0 (Channel A) and 1 (Channel

B) inputs before edge detection. The Timer/Counter then increments or decrements the counter, based

on the phase relation between the two inputs. The Quadrature Decoder Mode supports two channels,

but if a third channel (Z-terminal) is available, this can be connected to an external interrupt and trigger

a counter reset from the interrupt service routine. By connecting a periodic signal from another timer as

input capture on Compare/Capture Channel 2, it is also possible to calculate speed and acceleration.

Figure 20.7. TIMER Quadrature Decoder Configuration

Counter

(Controlled by TIMERn_CTRL)

Compare/Capture channel 1

(Controlled by TIMERn_CC1_CTRL)

Compare/Capture channel 0

(Controlled by TIMERn_CC0_CTRL)

TIMn_CC0

PRS channels

PRSSEL

INSEL

Filter

FILT

ICEDGE

Quadrature

Decoder

TIMn_CC1

PRS channels

PRSSEL

INSEL

Filter

FILT

ICEDGE

Input

Capture 0

Input

Capture 1

Counter

Inc

Dec

QDM MODE

Ch B

Ch A

The Quadrature Decoder can be set in either X2 or X4 mode, which is configured in the QDM bit in

TIMERn_CTRL. See Figure 20.7 (p. 527)

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20.3.1.6.1 X2 Decoding Mode

In X2 Decoding mode, the counter increments or decrements on every edge of Channel A, see

Table 20.1 (p. 528) and Figure 20.8 (p. 528) .

Table 20.1. TIMER Counter Response in X2 Decoding Mode

Channel A

Channel B Rising Falling

0 Increment Decrement

1 Decrement Increment

Figure 20.8. TIMER X2 Decoding Mode

Channel A

Channel B

CNT 3 4 5 6 7 834567 28

20.3.1.6.2 X4 Decoding Mode

In X4 Decoding mode, the counter increments or decrements on every edge of Channel A and Channel

B, see Figure 20.9 (p. 528) and Table 20.2 (p. 528) .

Table 20.2. TIMER Counter Response in X4 Decoding Mode

Channel A Channel BOpposite Channel

Rising Falling Rising Falling

Channel A = 0 Decrement Increment

Channel A = 1 Increment Decrement

Channel B = 0 Increment Decrement

Channel B = 1 Decrement Increment

Figure 20.9. TIMER X4 Decoding Mode

Channel A

Channel B

34567891011

3 4 5 6 7 8 9 10 11 2

CNT

20.3.1.6.3 TIMER Rotational Position

To calculate a position Equation 20.1 (p. 528) can be used.

TIMER Rotational Position Equation

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pos° = (CNT/X x N) x 360° (20.1)

where X = Encoding type and N = Number of pulses per revolution.

20.3.2 Compare/Capture Channels

The Timer contains 3 Compare/Capture channels, which can be configured in the following modes:

1. Input Capture

2. Output Compare

3. PWM

20.3.2.1 Input Pin Logic

Each Compare/Capture channel can be configured as an input source for the Capture Unit or as external

clock source for the Timer (see Figure 20.10 (p. 529) ). Compare/Capture channels 0 and 1 are the

inputs for the Quadrature Decoder Mode. The input channel can be filtered before it is used, which

requires the input to remain stable for 5 cycles in a row before the input is propagated to the output.

Figure 20.10. TIMER Input Pin Logic

TIMn_CCx

PRS channels

PRSSEL

INSEL

Filter

FILT

ICEDGE

Input

Capture x

20.3.2.2 Compare/Capture Registers

The Compare/Capture channel registers are prefixed with TIMERn_CCx_, where the x stands for the

channel number. Since the Compare/Capture channels serve three functions (input capture, compare,

PWM), the behavior of the Compare/Capture registers (TIMERn_CCx_CCV) and buffer registers

(TIMERn_CCx_CCVB) change depending on the mode the channel is set in.

20.3.2.2.1 Input Capture mode

When running in Input Capture mode, TIMERn_CCx_CCV and TIMERn_CCx_CCVB form a FIFO buffer,

and new capture values are added on a capture event, see Figure 20.11 (p. 530) . The first capture

can always be read from TIMERn_CCx_CCV, and reading this address will load the next capture value

into TIMERn_CCx_CCV from TIMERn_CCx_CCVB if it contains valid data. The CC value can be read

without altering the FIFO contents by reading TIMERn_CCx_CCVP. TIMERn_CCx_CCVB can also be

read without altering the FIFO contents. The ICV flag in TIMERn_STATUS indicates if there is a valid

unread capture in TIMERn_CCx_CCV.

In case a capture is triggered while both CCV and CCVB contain unread capture values, the buffer

overflow interrupt flag (ICBOF in TIMERn_IF) will be set. New capture values will on overflow overwrite

the value in TIMERn_CCx_CCVB.

Note In input capture mode, the timer will only trigger interrupts when it is running

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Figure 20.11. TIMER Input Capture Buffer Functionality

FIFO

CNT

CCV

CCVB

APB Data

20.3.2.2.2 Compare and PWM Mode

When running in Output Compare or PWM mode, the value in TIMERn_CCx_CCV will be compared

against the count value. In Compare mode the output can be configured to toggle, clear or set

on compare match, overflow and underflow through the CMOA, COFOA and CUFOA fields in

TIMERn_CCx_CTRL. TIMERn_CCx_CCV can be accessed directly or through the buffer register

TIMERn_CCx_CCVB, see Figure 20.12 (p. 530) . When writing to the buffer register, the value in

TIMERn_CCx_CCVB will be written to TIMERn_CCx_CCV on the next update event. This functionality

ensures glitch free PWM outputs. The CCVBV flag in TIMERn_STATUS indicates whether the

TIMERn_CCx_CCVB register contains data that have not yet been written to the TIMERn_CCx_CCV

counts from 0 to 1. Thus, the compare match for the next period will not happen until the timer reaches

0 again on the way down.

Figure 20.12. TIMER Output Compare/PWM Buffer Functionality

CCV

APB Write (CCB) CCVB

Load APB

CCVBV

Set

Clear

APB Write (CC)

Update event

Load CCB

APB Data

20.3.2.3 Input Capture

In Input Capture Mode, the counter value (TIMERn_CNT) can be captured in the Compare/Capture

is read-only. Together with the Compare/Capture Buffer Register (TIMERn_CCx_CCVB) the

TIMERn_CCx_CCV form a double-buffered capture registers allowing two subsequent capture events

to take place before a read-out is required. The CCPOL bits in TIMERn_STATUS indicate the polarity

the edge that triggered the capture in TIMERn_CCx_CCV.

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Figure 20.13. TIMER Input Capture

TIMERn_CCx_CCV m

TIMERn_CNT

Input

Read TIMERn_CCx_CCVB

TIMERn_CCx_CCVB m y

prev. val

20.3.2.3.1 Period/Pulse-Width Capture

Period and/or pulse-width capture can be achieved by setting the RISEA field in TIMERn_CTRL to

Clear&Start, and select the wanted input from either external pin or PRS, see Figure 20.14 (p. 531)

. For period capture, the Compare/Capture Channel 0 should then be set to input capture on a rising

edge of the same input signal. To capture the width of a high pulse, the channel should be set to capture

on a falling edge of the input signal. To start the measuring period on either a falling edge or measure

the low pulse-width of a signal, opposite polarities should be chosen.

Figure 20.14. TIMER Period and/or Pulse width Capture

Input

CNT

Clear&Start

Input Capture (frequency capture)

Input Capture (pulse-width capture)

20.3.2.4 Compare

Each Compare/Capture channel contains a comparator which outputs a compare match if the contents

of TIMERn_CCx_CCV matches the counter value, see Figure 20.15 (p. 532) . In compare mode, each

compare channel can be configured to either set, clear or toggle the output on an event (compare match,

overflow or underflow). The output from each channel is represented as an alternative function on the

port it is connected to, which needs to be enabled for the CC outputs to propagate to the pins.

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Figure 20.15. TIMER Block Diagram Showing Comparison Functionality

TnCCR0[15:0

]

TnCCR1[15:0

]

Underflow

Compare Match x

TIMERn_TOPTIMERn_CNT

TIMERn_CCx

Update

Condition

Note: For simplicity, all

TIMERn_CCx registers are

grouped together in the figure,

but they all have individual

Compare Register and logic

= 0

==TIMn_CC0

Compare and

PWM config

Compare and

PWM config

Compare and

PWM config

TIMn_CC1

TIMn_CC2

CNTCLK

Overflow

If occurring in the same cycle, match action will have priority over overflow or underflow action.

The input selected (through PRSSEL, INSEL and FILTSEL in TIMERn_CCx_CTRL) for the CC channel

will also be sampled on compare match and the result is found in the CCPOL bits in TIMERn_STATUS.

It is also possible to configure the CCPOL to always track the inputs by setting ATI in TIMERn_CTRL.

The COIST bit in TIMERn_CCx_CTRL is the initial state of the compare/PWM output. The COIST bit

can also be used as an initial value to the compare outputs on a reload-start when RSSCOIST is set in

TIMERn_CTRL. Also the resulting output can be inverted by setting OUTINV in TIMERn_CCx_CTRL. It

is recommended to turn off the CC channel before configuring the output state to avoid any pulses on

the output. The CC channel can be turned off by setting MODE to OFF in TIMER_CCx_CTRL.

Figure 20.16. TIMER Output Logic

TIMn_CCx

COIST

OUTINV

Output

Compare/

PWM x 0

20.3.2.4.1 Frequency Generation (FRG)

Frequency generation (see Figure 20.17 (p. 533) ) can be achieved in compare mode by:

• Setting the counter in up-count mode

• Enabling buffering of the TOP value.

• Setting the CC channels overflow action to toggle

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Figure 20.17. TIMER Up-count Frequency Generation

TIMERn_TOP

TIMERn_CCx_CCV

The output frequency is given by Equation 20.2 (p. 533)

TIMER Up-count Frequency Generation Equation

fFRG = fHFPERCLK/ ( 2^(PRESC + 1) x (TOP + 1) x 2) (20.2)

20.3.2.5 Pulse-Width Modulation (PWM)

In PWM mode, TIMERn_CCx_CCV is buffered to avoid glitches in the output. The settings in the

Compare Output Action configuration bits are ignored in PWM mode and PWM generation is only

supported for up-count and up/down-count mode.

20.3.2.6 Up-count (Single-slope) PWM

If the counter is set to up-count and the Compare/Capture channel is put in PWM mode, single slope

PWM output will be generated (see Figure 20.18 (p. 533) ). In up-count mode the PWM period is TOP

+1 cycles and the PWM output will be high for a number of cycles equal to TIMERn_CCx_CCV. This

means that a constant high output is achieved by setting TIMER_CCx to TOP+1 or higher. The PWM

resolution (in bits) is then given by Equation 20.3 (p. 533) .

Figure 20.18. TIMER Up-count PWM Generation

TIMERn_TOP

TIMERn_CCx_CCV

TIMn_CCx

Overflow

Compare match

Buffer update

TIMER Up-count PWM Resolution Equation

RPWMup = log(TOP+1)/log(2) (20.3)

The PWM frequency is given by Equation 20.4 (p. 533) :

TIMER Up-count PWM Frequency Equation

fPWMup/down = fHFPERCLK/ ( 2^PRESC x (TOP + 1) (20.4)

The high duty cycle is given by Equation 20.5 (p. 534)

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TIMER Up-count Duty Cycle Equation

DSup = CCVx/TOP (20.5)

20.3.2.6.1 2x Count Mode

When the Timer is set in 2x mode, the TIMER will count up by two. This will in effect make any odd Top

value be rounded down to the closest even number. Similarly, any odd CC value will generate a match

on the closest lower even value as shown in Figure 20.19 (p. 534)

Figure 20.19. TIMER CC out in 2x mode

2 4 0 2 40

Clock

CC Out

02 4 0 2 40 0

Top = 5

CC = 1

Top = 5

CC = 2

The mode is enabled by setting the X2CNT field in TIMERn_CTRL register. The intended use of the

2x mode is to generate 2x PWM frequency when the Compare/Capture channel is put in PWM mode.

Since the PWM output is updated on both edges of the clock, frequency prescaling will result in incorrect

result in this mode. The PWM resolution (in bits) is then given by Equation 20.6 (p. 534) .

TIMER 2x PWM Resolution Equation

RPWM2xmode = log(TOP/2+1)/log(2) (20.6)

The PWM frequency is given by Equation 20.7 (p. 534) :

TIMER 2x Mode PWM Frequency Equation( Up-count)

fPWM2xmode = 2 x fHFPERCLK/ floor(TOP/2)+1 (20.7)

The high duty cycle is given by Equation 20.8 (p. 534)

TIMER 2x Mode Duty Cycle Equation

DS2xmode = CCVx/TOP (20.8)

20.3.2.7 Up/Down-count (Dual-slope) PWM

If the counter is set to up-down count and the Compare/Capture channel is put in PWM mode, dual

slope PWM output will be generated by Figure 20.20 (p. 535) .The resolution (in bits) is given by

Equation 20.9 (p. 535) .

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Figure 20.20. TIMER Up/Down-count PWM Generation

TIMERn_TOP

TIMERn_CCx_CCV

TIMn_CCx

Overflow

Compare match

Buffer update

TIMER Up/Down-count PWM Resolution Equation

RPWMup/down = log(TOP+1)/log(2) (20.9)

The PWM frequency is given by Equation 20.10 (p. 535) :

TIMER Up/Down-count PWM Frequency Equation

fPWMup/down = fHFPERCLK/ ( 2^(PRESC+1) x TOP) (20.10)

The high duty cycle is given by Equation 20.11 (p. 535)

TIMER Up/Down-count Duty Cycle Equation

DSup/down = CCVx/TOP (20.11)

20.3.2.7.1 2x Count Mode

When the Timer is set in 2x mode, the TIMER will count up/down by two. This will in effect make any

odd Top value be rounded down to the closest even number. Similarly, any odd CC value will generate

a match on the closest lower even value as shown in Figure 20.21 (p. 535)

Figure 20.21. TIMER CC out in 2x mode

2 4 2 0 20

Clock

CC Out

42 4 2 0 20 4

Top = 5

CC = 1

Top = 5

CC = 2

The mode is enabled by setting the X2CNT field in TIMERn_CTRL register. The intended use of the

2x mode is to generate 2x PWM frequency when the Compare/Capture channel is put in PWM mode.

Since the PWM output is updated on both edges of the clock, frequency prescaling will result in incorrect

result in this mode. The PWM resolution (in bits) is then given by Equation 20.12 (p. 535) .

TIMER 2x PWM Resolution Equation

RPWM2xmode = log(TOP/2+1)/log(2) (20.12)

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The PWM frequency is given by Equation 20.7 (p. 534) :

TIMER 2x Mode PWM Frequency Equation( Up/Down-count)

fPWM2xmode = fHFPERCLK/ TOP (20.13)

The high duty cycle is given by Equation 20.14 (p. 536)

TIMER 2x Mode Duty Cycle Equation

DS2xmode = CCVx/TOP (20.14)

20.3.3 Dead-Time Insertion Unit (TIMER0 only)

The Dead-Time Insertion Unit aims to make control of BLDC motors safer and more efficient

by introducing complementary PWM outputs with dead-time insertion and fault handling, see

Figure 20.22 (p. 536) .

Figure 20.22. TIMER Dead-Time Insertion Unit Overview

Dead time

insertion

Original PWM (TIM0_CCx_pre) Fault

handling

Primary output (TIM0_CCx)

Complementary output (TIM0_CDTIx)

Fault sources

When used for motor control, the PWM outputs TIM0_CC0, TIM0_CC1 and TIM0_CC2 are often

connected to the high-side transistors of a triple half-bridge setup (UH, VH and WH), and the

complementary outputs connected to the respective low-side transistors (UL, VL, WL shown in

Figure 20.23 (p. 536) ). Transistors used in such a bridge often do not open/close instantaneously, and

using the exact complementary inputs for the high and low side of a half-bridge may result in situations

where both gates are open. This can give unnecessary current-draw and short circuit the power supply.

The DTI unit provides dead-time insertion to deal with this problem.

Figure 20.23. TIMER Triple Half-Bridge

UH VH WH

WLVLUL

For each of the 3 compare-match outputs of TIMER0, an additional complementary output is provided by

the DTI unit. These outputs, named TIM0_CDTI0, TIM0_CDTI1 and TIM0_CDTI2 are provided to make

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control of e.g. 3-channel BLDC or PMAC motors possible using only a single timer, see Figure 20.24 (p.

537) .

Figure 20.24. TIMER Overview of Dead-Time Insertion Block for a Single PWM channel

Clock control Counter

Select

DTFALLT DTRISET

Original PWM (TIM0_CCx_pre)

HFPERCLKTIMERn

Primary output (TIM0_CCx)

Complementary Output (TIM0_CDTIx)

The DTI unit is enabled by setting DTEN in TIMER0_DTCTRL. In addition to providing the

complementary outputs, the DTI unit then also overrides the compare match outputs from the timer.

The DTI unit gives the rising edges of the PWM outputs and the rising edges of the complementary

PWM outputs a configurable time delay. By doing this, the DTI unit introduces a dead-time where both

the primary and complementary outputs in a pair are inactive as seen in Figure 20.25 (p. 537) .

Figure 20.25. TIMER Polarity of Both Signals are Set as Active-High

Original PWM

TIM0_CC0

TIM0_CDTI0

dt1

dt2

Dead-time is specified individually for the rising and falling edge of the original PWM. These values

are shared across all the three PWM channels of the DTI unit. A single prescaler value is provided

for the DTI unit, meaning that both the rising and falling edge dead-times share prescaler value. The

prescaler divides the HFPERCLKTIMERn by a configurable factor between 1 and 1024, which is set in the

DTPRESC field in TIMER0_DTTIME. The rising and falling edge dead-times are configured in DTRISET

and DTFALLT in TIMER0_DTTIME to any number between 1-64 HFPERCLKTIMER0 cycles.

20.3.3.1 Output Polarity

The value of the primary and complementary outputs in a pair will never be set active at the same time by

the DTI unit. The polarity of the outputs can be changed however, if this is required by the application. The

active values of the primary and complementary outputs are set by two the TIMER0_DTCTRL register.

The DTIPOL bit of this register specifies the base polarity. If DTIPOL =0, then the outputs are active-high,

and if DTIPOL = 1 they are active-low. The relative phase of the primary and complementary outputs is

not changed by DTIPOL, as the polarity of both outputs is changed, see Figure 20.26 (p. 538)

In some applications, it may be required that the primary outputs are active-high, while the

complementary outputs are active-low. This can be accomplished by manipulating the DTCINV bit of

the TIMER0_DTCTRL register, which inverts the polarity of the complementary outputs relative to the

primary outputs.

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Example 20.1. TIMER DTI Example 1

DTIPOL = 0 and DTCINV = 0 results in outputs with opposite phase and active-high states.

Example 20.2. TIMER DTI Example 2

DTIPOL = 1 and DTCINV = 1 results in outputs with equal phase. The primary output will be active-high,

while the complementary will be active-low

Figure 20.26. TIMER Output Polarities

Original PWM

TIM0_CC0

TIM0_CDTI0

TIM0_CC0

TIM0_CDTI0

TIM0_CC0

TIM0_CDTI0

TIM0_CC0

TIM0_CDTI0

DTIPOL = 0

DTCINV = 0

DTIPOL = 1

DTCINV = 0

DTIPOL = 0

DTCINV = 1

DTIPOL = 1

DTCINV = 1

Output generation on the individual DTI outputs can be disabled by configuring TIMER0_DTOGEN.

When output generation on an output is disabled, it will go to and stay in its inactive state.

20.3.3.2 PRS Channel as Source

A PRS channel can optionally be used as input to the DTI module instead of the PWM output from the

timer. Setting DTPRSEN in TIMER0_DTCTRL will override the source of the first DTI channel, driving

TIM0_CC0 and TIM0_CDTI0, with the value on the PRS channel. The rest of the DTI channels will

continue to be driven by the PWM output from the timer. The PRS channel to use is chosen by configuring

DTPRSSEL in TIMER0_DTCTRL. Note that the timer must be running even when PRS is used as DTI

source.

The DTI prescaler, set by DTPRESC in TIMER0_DTTIME determines with which accuracy the DTI can

insert dead-time into a PRS signal. The maximum dead-time error equals 2DTPRESC clock cycles. With

zero prescaling, the inserted dead-times are therefore accurate, but they may be inaccurate for larger

prescaler settings.

20.3.3.3 Fault Handling

The fault handling system of the DTI unit allows the outputs of the DTI unit to be put in a well-defined

state in case of a fault. This hardware fault handling system makes a fast reaction to faults possible,

reducing the possibility of damage to the system.

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The fault sources which trigger a fault in the DTI module are determined by TIMER0_DTFSEN. Any

combination of the available error sources can be selected:

• PRS source 0, determined by DTPRS0FSEL in TIMER0_DTFC

• PRS source 1, determined by DTPRS1FSEL in TIMER0_DTFC

• Debugger

• Core Lockup

One or two PRS channels can be used as an error source. When PRS source 0 is selected as an error

source, DTPRS0FSEL determines which PRS channel is used for this source. DTPRS1FSEL determines

which PRS channel is selected as PRS source 1. Please note that for Core Lockup, the LOCKUPRDIS

in RMU_CTRL must be set. Otherwise this will generate a full reset of the EFM32.

20.3.3.3.1 Action on Fault

When a fault occurs, the bit representing the fault source is set in DTFS, and the outputs from the DTI unit

are set to a well-defined state. The following options are available, and can be enabled by configuring

DTFACT in TIMER0_DTFC:

• Set outputs to inactive level

• Clear outputs

• Tristate outputs

With the first option enabled, the output state in case of a fault depends on the polarity settings for the

individual outputs. An output set to be active high will be set low if a fault is detected, while an output

set to be active low will be driven high.

When a fault occurs, the fault source(s) can be read out of TIMER0_DTFS. TIMER0_DTFS is organized

in the same way as DTFSEN, with one bit for each source.

20.3.3.3.2 Exiting Fault State

When a fault is triggered by the PRS system, software intervention is required to re-enable the outputs

of the DTI unit. This is done by manually clearing TIMER0_DTFS. If the fault cause, determined by

TIMER0_DTFS, is the debugger alone, the outputs can optionally be re-enabled when the debugger

exits and the processor resumes normal operation. The corresponding bit in TIMER0_DTFS will in that

case be cleared by hardware. The automatic start-up functionality can be enabled by setting DTDAS in

TIMER0_DTCTRL. If more bits are still set in DTFS when the automatic start-up functionality has cleared

the debugger bit, the DTI module does not exit the fault state. The fault state is only exited when all the

bits in TIMER0_DTFS have been cleared.

20.3.3.4 Configuration Lock

To prevent software errors from making changes to the DTI configuration, a configuration lock is

available. Writing any value but 0xCE80 to LOCKKEY in TIMER0_DTLOCK results in TIMER0_DTFC,

TIMER0_DTCTRL, TIMER0_DTTIME and TIMER0_ROUTE being locked for writing. To unlock the

registers, write 0xCE80 to LOCKKEY in TIMER0_DTLOCK. The value of TIMER0_DTLOCK is 1 when

the lock is active, and 0 when the registers are unlocked.

20.3.4 Debug Mode

When the CPU is halted in debug mode, the timer can be configured to either continue to run or to be

frozen. This is configured in DBGHALT in TIMERn_CTRL.

20.3.5 Interrupts, DMA and PRS Output

The Timer has 5 output events:

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• Counter Underflow

• Counter Overflow

• Compare match or input capture (one per Compare/Capture channel)

Each of the events has its own interrupt flag. Also, there is one interrupt flag for each Compare/Capture

channel which is set on buffer overflow in capture mode. Buffer overflow happens when a new capture

pushes an old unread capture out of the TIMERn_CCx_CCV/TIMERn_CCx_CCVB register pair.

If the interrupt flags are set and the corresponding interrupt enable bits in TIMERn_IEN) are set high,

the Timer will send out an interrupt request. Each of the events will also lead to a one HFPERCLKTIMERn

cycle high pulse on individual PRS outputs.

Each of the events will also set a DMA request when they occur. The different DMA requests are cleared

when certain acknowledge conditions are met, see Table 20.3 (p. 540) . If DMACLRACT is set in

TIMERn_CTRL, the DMA request is cleared when the triggered DMA channel is active, without having

to access any timer registers.

Table 20.3. TIMER Events

Event Acknowledge

Underflow/Overflow Read or write to TIMERn_CNT or TIMERn_TOPB

CC 0 Read or write to TIMERn_CC0_CCV or

TIMERn_CC0_CCVB

CC 1 Read or write to TIMERn_CC1_CCV or

TIMERn_CC1_CCVB

CC 2 Read or write to TIMERn_CC2_CCV or

TIMERn_CC2_CCVB

20.3.6 GPIO Input/Output

The TIMn_CCx inputs/outputs and TIM0_CDTIx outputs are accessible as alternate functions through

GPIO. Each pin connection can be enabled/disabled separately by setting the corresponding CCxPEN

or CDTIxPEN bits in TIMERn_ROUTE. The LOCATION bits in the same register can be used to move

all enabled pins to alternate pins.

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20.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 TIMERn_CTRL RW Control Register

0x004 TIMERn_CMD W1 Command Register

0x008 TIMERn_STATUS R Status Register

0x00C TIMERn_IEN RW Interrupt Enable Register

0x010 TIMERn_IF R Interrupt Flag Register

0x014 TIMERn_IFS W1 Interrupt Flag Set Register

0x018 TIMERn_IFC W1 Interrupt Flag Clear Register

0x01C TIMERn_TOP RWH Counter Top Value Register

0x020 TIMERn_TOPB RW Counter Top Value Buffer Register

0x024 TIMERn_CNT RWH Counter Value Register

0x028 TIMERn_ROUTE RW I/O Routing Register

0x030 TIMERn_CC0_CTRL RW CC Channel Control Register

0x034 TIMERn_CC0_CCV RWH CC Channel Value Register

0x038 TIMERn_CC0_CCVP R CC Channel Value Peek Register

0x03C TIMERn_CC0_CCVB RWH CC Channel Buffer Register

0x040 TIMERn_CC1_CTRL RW CC Channel Control Register

0x044 TIMERn_CC1_CCV RWH CC Channel Value Register

0x048 TIMERn_CC1_CCVP R CC Channel Value Peek Register

0x04C TIMERn_CC1_CCVB RWH CC Channel Buffer Register

0x050 TIMERn_CC2_CTRL RW CC Channel Control Register

0x054 TIMERn_CC2_CCV RWH CC Channel Value Register

0x058 TIMERn_CC2_CCVP R CC Channel Value Peek Register

0x05C TIMERn_CC2_CCVB RWH CC Channel Buffer Register

0x070 TIMERn_DTCTRL RW DTI Control Register

0x074 TIMERn_DTTIME RW DTI Time Control Register

0x078 TIMERn_DTFC RW DTI Fault Configuration Register

0x07C TIMERn_DTOGEN RW DTI Output Generation Enable Register

0x080 TIMERn_DTFAULT R DTI Fault Register

0x084 TIMERn_DTFAULTC W1 DTI Fault Clear Register

0x088 TIMERn_DTLOCK RW DTI Configuration Lock Register

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20.5 Register Description

20.5.1 TIMERn_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

RSSCOIST

ATI

PRESC

CLKSEL

X2CNT

FALLA

RISEA

DMACLRACT

DEBUGRUN

QDM

OSMEN

SYNC

MODE

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

29 RSSCOIST 0 RW Reload-Start Sets Compare Output initial State

When enabled, compare output is set to COIST value at Reload-Start event

28 ATI 0 RW Always Track Inputs

Enable ATI makes CCPOL always track the polarity of the inputs

27:24 PRESC 0x0 RW Prescaler Setting

These bits select the prescaling factor.

Value Mode Description

0 DIV1 The HFPERCLK is undivided

1 DIV2 The HFPERCLK is divided by 2

2 DIV4 The HFPERCLK is divided by 4

3 DIV8 The HFPERCLK is divided by 8

4 DIV16 The HFPERCLK is divided by 16

5 DIV32 The HFPERCLK is divided by 32

6 DIV64 The HFPERCLK is divided by 64

7 DIV128 The HFPERCLK is divided by 128

8 DIV256 The HFPERCLK is divided by 256

9 DIV512 The HFPERCLK is divided by 512

10 DIV1024 The HFPERCLK is divided by 1024

23:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 CLKSEL 0x0 RW Clock Source Select

These bits select the clock source for the timer.

Value Mode Description

0 PRESCHFPERCLK Prescaled HFPERCLK

1 CC1 Compare/Capture Channel 1 Input

2 TIMEROUF Timer is clocked by underflow(down-count) or overflow(up-count) in the lower

numbered neighbor Timer

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 X2CNT 0 RW 2x Count Mode

Enable 2x count mode

12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:10 FALLA 0x0 RW Timer Falling Input Edge Action

These bits select the action taken in the counter when a falling edge occurs on the input.

Value Mode Description

0 NONE No action

1 START Start counter without reload

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Bit Name Reset Access Description

Value Mode Description

2 STOP Stop counter without reload

3 RELOADSTART Reload and start counter

9:8 RISEA 0x0 RW Timer Rising Input Edge Action

These bits select the action taken in the counter when a rising edge occurs on the input.

Value Mode Description

0 NONE No action

1 START Start counter without reload

2 STOP Stop counter without reload

3 RELOADSTART Reload and start counter

7 DMACLRACT 0 RW DMA Request Clear on Active

When this bit is set, the DMA requests are cleared when the corresponding DMA channel is active. This enables the timer DMA

requests to be cleared without accessing the timer.

6 DEBUGRUN 0 RW Debug Mode Run Enable

Set this bit to enable timer to run in debug mode.

Value Description

0 Timer is frozen in debug mode

1 Timer is running in debug mode

5 QDM 0 RW Quadrature Decoder Mode Selection

This bit sets the mode for the quadrature decoder.

Value Mode Description

0 X2 X2 mode selected

1 X4 X4 mode selected

4 OSMEN 0 RW One-shot Mode Enable

Enable/disable one shot mode.

3 SYNC 0 RW Timer Start/Stop/Reload Synchronization

When this bit is set, the Timer is started/stopped/reloaded by start/stop/reload commands in the other timers

Value Description

0 Timer is not started/stopped/reloaded by other timers

1 Timer is started/stopped/reloaded by other timers

2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 MODE 0x0 RW Timer Mode

These bit set the counting mode for the Timer. Note, when Quadrature Decoder Mode is selected (MODE = 'b11), the CLKSEL is

don't care. The Timer is clocked by the Decoder Mode clock output.

Value Mode Description

0 UP Up-count mode

1 DOWN Down-count mode

2 UPDOWN Up/down-count mode

3 QDEC Quadrature decoder mode

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20.5.2 TIMERn_CMD - Command Register

Offset Bit Position

0x004

Reset

Access

Name

STOP

START

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 STOP 0 W1 Stop Timer

Write a 1 to this bit to stop timer

0 START 0 W1 Start Timer

Write a 1 to this bit to start timer

20.5.3 TIMERn_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

CCPOL2

CCPOL1

CCPOL0

ICV2

ICV1

ICV0

CCVBV2

CCVBV1

CCVBV0

TOPBV

DIR

RUNNING

Bit Name Reset Access Description

31:27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 CCPOL2 0 R CC2 Polarity

In Input Capture mode, this bit indicates the polarity of the edge that triggered capture in TIMERn_CC2_CCV. In Compare/PWM

mode, this bit indicates the polarity of the selected input to CC channel 2. These bits are cleared when CCMODE is written to 0b00

(Off).

Value Mode Description

0 LOWRISE CC2 polarity low level/rising edge

1 HIGHFALL CC2 polarity high level/falling edge

25 CCPOL1 0 R CC1 Polarity

In Input Capture mode, this bit indicates the polarity of the edge that triggered capture in TIMERn_CC1_CCV. In Compare/PWM

mode, this bit indicates the polarity of the selected input to CC channel 1. These bits are cleared when CCMODE is written to 0b00

(Off).

Value Mode Description

0 LOWRISE CC1 polarity low level/rising edge

1 HIGHFALL CC1 polarity high level/falling edge

24 CCPOL0 0 R CC0 Polarity

In Input Capture mode, this bit indicates the polarity of the edge that triggered capture in TIMERn_CC0_CCV. In Compare/PWM

mode, this bit indicates the polarity of the selected input to CC channel 0. These bits are cleared when CCMODE is written to 0b00

(Off).

Value Mode Description

0 LOWRISE CC0 polarity low level/rising edge

1 HIGHFALL CC0 polarity high level/falling edge

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Bit Name Reset Access Description

23:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18 ICV2 0 R CC2 Input Capture Valid

This bit indicates that TIMERn_CC2_CCV contains a valid capture value. These bits are only used in input capture mode and are

cleared when CCMODE is written to 0b00 (Off).

Value Description

0 TIMERn_CC2_CCV does not contain a valid capture value(FIFO empty)

1 TIMERn_CC2_CCV contains a valid capture value(FIFO not empty)

17 ICV1 0 R CC1 Input Capture Valid

This bit indicates that TIMERn_CC1_CCV contains a valid capture value. These bits are only used in input capture mode and are

cleared when CCMODE is written to 0b00 (Off).

Value Description

0 TIMERn_CC1_CCV does not contain a valid capture value(FIFO empty)

1 TIMERn_CC1_CCV contains a valid capture value(FIFO not empty)

16 ICV0 0 R CC0 Input Capture Valid

This bit indicates that TIMERn_CC0_CCV contains a valid capture value. These bits are only used in input capture mode and are

cleared when CCMODE is written to 0b00 (Off).

Value Description

0 TIMERn_CC0_CCV does not contain a valid capture value(FIFO empty)

1 TIMERn_CC0_CCV contains a valid capture value(FIFO not empty)

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 CCVBV2 0 R CC2 CCVB Valid

This field indicates that the TIMERn_CC2_CCVB registers contain data which have not been written to TIMERn_CC2_CCV. These

bits are only used in output compare/pwm mode and are cleared when CCMODE is written to 0b00 (Off).

Value Description

0 TIMERn_CC2_CCVB does not contain valid data

1 TIMERn_CC2_CCVB contains valid data which will be written to TIMERn_CC2_CCV on the next update event

9 CCVBV1 0 R CC1 CCVB Valid

This field indicates that the TIMERn_CC1_CCVB registers contain data which have not been written to TIMERn_CC1_CCV. These

bits are only used in output compare/pwm mode and are cleared when CCMODE is written to 0b00 (Off).

Value Description

0 TIMERn_CC1_CCVB does not contain valid data

1 TIMERn_CC1_CCVB contains valid data which will be written to TIMERn_CC1_CCV on the next update event

8 CCVBV0 0 R CC0 CCVB Valid

This field indicates that the TIMERn_CC0_CCVB registers contain data which have not been written to TIMERn_CC0_CCV. These

bits are only used in output compare/pwm mode and are cleared when CCMODE is written to 0b00 (Off).

Value Description

0 TIMERn_CC0_CCVB does not contain valid data

1 TIMERn_CC0_CCVB contains valid data which will be written to TIMERn_CC0_CCV on the next update event

7:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 TOPBV 0 R TOPB Valid

This indicates that TIMERn_TOPB contains valid data that has not been written to TIMERn_TOP. This bit is also cleared when

TIMERn_TOP is written.

Value Description

0 TIMERn_TOPB does not contain valid data

1 TIMERn_TOPB contains valid data which will be written to TIMERn_TOP on the next update event

1 DIR 0 R Direction

Indicates count direction.

Value Mode Description

0 UP Counting up

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Bit Name Reset Access Description

Value Mode Description

1 DOWN Counting down

0 RUNNING 0 R Running

Indicates if timer is running or not.

20.5.4 TIMERn_IEN - Interrupt Enable Register

Offset Bit Position

0x00C

Reset

Access

Name

ICBOF2

ICBOF1

ICBOF0

CC2

CC1

CC0

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 ICBOF2 0 RW CC Channel 2 Input Capture Buffer Overflow Interrupt Enable

Enable/disable Compare/Capture ch 2 input capture buffer overflow interrupt.

9 ICBOF1 0 RW CC Channel 1 Input Capture Buffer Overflow Interrupt Enable

Enable/disable Compare/Capture ch 1 input capture buffer overflow interrupt.

8 ICBOF0 0 RW CC Channel 0 Input Capture Buffer Overflow Interrupt Enable

Enable/disable Compare/Capture ch 0 input capture buffer overflow interrupt.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 CC2 0 RW CC Channel 2 Interrupt Enable

Enable/disable Compare/Capture ch 2 interrupt.

5 CC1 0 RW CC Channel 1 Interrupt Enable

Enable/disable Compare/Capture ch 1 interrupt.

4 CC0 0 RW CC Channel 0 Interrupt Enable

Enable/disable Compare/Capture ch 0 interrupt.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 UF 0 RW Underflow Interrupt Enable

Enable/disable underflow interrupt.

0 OF 0 RW Overflow Interrupt Enable

Enable/disable overflow interrupt.

20.5.5 TIMERn_IF - Interrupt Flag Register

Offset Bit Position

0x010

Reset

Access

Name

ICBOF2

ICBOF1

ICBOF0

CC2

CC1

CC0

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Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 ICBOF2 0 R CC Channel 2 Input Capture Buffer Overflow Interrupt Flag

This bit indicates that a new capture value has pushed an unread value out of the TIMERn_CC2_CCV/TIMERn_CC2_CCVB register

pair.

9 ICBOF1 0 R CC Channel 1 Input Capture Buffer Overflow Interrupt Flag

This bit indicates that a new capture value has pushed an unread value out of the TIMERn_CC1_CCV/TIMERn_CC1_CCVB register

pair.

8 ICBOF0 0 R CC Channel 0 Input Capture Buffer Overflow Interrupt Flag

This bit indicates that a new capture value has pushed an unread value out of the TIMERn_CC0_CCV/TIMERn_CC0_CCVB register

pair.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 CC2 0 R CC Channel 2 Interrupt Flag

This bit indicates that there has been an interrupt event on Compare/Capture channel 2.

5 CC1 0 R CC Channel 1 Interrupt Flag

This bit indicates that there has been an interrupt event on Compare/Capture channel 1.

4 CC0 0 R CC Channel 0 Interrupt Flag

This bit indicates that there has been an interrupt event on Compare/Capture channel 0.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 UF 0 R Underflow Interrupt Flag

This bit indicates that there has been an underflow.

0 OF 0 R Overflow Interrupt Flag

This bit indicates that there has been an overflow.

20.5.6 TIMERn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x014

Reset

Access

Name

ICBOF2

ICBOF1

ICBOF0

CC2

CC1

CC0

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 ICBOF2 0 W1 CC Channel 2 Input Capture Buffer Overflow Interrupt Flag Set

Writing a 1 to this bit will set Compare/Capture channel 2 input capture buffer overflow interrupt flag.

9 ICBOF1 0 W1 CC Channel 1 Input Capture Buffer Overflow Interrupt Flag Set

Writing a 1 to this bit will set Compare/Capture channel 1 input capture buffer overflow interrupt flag.

8 ICBOF0 0 W1 CC Channel 0 Input Capture Buffer Overflow Interrupt Flag Set

Writing a 1 to this bit will set Compare/Capture channel 0 input capture buffer overflow interrupt flag.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 CC2 0 W1 CC Channel 2 Interrupt Flag Set

Writing a 1 to this bit will set Compare/Capture channel 2 interrupt flag.

5 CC1 0 W1 CC Channel 1 Interrupt Flag Set

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Bit Name Reset Access Description

Writing a 1 to this bit will set Compare/Capture channel 1 interrupt flag.

4 CC0 0 W1 CC Channel 0 Interrupt Flag Set

Writing a 1 to this bit will set Compare/Capture channel 0 interrupt flag.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 UF 0 W1 Underflow Interrupt Flag Set

Writing a 1 to this bit will set the underflow interrupt flag.

0 OF 0 W1 Overflow Interrupt Flag Set

Writing a 1 to this bit will set the overflow interrupt flag.

20.5.7 TIMERn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x018

Reset

Access

Name

ICBOF2

ICBOF1

ICBOF0

CC2

CC1

CC0

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 ICBOF2 0 W1 CC Channel 2 Input Capture Buffer Overflow Interrupt Flag Clear

Writing a 1 to this bit will clear Compare/Capture channel 2 input capture buffer overflow interrupt flag.

9 ICBOF1 0 W1 CC Channel 1 Input Capture Buffer Overflow Interrupt Flag Clear

Writing a 1 to this bit will clear Compare/Capture channel 1 input capture buffer overflow interrupt flag.

8 ICBOF0 0 W1 CC Channel 0 Input Capture Buffer Overflow Interrupt Flag Clear

Writing a 1 to this bit will clear Compare/Capture channel 0 input capture buffer overflow interrupt flag.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 CC2 0 W1 CC Channel 2 Interrupt Flag Clear

Writing a 1 to this bit will clear Compare/Capture interrupt flag 2.

5 CC1 0 W1 CC Channel 1 Interrupt Flag Clear

Writing a 1 to this bit will clear Compare/Capture interrupt flag 1.

4 CC0 0 W1 CC Channel 0 Interrupt Flag Clear

Writing a 1 to this bit will clear Compare/Capture interrupt flag 0.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 UF 0 W1 Underflow Interrupt Flag Clear

Writing a 1 to this bit will clear the underflow interrupt flag.

0 OF 0 W1 Overflow Interrupt Flag Clear

Writing a 1 to this bit will clear th overflow interrupt flag.

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20.5.8 TIMERn_TOP - Counter Top Value Register

Offset Bit Position

0x01C

Reset

0xFFFF

Access

RWH

Name

TOP

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 TOP 0xFFFF RWH Counter Top Value

These bits hold the TOP value for the counter.

20.5.9 TIMERn_TOPB - Counter Top Value Buffer Register

Offset Bit Position

0x020

Reset

0x0000

Access

Name

TOPB

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 TOPB 0x0000 RW Counter Top Value Buffer

These bits hold the TOP buffer value.

20.5.10 TIMERn_CNT - Counter Value Register

Offset Bit Position

0x024

Reset

0x0000

Access

RWH

Name

CNT

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Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CNT 0x0000 RWH Counter Value

These bits hold the counter value.

20.5.11 TIMERn_ROUTE - I/O Routing Register

Offset Bit Position

0x028

Reset

0x0

Access

Name

LOCATION

CDTI2PEN

CDTI1PEN

CDTI0PEN

CC2PEN

CC1PEN

CC0PEN

Bit Name Reset Access Description

31:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 LOCATION 0x0 RW I/O Location

Decides the location of the CC and CDTI pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

4 LOC4 Location 4

5 LOC5 Location 5

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 CDTI2PEN 0 RW CC Channel 2 Complementary Dead-Time Insertion Pin Enable

Enable/disable CC channel 2 complementary dead-time insertion output connection to pin.

9 CDTI1PEN 0 RW CC Channel 1 Complementary Dead-Time Insertion Pin Enable

Enable/disable CC channel 1 complementary dead-time insertion output connection to pin.

8 CDTI0PEN 0 RW CC Channel 0 Complementary Dead-Time Insertion Pin Enable

Enable/disable CC channel 0 complementary dead-time insertion output connection to pin.

7:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 CC2PEN 0 RW CC Channel 2 Pin Enable

Enable/disable CC channel 2 output/input connection to pin.

1 CC1PEN 0 RW CC Channel 1 Pin Enable

Enable/disable CC channel 1 output/input connection to pin.

0 CC0PEN 0 RW CC Channel 0 Pin Enable

Enable/disable CC Channel 0 output/input connection to pin.

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20.5.12 TIMERn_CCx_CTRL - CC Channel Control Register

Offset Bit Position

0x030

Reset

0x0

Access

Name

ICEVCTRL

ICEDGE

FILT

INSEL

PRSSEL

CUFOA

COFOA

CMOA

COIST

OUTINV

MODE

Bit Name Reset Access Description

31:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27:26 ICEVCTRL 0x0 RW Input Capture Event Control

These bits control when a Compare/Capture PRS output pulse, interrupt flag and DMA request is set.

Value Mode Description

0 EVERYEDGE PRS output pulse, interrupt flag and DMA request set on every capture

1 EVERYSECONDEDGE PRS output pulse, interrupt flag and DMA request set on every second capture

2 RISING PRS output pulse, interrupt flag and DMA request set on rising edge only (if ICEDGE

= BOTH)

3 FALLING PRS output pulse, interrupt flag and DMA request set on falling edge only (if ICEDGE

= BOTH)

25:24 ICEDGE 0x0 RW Input Capture Edge Select

These bits control which edges the edge detector triggers on. The output is used for input capture and external clock input.

Value Mode Description

0 RISING Rising edges detected

1 FALLING Falling edges detected

2 BOTH Both edges detected

3 NONE No edge detection, signal is left as it is

23:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21 FILT 0 RW Digital Filter

Enable digital filter.

Value Mode Description

0 DISABLE Digital filter disabled

1 ENABLE Digital filter enabled

20 INSEL 0 RW Input Selection

Select Compare/Capture channel input.

Value Mode Description

0 PIN TIMERnCCx pin is selected

1 PRS PRS input (selected by PRSSEL) is selected

19:16 PRSSEL 0x0 RW Compare/Capture Channel PRS Input Channel Selection

Select PRS input channel for Compare/Capture channel.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

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Bit Name Reset Access Description

Value Mode Description

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:12 CUFOA 0x0 RW Counter Underflow Output Action

Select output action on counter underflow.

Value Mode Description

0 NONE No action on counter underflow

1 TOGGLE Toggle output on counter underflow

2 CLEAR Clear output on counter underflow

3 SET Set output on counter underflow

11:10 COFOA 0x0 RW Counter Overflow Output Action

Select output action on counter overflow.

Value Mode Description

0 NONE No action on counter overflow

1 TOGGLE Toggle output on counter overflow

2 CLEAR Clear output on counter overflow

3 SET Set output on counter overflow

9:8 CMOA 0x0 RW Compare Match Output Action

Select output action on compare match.

Value Mode Description

0 NONE No action on compare match

1 TOGGLE Toggle output on compare match

2 CLEAR Clear output on compare match

3 SET Set output on compare match

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 COIST 0 RW Compare Output Initial State

This bit is only used in Output Compare and PWM mode. When this bit is set in compare mode,the output is set high when the counter

is disabled. When counting resumes, this value will represent the initial value for the output. If the bit is cleared, the output will be

cleared when the counter is disabled. In PWM mode, the output will always be low when disabled, regardless of this bit. However,

this bit will represent the initial value of the output, once it is enabled.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 OUTINV 0 RW Output Invert

Setting this bit inverts the output from the CC channel (Output compare,PWM).

1:0 MODE 0x0 RW CC Channel Mode

These bits select the mode for Compare/Capture channel.

Value Mode Description

0 OFF Compare/Capture channel turned off

1 INPUTCAPTURE Input capture

2 OUTPUTCOMPARE Output compare

3 PWM Pulse-Width Modulation

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20.5.13 TIMERn_CCx_CCV - CC Channel Value Register

Offset Bit Position

0x034

Reset

0x0000

Access

RWH

Name

CCV

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CCV 0x0000 RWH CC Channel Value

In input capture mode, this field holds the first unread capture value. When reading this register in input capture mode, then contents

of the TIMERn_CCx_CCVB register will be written to TIMERn_CCx_CCV in the next cycle. In compare mode, this fields holds the

compare value.

20.5.14 TIMERn_CCx_CCVP - CC Channel Value Peek Register

Offset Bit Position

0x038

Reset

0x0000

Access

Name

CCVP

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CCVP 0x0000 R CC Channel Value Peek

This field is used to read the CC value without pulling data through the FIFO in capture mode.

20.5.15 TIMERn_CCx_CCVB - CC Channel Buffer Register

Offset Bit Position

0x03C

Reset

0x0000

Access

RWH

Name

CCVB

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Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CCVB 0x0000 RWH CC Channel Value Buffer

In Input Capture mode, this field holds the last capture value if the TIMERn_CCx_CCV register already contains an earlier unread

capture value. In Output Compare or PWM mode, this field holds the CC buffer value which will be written to TIMERn_CCx_CCV

on an update event if TIMERn_CCx_CCVB contains valid data.

20.5.16 TIMERn_DTCTRL - DTI Control Register

Offset Bit Position

0x070

Reset

0x0

Access

Name

DTPRSEN

DTPRSSEL

DTCINV

DTIPOL

DTDAS

DTEN

Bit Name Reset Access Description

31:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24 DTPRSEN 0 RW DTI PRS Source Enable

Enable/disable PRS as DTI input.

23:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:4 DTPRSSEL 0x0 RW DTI PRS Source Channel Select

Select which PRS channel to listen to.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

3 DTCINV 0 RW DTI Complementary Output Invert.

Set to invert complementary outputs.

2 DTIPOL 0 RW DTI Inactive Polarity

Set inactive polarity for outputs.

1 DTDAS 0 RW DTI Automatic Start-up Functionality

Configure DTI restart on debugger exit.

Value Mode Description

0 NORESTART No DTI restart on debugger exit

1 RESTART DTI restart on debugger exit

0 DTEN 0 RW DTI Enable

Enable/disable DTI.

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20.5.17 TIMERn_DTTIME - DTI Time Control Register

Offset Bit Position

0x074

Reset

0x00

0x0

Access

Name

DTFALLT

DTRISET

DTPRESC

Bit Name Reset Access Description

31:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:16 DTFALLT 0x00 RW DTI Fall-time

Set time span for the falling edge.

Value Description

DTFALLT Fall time of DTFALLT+1 prescaled HFPERCLK cycles

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 DTRISET 0x00 RW DTI Rise-time

Set time span for the rising edge.

Value Description

DTRISET Rise time of DTRISET+1 prescaled HFPERCLK cycles

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 DTPRESC 0x0 RW DTI Prescaler Setting

Select prescaler for DTI.

Value Mode Description

0 DIV1 The HFPERCLK is undivided

1 DIV2 The HFPERCLK is divided by 2

2 DIV4 The HFPERCLK is divided by 4

3 DIV8 The HFPERCLK is divided by 8

4 DIV16 The HFPERCLK is divided by 16

5 DIV32 The HFPERCLK is divided by 32

6 DIV64 The HFPERCLK is divided by 64

7 DIV128 The HFPERCLK is divided by 128

8 DIV256 The HFPERCLK is divided by 256

9 DIV512 The HFPERCLK is divided by 512

10 DIV1024 The HFPERCLK is divided by 1024

20.5.18 TIMERn_DTFC - DTI Fault Configuration Register

Offset Bit Position

0x078

Reset

0x0

Access

Name

DTLOCKUPFEN

DTDBGFEN

DTPRS1FEN

DTPRS0FEN

DTFA

DTPRS1FSEL

DTPRS0FSEL

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Bit Name Reset Access Description

31:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27 DTLOCKUPFEN 0 RW DTI Lockup Fault Enable

Set this bit to 1 to enable core lockup as a fault source

26 DTDBGFEN 0 RW DTI Debugger Fault Enable

Set this bit to 1 to enable debugger as a fault source

25 DTPRS1FEN 0 RW DTI PRS 1 Fault Enable

Set this bit to 1 to enable PRS source 1(PRS channel determined by DTPRS1FSEL) as a fault source

24 DTPRS0FEN 0 RW DTI PRS 0 Fault Enable

Set this bit to 1 to enable PRS source 0(PRS channel determined by DTPRS0FSEL) as a fault source

23:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 DTFA 0x0 RW DTI Fault Action

Select fault action.

Value Mode Description

0 NONE No action on fault

1 INACTIVE Set outputs inactive

2 CLEAR Clear outputs

3 TRISTATE Tristate outputs

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 DTPRS1FSEL 0x0 RW DTI PRS Fault Source 1 Select

Select PRS channel for fault source 1.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as fault source 1

1 PRSCH1 PRS Channel 1 selected as fault source 1

2 PRSCH2 PRS Channel 2 selected as fault source 1

3 PRSCH3 PRS Channel 3 selected as fault source 1

4 PRSCH4 PRS Channel 4 selected as fault source 1

5 PRSCH5 PRS Channel 5 selected as fault source 1

6 PRSCH6 PRS Channel 6 selected as fault source 1

7 PRSCH7 PRS Channel 7 selected as fault source 1

7:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 DTPRS0FSEL 0x0 RW DTI PRS Fault Source 0 Select

Select PRS channel for fault source 0.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as fault source 0

1 PRSCH1 PRS Channel 1 selected as fault source 0

2 PRSCH2 PRS Channel 2 selected as fault source 0

3 PRSCH3 PRS Channel 3 selected as fault source 0

4 PRSCH4 PRS Channel 4 selected as fault source 0

5 PRSCH5 PRS Channel 5 selected as fault source 0

6 PRSCH6 PRS Channel 6 selected as fault source 0

7 PRSCH7 PRS Channel 7 selected as fault source 0

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20.5.19 TIMERn_DTOGEN - DTI Output Generation Enable Register

Offset Bit Position

0x07C

Reset

Access

Name

DTOGCDTI2EN

DTOGCDTI1EN

DTOGCDTI0EN

DTOGCC2EN

DTOGCC1EN

DTOGCC0EN

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DTOGCDTI2EN 0 RW DTI CDTI2 Output Generation Enable

This bit enables/disables output generation for the CDTI2 output from the DTI.

4 DTOGCDTI1EN 0 RW DTI CDTI1 Output Generation Enable

This bit enables/disables output generation for the CDTI1 output from the DTI.

3 DTOGCDTI0EN 0 RW DTI CDTI0 Output Generation Enable

This bit enables/disables output generation for the CDTI0 output from the DTI.

2 DTOGCC2EN 0 RW DTI CC2 Output Generation Enable

This bit enables/disables output generation for the CC2 output from the DTI.

1 DTOGCC1EN 0 RW DTI CC1 Output Generation Enable

This bit enables/disables output generation for the CC1 output from the DTI.

0 DTOGCC0EN 0 RW DTI CC0 Output Generation Enable

This bit enables/disables output generation for the CC0 output from the DTI.

20.5.20 TIMERn_DTFAULT - DTI Fault Register

Offset Bit Position

0x080

Reset

Access

Name

DTLOCKUPF

DTDBGF

DTPRS1F

DTPRS0F

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 DTLOCKUPF 0 R DTI Lockup Fault

This bit is set to 1 if a core lockup fault has occurred and DTLOCKUPFEN is set to 1. The TIMER0_DTFAULTC register can be

used to clear fault bits.

2 DTDBGF 0 R DTI Debugger Fault

This bit is set to 1 if a debugger fault has occurred and DTDBGFEN is set to 1. The TIMER0_DTFAULTC register can be used to

clear fault bits.

1 DTPRS1F 0 R DTI PRS 1 Fault

This bit is set to 1 if a PRS 1 fault has occurred and DTPRS1FEN is set to 1. The TIMER0_DTFAULTC register can be used to

clear fault bits.

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Bit Name Reset Access Description

0 DTPRS0F 0 R DTI PRS 0 Fault

This bit is set to 1 if a PRS 0 fault has occurred and DTPRS0FEN is set to 1. The TIMER0_DTFAULTC register can be used to

clear fault bits.

20.5.21 TIMERn_DTFAULTC - DTI Fault Clear Register

Offset Bit Position

0x084

Reset

Access

Name

TLOCKUPFC

DTDBGFC

DTPRS1FC

DTPRS0FC

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 TLOCKUPFC 0 W1 DTI Lockup Fault Clear

Write 1 to this bit to clear core lockup fault.

2 DTDBGFC 0 W1 DTI Debugger Fault Clear

Write 1 to this bit to clear debugger fault.

1 DTPRS1FC 0 W1 DTI PRS1 Fault Clear

Write 1 to this bit to clear PRS 1 fault.

0 DTPRS0FC 0 W1 DTI PRS0 Fault Clear

Write 1 to this bit to clear PRS 0 fault.

20.5.22 TIMERn_DTLOCK - DTI Configuration Lock Register

Offset Bit Position

0x088

Reset

0x0000

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 LOCKKEY 0x0000 RW DTI Lock Key

Write any other value than the unlock code to lock TIMER0_ROUTE, TIMER0_DTCTRL, TIMER0_DTTIME and TIMER0_DTFC from

editing. Write the unlock code to unlock. When reading the register, bit 0 is set when the lock is enabled.

Mode Value Description

Read Operation

UNLOCKED 0 TIMER DTI registers are unlocked

LOCKED 1 TIMER DTI registers are locked

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Bit Name Reset Access Description

Mode Value Description

Write Operation

LOCK 0 Lock TIMER DTI registers

UNLOCK 0xCE80 Unlock TIMER DTI registers

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21 RTC - Real Time Counter

01 2 3

Quick Facts

What?

The Real Time Counter (RTC) ensures

timekeeping in low energy modes. Combined

with two low power oscillators (XTAL or RC),

the RTC can run in EM2 with total current

consumption less than 0.95 µA, and in EM3

with total current consumption less than 0.65

µA.

Why?

Timekeeping over long time periods is

required in many applications, while using as

little power as possible.

How?

Selectable 1 kHz and 32.768 Hz oscillators

that can be used as clock source and two

different compare registers that can trigger

a wake-up. 24-bit resolution and selectable

prescaling allow the system to stay in EM2 or

EM3 for a long time and still maintain reliable

timekeeping.

21.1 Introduction

The Real Time Counter (RTC) contains a 24-bit counter and is clocked either by a 32.768 Hz crystal

oscillator, a 32.768 Hz RC oscillator, or a 1 kHz RC oscillator . In addition to energy modes EM0 and

EM1, the RTC is also available in EM2. This makes it ideal for keeping track of time since the RTC is

enabled in EM2 where most of the device is powered down. Using the 1 kHz ULFRCO as input clock,

the RTC can be used for timekeeping all the way down to EM3.

Two compare channels are available in the RTC. These can be used to trigger interrupts and to wake

the device up from a low energy mode. They can also be used with the LETIMER to generate various

output waveforms.

21.2 Features

• 24-bit Real Time Counter.

• Prescaler

• 32.768 kHz/2N, N = 0 - 15.

• Overflow @ 0.14 hours for prescaler setting = 0.

• Overflow @ 4660 hours (194 days) for prescaler setting = 15 (1 s tick).

• Two compare registers

• A compare match can potentially wake-up the device from low energy modes EM1 and EM2.

• Second compare register can be top value for RTC.

• Both compare channels can trigger LETIMER.

• Compare match events are available to other peripherals through the Peripheral Reflex System

(PRS).

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21.3 Functional Description

The RTC is a 24-bit counter with two compare channels. The RTC is closely coupled with the LETIMER,

and can be configured to trigger it on a compare match on one or both compare channels. An overview

of the RTC module is shown in Figure 21.1 (p. 561) .

Figure 21.1. RTC Overview

Counter (CNT)

Peripheral bus

Compare match 1

Compare match 0

RTC Control and

Status

LFACLKRTC Compare 0

(COMP0) Compare 1

(COMP1)

Clear

21.3.1 Counter

The RTC is enabled by setting the EN bit in the RTC_CTRL register. It counts up as long as it is

enabled, and will on an overflow simply wrap around and continue counting. The RTC is cleared when

it is disabled. The timer value is both readable and writable and the RTC always starts counting from 0

when enabled. The value of the counter can be read or modified using the RTC_CNT register.

21.3.1.1 Clock Source

The RTC clock source and its prescaler value are defined in the Register Description section of the Clock

Management Unit (CMU). The clock used by the RTC has a frequency given by Equation 21.1 (p. 561) .

RTC Frequency Equation

fRTC = fLFACLK/2RTC_PRESC (21.1)

where fLFACLK is the LFACLK frequency (32.768 kHz) and RTC_PRESC is a 4 bit value. Table 21.1 (p.

562) shows the time of overflow and resolution of the RTC at the available prescaler values.

To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0 in addition to

the module clock

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Table 21.1. RTC Resolution Vs Overflow

RTC_PRESC Resolution Overflow

0 30,5 µs 512 s

1 61,0 µs 1024 s

2 122 µs 2048 s

3 244 µs 1,14 hours

4 488 µs 2,28 hours

5 977 µs 4,55 hours

6 1,95 ms 9,10 hours

7 3,91 ms 18,2 hours

8 7,81 ms 1,52 days

9 15,6 ms 3,03 days

10 31,25 ms 6,07 days

11 62,5 ms 12,1 days

12 0,125 s 24,3 days

13 0,25 s 48,5 days

14 0,5 s 97,1 days

15 1 s 194 days

21.3.2 Compare Channels

Two compare channels are available in the RTC. The compare values can be set by writing to the RTC

compare channel registers RTC_COMPn, and when RTC_CNT is equal to one of these, the respective

compare interrupt flag COMPn is set.

If COMP0TOP is set, the compare value set for compare channel 0 is used as a top value for the RTC,

and the timer is cleared on a compare match with compare channel 0. If using the COMP0TOP setting,

make sure to set this bit prior to or at the same time the EN bit is set. Setting COMP0TOP after the EN

bit is set may cause unintended operation (i.e. if CNT > COMP0).

21.3.2.1 LETIMER Triggers

A compare event on either of the compare channels can start the LETIMER. See the LETIMER

documentation for more information on this feature.

21.3.2.2 PRS Sources

Both the compare channels of the RTC can be used as PRS sources. They will generate a pulse lasting

one RTC clock cycle on a compare match.

21.3.3 Interrupts

The interrupts generated by the RTC are combined into one interrupt vector. If interrupts for the RTC is

enabled, an interrupt will be made if one or more of the interrupt flags in RTC_IF and their corresponding

bits in RTC_IEN are set. Interrupt events are overflow and compare match on either compare channels.

Clearing of an interrupt flag is performed by writing to the corresponding bit in the RTC_IFC register.

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21.3.4 Debugrun

By default, the RTC is halted when code execution is halted from the debugger. By setting the

DEBUGRUN bit in the RTC_CTRL register, the RTC will continue to run even when the debugger is

halted.

21.3.5 Using the RTC in EM3

The RTC can be enabled all the way down to EM3 by using the ULFRCO as clock source. This is done

by clearing CMU_LFCLKSEL_LFA and setting CMU_LFCLKSEL_LFAE to 1. This will make the RTC

use the internal 1 kHz ultra low frequency RC oscillator (ULFRCO), consuming very little energy. Please

note that the ULFRCO is not accurate over temperature and voltage, and it should be verified that the

ULFRCO fulfills the timekeeping needs of the application before using this in the design.

21.3.6 Register access

This module is a Low Energy Peripheral, and supports immediate synchronization. For description

regarding immediate synchronization, the reader is referred to Section 5.3.1.1 (p. 20) .

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21.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 RTC_CTRL RW Control Register

0x004 RTC_CNT RWH Counter Value Register

0x008 RTC_COMP0 RW Compare Value Register 0

0x00C RTC_COMP1 RW Compare Value Register 1

0x010 RTC_IF R Interrupt Flag Register

0x014 RTC_IFS W1 Interrupt Flag Set Register

0x018 RTC_IFC W1 Interrupt Flag Clear Register

0x01C RTC_IEN RW Interrupt Enable Register

0x020 RTC_FREEZE RW Freeze Register

0x024 RTC_SYNCBUSY R Synchronization Busy Register

21.5 Register Description

21.5.1 RTC_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x000

Reset

Access

Name

COMP0TOP

DEBUGRUN

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 COMP0TOP 0 RW Compare Channel 0 is Top Value

When set, the counter is cleared in the clock cycle after a compare match with compare channel 0.

Value Mode Description

0 DISABLE The top value of the RTC is 16777215 (0xFFFFFF)

1 ENABLE The top value of the RTC is given by COMP0

1 DEBUGRUN 0 RW Debug Mode Run Enable

Set this bit to enable the RTC to keep running in debug.

Value Description

0 RTC is frozen in debug mode

1 RTC is running in debug mode

0 EN 0 RW RTC Enable

When this bit is set, the RTC is enabled and counts up. When cleared, the counter register CNT is reset.

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21.5.2 RTC_CNT - Counter Value Register

Offset Bit Position

0x004

Reset

0x000000

Access

RWH

Name

CNT

Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:0 CNT 0x000000 RWH Counter Value

Gives access to the counter value of the RTC.

21.5.3 RTC_COMP0 - Compare Value Register 0 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x008

Reset

0x000000

Access

Name

COMP0

Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:0 COMP0 0x000000 RW Compare Value 0

A compare match event occurs when CNT is equal to this value. This event sets the COMP0 interrupt flag, and can be used to start

the LETIMER. It is also available as a PRS signal.

21.5.4 RTC_COMP1 - Compare Value Register 1 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x00C

Reset

0x000000

Access

Name

COMP1

Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:0 COMP1 0x000000 RW Compare Value 1

A compare match event occurs when CNT is equal to this value. This event sets COMP1 interrupt flag, and can be used to start

the LETIMER. It is also available as a PRS signal.

21.5.5 RTC_IF - Interrupt Flag Register

Offset Bit Position

0x010

Reset

Access

Name

COMP1

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 COMP1 0 R Compare Match 1 Interrupt Flag

Set on a compare match between CNT and COMP1.

1 COMP0 0 R Compare Match 0 Interrupt Flag

Set on a compare match between CNT and COMP0.

0 OF 0 R Overflow Interrupt Flag

Set on a CNT value overflow.

21.5.6 RTC_IFS - Interrupt Flag Set Register

Offset Bit Position

0x014

Reset

Access

Name

COMP1

COMP0

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Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 COMP1 0 W1 Set Compare match 1 Interrupt Flag

Write to 1 to set the COMP1 interrupt flag.

1 COMP0 0 W1 Set Compare match 0 Interrupt Flag

Write to 1 to set the COMP0 interrupt flag.

0 OF 0 W1 Set Overflow Interrupt Flag

Write to 1 to set the OF interrupt flag.

21.5.7 RTC_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x018

Reset

Access

Name

COMP1

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 COMP1 0 W1 Clear Compare match 1 Interrupt Flag

Write to 1 to clear the COMP1 interrupt flag.

1 COMP0 0 W1 Clear Compare match 0 Interrupt Flag

Write to 1 to clear the COMP0 interrupt flag.

0 OF 0 W1 Clear Overflow Interrupt Flag

Write to 1 to clear the OF interrupt flag.

21.5.8 RTC_IEN - Interrupt Enable Register

Offset Bit Position

0x01C

Reset

Access

Name

COMP1

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 COMP1 0 RW Compare Match 1 Interrupt Enable

Enable interrupt on compare match 1.

1 COMP0 0 RW Compare Match 0 Interrupt Enable

Enable interrupt on compare match 0.

0 OF 0 RW Overflow Interrupt Enable

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Bit Name Reset Access Description

Enable interrupt on overflow.

21.5.9 RTC_FREEZE - Freeze Register

Offset Bit Position

0x020

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

When set, the update of the RTC is postponed until this bit is cleared. Use this bit to update several registers simultaneously.

Value Mode Description

0 UPDATE Each write access to an RTC register is updated into the Low Frequency domain as

soon as possible.

1 FREEZE The RTC is not updated with the new written value until the freeze bit is cleared.

21.5.10 RTC_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x024

Reset

Access

Name

COMP1

COMP0

CTRL

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 COMP1 0 R COMP1 Register Busy

Set when the value written to COMP1 is being synchronized.

1 COMP0 0 R COMP0 Register Busy

Set when the value written to COMP0 is being synchronized.

0 CTRL 0 R CTRL Register Busy

Set when the value written to CTRL is being synchronized.

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22 BURTC - Backup Real Time Counter

01 2 3 4

Quick Facts

What?

The Backup Real Time Counter (BURTC)

allows timekeeping in all energy modes.

Running on the LFXO, LFRCO, or ULFRCO,

the BURTC can run in EM4 with a total

current consumption less than 0.5uA. The

Backup RTC is also available when the

system is in backup mode.

Why?

Timekeeping over long time periods is

required in many applications, while using as

little power as possible.

How?

The 32-bit Backup RTC is available

in all energy modes and selectable

prescaling allows the system to stay in

low energy modes for long a time and

still maintain reliable timekeeping. The

BURTC also includes a feature allowing

seamless switching of clock frequency, while

maintaining resolution of the counter.

22.1 Introduction

The Backup Real Time Counter (BURTC) contains a 32-bit counter and is clocked either by a 32.768

kHz crystal oscillator, a 32.768 kHz RC oscillator, a 2kHz RC oscillator, or a 1kHz RC oscillator. A variety

of prescaler settings are also available for the 32.768 kHz oscillators. The Backup RTC is available in

all energy modes, making it ideal for time keeping with minimal energy consumption. The ability to keep

running while the system is in backup mode allows the Backup RTC to keep track of time, even if the

main power should drain out.

22.2 Features

• 32-bit Real Time Counter

• Prescaler for LFXO and LFRCO, 32.768 kHz/2N, N = 0-7

• Available in all energy modes and backup mode.

• Timestamp and optionally switch to low power mode upon entry to backup mode.

• Oscillator failure detection.

• EM4 operation and wake-up.

• Not reset by system reset, only by software, pin reset, or power loss.

• Seamless frequency shifting while keeping track of time.

• 512 bytes of general purpose data retention.

• Detection of corrupt writes to retention registers when losing main power.

• PRS producer.

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22.3 Functional Description

The Backup RTC is a 32-bit counter with one compare channel. The Backup RTC resides in a power

domain which can be configured to always be on, in EM0 through EM4. This domain also has the

possibility to be powered by a backup battery. For further details on the backup power domain, refer to

Section 10.3.4 (p. 111) . Available in all energy modes, the Backup RTC is ideal for applications where

keeping track of time in combination with extremely low energy consumption is essential. An overview

of the backup RTC is shown in Figure 22.1 (p. 570) .

Figure 22.1. BURTC Overview

Counter (CNT)

Peripheral bus

Compare match

COMP0

Clear

COMP0TOP

LFXO

LFRCO

CLKSEL

RTC control and status

CNT = COMP0 *

* Number of bits evaluated

varies in low power mode

ULFRCO

2-PRESC

22.3.1 Counter

The Backup RTC is enabled by configuring MODE in the BURTC_CTRL register. This configuration of

MODE determines in which energy modes the backup RTC is operational. It will always be operational in

EM0-EM2, and optionally in EM3 and EM4. The Backup RTC is available when the system is in backup

mode if MODE is set to EM4EN. The counter is cleared by setting RSTEN in the control register. A

system reset will not clear the counter. The counter value can be read through the CNT register.

22.3.2 Clock source

The Backup RTC is clocked by LFXO, LFRCO, or ULFRCO, depending on the configuration of CLKSEL

in BURTC_CTRL. The PRESC bit-field in BURTC_CTRL controls the clock prescaling factor. Prescaler

is only available for LFXO and LFRCO. When using the ULFRCO as clock source, only two frequency

options are available; 2kHz and 1kHz. The 2kHz clock is selected when PRESC in BURTC_CTRL is set

to DIV1, and the 1kHz clock is selected when PRESC is set to any other value. Available frequencies

when using LFXO or LFRCO are given in Equation 22.1 (p. 570) . CLKSEL should not be changed

while the backup RTC is running.

BURTC Frequency Equation

fBURTC = 32768/2PRESC Hz, PRESC = 0..7 (22.1)

When the LFXO or LFRCO is enabled, the Backup RTC will not use the clock until the timeout defined

in the CMU has run out, i.e. the LFXORDY/LFRCORDY flag in CMU_STATUS is set. When an oscillator

first has been enabled and is used by the Backup RTC, the Backup RTC will keep the selected clock

source enabled, independent of both energy mode and CMU settings.

22.3.3 Compare channel

The backup RTC has one compare channel. The compare value is set by writing to the COMP0 register.

When the value of CNT equals the value of COMP0, the COMP0 interrupt flag is set. If COMP0TOP

in CTRL is set, the counter will wrap around when reaching the value in the compare register, COMP.

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If COMP0TOP is cleared, the counter will continue counting, wrapping around when it overflows. On

overflow, the OF interrupt flag is set.

22.3.4 PRS Sources

The compare channel of the Backup RTC can be used as PRS source. A pulse lasting one clock cycle

will be generated on a compare match. A PRS pulse will also be generated on overflow.

22.3.5 Debugrun

By default, the backup RTC is halted when code execution is halted by the debugger. By setting the

DEBUGRUN bit in the CTRL register, the backup RTC will continue to run even when the system is

halted.

22.3.6 Low power mode

The Backup RTC has a low power mode which lowers the power consumption at the expense of

decreased resolution on compare matches. The low power mode is enabled by configuring the LPMODE

bit-field in BURTC_CTRL. When LPMODE is set to ENABLE, low power mode is always enabled, if

LPMODE is set to BUEN, the Backup RTC operates in normal mode until the system enters backup

mode, refer to Section 10.3.4 (p. 111) for details on backup mode. When the Backup RTC operates

in low power mode, a configurable number of the LSBs of COMP0 are ignored for compare match

evaluation. The number of bits ignored is configured in the LPCOMP bit-field in the BURTC_CTRL

In low power mode, the Backup RTC will decrease its frequency by a factor of 2-LPCOMP, and start

incrementing with 2LPCOMP instead of 1. When reading the counter value from software, full resolution is

maintained, the decrease in frequency will only affect the resolution on compare matches. Low power

mode can be entered and exited while the Backup RTC is running. When the Backup RTC is operating

in low power mode, LPMODEACT in BURTC_STATUS is set.

Low power mode compare match resolution

CMresolution = 2PRESC + LPCOMP + 1 / FCLK , PRESC + LPCOMP + 1 < 9 (22.2)

Table 22.1. Resolution and overflow

Normal mode Low power mode

PRESC Compare match

resolution Overflow Compare match

resolution Overflow

0 30.5 µs 1.52 days Equation 22.2 (p.

571) 1.52 days

1 61 µs 3.03 days Equation 22.2 (p.

571) 3.03 days

2 122 µs 6.07 days Equation 22.2 (p.

571) 6.07 days

3 244 µs 12.14 days Equation 22.2 (p.

571) 12.14 days

4 488 µs 24.27 days Equation 22.2 (p.

571) 24.27 days

5 977 µs 48.54 days Equation 22.2 (p.

571) 48.54 days

6 1.95 ms 97.09 days Equation 22.2 (p.

571) 97.09 days

7 3.91 ms 194.18 days Equation 22.2 (p.

571) 194.18 days

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Note Low power mode is only available when using LFXO or LFRCO.

22.3.7 Retention Registers

The Backup RTC includes 128 x 32 bit registers with possible retention in all energy modes. The registers

are accessible through the RETx_REG registers. Retention is by default enabled in EM0 through EM4.

The registers can be shut off to save power by setting RAM in BURTC_POWERDOWN. Note that the

retention registers cannot be accessed when RSTEN in BURTC_CTRL is set.

Note The retention registers are mapped to a RAM instance and have undefined state out of

reset.

If the system should lose main power and enter backup mode while writing to the retention registers,

the RAM write error flag, RAMWERR, in BURTC_STATUS will be set, and the attempted write will be

canceled. The RAMWERR flag is cleared by writing a 1 to CLRSTATUS in BURTC_CMD.

22.3.8 Backup operation

The Backup RTC and the retention registers reside in a separate power domain, which in addition to

being available in EM4 has the possibility to be powered by a backup battery. Refer to Section 10.3.4 (p.

111) for further details on this power domain.

22.3.9 Backup mode timestamp

The Backup RTC includes functionality for storing a timestamp when the system enters backup mode.

The timestamp is stored in the BURTC_TIMESTAMP register and is stored two cycles after entering

backup mode. If Low Power mode is enabled, ignored bits will not be stored in the timestamp register.

Timestamping is enabled by setting BUMODETSEN in BURTC_CTRL. When a timestamp is stored, the

BUMODETS bit in BUCTRL_STATUS is set. To prevent uncontrolled time stamping when entering and

exiting backup mode, this status bit has to be cleared before a new timestamp can be stored, by writing

a 1 to CLRSTATUS in BURTC_CMD. Note that upon clearing this bit, the data in BURTC_TIMESTAMP

is no longer valid.

22.3.10 LFXO failure detection

To be able to detect LFXO failure, the Backup RTC includes a five bit down counter with configurable

top value. The top value is configured in TOP in BURTC_LFXOFDET. The counter starts at the top

value and counts downwards on either LFRCO or ULFRCO, depending on the configuration of OSC

in BURTC_LFXOFDET. When LFRCO is selected as clock for the down counter, it will be prescaled

with a factor of 2PRESC + LPCOMP. The counter wraps to TOP when it reaches zero. If no LFXO clock has

arrived since the last time the counter reached zero , the BURTC clock is changed to the clock source

configured in OSC and the LFXOFAIL interrupt flag is set. Note that due to synchronization, the LFXO

clock needs to arrive at least two cycles before the counter reaches zero.

22.3.11 Register access

Most Backup RTC configuration should not be changed while the counter is running, i.e. they should

only be changed while RSTEN in BURTC_CTRL is set.

Registers allowed to change run-time are BURTC_COMP0, BURTC_LPMODE, and DEBUGRUN in

BURTC_CTRL. For further details on access to these registers, refer to Section 5.3 (p. 20) .

Note The Backup domain has its own reset signal which is active when the device powers up for

the first time. The reset is deactivated by clearing BURSTEN in RMU_CTRL. This has to be

done before any registers in the Backup RTC can be accessed.

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22.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 BURTC_CTRL RW Control Register

0x004 BURTC_LPMODE RW Low power mode configuration

0x008 BURTC_CNT R Counter Value Register

0x00C BURTC_COMP0 RW Counter Compare Value

0x010 BURTC_TIMESTAMP R Backup mode timestamp

0x014 BURTC_LFXOFDET RW LFXO

0x018 BURTC_STATUS R Status Register

0x01C BURTC_CMD W1 Command Register

0x020 BURTC_POWERDOWN RW Retention RAM power-down Register

0x024 BURTC_LOCK RW Configuration Lock Register

0x028 BURTC_IF R Interrupt Flag Register

0x02C BURTC_IFS W1 Interrupt Flag Set Register

0x030 BURTC_IFC W1 Interrupt Flag Clear Register

0x034 BURTC_IEN RW Interrupt Enable Register

0x038 BURTC_FREEZE RW Freeze Register

0x03C BURTC_SYNCBUSY R Synchronization Busy Register

0x100 RET0_REG RW Retention Register

... RETx_REG RW Retention Register

0x2FC RET127_REG RW Retention Register

22.5 Register Description

22.5.1 BURTC_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

BUMODETSEN

CLKSEL

PRESC

LPCOMP

COMP0TOP

RSTEN

DEBUGRUN

MODE

Bit Name Reset Access Description

31:15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14 BUMODETSEN 0 RW Backup mode timestamp enable

When set, the BURTC will store its counter value in the BURTC_TIMESTAMP register upon backup mode entry.

13:12 CLKSEL 0x0 RW Select BURTC clock source

Value Mode Description

0 NONE No clock source selected for BURTC.

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Bit Name Reset Access Description

Value Mode Description

1 LFRCO LFRCO selected as BURTC clock source.

2 LFXO LFXO selected as BURTC clock source.

3 ULFRCO ULFRCO selected as BURTC clock source.

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 PRESC 0x0 RW Select BURTC prescaler factor

The BURTC will be prescaled by a factor of 2PRESC

Value Mode Description

0 DIV1 No prescaling.

1 DIV2 Prescaling factor of 2

2 DIV4 Prescaling factor of 4

3 DIV8 Prescaling factor of 8

4 DIV16 Prescaling factor of 16

5 DIV32 Prescaling factor of 32

6 DIV64 Prescaling factor of 64

7 DIV128 Prescaling factor of 128

7:5 LPCOMP 0x0 RW Low power mode compare configuration

This bit-field configures which bits to be evaluated for compare match in low power mode.

Value Mode Description

0 IGN0LSB Do not ignore any bits for compare match evaluation.

1 IGN1LSB The LSB of the counter is ignored for compare match evaluation.

2 IGN2LSB The two LSBs of the counter are ignored for compare match evaluation.

3 IGN3LSB The three LSBs of the counter are ignored for compare match evaluation.

4 IGN4LSB The four LSBs of the counter are ignored for compare match evaluation.

5 IGN5LSB The five LSBs of the counter are ignored for compare match evaluation.

6 IGN6LSB The six LSBs of the counter are ignored for compare match evaluation.

7 IGN7LSB The seven LSBs of the counter are ignored for compare match evaluation.

4 COMP0TOP 0 RW Compare clear enable

When set, the counter wraps around when CNT equals COMP0

3 RSTEN 1 RW Enable BURTC reset

Reset the BURTC_CNT and BURTC_TIMESTAMP registers.

2 DEBUGRUN 0 RW Debug Mode Run Enable

Set this bit to keep the BURTC running during a debug halt.

Value Description

0 RTC is frozen in debug mode

1 RTC is running in debug mode

1:0 MODE 0x0 RW BURTC Enable

Configure in which energy modes the BURTC should keep running.

Value Mode Description

0 DISABLE The BURTC is disabled.

1 EM2EN The BURTC is in normal operating mode, operating in EM0-EM2. Oscillators must be

enabled in CMU for use.

2 EM3EN The BURTC is enabled in EM0-EM3. Will prevent CMU from disabling used oscillators

all the way down to EM3.

3 EM4EN The BURTC is enabled in EM0-EM4. Will prevent CMU from disabling used oscillators

all the way down to EM4.

22.5.2 BURTC_LPMODE - Low power mode configuration (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x004

Reset

0x0

Access

Name

LPMODE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 LPMODE 0x0 RW Low power mode configuration.

Value Mode Description

0 DISABLE Low power mode is disabled.

1 ENABLE Low power mode always enabled.

2 BUEN Low power mode enabled in backup mode.

22.5.3 BURTC_CNT - Counter Value Register

Offset Bit Position

0x008

Reset

0x00000000

Access

Name

CNT

Bit Name Reset Access Description

31:0 CNT 0x00000000 R Counter Value

Gives access to the BURTC counter value.

22.5.4 BURTC_COMP0 - Counter Compare Value (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x00C

Reset

0x00000000

Access

Name

COMP0

Bit Name Reset Access Description

31:0 COMP0 0x00000000 RW Compare match value

Gives access to the BURTC compare value.

22.5.5 BURTC_TIMESTAMP - Backup mode timestamp

Offset Bit Position

0x010

Reset

0x00000000

Access

Name

TIMESTAMP

Bit Name Reset Access Description

31:0 TIMESTAMP 0x00000000 R Backup mode timestamp.

Contains the timestamp stored upon backup mode entry.

22.5.6 BURTC_LFXOFDET - LFXO

Offset Bit Position

0x014

Reset

0x00

0x0

Access

Name

TOP

OSC

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Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:4 TOP 0x00 RW LFXO failure counter top value.

LFXO failure counter will wrap to this value when reaching zero.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 OSC 0x0 RW LFXO failure detection configuration.

Select oscillator for LFXO failure detection.

Value Mode Description

0 DISABLE LFXO failure detection disabled.

1 LFRCO LFRCO used for LFXO failure detection.

2 ULFRCO ULFRCO used for LFXO failure detection.

22.5.7 BURTC_STATUS - Status Register

Offset Bit Position

0x018

Reset

Access

Name

RAMWERR

BUMODETS

LPMODEACT

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 RAMWERR 0 R RAM write error.

Set if backup mode is entered during a write to the retention RAM.

1 BUMODETS 0 R Timestamp for backup mode entry stored.

Set when a timestamp has been stored in BURTC_TIMESTAMP.

0 LPMODEACT 0 R Low power mode active

Set when the BURTC is in low power mode

22.5.8 BURTC_CMD - Command Register

Offset Bit Position

0x01C

Reset

Access

Name

CLRSTATUS

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 CLRSTATUS 0 W1 Clear BURTC_STATUS register.

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Bit Name Reset Access Description

Clear RAMWERR and BUMODETS in BURTC_STATUS.

22.5.9 BURTC_POWERDOWN - Retention RAM power-down Register

Offset Bit Position

0x020

Reset

Access

Name

RAM

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 RAM 0 RW Retention RAM power-down

Shut off power to the Retention RAM. Once it is powered down, it cannot be powered up again

22.5.10 BURTC_LOCK - Configuration Lock Register

Offset Bit Position

0x024

Reset

0x0000

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 LOCKKEY 0x0000 RW Configuration Lock Key

Write any other value than the unlock code to lock BURTC_POWERDOWN, BURTC_CTRL, BURTC_LFXOFDET, and BURTC_IEN

registers from editing. Write the unlock code to unlock. When reading the register, bit 0 is set when the lock is enabled.

Mode Value Description

Read Operation

UNLOCKED 0 BURTC_POWERDOWN, BURTC_CTRL,

BURTC_LFXOFDET, and BURTC_IEN registers are unlocked

LOCKED 1 BURTC_POWERDOWN, BURTC_CTRL,

BURTC_LFXOFDET, and BURTC_IEN registers are locked

Write Operation

LOCK 0 Lock BURTC_POWERDOWN, BURTC_CTRL,

BURTC_LFXOFDET, and BURTC_IEN registers

UNLOCK 0xAEE8 Unlock BURTC registers

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22.5.11 BURTC_IF - Interrupt Flag Register

Offset Bit Position

0x028

Reset

Access

Name

LFXOFAIL

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 LFXOFAIL 0 R LFXO failure Interrupt Flag

Set on LFXO failure.

1 COMP0 0 R Compare match Interrupt Flag

Set on BURTC compare match.

0 OF 0 R Overflow Interrupt Flag

Set on BURTC overflow.

22.5.12 BURTC_IFS - Interrupt Flag Set Register

Offset Bit Position

0x02C

Reset

Access

Name

LFXOFAIL

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 LFXOFAIL 0 W1 Set LFXO fail Interrupt Flag

Write to 1 to set the LFXOFAIL interrupt flag

1 COMP0 0 W1 Set compare match Interrupt Flag

Write to 1 to set the COMP0 interrupt flag

0 OF 0 W1 Set Overflow Interrupt Flag

Write to 1 to set the OF interrupt flag

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22.5.13 BURTC_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x030

Reset

Access

Name

LFXOFAIL

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 LFXOFAIL 0 W1 Clear LFXO failure Interrupt Flag

Write to 1 to clear the LFXOFAIL interrupt flag

1 COMP0 0 W1 Clear compare match Interrupt Flag

Write to 1 to clear the COMP0 interrupt flag

0 OF 0 W1 Clear Overflow Interrupt Flag

Write to 1 to clear the OF interrupt flag

22.5.14 BURTC_IEN - Interrupt Enable Register

Offset Bit Position

0x034

Reset

Access

Name

LFXOFAIL

COMP0

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 LFXOFAIL 0 RW LFXO failure Interrupt Enable

Enable interrupt on LFXO failure

1 COMP0 0 RW Compare match Interrupt Enable

Enable interrupt on compare match

0 OF 0 RW Overflow Interrupt Enable

Enable interrupt on overflow

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22.5.15 BURTC_FREEZE - Freeze Register

Offset Bit Position

0x038

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

When set, the update of the BURTC is postponed until this bit is cleared. Use this bit to update several registers simultaneously.

Value Mode Description

0 UPDATE Each write access to an BURTC register is updated into the Low Frequency domain

as soon as possible.

1 FREEZE The BURTC is not updated with the new written value until the freeze bit is cleared.

22.5.16 BURTC_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x03C

Reset

Access

Name

COMP0

LPMODE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 COMP0 0 R COMP0 Register Busy

Set when the value written to COMP0 is being synchronized.

0 LPMODE 0 R LPMODE Register Busy

Set when the value written to LPMODE is being synchronized.

22.5.17 RETx_REG - Retention Register

Offset Bit Position

0x100

Reset

0xXXXXXXXX

Access

Name

REG

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Bit Name Reset Access Description

31:0 REG 0xXXXXXXXX RW General Purpose Retention Register

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23 LETIMER - Low Energy Timer

01 2 3 4

LETIMER

RTC

Quick Facts

What?

The LETIMER is a down-counter that can

keep track of time and output configurable

waveforms. Running on a 32.768 Hz clock

the LETIMER is available in EM2, while

using a 1 kHz clock the LETIMER is available

also in EM3, all this with sub µA current

consumption.

Why?

The LETIMER can be used to provide

repeatable waveforms to external

components while remaining in EM2. It is well

suited for e.g. metering systems or to provide

more compare values than available in the

RTC.

How?

With buffered repeat and top value registers,

the LETIMER can provide glitch-free

waveforms at frequencies up to 16 kHz.

It is tightly coupled to the RTC, which

allows advanced time-keeping and wake-up

functions in EM2 and EM3.

23.1 Introduction

The unique LETIMERTM, the Low Energy Timer, is a 16-bit timer that is available in energy mode EM2

and EM3, in addition to EM1 and EM0. Because of this, it can be used for timing and output generation

when most of the device is powered down, allowing simple tasks to be performed while the power

consumption of the system is kept at an absolute minimum.

The LETIMER can be used to output a variety of waveforms with minimal software intervention. It is

also connected to the Real Time Counter (RTC), and can be configured to start counting on compare

matches from the RTC.

23.2 Features

• 16-bit down count timer

• 2 Compare match registers

• Compare register 0 can be top timer top value

• Compare registers can be double buffered

• Double buffered 8-bit Repeat Register

• Same clock source as the Real Time Counter

• LETIMER can be triggered (started) by an RTC event or by software

• 2 output pins can optionally be configured to provide different waveforms on timer underflow:

• Toggle output pin

• Apply a positive pulse (pulse width of one LFACLKLETIMER period)

• PWM

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• Interrupt on:

• Compare matches

• Timer underflow

• Repeat done

• Optionally runs during debug

• PRS Output

23.3 Functional Description

An overview of the LETIMER module is shown in Figure 23.1 (p. 585) . The LETIMER is a

16-bit down-counter with two compare registers, LETIMERn_COMP0 and LETIMERn_COMP1. The

LETIMERn_COMP0 register can optionally act as a top value for the counter. The repeat counter

LETIMERn_REP0 allows the timer to count a specified number of times before it stops. Both the

LETIMERn_COMP0 and LETIMERn_REP0 registers can be double buffered by the LETIMERn_COMP1

and LETIMERn_REP1 registers to allow continuous operation. The timer can generate a single pin

output, or two linked outputs.

Figure 23.1. LETIMER Overview

Peripheral bus

= 0

COMP1

(Top Buffer)

COMP0

(Top)

CNT (Counter)

REP0

(Repeat)

REP1

(Repeat Buffer)

LETIMER Control

and Status

Reload

Update

Stop 0

LFACLKLETIMERn

Start

RTC event

SW pin

ctrl LETn_O0

Pulse

Control

Underflow

(UF interrupt flag)

REP0 Zero

(REP0 interrupt flag)

Buffer

Written Repeat

load logic

ctrl LETn_O1

Pulse

Control

Top load

logic

=1 REP1 Zero

(REP1 interrupt flag)

=COMP1 Match

(COMP1 interrupt flag)

COMP0 Match

(COMP0 interrupt flag)

PRS CH1

PRS CH0

23.3.1 Timer

The timer is started by setting command bit START in LETIMERn_CMD, and stopped by setting the

STOP command bit in the same register. RUNNING in LETIMERn_STATUS is set as long as the timer is

running. The timer can also be started on external signals, such as a compare match from the Real Time

Counter. If START and STOP are set at the same time, STOP has priority, and the timer will be stopped.

The timer value can be read using the LETIMERn_CNT register. The value cannot be written, but it

can be cleared by setting the CLEAR command bit in LETIMERn_CMD. If the CLEAR and START

commands are issued at the same time, the timer will be cleared, then start counting at the top value.

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23.3.2 Compare Registers

The LETIMER has two compare match registers, LETIMERn_COMP0 and LETIMERn_COMP1.

Each of these compare registers are capable of generating an interrupt when the counter value

LETIMERn_CNT becomes equal to their value. When LETIMERn_CNT becomes equal to the value

of LETIMERn_COMP0, the interrupt flag COMP0 in LETIMERn_IF is set, and when LETIMERn_CNT

becomes equal to the value of LETIMERn_COMP1, the interrupt flag COMP1 in LETIMERn_IF is set.

23.3.3 Top Value

If COMP0TOP in LETIMERn_CTRL is set, the value of LETIMERn_COMP0 acts as the top value of the

timer, and LETIMERn_COMP0 is loaded into LETIMERn_CNT on timer underflow. Else, the timer wraps

around to 0xFFFF. The underflow interrupt flag UF in LETIMERn_IF is set when the timer reaches zero.

23.3.3.1 Buffered Top Value

If BUFTOP in LETIMERn_CTRL is set, the value of LETIMERn_COMP0 is buffered by

LETIMERn_COMP1. In this mode, the value of LETIMERn_COMP1 is loaded into LETIMERn_COMP0

every time LETIMERn_REP0 is about to decrement to 0. This can for instance be used in conjunction

with the buffered repeat mode to generate continually changing output waveforms.

Write operations to LETIMERn_COMP0 have priority over buffer loads.

23.3.3.2 Repeat Modes

By default, the timer wraps around to the top value or 0xFFFF on each underflow, and continues counting.

The repeat counters can be used to get more control of the operation of the timer, including defining

the number of times the counter should wrap around. Four different repeat modes are available, see

Table 23.1 (p. 586) .

Table 23.1. LETIMER Repeat Modes

REPMODE Mode Description

00 Free The timer runs until it is stopped

01 One-shot The timer runs as long as

LETIMERn_REP0 != 0.

LETIMERn_REP0 is decremented at

each timer underflow.

10 Buffered The timer runs as long as

LETIMERn_REP0 != 0.

LETIMERn_REP0 is decremented

on each timer underflow. If

LETIMERn_REP1 has been written,

it is loaded into LETIMERn_REP0

when LETIMERn_REP0 is about to be

decremented to 0.

11 Double The timer runs as long as

LETIMERn_REP0 != 0 or

LETIMERn_REP1 != 0.

Both LETIMERn_REP0 and

LETIMERn_REP1 are decremented at

each timer underflow.

The interrupt flags REP0 and REP1 in LETIMERn_IF are set whenever LETIMERn_REP0 or

LETIMERn_REP1 are decremented to 0 respectively. REP0 is also set when the value of

LETIMERn_REP1 is loaded into LETIMERn_REP0 in buffered mode.

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23.3.3.2.1 Free Mode

In the free running mode, the LETIMER acts as a regular timer, and the repeat counter is disabled.

When started, the timer runs until it is stopped using the STOP command bit in LETIMERn_CMD. A

state machine for this mode is shown in Figure 23.2 (p. 587) .

Figure 23.2. LETIMER State Machine for Free-running Mode

(RUNNING or START)

and !STOP

YES

CNT == 0 CNT = CNT - 1

YES CNT = TOP*

If (STOP)

RUNNING = 0

Else if (START)

RUNNING = 1

End if

START = 0

STOP = 0

Wait for positive clock edge

If (COMP0TOP)

TOP* = COMP0

Else

TOP* = 0xFFFF

TOP*

Note that the CLEAR command bit in LETIMERn_CMD always has priority over other changes to

LETIMERn_CNT. When the clear command is used, LETIMERn_CNT is set to 0 and an underflow

event will not be generated when LETIMERn_CNT wraps around to the top value or 0xFFFF. Since

no underflow event is generated, no output action is performed. LETIMERn_REP0, LETIMERn_REP1,

LETIMERn_COMP0 and LETIMERn_COMP1 are also left untouched.

23.3.3.2.2 One-shot Mode

The one-shot repeat mode is the most basic repeat mode. In this mode, the repeat register

LETIMERn_REP0 is decremented every time the timer underflows, and the timer stops when

LETIMERn_REP0 goes from 1 to 0. In this mode, the timer counts down LETIMERn_REP0 times, i.e.

the timer underflows LETIMERn_REP0 times.

Note Note that write operations to LETIMERn_REP0 have priority over the decrementation

operation. So if LETIMERn_REP0 is assigned a new value in the same cycle it was

supposed to be decremented, it is assigned the new value instead of being decremented.

LETIMERn_REP0 can be written while the timer is running to allow the timer to run for longer periods

at a time without stopping. Figure 23.3 (p. 588) .

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Figure 23.3. LETIMER One-shot Repeat State Machine

RUNNING

YES

CNT == 0 CNT = CNT - 1

REP0 < 2

YES

STOP = 1

REP0 = 0

CNT = TOP*

If (!START)

REP0 = REP0 - 1

If (STOP)

RUNNING = 0

Else if (START)

RUNNING = 1

End if

START = 0

STOP = 0

Wait for positive clock edge

YES

If (!COMP0TOP)

TOP** = 0xFFFF

Else if (COMPBUF)

TOP** = COMP1

Else

TOP** = COMP0

If (COMP0TOP)

TOP* = COMP0

Else

TOP* = 0xFFFF

TOP* TOP**

START

YES

CNT == 0

REP0 == 0

YES

CNT = CNT - 1

CNT = TOP*

YES

23.3.3.2.3 Buffered Mode

The Buffered repeat mode allows buffered timer operation. When started, the timer runs

LETIMERn_REP0 number of times. If LETIMERn_REP1 has been written since the last time it was used

and it is nonzero, LETIMERn_REP1 is then loaded into LETIMERn_REP0, and counting continues the

new number of times. The timer keeps going as long as LETIMERn_REP1 is updated with a nonzero

value before LETIMERn_REP0 is finished counting down.

If the timer is started when both LETIMERn_CNT and LETIMERn_REP0 are zero but LETIMERn_REP1

is non-zero, LETIMERn_REP1 is loaded into LETIMERn_REP0, and the counter counts the loaded

number of times. The state machine for the one-shot repeat mode is shown in Figure 23.3 (p. 588) .

Used in conjunction with a buffered top value, enabled by setting BUFTOP in LETIMERn_CTRL, the

buffered mode allows buffered values of both the top and repeat values of the timer, and the timer can

for instance be set to run 4 times with period 7 (top value 6), 6 times with period 200, then 3 times with

period 50.

A state machine for the buffered repeat mode is shown in Figure 23.4 (p. 589) . REP1USED shown in the

state machine is an internal variable that keeps track of whether the value in LETIMERn_REP1 has been

loaded into LETIMERn_REP0 or not. The purpose of this is that a value written to LETIMERn_REP1

should only be counted once. REP1USED is cleared whenever LETIMERn_REP1 is written.

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Figure 23.4. LETIMER Buffered Repeat State Machine

RUNNING

YES

CNT == 0 CNT = CNT - 1

REP0 < 2

YES

!REP1USED and !REP1 != 0

CNT = TOP*

If (BUFTOP)

COMP0 = COMP1

REP0 = REP1

REP1USED = 1

YES

STOP = 1

REP0 = 0

CNT = TOP*

If (!START)

REP0 = REP0 - 1

If (STOP)

RUNNING = 0

Else if (START)

RUNNING = 1

End if

START = 0

STOP = 0

Wait for positive clock edge

YES

If (!COMP0TOP)

TOP** = 0xFFFF

Else if (BUFTOP)

TOP** = COMP1

Else

TOP** = COMP0

If (COMP0TOP)

TOP* = COMP0

Else

TOP* = 0xFFFF

TOP* TOP**

START

YES

CNT == 0

REP0 == 0

YES

CNT = CNT - 1

CNT = TOP**

If (BUFTOP)

COMP0 = COMP1

REP0 = REP1

REP1USED = 1

CNT = TOP*

YES

REP1 == 0

YES

23.3.3.2.4 Double Mode

The Double repeat mode works much like the one-shot repeat mode. The difference is that, where the

one-shot mode counts as long as LETIMERn_REP0 is larger than 0, the double mode counts as long as

either LETIMERn_REP0 or LETIMERn_REP1 is larger than 0. As an example, say LETIMERn_REP0

is 3 and LETIMERn_REP1 is 10 when the timer is started. If no further interaction is done with the

timer, LETIMERn_REP0 will now be decremented 3 times, and LETIMERn_REP1 will be decremented

10 times. The timer counts a total of 10 times, and LETIMERn_REP0 is 0 after the first three timer

underflows and stays at 0. LETIMERn_REP0 and LETIMERn_REP1 can be written at any time. After a

write to either of these, the timer is guaranteed to underflow at least the written number of times if the

timer is running. Use the Double repeat mode to generate output on both the LETIMER outputs at the

same time. The state machine for this repeat mode can be seen in Figure 23.5 (p. 590) .

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Figure 23.5. LETIMER Double Repeat State Machine

RUNNING

YES

CNT == 0 CNT = CNT - 1

REP0 < 2

And

REP1 < 2

YES

STOP = 1

REP0 = 0

CNT = TOP*

If (REP0 > 0)

REP0 = REP0 - 1

If (REP1 > 0)

REP1 = REP1 - 1

If (STOP)

RUNNING = 0

Else if (START)

RUNNING = 1

End if

START = 0

STOP = 0

Wait for positive clock edge

YES

If (COMP0TOP)

TOP* = COMP0

Else

TOP* = 0xFFFF

TOP*

START

YES

CNT == 0

REP0 == 0

and

REP1 == 0

YES

CNT = CNT - 1

CNT = TOP*

YES

23.3.3.3 Clock Source

The LETIMER clock source and its prescaler value are defined in the Clock Management Unit (CMU).

The LFACLKLETIMERn has a frequency given by Equation 23.1 (p. 590) .

LETIMER Clock Frequency

fLFACKL_LETIMERn = 32.768/2LETIMERn (23.1)

where the exponent LETIMERn is a 4 bit value in the CMU_LFAPRESC0 register.

To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0, in addition to

the module clock.

23.3.3.4 RTC Trigger

The LETIMER can be configured to start on compare match events from the Real Time Counter (RTC).

If RTCC0TEN in LETIMERn_CTRL is set, the LETIMER will start on a compare match on RTC compare

channel 0. In the same way, RTCC1TEN in LETIMERn_CTRL enables the LETIMER to start on a

compare match with RTC compare channel 1.

Note The LETIMER can only use compare match events from the RTC if the LETIMER runs

at a higher than or equal frequency than the RTC. Also, if the LETIMER runs at twice the

frequency of the RTC, a compare match event in the RTC will trigger the LETIMER twice.

Four times the frequency gives four consecutive triggers, etc. The LETIMER will only

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continue running if triggered while it is running, so the multiple-triggering will only have an

effect if you try to disable the RTC when it is being triggered.

23.3.3.5 Debug

If DEBUGRUN in LETIMERn_CTRL is cleared, the LETIMER automatically stops counting when the

CPU is halted during a debug session, and resumes operation when the CPU continues. Because of

synchronization, the LETIMER is halted two clock cycles after the CPU is halted, and continues running

two clock cycles after the CPU continues. RUNNING in LETIMERn_STATUS is not cleared when the

LETIMER stops because of a debug-session.

Set DEBUGRUN in LETIMERn_CTRL to allow the LETIMER to continue counting even when the CPU

is halted in debug mode.

23.3.4 Underflow Output Action

For each of the repeat registers, an underflow output action can be set. The configured output action is

performed every time the counter underflows while the respective repeat register is nonzero. In PWM

mode, the output is similarly only changed on COMP1 match if the repeat register is nonzero. As an

example, the timer will perform 7 output actions if LETIMERn_REP0 is set to 7 when starting the timer

in one-shot mode and leaving it untouched for a while.

The output actions can be set by configuring UFOA0 and UFOA1 in LETIMERn_CTRL. UFOA0 defines

the action on output 0, and is connected to LETIMERn_REP0, while UFOA1 defines the action on output

1 and is connected to LETIMERn_REP1. The possible actions are defined in Table 23.2 (p. 591) .

Table 23.2. LETIMER Underflow Output Actions

UF0A0/UF0A1 Mode Description

00 Idle The output is held at its idle value

01 Toggle The output is toggled on

LETIMERn_CNT underflow if

LEIMERn_REPx is nonzero

10 Pulse The output is held active for one clock

cycle on LETIMERn_CNT underflow if

LETIMERn_REPx is nonzero. It then

returns to its idle value

11 PWM The output is set idle on

LETIMERn_CNT underflow

and active on compare match

with LETIMERn_COMP1 if

LETIMERn_REPx is nonzero.

Note For the Pulse and PWM modes, the outputs will return to their idle states regardless of the

state of the corresponding LETIMERn_REPx registers. They will only be set active if the

LETIMERn_REPx registers are nonzero however.

The polarity of the outputs can be set individually by configuring OPOL0 and OPOL1 in

LETIMERn_CTRL. When these are cleared, their respective outputs have a low idle value and a high

active value. When they are set, the idle value is high, and the active value is low.

When using the toggle action, the outputs can be driven to their idle values by setting their respective

CTO0/CTO1 command bits in LETIMERn_CTRL. This can be used to put the output in a well-defined

state before beginning to generate toggle output, which may be important in some applications. The

command bit can also be used while the timer is running.

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Some simple waveforms generated with the different output modes are shown in Figure 23.6 (p.

592) . For the example, REPMODE in LETIMERn_CTRL has been cleared, COMP0TOP also in

LETIMERn_CTRL has been set and LETIMERn_COMP0 has been written to 3. As seen in the figure,

LETIMERn_COMP0 now decides the length of the signal periods. For the toggle mode, the period of the

output signal is 2(LETIMERn_COMP0 + 1), and for the pulse modes, the periods of the output signals

are LETIMERn_COMP0+1. Note that the pulse outputs are delayed by one period relative to the toggle

output. The pulses come at the end of their periods.

Figure 23.6. LETIMER Simple Waveforms Output

CNT

COMP0 3

Initial configuration

UFIFUFIF UFIF UFIF UFIF

Int. flags set

LFACLKLETIMERn

LETn_O0

UFOA0 = 01

LETn_O0

UFOA0 = 10

LETn_O0

UFOA0 = 00

UFIF

For the example in Figure 23.7 (p. 592) , the One-shot repeat mode has been selected, and

LETIMERn_REP0 has been written to 3. The resulting behavior is pretty similar to that shown in

Figure 6, but in this case, the timer stops after counting to zero LETIMERn_REP0 times. By using

LETIMERn_REP0 the user has full control of the number of pulses/toggles generated on the output.

Figure 23.7. LETIMER Repeated Counting

CNT

COMP0 3

Initial configuration

UFIFUFIF UFIF

Int. flags set

LFACLKLETIMERn

LETn_O0

UFOA0 = 01

LETn_O0

UFOA0 = 10

LETn_O0

UFOA0 = 00

REP0 33 3 3 22 2 2 11 1 1

Stop

REP0IF

Using the Double repeat mode, output can be generated on both the LETIMER outputs. Figure 23.8 (p.

593) shows an example of this. UFOA0 and UFOA1 in LETIMERn_CTRL are configured for pulse

output and the outputs are configured for low idle polarity. As seen in the figure, the number written to

the repeat registers determine the number of pulses generated on each of the outputs.

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Figure 23.8. LETIMER Dual Output

LETn_O0

LETn_O1

UFOA0 = 10

UFOA1 = 10

REP0 = 2

REP1 = 7

START REP0 = 3

START

REP0 = 2

REP1 = 3

START

23.3.5 PRS Output

The LETIMER outputs can be routed out onto the PRS system. LETn_O0 can be routed to PRS channel

0, and LETn_1O can be routed to PRS channel 1. Enabling the RRS connection can be done by setting

SOURCESEL to LETIMERx and SIGSEL to LETIMERxCHn in PRS_CHx_CTRL. The PRS register

description can be found in Section 13.5 (p. 167)

23.3.6 Examples

This section presents a couple of usage examples for the LETIMER.

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23.3.6.1 Triggered Output Generation

Example 23.1. LETIMER Triggered Output Generation

If both LETIMERn_CNT and LETIMERn_REP0 are 0 in buffered mode, and COMP0TOP and BUFTOP

in LETIMERn_CTRL are set, the values of LETIMERn_COMP1 and LETIMERn_REP1 are loaded into

LETIMERn_CNT and LETIMERn_REP0 respectively when the timer is started. If no additional writes to

LETIMERn_REP1 are done before the timer stops, LETIMERn_REP1 determines the number of pulses/

toggles generated on the output, and LETIMERn_COMP1 determines the period lengths.

As the RTC can be used to start the LETIMER, the RTC and LETIMER can thus be combined to generate

specific pulse-trains at given intervals. Software can update LETIMERn_COMP1 and LETIMERn_REP1

to change the number of pulses and pulse-period in each train, but if changes are not required, software

does not have to update the registers between each pulse train.

For the example in Figure 23.9 (p. 594) , the initial values cause the LETIMER to generate two pulses

with 3 cycle periods, or a single pulse 3 cycles wide every time the LETIMER is started. After the output

has been generated, the LETIMER stops, and is ready to be triggered again.

Figure 23.9. LETIMER Triggered Operation

CNT

TOP0

TOP1

REP0

REP1

Initial configuration,

REP1 just written

UFIF

REP0IF

UFIF UFIF UFIF

REP0IF

Int. flags set

LFACLKLETIMERn

2u2u2u

Stop

Write

START=1

Stop

UFIF

Write

START=1

LETn_O0

UFOA0 = 01

LETn_O1

UFOA0 = 10

2u2u2u2u2u2u2u2u2u2u2u2u

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23.3.6.2 Continuous Output Generation

Example 23.2. LETIMER Continuous Output Generation

In some scenarios, it might be desired to make LETIMER generate a continuous waveform. Very simple

constant waveforms can be generated without the repeat counter as shown in Figure 23.6 (p. 592) , but

to generate changing waveforms, using the repeat counter and buffer registers can prove advantageous.

For the example in Figure 23.10 (p. 595) , the goal is to produce a pulse train consisting of 3 sequences

with the following properties:

• 3 pulses with periods of 3 cycles

• 4 pulses with periods of 2 cycles

• 2 pulses with periods of 3 cycles

Figure 23.10. LETIMER Continuous Operation

CNT

COMP0

COMP1

REP0

REP1

Initial configuration,

REPB just written

UFIF

REP0IF

UFIF UFIF UFIF UFIF

Int. flags set

Stop,

final values

Write

COMP1 = 2

REP1 = 2

UFIF UFIF UFIF

REP0IF

44 4 4 4u4u4u22 2u2u2u2u

2u2u

REP0IF

LFACLKLETIMERn

LETn_O0

UFOA0 = 01

LETn_O1

UFOA0 = 10

Pulse Seq. 1 Pulse Seq. 2 Pulse Seq. 3

4 4 4 4 4 4 2 2 2

The first two sequences are loaded into the LETIMER before the timer is started.

LETIMERn_COMP0 is set to 2 (cycles – 1), and LETIMERn_REP0 is set to 3 for the first sequence, and

the second sequence is loaded into the buffer registers, i.e. COMP1 is set to 1 and LETIMERn_REP1

is set to 4.

The LETIMER is set to trigger an interrupt when LETIMERn_REP0 is done by setting REP0 in

LETIMERn_IEN. This interrupt is a good place to update the values of the buffers. Last but not least

REPMODE in LETIMERn_CTRL is set to buffered mode, and the timer is started.

In the interrupt routine the buffers are updated with the values for the third sequence. If this had not been

done, the timer would have stopped after the second sequence.

The final result is shown in Figure 23.10 (p. 595) . The pulse output is grouped to show which sequence

generated which output. Toggle output is also shown in the figure. Note that the toggle output is not

aligned with the pulse outputs.

Note

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Multiple LETIMER cycles are required to write a value to the LETIMER registers. The

example in Figure 23.10 (p. 595) assumes that writes are done in advance so they arrive

in the LETIMER as described in the figure.

Figure 23.11 (p. 596) shows an example where the LETIMER is started while LETIMERn_CNT is

nonzero. In this case the length of the first repetition is given by the value in LETIMERn_CNT.

Figure 23.11. LETIMER LETIMERn_CNT Not Initialized to 0

CNT

TOP0

TOP1

REP0

REP1

Initial configuration,

REP1 just written

UFIF

REP0IF

UFIF UFIF UFIF UFIF UFIF

REP0IF

Int. flags set

Stop,

final values

LFACLKLETIMERn

LETn_O0

UFOA0 = 01

LETn_O1

UFOA0 = 10

3 3 3 3 3 3 3 3u3u3u3u3u3u3u

3 3 3 3u3u3u

23.3.6.3 PWM Output

Example 23.3. LETIMER PWM Output

There are several ways of generating PWM output with the LETIMER, but the most straight-forward way

is using the PWM output mode. This mode is enabled by setting UFOA0 or OFUA1 in LETIMERn_CTRL

to 3. In PWM mode, the output is set idle on timer underflow, and active on LETIMERn_COMP1 match,

so if for instance COMP0TOP = 1 and OPOL0 = 0 in LETIMERn_CTRL, LETIMERn_COMP0 determines

the PWM period, and LETIMERn_LETIMERn_COMP1 determines the active period.

The PWM period in PWM mode is LETIMERn_COMP0 + 1. There is no special handling of the case

where LETIMERn_COMP1 > LETIMERn_COMP0, so if LETIMERn_COMP1 > LETIMERn_COMP0, the

PWM output is given by the idle output value. This means that for OPOLx = 0 in LETIMERn_CTRL, the

PWM output will always be 0 for at least one clock cycle, and for OPOLx = 1 LETIMERn_CTRL, the

PWM output will always be 1 for at least one clock cycle.

To generate a PWM signal using the full PWM range, invert OPOLx when LETIMERn_COMP1 is set

to a value larger than LETIMERn_COMP0.

23.3.6.4 Interrupts

Example 23.4. LETIMER PWM Output

The interrupts generated by the LETIMER are combined into one interrupt vector. If the interrupt for the

LETIMER is enabled, an interrupt will be made if one or more of the interrupt flags in LETIMERn_IF and

their corresponding bits in LETIMER_IEN are set.

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23.3.7 Using the LETIMER in EM3

The LETIMER can be enabled all the way down to EM3 by using the ULFRCO as clock source. This is

done by clearing CMU_LFCLKSEL_LFA and setting CMU_LFCLKSEL_LFAE to 1. This will make the

RTC use the internal 1 kHz ultra low frequency RC oscillator (ULFRCO), consuming very little energy.

Please note that the ULFRCO is not accurate over temperature and voltage, and it should be verified

that the ULFRCO fulfills the timekeeping needs of the application before using this in the design.

23.3.8 Register access

This module is a Low Energy Peripheral, and supports immediate synchronization. For description

regarding immediate synchronization, the reader is referred to Section 5.3.1.1 (p. 20) .

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23.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 LETIMERn_CTRL RW Control Register

0x004 LETIMERn_CMD W1 Command Register

0x008 LETIMERn_STATUS R Status Register

0x00C LETIMERn_CNT RWH Counter Value Register

0x010 LETIMERn_COMP0 RW Compare Value Register 0

0x014 LETIMERn_COMP1 RW Compare Value Register 1

0x018 LETIMERn_REP0 RW Repeat Counter Register 0

0x01C LETIMERn_REP1 RW Repeat Counter Register 1

0x020 LETIMERn_IF R Interrupt Flag Register

0x024 LETIMERn_IFS W1 Interrupt Flag Set Register

0x028 LETIMERn_IFC W1 Interrupt Flag Clear Register

0x02C LETIMERn_IEN RW Interrupt Enable Register

0x030 LETIMERn_FREEZE RW Freeze Register

0x034 LETIMERn_SYNCBUSY R Synchronization Busy Register

0x040 LETIMERn_ROUTE RW I/O Routing Register

23.5 Register Description

23.5.1 LETIMERn_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x000

Reset

0x0

Access

Name

DEBUGRUN

RTCC1TEN

RTCC0TEN

COMP0TOP

BUFTOP

OPOL1

OPOL0

UFOA1

UFOA0

REPMODE

Bit Name Reset Access Description

31:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 DEBUGRUN 0 RW Debug Mode Run Enable

Set to keep the LETIMER running in debug mode.

Value Description

0 LETIMER is frozen in debug mode

1 LETIMER is running in debug mode

11 RTCC1TEN 0 RW RTC Compare 1 Trigger Enable

Allows the LETIMER to be started on a compare match on RTC compare channel 1.

Value Description

0 LETIMER is not affected by RTC compare channel 1

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Bit Name Reset Access Description

Value Description

1 A compare match on RTC compare channel 1 starts the LETIMER if the LETIMER is not already started

10 RTCC0TEN 0 RW RTC Compare 0 Trigger Enable

Allows the LETIMER to be started on a compare match on RTC compare channel 0.

Value Description

0 LETIMER is not affected by RTC compare channel 0

1 A compare match on RTC compare channel 0 starts the LETIMER if the LETIMER is not already started

9 COMP0TOP 0 RW Compare Value 0 Is Top Value

When set, the counter is cleared in the clock cycle after a compare match with compare channel 0.

Value Description

0 The top value of the LETIMER is 65535 (0xFFFF)

1 The top value of the LETIMER is given by COMP0

8 BUFTOP 0 RW Buffered Top

Set to load COMP1 into COMP0 when REP0 reaches 0, allowing a buffered top value

Value Description

0 COMP0 is only written by software

1 COMP0 is set to COMP1 when REP0 reaches 0

7 OPOL1 0 RW Output 1 Polarity

Defines the idle value of output 1.

6 OPOL0 0 RW Output 0 Polarity

Defines the idle value of output 0.

5:4 UFOA1 0x0 RW Underflow Output Action 1

Defines the action on LETn_O1 on a LETIMER underflow.

Value Mode Description

0 NONE LETn_O1 is held at its idle value as defined by OPOL1.

1 TOGGLE LETn_O1 is toggled on CNT underflow.

2 PULSE LETn_O1 is held active for one LFACLKLETIMER0 clock cycle on CNT underflow. The

output then returns to its idle value as defined by OPOL1.

3 PWM LETn_O1 is set idle on CNT underflow, and active on compare match with COMP1

3:2 UFOA0 0x0 RW Underflow Output Action 0

Defines the action on LETn_O0 on a LETIMER underflow.

Value Mode Description

0 NONE LETn_O0 is held at its idle value as defined by OPOL0.

1 TOGGLE LETn_O0 is toggled on CNT underflow.

2 PULSE LETn_O0 is held active for one LFACLKLETIMER0 clock cycle on CNT underflow. The

output then returns to its idle value as defined by OPOL0.

3 PWM LETn_O0 is set idle on CNT underflow, and active on compare match with COMP1

1:0 REPMODE 0x0 RW Repeat Mode

Allows the repeat counter to be enabled and disabled.

Value Mode Description

0 FREE When started, the LETIMER counts down until it is stopped by software.

1 ONESHOT The counter counts REP0 times. When REP0 reaches zero, the counter stops.

2 BUFFERED The counter counts REP0 times. If REP1 has been written, it is loaded into REP0 when

REP0 reaches zero. Else the counter stops

3 DOUBLE Both REP0 and REP1 are decremented when the LETIMER wraps around. The

LETIMER counts until both REP0 and REP1 are zero

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23.5.2 LETIMERn_CMD - Command Register

Offset Bit Position

0x004

Reset

Access

Name

CTO1

CTO0

CLEAR

STOP

START

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 CTO1 0 W1 Clear Toggle Output 1

Set to drive toggle output 1 to its idle value

3 CTO0 0 W1 Clear Toggle Output 0

Set to drive toggle output 0 to its idle value

2 CLEAR 0 W1 Clear LETIMER

Set to clear LETIMER

1 STOP 0 W1 Stop LETIMER

Set to stop LETIMER

0 START 0 W1 Start LETIMER

Set to start LETIMER

23.5.3 LETIMERn_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

RUNNING

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 RUNNING 0 R LETIMER Running

Set when LETIMER is running.

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23.5.4 LETIMERn_CNT - Counter Value Register

Offset Bit Position

0x00C

Reset

0x0000

Access

RWH

Name

CNT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CNT 0x0000 RWH Counter Value

Use to read the current value of the LETIMER.

23.5.5 LETIMERn_COMP0 - Compare Value Register 0 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x010

Reset

0x0000

Access

Name

COMP0

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 COMP0 0x0000 RW Compare Value 0

Compare and optionally top value for LETIMER

23.5.6 LETIMERn_COMP1 - Compare Value Register 1 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x014

Reset

0x0000

Access

Name

COMP1

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 COMP1 0x0000 RW Compare Value 1

Compare and optionally buffered top value for LETIMER

23.5.7 LETIMERn_REP0 - Repeat Counter Register 0 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x018

Reset

0x00

Access

Name

REP0

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 REP0 0x00 RW Repeat Counter 0

Optional repeat counter.

23.5.8 LETIMERn_REP1 - Repeat Counter Register 1 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x01C

Reset

0x00

Access

Name

REP1

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

7:0 REP1 0x00 RW Repeat Counter 1

Optional repeat counter or buffer for REP0

23.5.9 LETIMERn_IF - Interrupt Flag Register

Offset Bit Position

0x020

Reset

Access

Name

REP1

REP0

COMP1

COMP0

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 REP1 0 R Repeat Counter 1 Interrupt Flag

Set when repeat counter 1 reaches zero.

3 REP0 0 R Repeat Counter 0 Interrupt Flag

Set when repeat counter 0 reaches zero or when the REP1 interrupt flag is loaded into the REP0 interrupt flag.

2 UF 0 R Underflow Interrupt Flag

Set on LETIMER underflow.

1 COMP1 0 R Compare Match 1 Interrupt Flag

Set when LETIMER reaches the value of COMP1

0 COMP0 0 R Compare Match 0 Interrupt Flag

Set when LETIMER reaches the value of COMP0

23.5.10 LETIMERn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x024

Reset

Access

Name

REP1

REP0

COMP1

COMP0

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 REP1 0 W1 Set Repeat Counter 1 Interrupt Flag

Write to 1 to set the REP1 interrupt flag.

3 REP0 0 W1 Set Repeat Counter 0 Interrupt Flag

Write to 1 to set the REP0 interrupt flag.

2 UF 0 W1 Set Underflow Interrupt Flag

Write to 1 to set the UF interrupt flag.

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Bit Name Reset Access Description

1 COMP1 0 W1 Set Compare Match 1 Interrupt Flag

Write to 1 to set the COMP1 interrupt flag.

0 COMP0 0 W1 Set Compare Match 0 Interrupt Flag

Write to 1 to set the COMP0 interrupt flag.

23.5.11 LETIMERn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x028

Reset

Access

Name

REP1

REP0

COMP1

COMP0

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 REP1 0 W1 Clear Repeat Counter 1 Interrupt Flag

Write to 1 to clear the REP1 interrupt flag.

3 REP0 0 W1 Clear Repeat Counter 0 Interrupt Flag

Write to 1 to clear the REP0 interrupt flag.

2 UF 0 W1 Clear Underflow Interrupt Flag

Write to 1 to clear the UF interrupt flag.

1 COMP1 0 W1 Clear Compare Match 1 Interrupt Flag

Write to 1 to clear the COMP1 interrupt flag.

0 COMP0 0 W1 Clear Compare Match 0 Interrupt Flag

Write to 1 to clear the COMP0 interrupt flag.

23.5.12 LETIMERn_IEN - Interrupt Enable Register

Offset Bit Position

0x02C

Reset

Access

Name

REP1

REP0

COMP1

COMP0

Bit Name Reset Access Description

31:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 REP1 0 RW Repeat Counter 1 Interrupt Enable

Set to enable interrupt on the REP1 interrupt flag.

3 REP0 0 RW Repeat Counter 0 Interrupt Enable

Set to enable interrupt on the REP0 interrupt flag.

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Bit Name Reset Access Description

2 UF 0 RW Underflow Interrupt Enable

Set to enable interrupt on the UF interrupt flag.

1 COMP1 0 RW Compare Match 1 Interrupt Enable

Set to enable interrupt on the COMP1 interrupt flag.

0 COMP0 0 RW Compare Match 0 Interrupt Enable

Set to enable interrupt on the COMP0 interrupt flag.

23.5.13 LETIMERn_FREEZE - Freeze Register

Offset Bit Position

0x030

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

With the immediate write synchronization scheme the REGFREEZE register is no longer used.

Value Mode Description

0 UPDATE Each write access to a LETIMER register is updated into the Low Frequency domain

as soon as possible.

1 FREEZE The LETIMER is not updated with the new written value.

23.5.14 LETIMERn_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x034

Reset

Access

Name

REP1

REP0

COMP1

COMP0

CMD

CTRL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 REP1 0 R REP1 Register Busy

Set when the value written to REP1 is being synchronized.

4 REP0 0 R REP0 Register Busy

Set when the value written to REP0 is being synchronized.

3 COMP1 0 R COMP1 Register Busy

Set when the value written to COMP1 is being synchronized.

2 COMP0 0 R COMP0 Register Busy

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Bit Name Reset Access Description

Set when the value written to COMP0 is being synchronized.

1 CMD 0 R CMD Register Busy

Set when the value written to CMD is being synchronized.

0 CTRL 0 R CTRL Register Busy

Set when the value written to CTRL is being synchronized.

23.5.15 LETIMERn_ROUTE - I/O Routing Register

Offset Bit Position

0x040

Reset

0x0

Access

Name

LOCATION

OUT1PEN

OUT0PEN

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 LOCATION 0x0 RW I/O Location

Decides the location of the LETIMER I/O pins

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 OUT1PEN 0 RW Output 1 Pin Enable

When set, output 1 of the LETIMER is enabled

Value Description

0 The LETn_O1 pin is disabled

1 The LETn_O1 pin is enabled

0 OUT0PEN 0 RW Output 0 Pin Enable

When set, output 0 of the LETIMER is enabled

Value Description

0 The LETn_O0 pin is disabled

1 The LETn_O0 pin is enabled

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24 PCNT - Pulse Counter

01 2 3 4

Reload value

Interrupt

Quadrature code

Quick Facts

What?

The Pulse Counter (PCNT) decodes

incoming pulses. The module has a

quadrature mode which may be used

to decode the speed and direction of a

mechanical shaft. PCNT can operate in EM0-

EM3.

Why?

The PCNT generates an interrupt after a

specific number of pulses (or rotations),

eliminating the need for timing- or I/O

interrupts and CPU processing to measure

pulse widths, etc.

How?

PCNT uses the LFACLK or may be externally

clocked from a pin. The module incorporates

an 8/16-bit up/down-counter to keep track of

incoming pulses or rotations.

24.1 Introduction

The Pulse Counter (PCNT) can be used for counting incoming pulses on a single input or to decode

quadrature encoded inputs. It can run from the internal LFACLK (EM0-EM2) while counting pulses on

the PCNTn_S0IN pin or using this pin as an external clock source (EM0-EM3) that runs both the PCNT

counter and register access.

24.2 Features

• 16/8-bit counter with reload register

• Auxiliary counter for counting a single direction

• Single input oversampling up/down counter mode (EM0-EM2)

• Externally clocked single input pulse up/down counter mode (EM0-EM3)

• Externally clocked quadrature decoder mode (EM0-EM3)

• Interrupt on counter underflow and overflow

• Interrupt when a direction change is detected (quadrature decoder mode only)

• Optional pulse width filter

• Optional input inversion/edge detect select

• PRS S0IN and S1IN input

24.3 Functional Description

An overview of the PCNT module is shown in Figure 24.1 (p. 608) .

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Figure 24.1. PCNT Overview

Peripheral bus

CNT

PCNTn_S0IN

Pulse Width

Filter

Inverter

PCNTn_S1IN

Inverter

Count

Enable

LFACLK

Clock

switch

CMU (conseptual)

TOPB

Quadrature

decoder

Edge

detector

OVR_SINGLE

EXTCLK_SINGLE

EXTCLK_QUAD

TOP

S0PRS Input

Analog de-glitch filter

S1PRS Input

CLKPCNT

24.3.1 Pulse Counter Modes

The pulse counter can operate in single input oversampling mode (OVSSINGLE), externally clocked

single input counter mode (EXTCLKSINGLE) and externally clocked quadrature decoder mode

(EXTCLKQUAD). The following sections describe operation of each of the three modes and how they

are enabled. Input timing constraints are described in Section 24.3.5 (p. 611) and Section 24.3.6 (p.

611) .

24.3.1.1 Single Input Oversampling Mode

This mode is enabled by writing OVSSINGLE to the MODE field in the PCNTn_CTRL register and

disabled by writing DISABLE to the same field. LFACLK is configured from the registers in the Clock

Management Unit (CMU), Chapter 11 (p. 124) .

The optional pulse width filter is enabled by setting the FILT bit in the PCNTn_CTRL register. Additionally,

the PCNTn_S0IN input may be inverted, so that falling edges are counted, by setting the EDGE bit in

the PCNTn_CTRL register.

If S1CDIR is cleared, PCNTn_S0IN is the only observed input in this mode. The PCNTn_S0IN input

is sampled by the LFACLK and the number of detected positive or negative edges on PCNTn_S0IN

appears in PCNTn_CNT. The counter may be configured to count down by setting the CNTDIR bit in

PCNTn_CTRL. Default is to count up.

The counting direction can also be controlled externally in this mode by setting S1CDIR in PCNTn_CTRL.

This will make the input value on PCNTn_S1IN decide the direction counted on a PCNTn_S0IN edge.

If PCNTn_S1IN is high, the count is done according to CNTDIR in PCNTn_CTRL. If low, the count

direction is opposite.

24.3.1.2 Externally Clocked Single Input Counter Mode

This mode is enabled by writing EXTCLKSINGLE to the MODE field in the PCNTn_CTRL register and

disabled by writing DISABLE to the same field. The external pin clock source must be configured from

the registers in the CMU (Chapter 11 (p. 124) ).

Positive edges on PCNTn_S0IN are used to clock the counter. Similar to the oversampled mode,

PCNTn_S1IN is used to determine the count direction if S1CDIR in PCNTn_CTRL is set. If not, CNTDIR

in PCNTn_CTRL solely defines count direction. As the LFACLK is not used in this mode, the PCNT

module can operate in EM3.

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The digital pulse width filter is not available in this mode. The analog de-glitch filter in the GPIO pads

is capable of removing some unwanted noise. However, this mode may be susceptible to spikes and

unintended pulses from devices such as mechanical switches, and is therefore most suited to take input

from electronic sensors etc. that generate single wire pulses.

24.3.1.3 Externally Clocked Quadrature Decoder Mode

This mode is enabled by writing EXTCLKQUAD to the MODE field in PCNTn_CTRL and disabled by

writing DISABLE to the same field. The external pin clock source must be configured from the registers

in the CMU, (Chapter 11 (p. 124) ).

Both edges on PCNTn_S0IN pin are used to sample PCNTn_S1IN pin to decode the quadrature code.

Consequently, this mode does not depend on the internal LFACLK and may be operated in EM3. A

quadrature coded signal contains information about the relative speed and direction of a rotating shaft

as illustrated by Figure 24.2 (p. 609) , hence the direction of the counter register PCNTn_CNT is

controlled automatically.

Figure 24.2. PCNT Quadrature Coding

X X

1 cycle/sector, 4 states

01 11 10

X X

1 cycle/sector, 4 states

00 10 11 01

X = sensor position

Clockwise direction

Counter clockwise

direction

PCNTn_S0IN

PCNTn_S1IN

PCNTn_S0IN

PCNTn_S1IN

PCNTn_CNT

Reset

0 0 12

PCNTn_CNT 0 0 PCNTn_TOP PCNTn_TOP-1

If PCNTn_S0IN leads PCNTn_S1IN in phase, the direction is clockwise, and if it lags in phase the

direction is counter-clockwise. Although the direction is automatically detected, the detected direction

may be inverted by writing 1 to the EDGE bit in the PCNTn_CTRL register. Default behavior is illustrated

by Figure 24.2 (p. 609) .

The counter direction may be read from the DIR bit in the PCNTn_STATUS register. Additionally, the

DIRCNG interrupt in the PCNTn_IF register is generated when a direction change is detected. When a

change is detected, the DIR bit in the PCNTn_STATUS register must be read to determine the current

new direction.

Note The sector disc illustrated in the figure may be finer grained in some systems. Typically,

they may generate 2-4 PCNTn_S0IN wave periods per 360° rotation.

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The direction of the quadrature code and control of the counter is generated by the simple binary function

outlined by Table 24.1 (p. 610) . Note that this function also filters some invalid inputs that may occur

when the shaft changes direction or temporarily toggles direction.

Table 24.1. PCNT QUAD Mode Counter Control Function

Inputs Control/Status

S1IN posedge S1IN negedge Count Enable CNTDIR status bit

0 0 0 0

0 1 1 0

1 0 1 1

1 1 0 0

Note PCNTn_S1IN is sampled on both edges of PCNTn_S0IN.

24.3.2 Hysteresis

By default the pulse counter wraps to 0 when passing the configured top value, and wraps to the top

value when counting down from 0. On these events, a system will likely want to wake up to store and

track the overflow count. This is fine if the pulse counter is tracking a monotonic value or a value that

does not change directions frequently. If you have the latter however, and the counter changes directions

around the overflow/underflow point, the system will have to wake up a lot to keep track of the rotations,

causing high current consumptions

To solve this, the pulse counter has a way of introducing hysteresis to the counter. When HYST in

PCNTn_CTRL is set, the pulse counter will always wrap to TOP/2 on underflows and overflows. This

takes the counter away from the area where it might overflow or underflow, removing the problem.

Given a starting value of 0 for the counter, the absolute count value when hysteresis is enabled can

be calculated with the equations Equation 24.1 (p. 610) or Equation 24.2 (p. 610) , depending on

whether the TOP value is even or odd.

Absolute position with hysteresis and even TOP value

CNTabs = CNT - UFCNT x (TOP/2+1) + OFCNT x (TOP/2+1) (24.1)

Absolute position with hysteresis and odd TOP value

CNTabs = CNT - UFCNT x (TOP/2+1) + OFCNT x (TOP/2+2) (24.2)

24.3.3 Auxiliary counter

To be able to keep explicit track of counting in one direction in addition to the regular counter which

counts both up and down, the auxiliary counter can be used. The pulse counter can for instance be

configured to keep track of the absolute rotation of the wheel, and at the same time the auxiliary counter

can keep track of how much the wheel has reversed.

The auxiliary counter is enabled by configuring AUXCNTEV in PCNTn_CTRL. It will always count up,

but it can be configured whether it should count up on up-events, down-events or both, keeping track

of rotation either way or general movement. The value of the auxiliary counter can be read from the

PCNTn_AUXCNT register.

Overflows on the auxiliary counter happen when the auxiliary counter passes the top value of the pulse

counter, configured in PCNTn_TOP. In that event, the AUXOF interrupt flag is set, and the auxiliary

counter wraps to 0.

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As the auxiliary counter, the main counter can be configured to count only on certain events. This is

done through CNTEV in PCNTn_CTRL, and it is possible like for the auxiliary counter, to make the

main counter count on only up and down events. The difference between the counters is that where the

auxiliary counter will only count up, the main counter will count up or down depending on the direction

of the count event.

24.3.4 Register Access

The counter-clock domain may be clocked externally. To update the counter-clock domain registers

from software in this mode, 2-3 clock pulses on the external clock are needed to synchronize accesses

to the externally clocked domain. Clock source switching is controlled from the registers in the CMU

(Chapter 11 (p. 124) ).

When the RSTEN bit in the PCNTn_CTRL register is set to 1, the PCNT clock domain is asynchronously

held in reset. The reset is synchronously released two PCNT clock edges after the RSTEN bit in the

PCNTn_CTRL register is cleared by software. This asynchronous reset restores the reset values in

PCNTn_TOP, PCNTn_CNT and other control registers in the PCNT clock domain.

Since this module is a Low Energy Peripheral, and runs off a clock which is asynchronous to

the HFCORECLK, special considerations must be taken when accessing registers. Please refer to

Section 5.3 (p. 20) for a description on how to perform register accesses to Low Energy Peripherals.

Note PCNTn_TOP and PCNTn_CNT are read-only registers. When writing to PCNTn_TOPB,

make sure that the counter value, PCNTn_CNT, can not exceed the value written to

PCNTn_TOPB within two clock cycles.

24.3.5 Clock Sources

The 32 kHz LFACLK is one of two possible clock sources. The clock select register is described in

Chapter 11 (p. 124) . The default clock source is the LFACLK.

This PCNT module may also use PCNTn_S0IN as an external clock to clock the counter

(EXTCLKSINGLE mode) and to sample PCNTn_S1IN (EXTCLKQUAD mode). Setup, hold and max

frequency constraints for PCNTn_S0IN and PCNTn_S1IN for these modes are specified in the device

datasheet.

To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0, in addition to

the module clock.

Note PCNT Clock Domain Reset, RSTEN, should be set when changing clock source for

PCNT. In addition to this, the PCNTn_SYNCBUSY value should be zero. If changing to an

external clock source, the clock pin has to be enabled as input prior to de-asserting RSTEN.

Changing clock source without asserting RSTEN results in undefined behaviour.

24.3.6 Input Filter

An optional pulse width filter is available in OVSSINGLE mode. The filter is enabled by writing 1 to the

FILT bit in the PCNTn_CTRL register. When enabled, the high and low periods of PCNTn_S0IN must

be stable for 5 consecutive clock cycles before the edge is passed to the edge detector.

In EXTCLKSINGLE and EXTCLKQUAD mode, there is no digital pulse width filter available.

24.3.7 Edge Polarity

The edge polarity can be set by configuring the EDGE bit in the PCNTn_CTRL register. When this bit

is cleared, the pulse counter counts positive edges in OVSSINGLE mode and negative edges if the bit

is set.

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In EXTCLKQUAD mode, the EDGE bit in PCNTn_CTRL inverts the direction of the counter (which is

automatically detected).

Note The EDGE bit in PCNTn_CTRL has no effect in EXTCLKSINGLE mode.

24.3.8 PRS S0IN and S1IN Input

It is possible to receive input from PRS on both SOIN and S1IN by setting S0PRSEN or S1PRSEN in

PCNTn_INPUT. The PRS channel used can be selected using S0PRSSEL in PCNTn_INPUT.

24.3.9 Interrupts

The interrupt generated by PCNT uses the PCNTn_INT interrupt vector. Software must read the

PCNTn_IF register to determine which module interrupt that generated the vector invocation.

24.3.9.1 Underflow and Overflow Interrupts

The underflow interrupt flag (UF) is set when the counter counts down from 0. I.e. when the value of

the counter is 0 and a new pulse is received. The PCNTn_CNT register is loaded with the PCNTn_TOP

value after this event.

The overflow interrupt flag (OF) is set when the counter counts up from the PCNTn_TOP (reload) value.

I.e. if PCNTn_CNT = PCNTn_TOP and a new pulse is received. The PCNTn_CNT register is loaded

with the value 0 after this event.

24.3.9.2 Direction Change Interrupt

The PCNTn_PCNT module sets the DIRCNG interrupt flag (PCNTn_IF register) when the direction of

the quadrature code changes. The behavior of this interrupt is illustrated by Figure 24.3 (p. 612) .

Figure 24.3. PCNT Direction Change Interrupt (DIRCNG) Generation

Standard async

handshake

interface

PCNTn_S0IN

PCNTn_S1IN

Interrupt

X X

Invalid pulse generated when

the shaft changes direction

n+1 n+2 n+3 n+2

PCNTn_CNT n

Delay from the shaft physically

changed direction until the

counter direction is changed

and the interrupt is generated

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24.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 PCNTn_CTRL RW Control Register

0x004 PCNTn_CMD W1 Command Register

0x008 PCNTn_STATUS R Status Register

0x00C PCNTn_CNT R Counter Value Register

0x010 PCNTn_TOP R Top Value Register

0x014 PCNTn_TOPB RW Top Value Buffer Register

0x018 PCNTn_IF R Interrupt Flag Register

0x01C PCNTn_IFS W1 Interrupt Flag Set Register

0x020 PCNTn_IFC W1 Interrupt Flag Clear Register

0x024 PCNTn_IEN RW Interrupt Enable Register

0x028 PCNTn_ROUTE RW I/O Routing Register

0x02C PCNTn_FREEZE RW Freeze Register

0x030 PCNTn_SYNCBUSY R Synchronization Busy Register

0x038 PCNTn_AUXCNT RWH Auxiliary Counter Value Register

0x03C PCNTn_INPUT RW PCNT Input Register

24.5 Register Description

24.5.1 PCNTn_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x000

Reset

0x0

Access

Name

AUXCNTEV

CNTEV

S1CDIR

HYST

RSTEN

FILT

EDGE

CNTDIR

MODE

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:14 AUXCNTEV 0x0 RW Controls when the auxiliary counter counts

Selects whether the auxiliary counter responds to up-count events, down-count events or both

Value Mode Description

0 NONE Never counts.

1 UP Counts up on up-count events.

2 DOWN Counts up on down-count events.

3 BOTH Counts up on both up-count and down-count events.

13:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:10 CNTEV 0x0 RW Controls when the counter counts

Selects whether the regular counter responds to up-count events, down-count events or both

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Bit Name Reset Access Description

Value Mode Description

0 BOTH Counts up on up-count and down on down-count events.

1 UP Only counts up on up-count events.

2 DOWN Only counts down on down-count events.

3 NONE Never counts.

9 S1CDIR 0 RW Count direction determined by S1

S1 gives the direction of counting when in the OVSSINGLE or EXTCLKSINGLE modes. When S1 is high, the count direction is given

by CNTDIR, and when S1 is low, the count direction is the opposite

8 HYST 0 RW Enable Hysteresis

When hysteresis is enabled, the PCNT will always overflow and underflow to TOP/2.

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 RSTEN 0 RW Enable PCNT Clock Domain Reset

The PCNT clock domain is asynchronously held in reset when this bit is set. The reset is synchronously released two PCNT clock

edges after this bit is cleared. If external clock used the reset should be performed by setting and clearing the bit without pending

for SYNCBUSY bit.

4 FILT 0 RW Enable Digital Pulse Width Filter

The filter passes all high and low periods that are at least 5 clock cycles long. This filter is only available in OVSSINGLE mode.

3 EDGE 0 RW Edge Select

Determines the polarity of the incoming edges. This bit should be written when PCNT is in DISABLE mode, otherwise the behavior

is unpredictable. This bit is ignored in EXTCLKSINGLE mode.

Value Mode Description

0 POS Positive edges on the PCNTn_S0IN inputs are counted in OVSSINGLE mode.

1 NEG Negative edges on the PCNTn_S0IN inputs are counted in OVSSINGLE mode, and

the counter direction is inverted in EXTCLKQUAD mode.

2 CNTDIR 0 RW Non-Quadrature Mode Counter Direction Control

The direction of the counter must be set in the OVSSINGLE and EXTCLKSINGLE modes. This bit is ignored in EXTCLKQUAD mode

as the direction is automatically detected.

Value Mode Description

0 UP Up counter mode.

1 DOWN Down counter mode.

1:0 MODE 0x0 RW Mode Select

Selects the mode of operation. The corresponding clock source must be selected from the CMU.

Value Mode Description

0 DISABLE The module is disabled.

1 OVSSINGLE Single input LFACLK oversampling mode (available in EM0-EM2).

2 EXTCLKSINGLE Externally clocked single input counter mode (available in EM0-EM3).

3 EXTCLKQUAD Externally clocked quadrature decoder mode (available in EM0-EM3).

24.5.2 PCNTn_CMD - Command Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x004

Reset

Access

Name

LTOPBIM

LCNTIM

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Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 LTOPBIM 0 W1 Load TOPB Immediately

This bit has no effect since TOPB is not buffered and it is loaded directly into TOP.

0 LCNTIM 0 W1 Load CNT Immediately

Load PCNTn_TOP into PCNTn_CNT on the next counter clock cycle.

24.5.3 PCNTn_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

DIR

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 DIR 0 R Current Counter Direction

Current direction status of the counter. This bit is valid in EXTCLKQUAD mode only.

Value Mode Description

0 UP Up counter mode (clockwise in EXTCLKQUAD mode with the NEDGE bit in

PCNTn_CTRL set to 0).

1 DOWN Down counter mode.

24.5.4 PCNTn_CNT - Counter Value Register

Offset Bit Position

0x00C

Reset

0x0000

Access

Name

CNT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CNT 0x0000 R Counter Value

Gives read access to the counter.

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24.5.5 PCNTn_TOP - Top Value Register

Offset Bit Position

0x010

Reset

0x00FF

Access

Name

TOP

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 TOP 0x00FF R Counter Top Value

When counting down, this value is reloaded into PCNTn_CNT when counting past 0. When counting up, 0 is written to the

PCNTn_CNT register when counting past this value.

24.5.6 PCNTn_TOPB - Top Value Buffer Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x014

Reset

0x00FF

Access

Name

TOPB

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 TOPB 0x00FF RW Counter Top Buffer

Loaded automatically to TOP when written.

24.5.7 PCNTn_IF - Interrupt Flag Register

Offset Bit Position

0x018

Reset

Access

Name

AUXOF

DIRCNG

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Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 AUXOF 0 R Overflow Interrupt Read Flag

Set when an Auxiliary CNT overflow occurs

2 DIRCNG 0 R Direction Change Detect Interrupt Flag

Set when the count direction changes. Set in EXTCLKQUAD mode only.

1 OF 0 R Overflow Interrupt Read Flag

Set when a CNT overflow occurs

0 UF 0 R Underflow Interrupt Read Flag

Set when a CNT underflow occurs

24.5.8 PCNTn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x01C

Reset

Access

Name

AUXOF

DIRCNG

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 AUXOF 0 W1 Auxiliary Overflow Interrupt Set

Write to 1 to set the auxiliary overflow interrupt flag

2 DIRCNG 0 W1 Direction Change Detect Interrupt Set

Write to 1 to set the direction change interrupt flag

1 OF 0 W1 Overflow Interrupt Set

Write to 1 to set the overflow interrupt flag

0 UF 0 W1 Underflow interrupt set

Write to 1 to set the underflow interrupt flag

24.5.9 PCNTn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x020

Reset

Access

Name

AUXOF

DIRCNG

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 AUXOF 0 W1 Auxiliary Overflow Interrupt Clear

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Bit Name Reset Access Description

Write to 1 to clear the auxiliary overflow interrupt flag

2 DIRCNG 0 W1 Direction Change Detect Interrupt Clear

Write to 1 to clear the direction change detect interrupt flag

1 OF 0 W1 Overflow Interrupt Clear

Write to 1 to clear the overflow interrupt flag

0 UF 0 W1 Underflow Interrupt Clear

Write to 1 to clear the underflow interrupt flag

24.5.10 PCNTn_IEN - Interrupt Enable Register

Offset Bit Position

0x024

Reset

Access

Name

AUXOF

DIRCNG

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 AUXOF 0 RW Auxiliary Overflow Interrupt Enable

Enable the auxiliary overflow interrupt

2 DIRCNG 0 RW Direction Change Detect Interrupt Enable

Enable the direction change detect interrupt.

1 OF 0 RW Overflow Interrupt Enable

Enable the overflow interrupt

0 UF 0 RW Underflow Interrupt Enable

Enable the underflow interrupt

24.5.11 PCNTn_ROUTE - I/O Routing Register

Offset Bit Position

0x028

Reset

0x0

Access

Name

LOCATION

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 LOCATION 0x0 RW I/O Location

Defines the location of the PCNT input pins. E.g. PCNTn_S0#0, #1 or #2.

Value Mode Description

0 LOC0 Location 0

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Bit Name Reset Access Description

Value Mode Description

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

7:0 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24.5.12 PCNTn_FREEZE - Freeze Register

Offset Bit Position

0x02C

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

When set, the update of the PCNT clock domain is postponed until this bit is cleared. Use this bit to update several registers

simultaneously.

Value Mode Description

0 UPDATE Each write access to a PCNT register is updated into the Low Frequency domain as

soon as possible.

1 FREEZE The PCNT clock domain is not updated with the new written value.

24.5.13 PCNTn_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x030

Reset

Access

Name

TOPB

CMD

CTRL

Bit Name Reset Access Description

31:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 TOPB 0 R TOPB Register Busy

Set when the value written to TOPB is being synchronized.

1 CMD 0 R CMD Register Busy

Set when the value written to CMD is being synchronized.

0 CTRL 0 R CTRL Register Busy

Set when the value written to CTRL is being synchronized.

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24.5.14 PCNTn_AUXCNT - Auxiliary Counter Value Register

Offset Bit Position

0x038

Reset

0x0000

Access

RWH

Name

AUXCNT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 AUXCNT 0x0000 RWH Auxiliary Counter Value

Gives read access to the auxiliary counter.

24.5.15 PCNTn_INPUT - PCNT Input Register

Offset Bit Position

0x03C

Reset

0x0

Access

Name

S1PRSEN

S1PRSSEL

S0PRSEN

S0PRSSEL

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10 S1PRSEN 0 RW S1IN PRS Enable

When set, the PRS channel is selected as input to S1IN.

9:6 S1PRSSEL 0x0 RW S1IN PRS Channel Select

Select PRS channel as input to S1IN.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected.

1 PRSCH1 PRS Channel 1 selected.

2 PRSCH2 PRS Channel 2 selected.

3 PRSCH3 PRS Channel 3 selected.

4 PRSCH4 PRS Channel 4 selected.

5 PRSCH5 PRS Channel 5 selected.

6 PRSCH6 PRS Channel 6 selected.

7 PRSCH7 PRS Channel 7 selected.

8 PRSCH8 PRS Channel 8 selected.

9 PRSCH9 PRS Channel 9 selected.

10 PRSCH10 PRS Channel 10 selected.

11 PRSCH11 PRS Channel 11 selected.

5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

4 S0PRSEN 0 RW S0IN PRS Enable

When set, the PRS channel is selected as input to S0IN.

3:0 S0PRSSEL 0x0 RW S0IN PRS Channel Select

Select PRS channel as input to S0IN.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected.

1 PRSCH1 PRS Channel 1 selected.

2 PRSCH2 PRS Channel 2 selected.

3 PRSCH3 PRS Channel 3 selected.

4 PRSCH4 PRS Channel 4 selected.

5 PRSCH5 PRS Channel 5 selected.

6 PRSCH6 PRS Channel 6 selected.

7 PRSCH7 PRS Channel 7 selected.

8 PRSCH8 PRS Channel 8 selected.

9 PRSCH9 PRS Channel 9 selected.

10 PRSCH10 PRS Channel 10 selected.

11 PRSCH11 PRS Channel 11 selected.

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25 LESENSE - Low Energy Sensor Interface

01 2 3 4

EFM32

ZZZZZ

Quick Facts

What?

LESENSE is a low energy sensor interface

capable of autonomously collecting and

processing data from multiple sensors even

when in EM2. Flexible configuration makes

LESENSE a versatile sensor interface

compatible with a wide range of sensors and

measurement schemes.

Why?

Capability to autonomously monitor sensors

allows the EFM32LG to reside in a low

energy mode for long periods of time while

keeping track of sensor status and sensor

events.

How?

LESENSE is highly configurable and is

capable of collecting data from a wide range

of sensor types. Once the data is collected,

the programmable state machine, LESENSE

decoder, is capable of processing sensor

data without CPU intervention. A large result

buffer allows the chip to remain in EM2 for

long periods of time while autonomously

collecting data.

25.1 Introduction

LESENSE is a low energy sensor interface which utilizes on-chip peripherals to perform measurement

of a configurable set of sensors. The results from sensor measurements can be processed by the

LESENSE decoder, which is a configurable state machine with up to 16 states. The results can also be

stored in a result buffer to be collected by CPU or DMA for further processing.

LESENSE operates in EM2, in addition to EM1 and EM0, and can wake up the CPU on configurable

events.

25.2 Features

• Up to 16 sensors

• Autonomous sensor monitoring in EM0, EM1, and EM2

• Highly configurable decoding of sensor results

• Interrupt on sensor events

• Configurable enable signals to external sensors

• Circular buffer for storage of up to 16 sensor results.

• Support for multiple sensor types

• LC sensors

• Capacitive sensing

• General analog sensors

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25.3 Functional description

LESENSE is a module capable of controlling on-chip peripherals in order to perform monitoring of

different sensors with little or no CPU intervention. LESENSE uses the analog comparators, ACMP, for

measurement of sensor signals. LESENSE can also control the DAC to generate accurate reference

voltages. Figure 25.1 (p. 623) shows an overview of the LESENSE module. LESENSE consists

of a sequencer, count and compare block, a decoder, and a RAM block used for configuration and

result storage. The sequencer handles interaction with other peripherals as well as timing of sensor

measurements. The count and compare block is used to count pulses from ACMP outputs before

comparing with a configurable threshold. To autonomously analyze sensor results, the LESENSE

decoder provides possibility to define a finite state machine with up to 16 states, and programmable

actions upon state transitions. This allows the decoder to implement a wide range of decoding schemes,

for instance quadrature decoding. A RAM block is used for storage of configuration and measurement

results. This allows LESENSE to have a relatively large result buffer enabling the chip to remain in a low

energy mode for long periods of time while collecting sensor data.

Figure 25.1. LESENSE block diagram

LESENSE

Counter

Compare

Decoder

PRS input

DAC0

AUXHFRCO

ACMP1

ACMP1_CHn

LES_ALTEXn

overridden by LESENSE

Scaler

1.25 V

2.5 V

VDD

VSS

ACMP0

ACMP0_CHn

PRS

CH0 CH1

DAC0_CH0

DAC0_CH1

DAC0_CH0

DAC0_CH1

DAC0_CH0

DAC0_CH1

Scaler

1.25 V

2.5 V

VDD

VSS

DAC0_CH0

DAC0_CH1

ACMP0INV

ACMP1INV

VDDLEVEL

POSSEL

VDDLEVEL

RAMSequencer

ACMP sample reg

CONVMODE*

OUTMODE*

CHxCTRL_EN

CHxDATA

DAC

interface

* LESENSE controls CONVMODE and

OUTMODE individually for the DAC

channels

25.3.1 Channel configuration

LESENSE has 16 individually configurable channels, the first eight are mapped to the channels of

ACMP0, while the last eight are mapped to the channels of ACMP1. Each LESENSE channel has

its own set of configuration registers. Channel configuration is split into three registers; CHx_TIMING,

CHx_INTERACT, and CHx_EVAL. Individual timing for each sensor is configured in CHx_TIMING,

sensor interaction is configured in CHx_INTERACT, and configurations regarding evaluation of the

measurements are done in CHx_EVAL. For improved readability, CHx_CONF will be used to address

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the channel configuration registers, CHx_TIMING, CHx_INTERACT, and CHx_EVAL, throughout this

chapter.

By default, the channel configuration registers are directly mapped to the channel number. Configuring

SCANCONF in CTRL makes it possible to alter this mapping.

Configuring SCANCONF to INVMAP will make channels 0-7 use the channel configuration registers

for channels 8-15, and vice versa. This feature allows an application to quickly and easily switch

configuration set for the channels.

Setting SCANCONF to TOGGLE will make channel x alternate between using CHX_CONF and CHX

+8_CONF. The configuration used is decided by the state of the corresponding bit in SCANRES. For

instance, if channel 3 is performing a scan and bit 3 in SCANRES is set, CH11_CONF will be used.

Channels 8 through 15 will toggle between CHX_CONF and CHX-8_CONF. This mode provides an easy

way for implementation of hysteresis on channel events as threshold values can be changed depending

on sensor status.

Setting SCANCONF to DECDEF will make the state of the decoder define which scan configuration

to be used. If the decoder state is at index 8 or higher, channel x will use CHX+8_CONF, otherwise it

will use CHX configuration. Similarly, channels 8 through 15 will use CHX configuration when decoder

state index is less than 8 and CHX-8_CONF when decoder state index is higher than 7. Allowing

the decoder state to define which configuration to use, enables easy implementation of for instance

hysteresis, as different threshold values can be used for the same channel, depending on the state of

the application. Table 25.1 (p. 624) summarizes how channel configuration is selected for different

setting of SCANCONF.

Table 25.1. LESENSE scan configuration selection

SCANCONF

DIRMAP INVMAP TOGGLE DECDEF

LESENSE

channel x SCANRES[n] = 0 SCANRES[n] = 1 DECSTATE < 8 DECSTATE >= 8

0 <= x < 8 CHx_CONF CHx

+8_CONF CHx_CONF CHx+8_CONF CHx_CONF CHx+8_CONF

8 <= x < 16 CHx_CONF CHx-8_CONF CHx_CONF CHx-8_CONF CHx_CONF CHx-8_CONF

Channels are enabled in the CHEN register, where bit x enables channel x. During a scan, all enabled

channels are measured, starting with the lowest indexed channel. Figure 25.2 (p. 625) illustrates a

scan sequence with channels 3, 5, and 9 enabled.

25.3.2 Scan sequence

LESENSE runs on LFACLKLESENSE, which is a prescaled version of LFACLK. The prescaling factor for

LFACLKLESENSE is selected in the CMU, available prescaling factors are:

• DIV1: LFACLKLESENSE = LFACLK/1

• DIV2: LFACLKLESENSE = LFACLK/2

• DIV4: LFACLKLESENSE = LFACLK/4

• DIV8: LFACLKLESENSE = LFACLK/8

Note LFACLKLESENSE should not exceed 50kHz.

All enabled channels are scanned each scan period. How a new scan is started is configured in the

SCANMODE bit field in CTRL. If set to PERIODIC, the scan frequency is generated using a counter which

is clocked by LFACLKLESENSE. This counter has its own prescaler. This prescaling factor is configured in

PCPRESC in TIMCTRL. A new scan sequence is started each time the counter reaches the top value,

PCTOP. The scan frequency is calculated using Equation 25.1 (p. 625) . If SCANMODE is set to

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ONESHOT, a single scan will be made when START in CMD is set. To start a new scan on a PRS

event, set START in CMD, set SCANMODE to PRS and configure PRS channel in PRSSEL. The PRS

start signal needs to be active for at least one LFACLKLESENSE cycle to make sure LESENSE is able

to register it.

Scan frequency

Fscan = LFACLKLESENSE/((1 + PCTOP)*2PCPRESC) (25.1)

It is possible to interleave additional sensor measurements in between the periodic scans. Issuing a start

command when LESENSE is idle will immediately start a new scan, without disrupting the frequency of

the periodic scans. If the period counter overflows during the interleaved scan, the periodically scheduled

scan will start immediately after the interleaved scan completes.

Figure 25.2. Scan sequence

CH3 CH5 CH9 CH3 CH5 CH9

START START

Scan period

25.3.3 Sensor timing

For each channel in the scan sequence, the LESENSE interface goes through three phases: Idle

phase, excite phase, and measure phase. The durations of the excite and measure phases are

configured in the CHx_TIMING registers. LESENSE includes two timers: A low frequency timer,

running on LFACLKLESENSE, and a high frequency timer, running on AUXHFRCO. Timing of the excite

phase is done using these timers and can be either a number of prescaled AUXHFRCO cycles or

a number of prescaled LFACLKLESENSE cycles, depending on which one is selected in EXCLK. The

prescaling can be done by configuring LFPRESC in TIMCTRL for the low frequency timer, and the

high frequency timer prescaling factor is configured in AUXPRESC in the same register. The duration

of the measure phase is programmed via MEASUREDLY and SAMPLEDLY. The output of the ACMP

will be inactive for MEASUREDLY EXCLK cycles after start of the sensor measurement. Sampling of

the sensor will happen after SAMPLEDLY LFACLKLESENSE, or AUXHFRCO cycles, depending on the

configuration of SAMPLECLK. Figure 25.3 (p. 625) depicts a sensor sequence where excitation and

measure delay is timed using AUXHFRCO and the sample delay is timed using LFACLKLESENSE. The

configurable measure- and sample delays enables LESENSE to easily define exact time windows for

sensor measurements. A start delay can be inserted before sensor measurement begin by configuring

STARTDLY in TIMCTRL. This delay can be used to ensure that the DAC is done and voltages have

stabilized before sensor measurement begins.

Figure 25.3. Timing diagram, short excitation

EXCITE

SAMPLE

LFACLKLESENSE

Idle phase Excite phase Idle phase

Sample delay

Measure phase

START

AUXHFRCO

INIT

Start delay Measure delay

DAC refresh start

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25.3.4 Sensor interaction

Many sensor types require some type of excitation in order to work. LESENSE can generate a variety

of sensor stimuli, both on the same pin as the measurement is to be made on, and on alternative pins.

By default, excitation is performed on the pin associated with the channel, i.e. excitation and sensor

measurement is performed on the same pin. The mode of the pin during the excitation phase is

configured in EXMODE in CHx_INTERACT. The available modes during the excite phase are:

• DISABLED: The pin is disabled.

• HIGH: The pin is driven high.

• LOW: The pin is driven low.

• DACOUT: The pin is connected to the output of a DAC channel.

Note Excitation with DAC output is only available on channels 0, 1, 2, and 3 (DAC0_CH0) and

channels 12, 13, 14, and 15 (DAC0_CH1).

If the DAC is in opamp-mode, setting EXMODE to DACOUT will result in excitation with

output from the opamp.

LESENSE is able to perform sensor excitation on another pin than the one to be measured. When

ALTEX in CHx_INTERACT is set, the excitation will occur on the alternative excite pin associated with

the given channel. All LESENSE channels mapped to ACMP0 have their alternative channel mapped

to the corresponding channel on ACMP1, and vice versa. Alternatively, the alternative excite pins can

be routed to the LES_ALTEX pins. Mapping of the alternative excite pins is configured in ALTEXMAP

in CTRL. Table 25.2 (p. 626) summarizes the mapping of excitation pins for different configurations.

Table 25.2. LESENSE excitation pin mapping

ALTEX = 0 ALTEX = 1

LESENSE channel ALTEXMAP = ACMP ALTEXMAP = ALTEX

0 ACMP0_CH0 ACMP1_CH0 LES_ALTEX0

1 ACMP0_CH1 ACMP1_CH1 LES_ALTEX1

2 ACMP0_CH2 ACMP1_CH2 LES_ALTEX2

3 ACMP0_CH3 ACMP1_CH3 LES_ALTEX3

4 ACMP0_CH4 ACMP1_CH4 LES_ALTEX4

5 ACMP0_CH5 ACMP1_CH5 LES_ALTEX5

6 ACMP0_CH6 ACMP1_CH6 LES_ALTEX6

7 ACMP0_CH7 ACMP1_CH7 LES_ALTEX7

8 ACMP1_CH0 ACMP0_CH0 LES_ALTEX0

9 ACMP1_CH1 ACMP0_CH1 LES_ALTEX1

10 ACMP1_CH2 ACMP0_CH2 LES_ALTEX2

11 ACMP1_CH3 ACMP0_CH3 LES_ALTEX3

12 ACMP1_CH4 ACMP0_CH4 LES_ALTEX4

13 ACMP1_CH5 ACMP0_CH5 LES_ALTEX5

14 ACMP1_CH6 ACMP0_CH6 LES_ALTEX6

15 ACMP1_CH7 ACMP0_CH7 LES_ALTEX7

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Figure 25.4 (p. 627) illustrates the sequencing of the pin associated with the active channel and its

alternative excite pin.

Figure 25.4. Pin sequencing

EXCITE

LFACLKLESENSE

Idle phase Excite phase Idle phaseMeasure phase

IDLECONF EXMODE Z IDLECONF

Channel pin

IDLECONF

Alternate excite pin

IDLECONF EXMODE IDLECONF

Alternate excite pin

IDLECONF Z IDLECONF

Channel pin

ALTEX=1

ALTEX=0

The alternative excite pins, LES_ALTEXn, have the possibility to excite regardless of what channel is

active. Setting AEXn in ALTEXCONF will make LES_ALTEXn excite for all channels using alternative

excitation, i.e. ALTEX in CHx_INTERACT is set.

Note When exciting on the pin associated with the active channel, the pin will go through a tri-

stated phase before returning to the idle configuration. This will not happen on pins used as

alternative excitation pins.

The pin configuration for the idle phase can be configured individually for each LESENSE channel and

alternative excite pin in the IDLECONF and ALTEXCONF registers. The modes available are the same

as the modes available in the excitation phase. In the measure phase, the pin mode on the active channel

is always disabled (analog input).

To enable LESENSE to control GPIO, the pin has to be enabled in the ROUTE register. In addition,

the given pin must be configured as push-pull. IDLECONF configuration should not be altered when pin

enable for the given pin is set in ROUTE.

25.3.5 Sensor evaluation

Sensor evaluation can be based on either analog comparator outputs, or the counter output. This is

configured in the SAMPLE bit-field in CHx_INTERACT. The LESENSE counter is used to count pulses

on the ACMP output in the measurement phase. When a measurement phase is completed, the counter

value is compared to the value configured in COMPTHRES in CHx_EVAL. By configuring COMP, it is

possible to choose comparison mode: Less than, or greater than or equal. If a comparison for a channel

triggers, the corresponding bit in the result register, SCANRES, is set. To set an interrupt flag on a sensor

event, configure SETIF in CHx_INTERACT. Figure 25.5 (p. 628) illustrates how the counter value or

ACMP sample is used for evaluation and interrupt generation.

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Figure 25.5. Scan result and interrupt generation

ACMP

sample

LESENSE

counter

ACMP

COUNTER

CHx_EVAL_SCANRESINV

COUNTER >= COMPTHRES

COUNTER < COMPTHRES

LESS

CHx_EVAL_COMP

CHx_INTERACT_SAMPLE NONE

LEVEL

POSEDGE

NEGEDGE

CHx_INTERACT_SETIF

Set

interrupt

flag

SCANRES[x]

SENSORSTATE

LESENSE includes the possibility to sample both analog comparators simultaneously, effectively cutting

the time spent on sensor interaction in some applications in half. Setting DUALSAMPLE in CTRL enables

this mode. In dual sample mode, the channels of ACMP0 are paired together with the corresponding

channel on ACMP1, i.e. channel x on ACMP0 and channel x on ACMP1 are sampled simultaneously.

The results from sensor measurements can be fed into the decoder register and/or stored in the result

buffer. In this mode, the samples from the AMCPs are placed in the two LSBs of the result stored in the

result buffer. Results from both ACMPs will be evaluated for interrupt generation.

25.3.6 Decoder

Many applications require some sort of processing of the sensor readings, for instance in the case of

quadrature decoding. In quadrature decoding, the sensors repeatedly pass through a set of states which

corresponds to the position of the sensors. This sequence, and many other decoding schemes, can be

described as a finite state machine. To support this type of decoding without CPU intervention, LESENSE

includes a highly configurable decoder, capable of decoding input from up to four sensors. The decoder

is implemented as a programmable state machine with up to 16 states. When doing a sensor scan,

the results from the sensors are placed in the decoder input register, SENSORSTATE, if DECODE in

CHx_INTERACT is set. The resulting position after a scan is illustrated in Figure 25.6 (p. 628) , where

the bottom blocks show how the SENSORSTATE register is filled. When the scan sequence is complete,

the decoder evaluates the state of the sensors chosen for decoding, as depicted in Figure 25.6 (p. 628)

Figure 25.6. Sensor scan and decode sequence

CH0 CH1

START START

Scan period

DecodeCH2 CH3 CH0 CH1 DecodeCH2 CH3

CH0

result

CH0

result

CH1

result

CH0

result

CH1

result

CH2

result

CH0

result

CH1

result

CH2

result

CH3

result

SENSORSTATE[0]

SENSORSTATE[3]

CH0

result

CH1

result

CH2

result

CH3

result

CH0

result

CH1

result

CH2

result

CH3

result

CH0

result

CH1

result

CH2

result

CH3

result

CH0

result

CH1

result

CH2

result

CH3

result

The decoder is a programmable state machine with support for up to 16 states. The behavior of each

state is individually configured in the STx_TCONFA and STx_TCONFB registers. The registers define

possible transitions from the present state. If the sensor state matches COMP in either STx_TCONFA

or STx_TCONFB, a transition to the state defined in NEXTSTATE will be made. It is also possible to

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mask out one or more sensors using the MASK bit field. The state of a masked sensor is interpreted

as don't care.

Upon a state transition, LESENSE can generate a pulse on one or more of the decoder PRS channels.

Which channel to generate a pulse on is configured in the PRSACT bit field. If PRSCNT in DECCTRL

is set, count signals will be generated on decoder PRS channels 0 and 1 according to the PRSACT

configuration. In this mode, channel 0 will pulse each time a count event occurs while channel 1 indicates

the count direction, 1 being up and 0 being down. The count direction will be kept at its previous state

in between count events. The EFM32LG pulse counter may be used to keep track of events based on

these PRS outputs.

If SETIF is set, the DECODER interrupt flag will be set when the transition occurs. If INTMAP in

DECCTRL and SETIF is set, a transition from state x will set the CHx interrupt flag in addition to the

DECODER flag.

Setting CHAIN in STx_TCONFA enables the decoder to evaluate more than two possible transitions for

each state. If none of the transitions defined in STx_TCONFA or STx_TCONFB matches, the decoder

will jump to the next descriptor pair and evaluate the transitions defined there. The decoder uses two

LFACLKLESENSE cycles for each descriptor pair to be evaluated. If ERRCHK in CTRL is set, the decoder

will check that the sensor state has not changed if none of the defined transitions match. The DECERR

interrupt flag will be set if none of the transitions match and the sensor state has changed. Figure 25.7 (p.

630) illustrates state transitions. The "Generate PRS signals and set interrupt flag" blocks will perform

actions according to the configuration in STx_TCONFA and STx_TCONFB.

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Figure 25.7. Decoder state transition evaluation

STi+1_TCONF

STi_TCONF

STATEi

NEXTSTATEAi

NEXTSTATEBi

NEXTSTATEAi+1

NEXTSTATEBi+1

Generate PRS

signals and set

interrupt flag

Generate PRS

signals and set

interrupt flag

Generate PRS

signals and set

interrupt flag

Generate PRS

signals and set

interrupt flag

Set DECERR

interrupt flag

SENSORSTATE & ~MASKAi =

COMPAi & ~MASKAi

Y N

SENSORSTATE & ~MASKBi =

COMPBi & ~MASKBi

Y N

CHAINi = 1

Y N

SENSORSTATE & ~MASKAi+1 =

COMPAi+1 & ~MASKAi+1

Y N

SENSORSTATE & ~MASKBi+1 =

COMPBi+1 & ~MASKBi+1

Y N

SENSORSTATE changed &&

ERRCHK=1

Y N

CHAINi+1 = 1

Y N

Note If only one transition from a state is used, STx_TCONFA and STx_TCONFB should be

configured equally.

To prevent unnecessary interrupt requests or PRS outputs when the decoder toggles back and forth

between two states, a hysteresis option is available. The hysteresis function is triggered if a type A

transition is preceded by a type B transition, and vice versa. A type A transition is a transition defined in

STx_TCONFA, and a type B transition is a transition defined in STx_TCONFB. When descriptor chaining

is used, a jump to another descriptor will cancel out the hysteresis effect. Figure 25.8 (p. 631) illustrates

how the hysteresis triggers upon state transitions.

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Figure 25.8. Decoder hysteresis

State 0

State 1

1: B transition, no hysteresis

State 2

2: A transition, hysteresis

State 3

5: A transition, no hysteresis

3: B transition, hysteresis 4: A transition, hysteresis

A transition: Transition defined in TCONFA

B transition: Transition defined in TCONFB

The events suppressed by the hysteresis are configured in bit fields HYSTPRS0-2 and HYSTIRQ in

DECCTRL.

• When HYSTPRSx is set, PRS signal x is suppressed when the hysteresis triggers.

• When HYSTIRQ is set, interrupt requests are suppressed when the hysteresis triggers.

Note The decoder error interrupt flag, DECERR, is not affected by the hysteresis.

25.3.7 Measurement results

Part of the LESENSE RAM is treated as a circular buffer for storage of up to 16 results from sensor

measurements. Each time LESENSE writes data to the result buffer, the result write pointer, PTR_WR,

is incremented. Each time a new result is read through the BUFDATA register, the result read pointer,

PTR_RD, is incremented. The read pointer will not be incremented if there is no valid, unread data in

the result buffer. By default LESENSE will not write additional data to a full result buffer until the data is

read by software or DMA. Setting BUFOW in CTRL enables LESENSE to write to the result buffer, even

if it is full. In this mode, the result read pointer will follow the write pointer if the buffer is full. The result of

this is that data read from the result read register, BUFDATA, is the oldest unread result. The location

pointers are available in PTR. The result buffer has three status flags; BUFDATAV, BUFHALFFULL,

and BUFFULL. The flags indicate when new data is available, when the buffer is half full, and when it is

full, respectively. The interrupt flag BUFDATAV is set when data is available in the buffer. BUFLEVEL

is set when the buffer is either full or half-full, depending on the configuration of BUFIDL in CTRL. If the

result buffer overflows, the BUFOF interrupt flag will be set.

During a scan, the state of each sensor is stored in SCANRES. If a sensor triggers, a 1 is stored in

SCANRES, else a 0 is stored in SCANRES. Whether or not a sensor is said to be triggered depends of

the configuration for the given channel. If SAMPLE is set to ACMP, the sensor is said to be triggered

if the output from the analog comparator is 1 when sensor sampling is performed. If SAMPLE is set to

COUNTER, a sensor is said to be triggered if the LESENSE counter value is greater than or equal, or

less than COMPTHRES, depending on the configuration of COMP. If STRSAMPLE in CHx_EVAL is

set, the counter value or ACMP sample for each channel will be stored in the LESENSE result buffer. If

STRSCANRES in CTRL is set, the result vector, SCANRES, will also be stored in the result buffer. This

will be stored after each scan and will be interleaved with the counter values. The contents of the result

buffer can be read from BUFDATA or from BUF[x]_DATA. When reading from BUF[x]_DATA, neither

the result read pointer or the status flags BUFDATAV, BUFHALFFULL, or BUFFULL will be updated.

When reading through the BUFDATA register, the oldest unread result will be read.

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Figure 25.9. Circular result buffer

BUF0_DATA

BUF1_DATA

BUF2_DATA

BUF3_DATA

BUF12_DATA

BUF13_DATA

BUF14_DATA

BUF15_DATA

BUFDATA

PTR_RD

LESENSE

PTR_WR

CH3 result

CH5 result

CH9 result

SCANRES

CH3 result

CH5 result

CH9 result

SCANRES

The right hand side of Figure 25.9 (p. 632) illustrates how the result buffer would be filled when

channels 3,5, and 9 are enabled and have STRSAMPLE in CHx_EVAL set, in addition to STRSCANRES

in CTRL. The measurement result from the three channels will be sequentially written during the scan,

while SCANRES is written to the result buffer upon scan completion.

25.3.8 DAC interface

LESENSE is able to drive the DAC for generation of accurate reference voltages. DAC channels

0 and 1 are individually configured in the PERCTRL register. The conversion mode can be set

to either continuous, sample/hold or sample/off. For further details about these modes, refer to

Section 29.3.1 (p. 712) . Both DAC channels are refreshed prior to each sensor measurement, as

depicted in Figure 25.3 (p. 625) . The conversion data is either taken from the data registers in

the EFM32LG DAC interface (DAC0_CH0DATA and DAC0_CH1DATA) or from the ACMPTHRES bit-

field in the CHx_INTERACT register for the active LESENSE channel. DAC data used is configured in

DACCHxDATA in PERCTRL.

The DAC interface runs on AUXHFRCO and will enable this when it is needed. The DACPRESC bit-field

in PERCTRL is used to prescale the AUXHFRCO to achieve wanted clock frequency for the LESENSE

DAC interface. The frequency should not exceed 500kHz, i.e. DACPRESC has to be set to at least 1.

The prescaler may also be used to tune how long the DAC should drive its outputs in sample/off mode.

Bias configuration, calibration and reference selection is done in the EFM32LG DAC module and

LESENSE will not override these configurations. If a bandgap reference is selected for the DAC, the

DACREF bit in PERCTRL should be set to BANDGAP.

LESENSE has the possibility to control switches that connect the DAC outputs to the pins associated

with ACMP0_CH0-3 and ACMP1_CH12-15. This makes LESENSE able to excite sensors with output

from the DAC channels.

The DAC may be chosen as reference to the analog comparators for accurate reference generation. If

the DAC is configured in continuous or sample/hold mode this does not require any external components.

If sample/off mode is used, an external capacitor is needed to keep the voltage in between samples.

To connect the input from the DAC to the ACMP to this external capacitor, connect the capacitor to the

DAC pin for the given channel and set OPAxSHORT in DAC_OPACTRL.

Note The DAC mode should not be altered while DACACTIVE in STATUS is set

25.3.9 ACMP interface

The ACMPs are used to measure the sensors, and have to be configured according to the application

in order for LESENSE to work properly. Depending on the configuration in the ACMP0MODE and

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ACMP1MODE bit-fields in PERCTRL, LESENSE will take control of the positive input mux and the

Vdd scaling factor (VDDLEVEL) for ACMP0 and ACMP1. The remaining configuration of the analog

comparators are done in the ACMP register interface. It is recommended to set the MUXEN bit in

ACMPn_CTRL for the ACMPs used by LESENSE. Each channel has the possibility to control the value

of the Vdd scaling factor on the negative input of the ACMP, VDDLEVEL in ACMP_INPUTSEL. This is

done in the 6 LSBs of ACMPTHRES in CHx_INTERACT. LESENSE automatically controls the ACMP

mux to connect the correct channel.

25.3.10 ACMP and DAC duty cycling

By default, the analog comparators and DAC are shut down in between LESENSE scans to save energy.

If this is not wanted, WARMUPMODE in PERCTRL can be configured to prevent them from being shut

down.

Both the DAC and analog comparators rely on a bias module for correct operation. This bias module

has a low power mode which consumes less energy at the cost of reduced accuracy. BIASMODE in

BIASCTRL configures how the bias module is controlled by LESENSE. When set to DUTYCYCLE,

LESENSE will set the bias module in high accuracy mode whenever LESENSE is active, and keep it

in the low power mode otherwise. When BIASMODE is set to HIGHACC, the high accuracy mode is

always selected. When set to DONTTOUCH, LESENSE will not control the bias module.

25.3.11 DMA requests

LESENSE issues a DMA request when the result buffer is either full or half full, depending on the

configuration of BUFIDL in CTRL. The request is cleared when the buffer level drops below the threshold

defined in BUFIDL. A single DMA request is also set whenever there is unread data in the buffer. DMAWU

in CTRL configures at which buffer level LESENSE should wake-up the DMA when in EM2.

Note The DMA controller should always fetch data from the BUFDATA register.

25.3.12 PRS output

LESENSE is an asynchronous PRS producer and has nineteen PRS outputs. The decoder has three

outputs and in addition, all bits in the SCANRES register are available as PRS outputs. For further

information on the decoder PRS output, refer to Section 25.3.6 (p. 628) .

25.3.13 RAM

LESENSE includes a RAM block used for storage of configuration and results. If LESENSE is not

used, this RAM block can be powered down eliminating its current consumption due to leakage. The

RAM is powered down by setting the RAM bit in the POWERDOWN register. Once the RAM has been

shut down it cannot be turned back on without a reset of the chip. Registers mapped to the RAM

include: STx_TCONFA, STx_TCONFB, BUFx_DATA, BUFDATA, CHx_TIMING, CHx_INTERACT, and

CHx_EVAL. These registers have unknown value out of reset and have to be initialized before use.

Note Read-modify-write operations on uninitialized RAM register produces undefined values.

25.3.14 Application examples

25.3.14.1 Capacitive sense

Figure 25.10 (p. 634) illustrates how the EFM32LG can be configured to monitor four capacitive

buttons.

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Figure 25.10. Capacitive sense setup

EFM32

ACMP0_CH0

ACMP0_CH1

ACMP0_CH2

ACMP0_CH3

The following steps show how to configure LESENSE to scan through the four buttons 100 times per

second, issuing an interrupt if one of them is pressed.

1. Assuming LFACLKLESENSE is 32kHz, set PCPRESC to 3 and PCTOP to 39 in CTRL. This will make

the LESENSE scan frequency 100Hz.

2. Enable channels 0 through 3 in CHEN and set IDLECONF for these channels to DISABLED. In

capacitive sense mode, the GPIO should always be disabled (analog input).

3. Configure the ACMP to operate in CAPSENSE mode, refer to Section 26.3.5 (p. 671) for details.

4. Configure the following bit fields in CHx_CONF, for channels 0 through 3:

a. Set EXTIME to 0. No excitation is needed in this mode.

b. Set SAMPLE to COUNTER and COMP to LESS. This makes LESENSE interpret a sensor as

active if the frequency on a channel drops below the threshold, i.e. the button is pressed.

c. Set SAMPLEDLY to an appropriate value, each sensor will be measured for SAMPLEDLY/

LFACLKLESENSE seconds. MEASUREDLY should be set to 0

5. Set CTRTHRESHOLD to an appropriate value. An interrupt will be issued if the counter value for a

sensor is below this threshold after the measurement phase.

6. Enable interrupts on channels 0 through 3.

7. Start scan sequence by writing a 1 to START in CMD.

In a capacitive sense application, it might be required to calibrate the threshold values on a periodic

basis, this is done in order to compensate for humidity and other physical variations. LESENSE is able

to store up to 16 counter values from a configurable number of channels, making it possible to collect

sample data while in EM2. When calibration is to be performed, the CPU only has to be woken up for a

short period of time as the data to be processed already lies in the result registers. To enable storing of

the count value for a channel, set STRSAMPLE in the CHx_INTERACT register.

25.3.14.2 LC sensor

Figure 25.11 (p. 634) below illustrates how the EFM32LG can be set up to monitor four LC sensors.

Figure 25.11. LC sensor setup

EFM32

ACMP0_CH0

ACMP0_CH1

ACMP0_CH2

DAC0_OUT0

ACMP0_CH3

LESENSE can be used to excite and measure the damping factor in LC sensor oscillations. To measure

the damping factor, the ACMP can be used to generate a high output each time the sensor voltage

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exceeds a certain level. These pulses are counted using an asynchronous counter and compared with

the threshold in COMPTHRES in the CHx_EVAL register. If the number of pulses exceeds the threshold

level, the sensor is said to be active, otherwise it is inactive. Figure 25.12 (p. 635) illustrates how

the output pulses from the ACMP correspond to damping of the oscillations. The results from sensor

evaluation can automatically be fed into the decoder in order to keep track of rotations.

Figure 25.12. LC sensor oscillations

The following steps show how to configure LESENSE to scan through the four LC sensors 100 times

per second.

1. Assuming LFACLKLESENSE is 32kHz, set PCPRESC to 3 and PCTOP to 39 in CTRL. This will make

the LESENSE scan frequency 100Hz.

2. Enable the DAC and configure it to produce a voltage of Vdd/2.

3. Enable channels 0 through 3 in CHEN. Set IDLECONF for the active channels to DACOUT. The

channel pins should be set to Vdd/2 in the idle phase to damp the oscillations.

4. Configure the ACMP to use scaled Vdd as negative input, refer to ACMP chapter for details.

5. Enable and configure PCNT and asynchronous PRS.

6. Configure the GPIOs used as PUSHPULL.

7. Configure the following bit fields in CHx_CONF, for channels 0 through 3:

a. Set EXCLK to AUXHFRCO. AUXHFRCO is needed to achieve short excitation time.

b. Set EXTIME to an appropriate value. Excitation will last for EXTIME/AUXHFRCO seconds

(prescalar value in AUXPRESC in TIMCTRL is 0).

c. Set EXMODE to LOW. The LC sensors are excited by pulling the excitation pin low.

d. Set SAMPLE to COUNTER and COMP to LESS. Status of each sensor is evaluated based on the

number of pulses generated by the ACMP. If they are less than the threshold value, the sensor

is said to be active.

e. Set SAMPLEDLY to an appropriate value, each sensor will be measured for SAMPLEDLY/

LFACLKLESENSE seconds.

8. Set CTRTHRESHOLD to an appropriate value. If the sensor is active, the counter value after the

measurement phase should be less than the threshold. If it inactive, the counter value should be

greater than the threshold.

9. Start scan sequence by writing a 1 to START in CMD.

25.3.14.3 LESENSE decoder 1

The example below illustrates how the LESENSE module can be used for decoding using three sensors

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Figure 25.13. FSM example 1

0 1 2 3

7 6 5 4

001

000

011

001

010

011

110

111

101

100

010 110

000 100

xxxState Index Sensor value

To set up the decoder to decode rotation using the encoding scheme seen in Figure 25.13 (p. 636)

, configure the following LESENSE registers:

1. Configure the channels to be used, be sure to set DECODE in CHx_EVAL.

2. Set PRSCNT to enable generation of count waveforms on PRS. Also configure a PCNT to listen to

the PRS channels and count accordingly.

3. Configure the following in STx_TCONFA and STx_TCONFB:

a. Set MASK = 0b1000 in STx_TCONFA and STx_TCONFB for all used states. This enables three

sensors to be evaluated by the decoder.

b. Configure the remaining bit fields in STx_TCONFA and STx_TCONFB as described in

Table 25.3 (p. 636) .

Table 25.3. LESENSE decoder configuration

ST0 1 0b001 UP 7 0b100 DOWN

ST1 2 0b011 UP 0 0b000 DOWN

ST2 3 0b010 UP 1 0b001 DOWN

ST3 4 0b110 UP 2 0b011 DOWN

ST4 5 0b111 UP 3 0b010 DOWN

ST5 6 0b101 UP 4 0b110 DOWN

ST6 7 0b100 UP 5 0b111 DOWN

ST7 0 0b000 UP 6 0b101 DOWN

4. To initialize the decoder, run one scan, and read the present sensor status from SENSORSTATE.

Then write the index of this state to DECSTATE.

5. Write to START in CMD to start scanning of sensors and decoding.

25.3.14.4 LESENSE decoder 2

The example below illustrates how the LESENSE decoder can be used to implement the state machine

seen in Figure 25.14 (p. 636) .

Figure 25.14. FSM example 2

0010

0000

0001

0000

0001

0011

0010 1XXX

1XXX

State Index Sensor value

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1. Configure STx_TCONFA and STx_TCONFB as described in Table 25.4 (p. 637) .

Table 25.4. LESENSE decoder configuration

ST0_TCONFA 8 0b1000 0b0111 1

ST0_TCONFB 2 0b0001 0b1000 -

ST1_TCONFA 6 0b0010 0b1000 0

ST1_TCONFB 6 0b0010 0b1000 -

ST2_TCONFA 8 0b1000 0b0111 1

ST2_TCONFB 4 0b0011 0b1000 -

ST3_TCONFA 0 0b0000 0b1000 0

ST3_TCONFB 0 0b0000 0b1000 -

ST4_TCONFA 8 0b1000 0b0111 1

ST4_TCONFB 6 0b0010 0b1000 -

ST5_TCONFA 2 0b0001 0b1000 0

ST5_TCONFB 2 0b0001 0b1000 -

ST6_TCONFA 8 0b1000 0b0111 1

ST6_TCONFB 0 0b0000 0b1000 -

ST7_TCONFA 4 0b0011 0b1000 0

ST7_TCONFB 4 0b0011 0b1000 -

2. To initialize the decoder, run one scan, and read the present sensor status from SENSORSTATE.

Then write the index of this state to DECSTATE.

3. Write to START in CMD to start scanning of sensors and decoding.

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25.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 LESENSE_CTRL RW Control Register

0x004 LESENSE_TIMCTRL RW Timing Control Register

0x008 LESENSE_PERCTRL RW Peripheral Control Register

0x00C LESENSE_DECCTRL RW Decoder control Register

0x010 LESENSE_BIASCTRL RW Bias Control Register

0x014 LESENSE_CMD W1 Command Register

0x018 LESENSE_CHEN RW Channel enable Register

0x01C LESENSE_SCANRES R Scan result register

0x020 LESENSE_STATUS R Status Register

0x024 LESENSE_PTR R Result buffer pointers

0x028 LESENSE_BUFDATA R Result buffer data register

0x02C LESENSE_CURCH R Current channel index

0x030 LESENSE_DECSTATE RWH Current decoder state

0x034 LESENSE_SENSORSTATE RWH Decoder input register

0x038 LESENSE_IDLECONF RW GPIO Idle phase configuration

0x03C LESENSE_ALTEXCONF RW Alternative excite pin configuration

0x040 LESENSE_IF R Interrupt Flag Register

0x044 LESENSE_IFC W1 Interrupt Flag Clear Register

0x048 LESENSE_IFS W1 Interrupt Flag Set Register

0x04C LESENSE_IEN RW Interrupt Enable Register

0x050 LESENSE_SYNCBUSY R Synchronization Busy Register

0x054 LESENSE_ROUTE RW I/O Routing Register

0x058 LESENSE_POWERDOWN RW LESENSE RAM power-down register

0x200 LESENSE_ST0_TCONFA RW State transition configuration A

0x204 LESENSE_ST0_TCONFB RW State transition configuration B

... LESENSE_STx_TCONFA RW State transition configuration A

... LESENSE_STx_TCONFB RW State transition configuration B

0x278 LESENSE_ST15_TCONFA RW State transition configuration A

0x27C LESENSE_ST15_TCONFB RW State transition configuration B

0x280 LESENSE_BUF0_DATA RW Scan results

... LESENSE_BUFx_DATA RW Scan results

0x2BC LESENSE_BUF15_DATA RW Scan results

0x2C0 LESENSE_CH0_TIMING RW Scan configuration

0x2C4 LESENSE_CH0_INTERACT RW Scan configuration

0x2C8 LESENSE_CH0_EVAL RW Scan configuration

... LESENSE_CHx_TIMING RW Scan configuration

... LESENSE_CHx_INTERACT RW Scan configuration

... LESENSE_CHx_EVAL RW Scan configuration

0x3B0 LESENSE_CH15_TIMING RW Scan configuration

0x3B4 LESENSE_CH15_INTERACT RW Scan configuration

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Offset Name Type Description

0x3B8 LESENSE_CH15_EVAL RW Scan configuration

25.5 Register Description

25.5.1 LESENSE_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x000

Reset

0x0

Access

Name

DEBUGRUN

DMAWU

BUFIDL

STRSCANRES

BUFOW

DUALSAMPLE

ALTEXMAP

ACMP1INV

ACMP0INV

SCANCONF

PRSSEL

SCANMODE

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 DEBUGRUN 0 RW Debug Mode Run Enable

Set to keep LESENSE running in debug mode.

Value Description

0 LESENSE can not start new scans in debug mode

1 LESENSE can start new scans in debug mode

21:20 DMAWU 0x0 RW DMA wake-up from EM2

Value Mode Description

0 DISABLE No DMA wake-up from EM2

1 BUFDATAV DMA wake-up from EM2 when data is valid in the result buffer

2 BUFLEVEL DMA wake-up from EM2 when the result buffer is full/half-full depending on BUFIDL

configuration

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18 BUFIDL 0 RW Result buffer interrupt and DMA trigger level

Value Mode Description

0 HALFFULL DMA and interrupt flags set when result buffer is half-full

1 FULL DMA and interrupt flags set when result buffer is full

17 STRSCANRES 0 RW Enable storing of SCANRES

When set, SCANRES will be stored in the result buffer after each scan

16 BUFOW 0 RW Result buffer overwrite

If set, LESENSE will always write to the result buffer, even if it is full

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13 DUALSAMPLE 0 RW Enable dual sample mode

When set, both ACMPs will be sampled simultaneously.

12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11 ALTEXMAP 0 RW Alternative excitation map

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Bit Name Reset Access Description

Value Mode Description

0 ALTEX Alternative excitation is mapped to the LES_ALTEX pins.

1 ACMP Alternative excitation is mapped to the pins of the other ACMP.

10 ACMP1INV 0 RW Invert analog comparator 1 output

9 ACMP0INV 0 RW Invert analog comparator 0 output

8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:6 SCANCONF 0x0 RW Select scan configuration

These bits control which CHx_CONF registers to be used.

Value Mode Description

0 DIRMAP The channel configuration register registers used are directly mapped to the channel

number.

1 INVMAP The channel configuration register registers used are CHX+8_CONF for channels 0-7

and CHX-8_CONF for channels 8-15.

2 TOGGLE The channel configuration register registers used toggles between CHX_CONF and

CHX+8_CONF when channel x triggers

3 DECDEF The decoder state defines the CONF registers to be used.

5:2 PRSSEL 0x0 RW Scan start PRS select

Select PRS source for scan start if SCANMODE is set to PRS.

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

1:0 SCANMODE 0x0 RW Configure scan mode

These bits control how the scan frequency is decided

Value Mode Description

0 PERIODIC A new scan is started each time the period counter overflows

1 ONESHOT A single scan is performed when START in CMD is set

2 PRS Pulse on PRS channel

25.5.2 LESENSE_TIMCTRL - Timing Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x004

Reset

0x0

0x00

0x0

Access

Name

STARTDLY

PCTOP

PCPRESC

LFPRESC

AUXPRESC

Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:22 STARTDLY 0x0 RW Start delay configuration

Delay sensor interaction STARTDELAY LFACLKLESENSE cycles for each channel

21:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:12 PCTOP 0x00 RW Period counter top value

These bits contain the top value for the period counter.

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 PCPRESC 0x0 RW Period counter prescaling

Value Mode Description

0 DIV1 The period counter clock frequency is LFACLKLESENSE/1

1 DIV2 The period counter clock frequency is LFACLKLESENSE/2

2 DIV4 The period counter clock frequency is LFACLKLESENSE/4

3 DIV8 The period counter clock frequency is LFACLKLESENSE/8

4 DIV16 The period counter clock frequency is LFACLKLESENSE/16

5 DIV32 The period counter clock frequency is LFACLKLESENSE/32

6 DIV64 The period counter clock frequency is LFACLKLESENSE/64

7 DIV128 The period counter clock frequency is LFACLKLESENSE/128

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:4 LFPRESC 0x0 RW Prescaling factor for low frequency timer

Value Mode Description

0 DIV1 Low frequency timer is clocked with LFACLKLESENSE/1

1 DIV2 Low frequency timer is clocked with LFACLKLESENSE/2

2 DIV4 Low frequency timer is clocked with LFACLKLESENSE/4

3 DIV8 Low frequency timer is clocked with LFACLKLESENSE/8

4 DIV16 Low frequency timer is clocked with LFACLKLESENSE/16

5 DIV32 Low frequency timer is clocked with LFACLKLESENSE/32

6 DIV64 Low frequency timer is clocked with LFACLKLESENSE/64

7 DIV128 Low frequency timer is clocked with LFACLKLESENSE/128

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 AUXPRESC 0x0 RW Prescaling factor for high frequency timer

Value Mode Description

0 DIV1 High frequency timer is clocked with AUXHFRCO/1

1 DIV2 High frequency timer is clocked with AUXHFRCO/2

2 DIV4 High frequency timer is clocked with AUXHFRCO/4

3 DIV8 High frequency timer is clocked with AUXHFRCO/8

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25.5.3 LESENSE_PERCTRL - Peripheral Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x008

Reset

0x0

0x00

0x0

Access

Name

WARMUPMODE

ACMP1MODE

ACMP0MODE

DACREF

DACPRESC

DACCH1OUT

DACCH0OUT

DACCH1CONV

DACCH0CONV

DACCH1DATA

DACCH0DATA

Bit Name Reset Access Description

31:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27:26 WARMUPMODE 0x0 RW ACMP and DAC duty cycle mode

Value Mode Description

0 NORMAL The analog comparators and DAC are shut down when LESENSE is idle

1 KEEPACMPWARM The analog comparators are kept powered up when LESENSE is idle

2 KEEPDACWARM The DAC is kept powered up when LESENSE is idle

3 KEEPACMPDACWARM The analog comparators and DAC are kept powered up when LESENSE is idle

25:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:22 ACMP1MODE 0x0 RW ACMP1 mode

Configure how LESENSE controls ACMP1

Value Mode Description

0 DISABLE LESENSE does not control ACMP1

1 MUX LESENSE controls the input mux (POSSEL) of ACMP1

2 MUXTHRES LESENSE controls the input mux and the threshold value (VDDLEVEL) of ACMP1

21:20 ACMP0MODE 0x0 RW ACMP0 mode

Configure how LESENSE controls ACMP0

Value Mode Description

0 DISABLE LESENSE does not control ACMP0

1 MUX LESENSE controls the input mux (POSSEL) of ACMP0

2 MUXTHRES LESENSE controls the input mux (POSSEL) and the threshold value (VDDLEVEL) of

ACMP0

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18 DACREF 0 RW DAC bandgap reference used

Set to BANDGAP if the DAC is configured to use bandgap reference

Value Mode Description

0 VDD DAC uses VDD reference

1 BANDGAP DAC uses bandgap reference

17:15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:10 DACPRESC 0x00 RW DAC prescaler configuration.

Prescaling factor of DACPRESC+1 for the LESENSE DAC interface

9:8 DACCH1OUT 0x0 RW DAC channel 1 output mode

Value Mode Description

0 DISABLE DAC CH1 output to pin and ACMP/ADC disabled

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Bit Name Reset Access Description

Value Mode Description

1 PIN DAC CH1 output to pin enabled, output to ADC and ACMP disabled

2 ADCACMP DAC CH1 output to pin disabled, output to ADC and ACMP enabled

3 PINADCACMP DAC CH1 output to pin, ADC, and ACMP enabled.

7:6 DACCH0OUT 0x0 RW DAC channel 0 output mode

Value Mode Description

0 DISABLE DAC CH0 output to pin and ACMP/ADC disabled

1 PIN DAC CH0 output to pin enabled, output to ADC and ACMP disabled

2 ADCACMP DAC CH0 output to pin disabled, output to ADC and ACMP enabled

3 PINADCACMP DAC CH0 output to pin, ADC, and ACMP enabled.

5:4 DACCH1CONV 0x0 RW DAC channel 1 conversion mode

Value Mode Description

0 DISABLE LESENSE does not control DAC CH1.

1 CONTINUOUS DAC channel 1 is driven in continuous mode.

2 SAMPLEHOLD DAC channel 1 is driven in sample hold mode.

3 SAMPLEOFF DAC channel 1 is driven in sample off mode.

3:2 DACCH0CONV 0x0 RW DAC channel 0 conversion mode

Value Mode Description

0 DISABLE LESENSE does not control DAC CH0.

1 CONTINUOUS DAC channel 0 is driven in continuous mode.

2 SAMPLEHOLD DAC channel 0 is driven in sample hold mode.

3 SAMPLEOFF DAC channel 0 is driven in sample off mode.

1 DACCH1DATA 0 RW DAC CH1 data selection.

Configure DAC data control.

Value Mode Description

0 DACDATA DAC data is defined by CH1DATA in the DAC interface.

1 ACMPTHRES DAC data is defined by ACMPTHRES in CHx_INTERACT.

0 DACCH0DATA 0 RW DAC CH0 data selection.

Value Mode Description

0 DACDATA DAC data is defined by CH0DATA in the DAC interface.

1 ACMPTHRES DAC data is defined by ACMPTHRES in CHx_INTERACT.

25.5.4 LESENSE_DECCTRL - Decoder control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x00C

Reset

0x0

Access

Name

PRSSEL3

PRSSEL2

PRSSEL1

PRSSEL0

INPUT

PRSCNT

HYSTIRQ

HYSTPRS2

HYSTPRS1

HYSTPRS0

INTMAP

ERRCHK

DISABLE

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Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:22 PRSSEL3 0x0 RW

Select PRS input for bit 3 of the LESENSE decoder

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

21:18 PRSSEL2 0x0 RW

Select PRS input for bit 2 of the LESENSE decoder

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

17:14 PRSSEL1 0x0 RW

Select PRS input for the bit 1 of the LESENSE decoder

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

13:10 PRSSEL0 0x0 RW

Select PRS input for the bit 0 of the LESENSE decoder

Value Mode Description

0 PRSCH0 PRS Channel 0 selected as input

1 PRSCH1 PRS Channel 1 selected as input

2 PRSCH2 PRS Channel 2 selected as input

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Bit Name Reset Access Description

Value Mode Description

3 PRSCH3 PRS Channel 3 selected as input

4 PRSCH4 PRS Channel 4 selected as input

5 PRSCH5 PRS Channel 5 selected as input

6 PRSCH6 PRS Channel 6 selected as input

7 PRSCH7 PRS Channel 7 selected as input

8 PRSCH8 PRS Channel 8 selected as input

9 PRSCH9 PRS Channel 9 selected as input

10 PRSCH10 PRS Channel 10 selected as input

11 PRSCH11 PRS Channel 11 selected as input

9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 INPUT 0 RW

Select input to the LESENSE decoder

Value Mode Description

0 SENSORSTATE The SENSORSTATE register is used as input to the decoder.

1 PRS PRS channels are used as input to the decoder.

7 PRSCNT 0 RW Enable count mode on decoder PRS channels 0 and 1

When set, decoder PRS0 and PRS1 will be used to produce output which can be used by a PCNT to count up or down.

6 HYSTIRQ 0 RW Enable decoder hysteresis on interrupt requests

When set, hysteresis is enabled in the decoder, suppressing interrupt requests.

5 HYSTPRS2 0 RW Enable decoder hysteresis on PRS2 output

When set, hysteresis is enabled in the decoder, suppressing changes on PRS channel 2

4 HYSTPRS1 0 RW Enable decoder hysteresis on PRS1 output

When set, hysteresis is enabled in the decoder, suppressing changes on PRS channel 1

3 HYSTPRS0 0 RW Enable decoder hysteresis on PRS0 output

When set, hysteresis is enabled in the decoder, suppressing changes on PRS channel 0

2 INTMAP 0 RW Enable decoder to channel interrupt mapping

When set, a transition from state x in the decoder will set interrupt flag CHx

1 ERRCHK 0 RW Enable check of current state

When set, the decoder checks the current state in addition to the states defined in TCONF

0 DISABLE 0 RW Disable the decoder

When set, the decoder is disabled. When disabled the decoder will keep its current state

25.5.5 LESENSE_BIASCTRL - Bias Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x010

Reset

0x0

Access

Name

BIASMODE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

1:0 BIASMODE 0x0 RW Select bias mode

Value Mode Description

0 DUTYCYCLE Bias module duty cycled between low power and high accuracy mode

1 HIGHACC Bias module always in high accuracy mode

2 DONTTOUCH Bias module not affected by LESENSE

25.5.6 LESENSE_CMD - Command Register

Offset Bit Position

0x014

Reset

Access

Name

CLEARBUF

DECODE

STOP

START

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 CLEARBUF 0 W1 Clear result buffer

2 DECODE 0 W1 Start decoder

1 STOP 0 W1 Stop scanning of sensors

If issued during a scan, the command will take effect after scan completion.

0 START 0 W1 Start scanning of sensors.

25.5.7 LESENSE_CHEN - Channel enable Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x018

Reset

0x0000

Access

Name

CHEN

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 CHEN 0x0000 RW Enable scan channel

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Bit Name Reset Access Description

Set bit X to enable channel X

25.5.8 LESENSE_SCANRES - Scan result register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x01C

Reset

0x0000

Access

Name

SCANRES

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 SCANRES 0x0000 R Scan results

Bit X will be set depending on channel X evaluation

25.5.9 LESENSE_STATUS - Status Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x020

Reset

Access

Name

DACACTIVE

SCANACTIVE

RUNNING

BUFFULL

BUFHALFFULL

BUFDATAV

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 DACACTIVE 0 R LESENSE DAC interface is active

4 SCANACTIVE 0 R LESENSE is currently interfacing sensors.

3 RUNNING 0 R LESENSE is active

2 BUFFULL 0 R Result buffer full

Set when the result buffer is full

1 BUFHALFFULL 0 R Result buffer half full

Set when the result buffer is half full

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Bit Name Reset Access Description

0 BUFDATAV 0 R Result data valid

Set when data is available in the result buffer. Cleared when the buffer is empty.

25.5.10 LESENSE_PTR - Result buffer pointers (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x024

Reset

0x0

Access

Name

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8:5 WR 0x0 R Result buffer write pointer.

These bits show the next index in the result buffer to be written to. Incremented when LESENSE writes to result buffer

4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 RD 0x0 R Result buffer read pointer.

These bits show the index of the oldest unread data in the result buffer. Incremented on read from BUFDATA.

25.5.11 LESENSE_BUFDATA - Result buffer data register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x028

Reset

0xXXXX

Access

Name

BUFDATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 BUFDATA 0xXXXX R Result data

This register can be used to read the oldest unread data from the result buffer.

25.5.12 LESENSE_CURCH - Current channel index (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x02C

Reset

0x0

Access

Name

CURCH

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 CURCH 0x0 R Shows the index of the current channel

25.5.13 LESENSE_DECSTATE - Current decoder state (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x030

Reset

0x0

Access

RWH

Name

DECSTATE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 DECSTATE 0x0 RWH Shows the current decoder state

25.5.14 LESENSE_SENSORSTATE - Decoder input register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x034

Reset

0x0

Access

RWH

Name

SENSORSTATE

Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 SENSORSTATE 0x0 RWH Shows the status of sensors chosen as input to the decoder

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25.5.15 LESENSE_IDLECONF - GPIO Idle phase configuration (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x038

Reset

0x0

Access

Name

CH15

CH14

CH13

CH12

CH11

CH10

CH9

CH8

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

Bit Name Reset Access Description

31:30 CH15 0x0 RW Channel 15 idle phase configuration

Value Mode Description

0 DISABLE CH15 output is disabled in idle phase

1 HIGH CH15 output is high in idle phase

2 LOW CH15 output is low in idle phase

3 DACCH1 CH15 output is connected to DAC CH1 output in idle phase

29:28 CH14 0x0 RW Channel 14 idle phase configuration

Value Mode Description

0 DISABLE CH14 output is disabled in idle phase

1 HIGH CH14 output is high in idle phase

2 LOW CH14 output is low in idle phase

3 DACCH1 CH14 output is connected to DAC CH1 output in idle phase

27:26 CH13 0x0 RW Channel 13 idle phase configuration

Value Mode Description

0 DISABLE CH13 output is disabled in idle phase

1 HIGH CH13 output is high in idle phase

2 LOW CH13 output is low in idle phase

3 DACCH1 CH13 output is connected to DAC CH1 output in idle phase

25:24 CH12 0x0 RW Channel 12 idle phase configuration

Value Mode Description

0 DISABLE CH12 output is disabled in idle phase

1 HIGH CH12 output is high in idle phase

2 LOW CH12 output is low in idle phase

3 DACCH1 CH12 output is connected to DAC CH1 output in idle phase

23:22 CH11 0x0 RW Channel 11 idle phase configuration

Value Mode Description

0 DISABLE CH11 output is disabled in idle phase

1 HIGH CH11 output is high in idle phase

2 LOW CH11 output is low in idle phase

21:20 CH10 0x0 RW Channel 10 idle phase configuration

Value Mode Description

0 DISABLE CH10 output is disabled in idle phase

1 HIGH CH10 output is high in idle phase

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Bit Name Reset Access Description

Value Mode Description

2 LOW CH10 output is low in idle phase

19:18 CH9 0x0 RW Channel 9 idle phase configuration

Value Mode Description

0 DISABLE CH9 output is disabled in idle phase

1 HIGH CH9 output is high in idle phase

2 LOW CH9 output is low in idle phase

17:16 CH8 0x0 RW Channel 8 idle phase configuration

Value Mode Description

0 DISABLE CH8 output is disabled in idle phase

1 HIGH CH8 output is high in idle phase

2 LOW CH8 output is low in idle phase

15:14 CH7 0x0 RW Channel 7 idle phase configuration

Value Mode Description

0 DISABLE CH7 output is disabled in idle phase

1 HIGH CH7 output is high in idle phase

2 LOW CH7 output is low in idle phase

13:12 CH6 0x0 RW Channel 6 idle phase configuration

Value Mode Description

0 DISABLE CH6 output is disabled in idle phase

1 HIGH CH6 output is high in idle phase

2 LOW CH6 output is low in idle phase

11:10 CH5 0x0 RW Channel 5 idle phase configuration

Value Mode Description

0 DISABLE CH5 output is disabled in idle phase

1 HIGH CH5 output is high in idle phase

2 LOW CH5 output is low in idle phase

9:8 CH4 0x0 RW Channel 4 idle phase configuration

Value Mode Description

0 DISABLE CH4 output is disabled in idle phase

1 HIGH CH4 output is high in idle phase

2 LOW CH4 output is low in idle phase

7:6 CH3 0x0 RW Channel 3 idle phase configuration

Value Mode Description

0 DISABLE CH3 output is disabled in idle phase

1 HIGH CH3 output is high in idle phase

2 LOW CH3 output is low in idle phase

3 DACCH0 CH3 output is connected to DAC CH0 output in idle phase

5:4 CH2 0x0 RW Channel 2 idle phase configuration

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Bit Name Reset Access Description

Value Mode Description

0 DISABLE CH2 output is disabled in idle phase

1 HIGH CH2 output is high in idle phase

2 LOW CH2 output is low in idle phase

3 DACCH0 CH2 output is connected to DAC CH0 output in idle phase

3:2 CH1 0x0 RW Channel 1 idle phase configuration

Value Mode Description

0 DISABLE CH1 output is disabled in idle phase

1 HIGH CH1 output is high in idle phase

2 LOW CH1 output is low in idle phase

3 DACCH0 CH1 output is connected to DAC CH0 output in idle phase

1:0 CH0 0x0 RW Channel 0 idle phase configuration

Value Mode Description

0 DISABLE CH0 output is disabled in idle phase

1 HIGH CH0 output is high in idle phase

2 LOW CH0 output is low in idle phase

3 DACCH0 CH0 output is connected to DAC CH0 output in idle phase

25.5.16 LESENSE_ALTEXCONF - Alternative excite pin configuration

(Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x03C

Reset

0x0

Access

Name

AEX7

AEX6

AEX5

AEX4

AEX3

AEX2

AEX1

AEX0

IDLECONF7

IDLECONF6

IDLECONF5

IDLECONF4

IDLECONF3

IDLECONF2

IDLECONF1

IDLECONF0

Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23 AEX7 0 RW ALTEX7 always excite enable

22 AEX6 0 RW ALTEX6 always excite enable

21 AEX5 0 RW ALTEX5 always excite enable

20 AEX4 0 RW ALTEX4 always excite enable

19 AEX3 0 RW ALTEX3 always excite enable

18 AEX2 0 RW ALTEX2 always excite enable

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Bit Name Reset Access Description

17 AEX1 0 RW ALTEX1 always excite enable

16 AEX0 0 RW ALTEX0 always excite enable

15:14 IDLECONF7 0x0 RW ALTEX7 idle phase configuration

Value Mode Description

0 DISABLE ALTEX7 output is disabled in idle phase

1 HIGH ALTEX7 output is high in idle phase

2 LOW ALTEX7 output is low in idle phase

13:12 IDLECONF6 0x0 RW ALTEX6 idle phase configuration

Value Mode Description

0 DISABLE ALTEX6 output is disabled in idle phase

1 HIGH ALTEX6 output is high in idle phase

2 LOW ALTEX6 output is low in idle phase

11:10 IDLECONF5 0x0 RW ALTEX5 idle phase configuration

Value Mode Description

0 DISABLE ALTEX5 output is disabled in idle phase

1 HIGH ALTEX5 output is high in idle phase

2 LOW ALTEX5 output is low in idle phase

9:8 IDLECONF4 0x0 RW ALTEX4 idle phase configuration

Value Mode Description

0 DISABLE ALTEX4 output is disabled in idle phase

1 HIGH ALTEX4 output is high in idle phase

2 LOW ALTEX4 output is low in idle phase

7:6 IDLECONF3 0x0 RW ALTEX3 idle phase configuration

Value Mode Description

0 DISABLE ALTEX3 output is disabled in idle phase

1 HIGH ALTEX3 output is high in idle phase

2 LOW ALTEX3 output is low in idle phase

5:4 IDLECONF2 0x0 RW ALTEX2 idle phase configuration

Value Mode Description

0 DISABLE ALTEX2 output is disabled in idle phase

1 HIGH ALTEX2 output is high in idle phase

2 LOW ALTEX2 output is low in idle phase

3:2 IDLECONF1 0x0 RW ALTEX1 idle phase configuration

Value Mode Description

0 DISABLE ALTEX1 output is disabled in idle phase

1 HIGH ALTEX1 output is high in idle phase

2 LOW ALTEX1 output is low in idle phase

1:0 IDLECONF0 0x0 RW ALTEX0 idle phase configuration

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Bit Name Reset Access Description

Value Mode Description

0 DISABLE ALTEX0 output is disabled in idle phase

1 HIGH ALTEX0 output is high in idle phase

2 LOW ALTEX0 output is low in idle phase

25.5.17 LESENSE_IF - Interrupt Flag Register

Offset Bit Position

0x040

Reset

Access

Name

CNTOF

BUFOF

BUFLEVEL

BUFDATAV

DECERR

DEC

SCANCOMPLETE

CH15

CH14

CH13

CH12

CH11

CH10

CH9

CH8

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 CNTOF 0 R

Set when the LESENSE counter overflows.

21 BUFOF 0 R

Set when the result buffer overflows

20 BUFLEVEL 0 R

Set when the data buffer is full.

19 BUFDATAV 0 R

Set when data is available in the result buffer.

18 DECERR 0 R

Set when the decoder detects an error

17 DEC 0 R

Set when the decoder has issued and interrupt request

16 SCANCOMPLETE 0 R

Set when a scan sequence is completed

15 CH15 0 R

Set when channel 15 triggers

14 CH14 0 R

Set when channel 14 triggers

13 CH13 0 R

Set when channel 13 triggers

12 CH12 0 R

Set when channel 12 triggers

11 CH11 0 R

Set when channel 11 triggers

10 CH10 0 R

Set when channel 10 triggers

9 CH9 0 R

Set when channel 9 triggers

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Bit Name Reset Access Description

8 CH8 0 R

Set when channel 8 triggers

7 CH7 0 R

Set when channel 7 triggers

6 CH6 0 R

Set when channel 6 triggers

5 CH5 0 R

Set when channel 5 triggers

4 CH4 0 R

Set when channel 4 triggers

3 CH3 0 R

Set when channel 3 triggers

2 CH2 0 R

Set when channel 2 triggers

1 CH1 0 R

Set when channel 1 triggers

0 CH0 0 R

Set when channel 0 triggers

25.5.18 LESENSE_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x044

Reset

Access

Name

CNTOF

BUFOF

BUFLEVEL

BUFDATAV

DECERR

DEC

SCANCOMPLETE

CH15

CH14

CH13

CH12

CH11

CH10

CH9

CH8

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 CNTOF 0 W1

Write to 1 to clear CNTOF interrupt flag

21 BUFOF 0 W1

Write to 1 to clear BUFOF interrupt flag

20 BUFLEVEL 0 W1

Write to 1 to clear BUFLEVEL interrupt flag

19 BUFDATAV 0 W1

Write to 1 to clear BUFDATAV interrupt flag

18 DECERR 0 W1

Write to 1 to clear DECERR interrupt flag

17 DEC 0 W1

Write to 1 to clear DEC interrupt flag

16 SCANCOMPLETE 0 W1

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Bit Name Reset Access Description

Write to 1 to clear SCANCOMPLETE interrupt flag

15 CH15 0 W1

Write to 1 to clear CH15 interrupt flag

14 CH14 0 W1

Write to 1 to clear CH14 interrupt flag

13 CH13 0 W1

Write to 1 to clear CH13 interrupt flag

12 CH12 0 W1

Write to 1 to clear CH12 interrupt flag

11 CH11 0 W1

Write to 1 to clear CH11 interrupt flag

10 CH10 0 W1

Write to 1 to clear CH10 interrupt flag

9 CH9 0 W1

Write to 1 to clear CH9 interrupt flag

8 CH8 0 W1

Write to 1 to clear CH8 interrupt flag

7 CH7 0 W1

Write to 1 to clear CH7 interrupt flag

6 CH6 0 W1

Write to 1 to clear CH6 interrupt flag

5 CH5 0 W1

Write to 1 to clear CH5 interrupt flag

4 CH4 0 W1

Write to 1 to clear CH4 interrupt flag

3 CH3 0 W1

Write to 1 to clear CH3 interrupt flag

2 CH2 0 W1

Write to 1 to clear CH2 interrupt flag

1 CH1 0 W1

Write to 1 to clear CH1 interrupt flag

0 CH0 0 W1

Write to 1 to clear CH0 interrupt flag

25.5.19 LESENSE_IFS - Interrupt Flag Set Register

Offset Bit Position

0x048

Reset

Access

Name

CNTOF

BUFOF

BUFLEVEL

BUFDATAV

DECERR

DEC

SCANCOMPLETE

CH15

CH14

CH13

CH12

CH11

CH10

CH9

CH8

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

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Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 CNTOF 0 W1

Write to 1 to set the CNTOF interrupt flag

21 BUFOF 0 W1

Write to 1 to set the BUFOF interrupt flag

20 BUFLEVEL 0 W1

Write to 1 to set the BUFLEVEL interrupt flag

19 BUFDATAV 0 W1

Write to 1 to set the BUFDATAV interrupt flag

18 DECERR 0 W1

Write to 1 to set the DECERR interrupt flag

17 DEC 0 W1

Write to 1 to set the DEC interrupt flag

16 SCANCOMPLETE 0 W1

Write to 1 to set the SCANCOMPLETE interrupt flag

15 CH15 0 W1

Write to 1 to set the CH15 interrupt flag

14 CH14 0 W1

Write to 1 to set the CH14 interrupt flag

13 CH13 0 W1

Write to 1 to set the CH13 interrupt flag

12 CH12 0 W1

Write to 1 to set the CH12 interrupt flag

11 CH11 0 W1

Write to 1 to set the CH11 interrupt flag

10 CH10 0 W1

Write to 1 to set the CH10 interrupt flag

9 CH9 0 W1

Write to 1 to set the CH9 interrupt flag

8 CH8 0 W1

Write to 1 to set the CH8 interrupt flag

7 CH7 0 W1

Write to 1 to set the CH7 interrupt flag

6 CH6 0 W1

Write to 1 to set the CH6 interrupt flag

5 CH5 0 W1

Write to 1 to set the CH5 interrupt flag

4 CH4 0 W1

Write to 1 to set the CH4 interrupt flag

3 CH3 0 W1

Write to 1 to set the CH3 interrupt flag

2 CH2 0 W1

Write to 1 to set the CH2 interrupt flag

1 CH1 0 W1

Write to 1 to set the CH1 interrupt flag

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Bit Name Reset Access Description

0 CH0 0 W1

Write to 1 to set the CH0 interrupt flag

25.5.20 LESENSE_IEN - Interrupt Enable Register

Offset Bit Position

0x04C

Reset

Access

Name

CNTOF

BUFOF

BUFLEVEL

BUFDATAV

DECERR

DEC

SCANCOMPLETE

CH15

CH14

CH13

CH12

CH11

CH10

CH9

CH8

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 CNTOF 0 RW

Set to enable interrupt on the CNTOF interrupt flag

21 BUFOF 0 RW

Set to enable interrupt on the BUFOF interrupt flag

20 BUFLEVEL 0 RW

Set to enable interrupt on the BUFLEVEL interrupt flag

19 BUFDATAV 0 RW

Set to enable interrupt on the BUFDATAV interrupt flag

18 DECERR 0 RW

Set to enable interrupt on the DECERR interrupt flag

17 DEC 0 RW

Set to enable interrupt on the DEC interrupt flag

16 SCANCOMPLETE 0 RW

Set to enable interrupt on the SCANCOMPLETE interrupt flag

15 CH15 0 RW

Set to enable interrupt on the CH15 interrupt flag

14 CH14 0 RW

Set to enable interrupt on the CH14 interrupt flag

13 CH13 0 RW

Set to enable interrupt on the CH13 interrupt flag

12 CH12 0 RW

Set to enable interrupt on the CH12 interrupt flag

11 CH11 0 RW

Set to enable interrupt on the CH11 interrupt flag

10 CH10 0 RW

Set to enable interrupt on the CH10 interrupt flag

9 CH9 0 RW

Set to enable interrupt on the CH9 interrupt flag

8 CH8 0 RW

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Bit Name Reset Access Description

Set to enable interrupt on the CH8 interrupt flag

7 CH7 0 RW

Set to enable interrupt on the CH7 interrupt flag

6 CH6 0 RW

Set to enable interrupt on the CH6 interrupt flag

5 CH5 0 RW

Set to enable interrupt on the CH5 interrupt flag

4 CH4 0 RW

Set to enable interrupt on the CH4 interrupt flag

3 CH3 0 RW

Set to enable interrupt on the CH3 interrupt flag

2 CH2 0 RW

Set to enable interrupt on the CH2 interrupt flag

1 CH1 0 RW

Set to enable interrupt on the CH1 interrupt flag

0 CH0 0 RW

Set to enable interrupt on the CH0 interrupt flag

25.5.21 LESENSE_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x050

Reset

Access

Name

EVAL

INTERACT

TIMING

DATA

TCONFB

TCONFA

POWERDOWN

ROUTE

ALTEXCONF

IDLECONF

SENSORSTATE

DECSTATE

CURCH

BUFDATA

PTR

STATUS

SCANRES

CHEN

CMD

BIASCTRL

DECCTRL

PERCTRL

TIMCTRL

CTRL

Bit Name Reset Access Description

31:27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 EVAL 0 R LESENSE_CHx_EVAL Register Busy

Set when the value written to LESENSE_CHx_EVAL is being synchronized.

25 INTERACT 0 R LESENSE_CHx_INTERACT Register Busy

Set when the value written to LESENSE_CHx_INTERACT is being synchronized.

24 TIMING 0 R LESENSE_CHx_TIMING Register Busy

Set when the value written to LESENSE_CHx_TIMING is being synchronized.

23 DATA 0 R LESENSE_BUFx_DATA Register Busy

Set when the value written to LESENSE_BUFx_DATA is being synchronized.

22 TCONFB 0 R LESENSE_STx_TCONFB Register Busy

Set when the value written to LESENSE_STx_TCONFB is being synchronized.

21 TCONFA 0 R LESENSE_STx_TCONFA Register Busy

Set when the value written to LESENSE_STx_TCONFA is being synchronized.

20:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 POWERDOWN 0 R LESENSE_POWERDOWN Register Busy

Set when the value written to LESENSE_POWERDOWN is being synchronized.

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Bit Name Reset Access Description

16 ROUTE 0 R LESENSE_ROUTE Register Busy

Set when the value written to LESENSE_ROUTE is being synchronized.

15 ALTEXCONF 0 R LESENSE_ALTEXCONF Register Busy

Set when the value written to LESENSE_ALTEXCONF is being synchronized.

14 IDLECONF 0 R LESENSE_IDLECONF Register Busy

Set when the value written to LESENSE_IDLECONF is being synchronized.

13 SENSORSTATE 0 R LESENSE_SENSORSTATE Register Busy

Set when the value written to LESENSE_SENSORSTATE is being synchronized.

12 DECSTATE 0 R LESENSE_DECSTATE Register Busy

Set when the value written to LESENSE_DECSTATE is being synchronized.

11 CURCH 0 R LESENSE_CURCH Register Busy

Set when the value written to LESENSE_CURCH is being synchronized.

10 BUFDATA 0 R LESENSE_BUFDATA Register Busy

Set when the value written to LESENSE_BUFDATA is being synchronized.

9 PTR 0 R LESENSE_PTR Register Busy

Set when the value written to LESENSE_PTR is being synchronized.

8 STATUS 0 R LESENSE_STATUS Register Busy

Set when the value written to LESENSE_STATUS is being synchronized.

7 SCANRES 0 R LESENSE_SCANRES Register Busy

Set when the value written to LESENSE_SCANRES is being synchronized.

6 CHEN 0 R LESENSE_CHEN Register Busy

Set when the value written to LESENSE_CHEN is being synchronized.

5 CMD 0 R LESENSE_CMD Register Busy

Set when the value written to LESENSE_CMD is being synchronized.

4 BIASCTRL 0 R LESENSE_BIASCTRL Register Busy

Set when the value written to LESENSE_BIASCTRL is being synchronized.

3 DECCTRL 0 R LESENSE_DECCTRL Register Busy

Set when the value written to LESENSE_DECCTRL is being synchronized.

2 PERCTRL 0 R LESENSE_PERCTRL Register Busy

Set when the value written to LESENSE_PERCTRL is being synchronized.

1 TIMCTRL 0 R LESENSE_TIMCTRL Register Busy

Set when the value written to LESENSE_TIMCTRL is being synchronized.

0 CTRL 0 R LESENSE_CTRL Register Busy

Set when the value written to LESENSE_CTRL is being synchronized.

25.5.22 LESENSE_ROUTE - I/O Routing Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x054

Reset

Access

Name

ALTEX7PEN

ALTEX6PEN

ALTEX5PEN

ALTEX4PEN

ALTEX3PEN

ALTEX2PEN

ALTEX1PEN

ALTEX0PEN

CH15PEN

CH14PEN

CH13PEN

CH12PEN

CH11PEN

CH10PEN

CH9PEN

CH8PEN

CH7PEN

CH6PEN

CH5PEN

CH4PEN

CH3PEN

CH2PEN

CH1PEN

CH0PEN

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Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23 ALTEX7PEN 0 RW ALTEX7 Pin Enable

22 ALTEX6PEN 0 RW ALTEX6 Pin Enable

21 ALTEX5PEN 0 RW ALTEX5 Pin Enable

20 ALTEX4PEN 0 RW ALTEX4 Pin Enable

19 ALTEX3PEN 0 RW ALTEX3 Pin Enable

18 ALTEX2PEN 0 RW ALTEX2 Pin Enable

17 ALTEX1PEN 0 RW ALTEX1 Pin Enable

16 ALTEX0PEN 0 RW ALTEX0 Pin Enable

15 CH15PEN 0 RW CH15 Pin Enable

14 CH14PEN 0 RW CH14 Pin Enable

13 CH13PEN 0 RW CH13 Pin Enable

12 CH12PEN 0 RW CH12 Pin Enable

11 CH11PEN 0 RW CH11 Pin Enable

10 CH10PEN 0 RW CH10 Pin Enable

9 CH9PEN 0 RW CH9 Pin Enable

8 CH8PEN 0 RW CH8 Pin Enable

7 CH7PEN 0 RW CH7 Pin Enable

6 CH6PEN 0 RW CH6 Pin Enable

5 CH5PEN 0 RW CH5 Pin Enable

4 CH4PEN 0 RW CH4 Pin Enable

3 CH3PEN 0 RW CH3 Pin Enable

2 CH2PEN 0 RW CH2 Pin Enable

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Bit Name Reset Access Description

1 CH1PEN 0 RW CH0 Pin Enable

0 CH0PEN 0 RW CH0 Pin Enable

25.5.23 LESENSE_POWERDOWN - LESENSE RAM power-down register

(Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x058

Reset

Access

Name

RAM

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 RAM 0 RW LESENSE RAM power-down

Shut off power to the LESENSE RAM. Once it is powered down, it cannot be powered up again

25.5.24 LESENSE_STx_TCONFA - State transition configuration A (Async

Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x200

Reset

0xX

Access

Name

CHAIN

SETIF

PRSACT

NEXTSTATE

MASK

COMP

Bit Name Reset Access Description

31:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18 CHAIN X RW Enable state descriptor chaining

When set, descriptor in the next location will also be evaluated

17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 SETIF X RW Set interrupt flag enable

Set interrupt flag when sensor state equals COMP

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Bit Name Reset Access Description

15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:12 PRSACT 0xX RW Configure transition action

Configure which action to perform when sensor state equals COMP

DECCTRL_PRSCNT = 0

Mode Value Description

NONE 0 No PRS pulses generated

PRS0 1 Generate pulse on LESPRS0

PRS1 2 Generate pulse on LESPRS1

PRS01 3 Generate pulse on LESPRS0 and LESPRS1

PRS2 4 Generate pulse on LESPRS2

PRS02 5 Generate pulse on LESPRS0 and LESPRS2

PRS12 6 Generate pulse on LESPRS1 and LESPRS2

PRS012 7 Generate pulse on LESPRS0, LESPRS1 and LESPRS2

DECCTRL_PRSCNT = 1

NONE 0 Do not count

UP 1 Count up

DOWN 2 Count down

PRS2 4 Generate pulse on LESPRS2

UPANDPRS2 5 Count up and generate pulse on LESPRS2.

DOWNANDPRS2 6 Count down and generate pulse on LESPRS2.

11:8 NEXTSTATE 0xX RW Next state index

Index of next state to be entered if the sensor state equals COMP

7:4 MASK 0xX RW Sensor mask

Set bit X to exclude sensor X from evaluation.

3:0 COMP 0xX RW Sensor compare value

State transition is triggered when sensor state equals COMP

25.5.25 LESENSE_STx_TCONFB - State transition configuration B (Async

Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x204

Reset

0xX

Access

Name

SETIF

PRSACT

NEXTSTATE

MASK

COMP

Bit Name Reset Access Description

31:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 SETIF X RW Set interrupt flag

Set interrupt flag when sensor state equals COMP

15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:12 PRSACT 0xX RW Configure transition action

Configure which action to perform when sensor state equals COMP

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Bit Name Reset Access Description

DECCTRL_PRSCNT = 0

Mode Value Description

NONE 0 No PRS pulses generated

PRS0 1 Generate pulse on PRS0

PRS1 2 Generate pulse on PRS1

PRS01 3 Generate pulse on PRS0 and PRS1

PRS2 4 Generate pulse on PRS2

PRS02 5 Generate pulse on PRS0 and PRS2

PRS12 6 Generate pulse on PRS1 and PRS2

PRS012 7 Generate pulse on PRS0, PRS1 and PRS2

DECCTRL_PRSCNT = 1

NONE 0 Do not count

UP 1 Count up

DOWN 2 Count down

PRS2 4 Generate pulse on PRS2

UPANDPRS2 5 Count up and generate pulse on PRS2.

DOWNANDPRS2 6 Count down and generate pulse on PRS2.

11:8 NEXTSTATE 0xX RW Next state index

Index of next state to be entered if the sensor state equals COMP

7:4 MASK 0xX RW Sensor mask

Set bit X to exclude sensor X from evaluation.

3:0 COMP 0xX RW Sensor compare value

State transition is triggered when sensor state equals COMP

25.5.26 LESENSE_BUFx_DATA - Scan results (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x280

Reset

0xXXXX

Access

Name

DATA

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DATA 0xXXXX RW Scan result buffer

25.5.27 LESENSE_CHx_TIMING - Scan configuration (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x2C0

Reset

0xXX

Access

Name

MEASUREDLY

SAMPLEDLY

EXTIME

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19:13 MEASUREDLY 0xXX RW Set measure delay

Configure measure delay. Sensor measuring is delayed for MEASUREDLY+1 EXCLK cycles.

12:6 SAMPLEDLY 0xXX RW Set sample delay

Configure sample delay. Sampling will occur after SAMPLEDLY+1 SAMPLECLK cycles.

5:0 EXTIME 0xXX RW Set excitation time

Configure excitation time. Excitation will last EXTIME+1 EXCLK cycles.

25.5.28 LESENSE_CHx_INTERACT - Scan configuration (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x2C4

Reset

0xX

0xXXX

Access

Name

ALTEX

SAMPLECLK

EXCLK

EXMODE

SETIF

SAMPLE

ACMPTHRES

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19 ALTEX X RW Use alternative excite pin

If set, alternative excite pin will be used for excitation

18 SAMPLECLK X RW Select clock used for timing of sample delay

Value Mode Description

0 LFACLK LFACLK will be used for timing

1 AUXHFRCO AUXHFRCO will be used for timing

17 EXCLK X RW Select clock used for excitation timing

Value Mode Description

0 LFACLK LFACLK will be used for timing

1 AUXHFRCO AUXHFRCO will be used for timing

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Bit Name Reset Access Description

16:15 EXMODE 0xX RW Set GPIO mode

GPIO mode for the excitation phase of the scan sequence. Note that DACOUT is only available on channels 0, 1, 2, 3, 12, 13, 14,

and 15.

Value Mode Description

0 DISABLE Disabled

1 HIGH Push Pull, GPIO is driven high

2 LOW Push Pull, GPIO is driven low

3 DACOUT DAC output

14:13 SETIF 0xX RW Enable interrupt generation

Select interrupt generation mode for CHx interrupt flag.

Value Mode Description

0 NONE No interrupt is generated

1 LEVEL Set interrupt flag if the sensor triggers.

2 POSEDGE Set interrupt flag on positive edge on the sensor state

3 NEGEDGE Set interrupt flag on negative edge on the sensor state

12 SAMPLE X RW Select sample mode

Select if ACMP output or counter output should be used in comparison

Value Mode Description

0 COUNTER Counter output will be used in comparison

1 ACMP ACMP output will be used in comparison

11:0 ACMPTHRES 0xXXX RW Set ACMP threshold

Select ACMP threshold.

25.5.29 LESENSE_CHx_EVAL - Scan configuration (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x2C8

Reset

0xXXXX

Access

Name

SCANRESINV

STRSAMPLE

DECODE

COMP

COMPTHRES

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19 SCANRESINV X RW Enable inversion of result

If set, the bit stored in SCANRES will be inverted.

18 STRSAMPLE X RW Select if counter result should be stored

If set, the counter value will be stored and available in the result buffer

17 DECODE X RW Send result to decoder

If set, the result from this channel will be shifted into the decoder register.

16 COMP X RW Select mode for counter comparison

Set compare mode

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Bit Name Reset Access Description

CH_INTERACT_SAMPLE =

COUNTER

Mode Value Description

LESS 0 Comparison evaluates to 1 if counter value is less than

COMPTHRES.

GE 1 Comparison evaluates to 1 if counter value is greater than, or equal

to COMPTHRES.

CH_INTERACT_SAMPLE =

ACMP

LESS 0 Comparison evaluates to 1 if the ACMP output is 0.

GE 1 Comparison evaluates to 1 if the ACMP output is 1.

15:0 COMPTHRES 0xXXXX RW Decision threshold for counter

Set counter threshold

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26 ACMP - Analog Comparator

01 2 3 4

Quick Facts

What?

The ACMP (Analog Comparator) compares

two analog signals and returns a digital value

telling which is greater.

Why?

Applications often do not need to know the

exact value of an analog signal, only if it has

passed a certain threshold. Often the voltage

must be monitored continuously, which

requires extremely low power consumption.

How?

Available down to Energy Mode 3 and using

as little as 100 nA, the ACMP can wake

up the system when input signals pass

the threshold. The analog comparator can

compare two analog signals or one analog

signal and a highly configurable internal

reference.

26.1 Introduction

The Analog Comparator is used to compare the voltage of two analog inputs, with a digital output

indicating which input voltage is higher. Inputs can either be one of the selectable internal references

or from external pins. Response time and thereby also the current consumption can be configured by

altering the current supply to the comparator.

26.2 Features

• 8 selectable external positive inputs

• 8 selectable external negative inputs

• 5 selectable internal negative inputs

• Internal 1.25 V bandgap

• Internal 2.5 V bandgap

• VDD scaled by 64 selectable factors

• DAC channel 0 and 1

• Low power mode for internal VDD and bandgap references

• Selectable hysteresis

• 8 levels between 0 and ±70 mV

• Selectable response time

• Asynchronous interrupt generation on selectable edges

• Rising edge

• Falling edge

• Both edges

• Operational in EM0-EM3

• Dedicated capacitive sense mode with up to 8 inputs

• Adjustable internal resistor

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• Configurable inversion of comparator output

• Configurable output when inactive

• Comparator output direct on PRS

• Comparator output on GPIO through alternate functionality

• Output inversion available

26.3 Functional Description

An overview of the ACMP is shown in Figure 26.1 (p. 669) .

Figure 26.1. ACMP Overview

Scaler

1.25 V

2.5 V

ACMPn_CH7

ACMPn_CH0

ACMPn_CH6

ACMPn_CH5

ACMPn_CH4

ACMPn_CH3

ACMPn_CH2

ACMPn_CH1

Output to PRS

Output to GPIO

VDDLEVELNEGSEL

POSSEL

BIASPROG

HYSTSEL

EN ACMPACT

ACMPOUT

INACTVAL

Warm-up

counter

GPIOINV

000

111

0000

1101

VDD

Read only registers

Read/Write registers

LPREF

Edge interrupt

Warmup interrupt

HALFBIAS

FULLBIAS

VDD_SCALED

DAC0_CH0

DAC0_CH1

The comparator has two analog inputs, one positive and one negative. When the comparator is active,

the output indicates which of the two input voltages is higher. When the voltage on the positive input is

higher than the voltage on the negative input, the digital output is high and vice versa.

The output of the comparator can be read in the ACMPOUT bit in ACMPn_STATUS. It is possible to

switch inputs while the comparator is enabled, but all other configuration should only be changed while

the comparator is disabled.

26.3.1 Warm-up Time

The analog comparator is enabled by setting the EN bit in ACMPn_CTRL. When this bit is set, the

comparator must stabilize before becoming active and the outputs can be used. This time period is called

the warm-up time. The warm-up time is a configurable number of peripheral clock (HFPERCLK) cycles,

set in WARMTIME, which should be set to at least 10 µs but lengthens to up to 1ms if LPREF is enabled.

The ACMP should always start in active mode and then enable the LPREF after warm-up time. When

the comparator is enabled and warmed up, the ACMPACT bit in ACMPn_STATUS will indicate that the

comparator is active. The output value when the comparator is inactive is set to the value in INACTVAL

in ACMPn_CTRL (see Figure 26.1 (p. 669) ).

An edge interrupt will be generated after the warm-up time if edge interrupt is enabled and the value set

in INACTVAL is different from ACMPOUT after warm-up.

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One should wait until the warm-up period is over before entering EM2 or EM3, otherwise no comparator

interrupts will be detected. EM1 can still be entered during warm-up. After the warm-up period is

completed, interrupts will be detected in EM2 and EM3.

26.3.2 Response Time

There is a delay from when the actual input voltage changes polarity, to when the output toggles. This

period is called the response time and can be altered by increasing or decreasing the bias current to

the comparator through the BIASPROG, FULLBIASPROG and HALFBIAS fields in the ACMPn_CTRL

halves the current. Setting a lower bias current will result in lower power consumption, but a longer

response time.

If the FULLBIAS bit is set, the highest hysteresis level should be used to avoid glitches on the output.

Table 26.1. Bias Configuration

Bias Current (µA), HYSTSEL=0BIASPROG

FULLBIAS=0,

HALFBIAS=1 FULLBIAS=0,

HALFBIAS=0 FULLBIAS=1,

HALFBIAS=1 FULLBIAS=1,

HALFBIAS=0

0b0000 0.05 0.1 3.3 6.5

0b0001 0.1 0.2 6.5 13

0b0010 0.2 0.4 13 26

0b0011 0.3 0.6 20 39

0b0100 0.4 0.8 26 52

0b0101 0.5 1.0 33 65

0b0110 0.6 1.2 39 78

0b0111 0.7 1.4 46 91

0b1000 1.0 2.0 65 130

0b1001 1.1 2.2 72 143

0b1010 1.2 2.4 78 156

0b1011 1.3 2.6 85 169

0b1100 1.4 2.8 91 182

0b1101 1.5 3.0 98 195

0b1110 1.6 3.2 104 208

0b1111 1.7 3.4 111 221

26.3.3 Hysteresis

In the analog comparator, hysteresis can be configured to 8 different levels, including off which is level

0, through the HYSTSEL field in ACMPn_CTRL. When the hysteresis level is set above 0, the digital

output will not toggle until the positive input voltage is at a voltage equal to the hysteresis level above

or below the negative input voltage (see Figure 26.2 (p. 671) ). This feature can be used to filter

out uninteresting input fluctuations around zero and only show changes that are big enough to breach

the hysteresis threshold. Note that the ACMP current consumption will be influenced by the selected

hysteresis level and in general decrease with increasing HYSTSEL values.

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Figure 26.2. 20 mV Hysteresis Selected

InNEG

ACMPOUT with hysteresis

InNEG +20mV

InNEG -20mV

ACMPOUT without hysteresis

Time

InPOS

26.3.4 Input Selection

The POSSEL and NEGSEL fields in ACMPn_INPUTSEL controls which signals are connected to the

two inputs of the comparator. 8 external pins are available for both the negative and positive input. For

the negative input, 5 additional internal reference sources are available; 1.25 V bandgap, 2.5V bandgap,

DAC channel 0, DAC channel 1, and VDD. The VDD reference can be scaled by a configurable factor,

which is set in VDDLEVEL (in ACMPn_INPUTSEL) according to the following formula:

VDD Scaled

VDD_SCALED = VDD×VDDLEVEL/63 (26.1)

A low power reference mode can be enabled by setting the LPREF bit in ACMPn_INPUTSEL. In this

mode, the power consumption in the reference buffer (VDD and bandgap) is lowered at the cost of

accuracy. Low power mode will only save power if VDD with VDDLEVEL higher than 0 or a bandgap

reference is selected.

Normally the analog comparator input mux is disabled when the EN (in ACMPn_CTRL) bit is set low.

However if the MUXEN bit in ACMPn_CTRL is set, the mux is enabled regardless of the EN bit. This will

minimize kickback noise on the mux inputs when the EN bit is toggled.

26.3.5 Capacitive Sense Mode

The analog comparator includes specialized hardware for capacitive sensing of passive push buttons.

Such buttons are traces on PCB laid out in a way that creates a parasitic capacitor between the button

and the ground node. Because a human finger will have a small intrinsic capacitance to ground, the

capacitance of the button will increase when the button is touched. The capacitance is measured by

including the capacitor in a free-running RC oscillator (see Figure 26.3 (p. 672) ). The frequency

produced will decrease when the button is touched compared to when it is not touched. By measuring

the output frequency with a timer (e.g. through PRS), the change in capacitance can be calculated.

The analog comparator contains a complete feedback loop including an optional internal resistor.

This resistor is enabled by setting the CSRESEN bit in ACMPn_INPUTSEL. The resistance can be

set to one of four values by configuring the CSRESSEL bits in ACMPn_INPUTSEL. If the internal

resistor is not enabled, the circuit will be open. The capacitive sense mode is enabled by setting

the NEGSEL field in ACMPn_INPUTSEL to CAPSENSE. The input pin is selected through the

POSSEL bits in ACMPn_INPUTSEL. The scaled VDD in Figure 26.3 (p. 672) can be altered by

configuring the VDDLEVEL in ACMPn_INPUTSEL. It is recommended to set the hysteresis (HYSTSEL

in ACMPn_CTRL) higher than the lowest level when using the analog comparator in capacitive sense

mode.

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Figure 26.3. Capacitive Sensing Set-up

VDD/4

VDD_SCALED

Buttons

POSSEL

26.3.6 Interrupts and PRS Output

The analog comparator includes an edge triggered interrupt flag (EDGE in ACMPn_IF). If either IRISE

and/or IFALL in ACMPn_CTRL is set, the EDGE interrupt flag will be set on rising and/or falling edge

of the comparator output, respectively. An interrupt request will be sent if the EDGE interrupt flag in

ACMPn_IF is set and enabled through the EDGE bit in ACMPn_IEN. The edge interrupt can also be

used to wake up the device from EM3-EM1.

The analog comparator also includes an interrupt flag, WARMUP in ACMPn_IF, which is set when

a warm-up sequence has finished. An interrupt request will be sent if the WARMUP interrupt flag in

ACMPn_IF is set and enabled through the WARMUP bit in ACMPn_IEN.

The comparator output is also available as a PRS signal.

26.3.7 Output to GPIO

The output from the comparator is available as alternate function to the GPIO pins. Set the ACMPPEN

bit in ACMPn_ROUTE to enable output to pin, and the LOCATION bits to select output location. The

GPIO-pin must also be set as output. The output to the GPIO can be inverted by setting the GPIOINV

bit in ACMPn_CTRL.

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26.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 ACMPn_CTRL RW Control Register

0x004 ACMPn_INPUTSEL RW Input Selection Register

0x008 ACMPn_STATUS R Status Register

0x00C ACMPn_IEN RW Interrupt Enable Register

0x010 ACMPn_IF R Interrupt Flag Register

0x014 ACMPn_IFS W1 Interrupt Flag Set Register

0x018 ACMPn_IFC W1 Interrupt Flag Clear Register

0x01C ACMPn_ROUTE RW I/O Routing Register

26.5 Register Description

26.5.1 ACMPn_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x7

0x0

Access

Name

FULLBIAS

HALFBIAS

BIASPROG

IFALL

IRISE

WARMTIME

HYSTSEL

GPIOINV

INACTVAL

MUXEN

Bit Name Reset Access Description

31 FULLBIAS 0 RW Full Bias Current

Set this bit to 1 for full bias current in accordance with Table 26.1 (p. 670) .

30 HALFBIAS 1 RW Half Bias Current

Set this bit to 1 to halve the bias current in accordance with Table 26.1 (p. 670) .

29:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27:24 BIASPROG 0x7 RW Bias Configuration

These bits control the bias current level in accordance with Table 26.1 (p. 670) .

23:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 IFALL 0 RW Falling Edge Interrupt Sense

Set this bit to 1 to set the EDGE interrupt flag on falling edges of comparator output.

Value Mode Description

0 DISABLED Interrupt flag is not set on falling edges.

1 ENABLED Interrupt flag is set on falling edges.

16 IRISE 0 RW Rising Edge Interrupt Sense

Set this bit to 1 to set the EDGE interrupt flag on rising edges of comparator output.

Value Mode Description

0 DISABLED Interrupt flag is not set on rising edges.

1 ENABLED Interrupt flag is set on rising edges.

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 WARMTIME 0x0 RW Warm-up Time

Set analog comparator warm-up time.

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Bit Name Reset Access Description

Value Mode Description

0 4CYCLES 4 HFPERCLK cycles.

1 8CYCLES 8 HFPERCLK cycles.

2 16CYCLES 16 HFPERCLK cycles.

3 32CYCLES 32 HFPERCLK cycles.

4 64CYCLES 64 HFPERCLK cycles.

5 128CYCLES 128 HFPERCLK cycles.

6 256CYCLES 256 HFPERCLK cycles.

7 512CYCLES 512 HFPERCLK cycles.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:4 HYSTSEL 0x0 RW Hysteresis Select

Select hysteresis level. The hysteresis levels can vary, please see the electrical characteristics for the device for more information.

Value Mode Description

0 HYST0 No hysteresis.

1 HYST1 ~15 mV hysteresis.

2 HYST2 ~22 mV hysteresis.

3 HYST3 ~29 mV hysteresis.

4 HYST4 ~36 mV hysteresis.

5 HYST5 ~43 mV hysteresis.

6 HYST6 ~50 mV hysteresis.

7 HYST7 ~57 mV hysteresis.

3 GPIOINV 0 RW Comparator GPIO Output Invert

Set this bit to 1 to invert the comparator alternate function output to GPIO.

Value Mode Description

0 NOTINV The comparator output to GPIO is not inverted.

1 INV The comparator output to GPIO is inverted.

2 INACTVAL 0 RW Inactive Value

The value of this bit is used as the comparator output when the comparator is inactive.

Value Mode Description

0 LOW The inactive value is 0.

1 HIGH The inactive state is 1.

1 MUXEN 0 RW Input Mux Enable

Enable Input Mux. Setting the EN bit will also enable the input mux.

0 EN 0 RW Analog Comparator Enable

Enable/disable analog comparator.

26.5.2 ACMPn_INPUTSEL - Input Selection Register

Offset Bit Position

0x004

Reset

0x0

0x00

0x8

0x0

Access

Name

CSRESSEL

CSRESEN

LPREF

VDDLEVEL

NEGSEL

POSSEL

Bit Name Reset Access Description

31:30 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

29:28 CSRESSEL 0x0 RW Capacitive Sense Mode Internal Resistor Select

These bits select the resistance value for the internal capacitive sense resistor. Resulting actual resistor values are given in the

device datasheets.

Value Mode Description

0 RES0 Internal capacitive sense resistor value 0.

1 RES1 Internal capacitive sense resistor value 1.

2 RES2 Internal capacitive sense resistor value 2.

3 RES3 Internal capacitive sense resistor value 3.

27:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24 CSRESEN 0 RW Capacitive Sense Mode Internal Resistor Enable

Enable/disable the internal capacitive sense resistor.

23:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 LPREF 1 RW Low Power Reference Mode

Enable low power mode for VDD and bandgap references.

Value Description

0 Low power mode disabled.

1 Low power mode enabled.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 VDDLEVEL 0x00 RW VDD Reference Level

Select scaling factor for VDD reference level.VDD_SCALED = VDD×VDDLEVEL/63.

7:4 NEGSEL 0x8 RW Negative Input Select

Select negative input.

Value Mode Description

0 CH0 Channel 0 as negative input.

1 CH1 Channel 1 as negative input.

2 CH2 Channel 2 as negative input.

3 CH3 Channel 3 as negative input.

4 CH4 Channel 4 as negative input.

5 CH5 Channel 5 as negative input.

6 CH6 Channel 6 as negative input.

7 CH7 Channel 7 as negative input.

8 1V25 1.25 V as negative input.

9 2V5 2.5 V as negative input.

10 VDD Scaled VDD as negative input.

11 CAPSENSE Capacitive sense mode.

12 DAC0CH0 DAC0 channel 0.

13 DAC0CH1 DAC0 channel 1.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 POSSEL 0x0 RW Positive Input Select

Select positive input.

Value Mode Description

0 CH0 Channel 0 as positive input.

1 CH1 Channel 1 as positive input.

2 CH2 Channel 2 as positive input.

3 CH3 Channel 3 as positive input.

4 CH4 Channel 4 as positive input.

5 CH5 Channel 5 as positive input.

6 CH6 Channel 6 as positive input.

7 CH7 Channel 7 as positive input.

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26.5.3 ACMPn_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

ACMPOUT

ACMPACT

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 ACMPOUT 0 R Analog Comparator Output

Analog comparator output value.

0 ACMPACT 0 R Analog Comparator Active

Analog comparator active status.

26.5.4 ACMPn_IEN - Interrupt Enable Register

Offset Bit Position

0x00C

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 RW Warm-up Interrupt Enable

Enable/disable interrupt on finished warm-up.

0 EDGE 0 RW Edge Trigger Interrupt Enable

Enable/disable edge triggered interrupt.

26.5.5 ACMPn_IF - Interrupt Flag Register

Offset Bit Position

0x010

Reset

Access

Name

WARMUP

EDGE

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Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 R Warm-up Interrupt Flag

Indicates that the analog comparator warm-up period is finished.

0 EDGE 0 R Edge Triggered Interrupt Flag

Indicates that there has been a rising or falling edge on the analog comparator output.

26.5.6 ACMPn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x014

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 W1 Warm-up Interrupt Flag Set

Write to 1 to set warm-up finished interrupt flag.

0 EDGE 0 W1 Edge Triggered Interrupt Flag Set

Write to 1 to set edge triggered interrupt flag.

26.5.7 ACMPn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x018

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 W1 Warm-up Interrupt Flag Clear

Write to 1 to clear warm-up finished interrupt flag.

0 EDGE 0 W1 Edge Triggered Interrupt Flag Clear

Write to 1 to clear edge triggered interrupt flag.

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26.5.8 ACMPn_ROUTE - I/O Routing Register

Offset Bit Position

0x01C

Reset

0x0

Access

Name

LOCATION

ACMPPEN

Bit Name Reset Access Description

31:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 LOCATION 0x0 RW I/O Location

Decides the location of the ACMP I/O pin.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

7:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 ACMPPEN 0 RW ACMP Output Pin Enable

Enable/disable analog comparator output to pin.

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27 VCMP - Voltage Comparator

01 2 3 4

Interrupts

VDD > X ?

Battery

VDD < X ?

VCMP

VDD

GND

Quick Facts

What?

The Voltage Supply Comparator (VCMP)

monitors the input voltage supply and

generates software interrupts on events using

as little as 100 nA.

Why?

The VCMP can be used for simple power

supply monitoring, e.g. for a battery level

indicator.

How?

The scaled power supply is compared to a

programmable reference voltage, and an

interrupt can be generated when the supply

is higher or lower than the reference. The

VCMP can also be duty-cycled by software to

further reduce the energy consumption.

27.1 Introduction

The Voltage Supply Comparator is used to monitor the supply voltage from software. An interrupt can

be generated when the supply falls below or rises above a programmable threshold.

Note Note that VCMP comes in addition to the Power-on Reset and Brown-out Detector

peripherals, that both generate reset signals when the voltage supply is insufficient for

reliable operation. VCMP does not generate reset, only interrupt. Also note that the ADC is

capable of sampling the input voltage supply.

27.2 Features

• Voltage supply monitoring

• Scalable VDD in 64 steps selectable as positive comparator input

• Internal 1.25 V bandgap reference

• Low power mode for internal VDD and bandgap references

• Selectable hysteresis

• 0 or ±20 mV

• Selectable response time

• Asynchronous interrupt generation on selectable edges

• Rising edge

• Falling edge

• Rising and Falling edges

• Operational in EM0-EM3

• Comparator output direct on PRS

• Configurable output when inactive to avoid unwanted interrupts

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27.3 Functional Description

An overview of the VCMP is shown in Figure 27.1 (p. 680) .

Figure 27.1. VCMP Overview

1.25V

BIASPROG

HYSTEN

EN Warm-up

counter

Read only register

Read/Write registers

LPREF

Scaler

TRIGLEVEL

VDD

VCMPACT

VCMPOUT

INACTVAL

Edge interrupt

Warmup interrupt

PRS

HALFBIAS

The comparator has two analog inputs, one positive and one negative. When the comparator is active,

the output indicates which of the two input voltages is higher. When the voltage on the positive input is

higher than the negative input voltage, the digital output is high and vice versa.

The output of the comparator can be read in the VCMPOUT bit in VCMP_STATUS. Configuration

registers should only be changed while the comparator is disabled.

27.3.1 Warm-up Time

VCMP is enabled by setting the EN bit in VCMP_CTRL. When this bit is set, the comparator must stabilize

before becoming active and the outputs can be used. This time period is called the warm-up time. The

warm-up time is a configurable number of HFPERCLK cycles, set in WARMTIME, which should be set to

at least 10 µs. When the comparator is enabled and warmed up, the VCMPACT bit in VCMP_STATUS

will be set to indicate that the comparator is active.

As long as the comparator is not enabled or not warmed up, VCMPACT will be cleared and the

comparator output value is set to the value in INACTVAL in VCMP_CTRL.

One should wait until the warm-up period is over before entering EM2 or EM3, otherwise no comparator

interrupts will be detected. EM1 can still be entered during warm-up. After the warm-up period is

completed, interrupts will be detected in EM2 and EM3.

27.3.2 Response Time

There is a delay from when the actual input voltage changes polarity, to when the output toggles. This

period is called the response time and can be altered by increasing or decreasing the bias current to the

comparator through the BIAS and HALFBIAS fields in VCMP_CTRL as shown in Table 27.1 (p. 680)

. Setting a lower bias current will result in lower power consumption, but a longer response time.

Table 27.1. Bias Configuration

Bias Current (µA)BIAS

HALFBIAS=0 HALFBIAS=1

0b0000 0.1 0.05

0b0001 0.2 0.1

0b0010 0.4 0.2

0b0011 0.6 0.3

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Bias Current (µA)BIAS

HALFBIAS=0 HALFBIAS=1

0b0100 0.8 0.4

0b0101 1.0 0.5

0b0110 1.2 0.6

0b0111 1.4 0.7

0b1000 2.0 1.0

0b1001 2.2 1.1

0b1010 2.4 1.2

0b1011 2.6 1.3

0b1100 2.8 1.4

0b1101 3.0 1.5

0b1110 3.2 1.6

0b1111 3.4 1.7

27.3.3 Hysteresis

In the voltage supply comparator, hysteresis can be enabled by setting HYSTEN in VCMP_CTRL. When

HYSTEN is set, the digital output will not toggle until the positive input voltage is at least 20mV above

or below the negative input voltage. This feature can be used to filter out uninteresting input fluctuations

around zero and only show changes that are big enough to breach the hysteresis threshold.

Figure 27.2. VCMP 20 mV Hysteresis Enabled

InNEG

VCMPOUT with hysteresis

InNEG +20mV

InNEG -20mV

VCMPOUT without hysteresis

Time

InPOS

27.3.4 Input Selection

The positive comparator input is always connected to the scaled power supply input. The negative

comparator input is connected to the internal 1.25 V bandgap reference. The VDD trigger level can be

configured by setting the TRIGLEVEL field in VCMP_CTRL according to the following formula:

VCMP VDD Trigger Level

VDD Trigger Level= 1.667V + 0.034V × TRIGLEVEL (27.1)

A low power reference mode can be enabled by setting the LPREF bit in VCMP_INPUTSEL. In this mode,

the power consumption in the reference buffer (VDD and bandgap) is lowered at the cost of accuracy.

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27.3.5 Interrupts and PRS Output

The VCMP includes an edge triggered interrupt flag (EDGE in VCMP_IF). If either IRISE and/or IFALL in

VCMPn_CTRL is set, the EDGE interrupt flag will be set on rising and/or falling edge of the comparator

output respectively. An interrupt request will be sent if the EDGE interrupt flag in VCMP_IF is set and

enabled through the EDGE bit in VCMPn_IEN. The edge interrupt can also be used to wake up the

device from EM3-EM1. VCMP also includes an interrupt flag, WARMUP in VCMP_IF, which is set when

a warm-up sequence has finished. An interrupt request will be sent if the WARMUP interrupt flag in

VCMP_IF is set and enabled through the WARMUP bit in VCMPn_IEN. The synchronized comparator

output is also available as a PRS output signal.

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27.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 VCMP_CTRL RW Control Register

0x004 VCMP_INPUTSEL RW Input Selection Register

0x008 VCMP_STATUS R Status Register

0x00C VCMP_IEN RW Interrupt Enable Register

0x010 VCMP_IF R Interrupt Flag Register

0x014 VCMP_IFS W1 Interrupt Flag Set Register

0x018 VCMP_IFC W1 Interrupt Flag Clear Register

27.5 Register Description

27.5.1 VCMP_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x7

0x0

Access

Name

HALFBIAS

BIASPROG

IFALL

IRISE

WARMTIME

HYSTEN

INACTVAL

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30 HALFBIAS 1 RW Half Bias Current

Set this bit to 1 to halve the bias current. Table 27.1 (p. 680) .

29:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27:24 BIASPROG 0x7 RW VCMP Bias Programming Value

These bits control the bias current level. Table 27.1 (p. 680) .

23:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 IFALL 0 RW Falling Edge Interrupt Sense

Set this bit to 1 to set the EDGE interrupt flag on falling edges of comparator output.

16 IRISE 0 RW Rising Edge Interrupt Sense

Set this bit to 1 to set the EDGE interrupt flag on rising edges of comparator output.

15:11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 WARMTIME 0x0 RW Warm-Up Time

Set warm-up time

Value Mode Description

0 4CYCLES 4 HFPERCLK cycles

1 8CYCLES 8 HFPERCLK cycles

2 16CYCLES 16 HFPERCLK cycles

3 32CYCLES 32 HFPERCLK cycles

4 64CYCLES 64 HFPERCLK cycles

5 128CYCLES 128 HFPERCLK cycles

6 256CYCLES 256 HFPERCLK cycles

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Bit Name Reset Access Description

Value Mode Description

7 512CYCLES 512 HFPERCLK cycles

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 HYSTEN 0 RW Hysteresis Enable

Enable hysteresis.

Value Description

0 No hysteresis

1 +-20 mV hysteresis

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 INACTVAL 0 RW Inactive Value

Configure the output value when the comparator is inactive.

1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 EN 0 RW Voltage Supply Comparator Enable

Enable/disable voltage supply comparator.

27.5.2 VCMP_INPUTSEL - Input Selection Register

Offset Bit Position

0x004

Reset

0x00

Access

Name

LPREF

TRIGLEVEL

Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 LPREF 0 RW Low Power Reference

Enable/disable low power mode for VDD and bandgap reference. When using this bit, always leave it as 0 during warm-up and then

set it to 1 if desired when the warm-up is done.

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 TRIGLEVEL 0x00 RW Trigger Level

Select VDD trigger level. Vtrig = 1.667V+0.034V×TRIGLEVEL.

27.5.3 VCMP_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

VCMPOUT

VCMPACT

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Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 VCMPOUT 0 R Voltage Supply Comparator Output

Voltage supply comparator output value

0 VCMPACT 0 R Voltage Supply Comparator Active

Voltage supply comparator active status.

27.5.4 VCMP_IEN - Interrupt Enable Register

Offset Bit Position

0x00C

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 RW Warm-up Interrupt Enable

Enable/disable interrupt on finished warm-up.

0 EDGE 0 RW Edge Trigger Interrupt Enable

Enable/disable edge triggered interrupt.

27.5.5 VCMP_IF - Interrupt Flag Register

Offset Bit Position

0x010

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 R Warm-up Interrupt Flag

Indicates that warm-up has finished.

0 EDGE 0 R Edge Triggered Interrupt Flag

Indicates that there has been a rising and/or falling edge on the VCMP output.

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27.5.6 VCMP_IFS - Interrupt Flag Set Register

Offset Bit Position

0x014

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 W1 Warm-up Interrupt Flag Set

Write to 1 to set warm-up finished interrupt flag

0 EDGE 0 W1 Edge Triggered Interrupt Flag Set

Write to 1 to set edge triggered interrupt flag

27.5.7 VCMP_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x018

Reset

Access

Name

WARMUP

EDGE

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 WARMUP 0 W1 Warm-up Interrupt Flag Clear

Write to 1 to clear warm-up finished interrupt flag

0 EDGE 0 W1 Edge Triggered Interrupt Flag Clear

Write to 1 to clear edge triggered interrupt flag

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28 ADC - Analog to Digital Converter

01 2 3 4

ADC ...0101110...

Quick Facts

What?

The ADC is used to convert analog signals

into a digital representation and features 8

external input channels

Why?

In many applications there is a need to

measure analog signals and record them in

a digital representation, without exhausting

your energy source.

How?

A low power Successive Approximation

in a programmable sequence. With the help

of PRS and DMA, the ADC can operate

without CPU intervention, minimizing the

number of powered up resources. The ADC

can further be duty-cycled to reduce the

energy consumption.

28.1 Introduction

The ADC is a Successive Approximation Register (SAR) architecture, with a resolution of up to 12 bits

at up to one million samples per second. The integrated input mux can select inputs from 8 external

pins and 6 internal signals.

28.2 Features

• Programmable resolution (6/8/12-bit)

• 13 prescaled clock (ADC_CLK) cycles per conversion

• Maximum 1 MSPS @ 12-bit

• Maximum 1.86 MSPS @ 6-bit

• Configurable acquisition time

• Integrated prescaler

• Selectable clock division factor from 1 to 128

• 13 MHz to 32 kHz allowed for ADC_CLK

• 18 input channels

• 8 external single ended channels

• 6 internal single ended channels

• Including temperature sensor

• 4 external differential channels

• Integrated input filter

• Low pass RC filter

• Decoupling capacitor

• Left or right adjusted results

• Results in 2’s complement representation

• Differential results sign extended to 32-bit results

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• Programmable scan sequence

• Up to 8 configurable samples in scan sequence

• Mask to select which pins are included in the sequence

• Triggered by software or PRS input

• One shot or repetitive mode

• Oversampling available

• Overflow interrupt flag set when overwriting unread results

• Conversion tailgating support for predictable periodic scans

• Programmable single conversion

• Triggered by software or PRS input

• Can be interleaved between two scan sequences

• One shot or repetitive mode

• Oversampling available

• Overflow interrupt flag set when overwriting unread results

• Hardware oversampling support

• 1st order accumulate and dump filter

• From 2 to 4096 oversampling ratio (OSR)

• Results in 16-bit representation

• Enabled individually for scan sequence and single sample mode

• Common OSR select

• Individually selectable voltage reference for scan and single mode

• Internal 1.25V reference

• Internal 2.5V reference

• VDD

• Internal 5 V differential reference

• Single ended external reference

• Differential external reference

• Unbuffered 2xVDD

• Support for offset and gain calibration

• Interrupt generation and/or DMA request

• Finished single conversion

• Finished scan conversion

• Single conversion results overflow

• Scan sequence results overflow

• Loopback configuration with DAC output measurement

28.3 Functional Description

An overview of the ADC is shown in Figure 28.1 (p. 689) .

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Figure 28.1. ADC Overview

SAR

ADCn_CH0

ADCn_CH7 Temp

VSS

VDD

VDD/3

DAC0/OPA0

ADCn_CH1

ADCn_CH2

ADCn_CH3

ADCn_CH4

ADCn_CH5

ADCn_CH6

2.5 V

1.25 V

VDD

Sequencer Result

buffer

Control

ADCn_SINGLEDATA

ADCn_SCANDATA

ADCn_SCANCTRL

ADCn_CTRL

ADCn_SINGLECTRL

Prescaler ADC_CLKHFPERCLKADCn

DAC1/OPA1

Oversampling

filter

ADCn_CMD

ADCn_STATUS

2x(VDD-VSS)

5 V differential

Vref/2

28.3.1 Clock Selection

The ADC has an internal prescaler (PRESC bits in ADCn_CTRL) which can divide the peripheral clock

(HFPERCLK) by any factor between 1 and 128. Note that the resulting ADC_CLK should not be set to

a higher frequency than 13 MHz and not lower than 32 kHz.

28.3.2 Conversions

A conversion consists of two phases. The input is sampled in the acquisition phase before it is converted

to digital representation during the approximation phase. The acquisition time can be configured

independently for scan and single conversions (see Section 28.3.7 (p. 693) ) by setting AT in

ADCn_SINGLECTRL/ADCn_SCANCTRL. The acquisition times can be set to any integer power of 2

from 1 to 256 ADC_CLK cycles.

Note For high impedance sources the acquisition time should be adjusted to allow enough time

for the internal sample capacitor to fully charge. The minimum acquisition time for the

internal temperature sensor and Vdd/3 is given in the electrical characteristics for the device.

The analog to digital converter core uses one clock cycle per output bit in the approximation phase.

ADC Total Conversion Time (in ADC_CLK cycles) Per Output

Tconv= (TA+N) x OSR (28.1)

TA equals the number of acquisition cycles and N is the resolution. OSR is the oversampling ratio (see

Section 28.3.7.7 (p. 695) ). The minimum conversion time is 7 ADC_CYCLES with 6 bit resolution and

13 ADC_CYCLES with 12 bit resolution. The maximum conversion time is 1097728 ADC_CYCLES with

the longest acquisition time, 12 bit resolution and highest oversampling rate.

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Figure 28.2. ADC Conversion Timing

Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

SINGLEAT/

SCANAT

6-bit value ready 8-bit value ready 12-bit value ready

HFPERCLKADCn

Prescaled clock (4x)

ADC action

28.3.3 Warm-up Time

The ADC needs to be warmed up some time before a conversion can take place. This time period is

called the warm-up time. When enabling the ADC or changing references between samples, the ADC

is automatically warmed up for 1µs and an additional 5 µs if the bandgap is selected as reference.

Normally, the ADC will be warmed up only when samples are requested and is shut off when there are

no more samples waiting. However, if lower latency is needed, configuring the WARMUPMODE field in

ADCn_CTRL allows the ADC and/or reference to stay warm between samples, eliminating the need for

warm-up. Figure 28.3 (p. 691) shows the analog power consumption in scenarios using the different

WARMUPMODE settings.

Only the bandgap reference selected for scan mode can be kept warm. If a different bandgap reference

is selected for single mode, the warm-up time still applies.

• NORMAL: ADC and references are shut off when there are no samples waiting. a) in Figure 28.3 (p.

691) shows this mode used with an internal bandgap reference. Figure d) shows this mode when

using VDD or an external reference.

• FASTBG: Bandgap warm-up is eliminated, but with reduced reference accuracy. d) in Figure 28.3 (p.

691) shows this mode used with an internal bandgap reference.

• KEEPSCANREFWARM: The reference selected for scan mode is kept warm. The ADC will still need

to be warmed up before conversion. b) in Figure 28.3 (p. 691) shows this mode used with an internal

bandgap reference.

• KEEPADCWARM: The ADC and the reference selected for scan mode is kept warm. c) in

Figure 28.3 (p. 691) shows this mode used with an internal bandgap reference.

The minimum warm-up times are given in µs. The timing is done automatically by the ADC, given that

a proper time base is given in the TIMEBASE bits in ADCn_CTRL. The TIMEBASE must be set to the

number of HFPERCLK which corresponds to at least 1 µs. The TIMEBASE only affects the timing of the

warm-up sequence and not the ADC_CLK.

When entering Energy Modes 2 or 3, the ADC must be stopped and WARMUPMODE in ADCn_CTRL

written to 0.

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Figure 28.3. ADC Analog Power Consumption With Different WARMUPMODE Settings

ADC enabled Conversion trigger Conversion trigger

Power

Time

ADC warm-up

ADC conversion

Bandgap reference warm-up

5 µs

1 µs 1 µs

5 µs5 µs

5 µs

NORMAL

KEEPSCANREFWARM

(w SCANREF = internal bandgap)

KEEPADCWARM

(w SCANREF = internal bandgap)

Power

Time

FASTBG

(w SCANREF = any)

NORMAL

(w SCANREF = external or VDD)

28.3.4 Input Selection

The ADC is connected to 8 external input pins, which can be selected as 8 different single ended inputs or

4 differential inputs. In addition, 6 single ended internal inputs can be selected. The available selections

are given in the register description for ADCn_SINGLECTRL and ADCn_SCANCTRL.

For offset calibration purposes it is possible to internally short the differential ADC inputs and thereby

measure a 0 V differential. Differential 0 V is selected by writing the DIFF bit to 1 and INPUTSEL to 4 in

ADCn_SINGLECTRL. Calibration is described in detail in Section 28.3.10 (p. 696) .

Note When VDD/3 is sampled, the acquisition time should be above a lower limit. The reader is

referred to the datasheet for minimum VDD/3 acquisition time.

28.3.4.1 Input Filtering

The selected input signal can be filtered, either through an internal low pass RC filter or an internal

decoupling capacitor. The different filter configurations can be enabled through the LPFMODE bits in

ADCn_CTRL. For maximum SNR, LPFMODE is recommended set to DECAP, with a cutoff frequency

of 31.5 MHz.

The RC input filter configuration is given in Figure 28.4 (p. 692) . The resistance and capacitance values

are given in the electrical characteristics for the device, named RADCFILT and CADCFILT respectively.

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Figure 28.4. ADC RC Input Filter Configuration

ADC

Input R

28.3.4.2 Temperature Measurement

The ADC includes an internal temperature sensor. This sensor is characterized during production and the

temperature readout from the ADC at production temperature, ADC0_TEMP_0_READ_1V25, is given

in the Device Information (DI) page. The production temperature, CAL_TEMP_0, is also given in this

page. The temperature gradient, TGRAD_ADCTH (mV/degree Celsius), for the sensor is found in the

datasheet for the devices. By selecting 1.25 V internal reference and measuring the internal temperature

sensor with 12 bit resolution, the temperature can be calculated according to the following formula:

ADC Temperature Measurement

TCELSIUS=CAL_TEMP_0-(ADC0_TEMP_0_READ_1V25-

ADC_result)×Vref/(4096×TGRAD_ADCTH) (28.2)

Note The minimum acquisition time for the temperature reference is found in the electrical

characteristics for the device.

28.3.5 Reference Selection

The reference voltage can be selected from these sources:

• 1.25 V internal bandgap.

• 2.5 V internal bandgap.

• VDD.

• 5 V internal differential bandgap.

• External single ended input from Ch. 6.

• Differential input, 2x(Ch. 6 - Ch. 7).

• Unbuffered 2xVDD.

• The 2.5 V reference needs a supply voltage higher than 2.5 V.

• The differential 5 V reference needs a supply voltage higher than 2.75 V.

Since the 2xVDD differential reference is unbuffered, it is directly connected to the ADC supply voltage

and more susceptible to supply noise. The VDD reference is buffered both in single ended and differential

mode.

If a differential reference with a larger range than the supply voltage is combined with single ended

measurements, for instance the 5 V internal reference, the full ADC range will not be available because

the maximum input voltage is limited by the maximum electrical ratings.

Note Single ended measurements with the external differential reference are not supported.

28.3.6 Programming of Bias Current

The bias current of the bandgap reference and the ADC comparator can be scaled by the BIASPROG,

HALFBIAS and COMPBIAS bit fields of the ADCn_BIASPROG register. The BIASPROG and HALFBIAS

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bitfields scale the current of ADC bandgap reference, and the COMPBIAS bits provide an additional

bias programming for the ADC comparator as illustrated in Figure 28.5 (p. 693) . The electrical

characteristics given in the datasheet require the bias configuration to be set to the default values, where

no other bias values are given.

Figure 28.5. ADC Bias Programming

COMPBIAS

BIASPROG

HALFBIAS

Reference

Current

Internal

bandgap

reference

ADC

Comparator

The minimum value of the BIASPROG and COMPBIAS bitfields of the ADCn_BIASPROG register

(i.e. BIASPROG=0b0000, COMPBIAS=0b0000) represent the minimum bias currents. Similarly

BIASPROG=0b1111 and COMPBIAS=0b1111 represent the maximum bias currents. Additionally, the

bias current defined by the BIASPROG setting can be halved by setting the HALFBIAS bit of the

ADCn_BIASPROG register.

The bias current settings should only be changed while the ADC is disabled.

28.3.7 ADC Modes

The ADC contains two separate programmable modes, one single sample mode and one scan mode.

Both modes have separate configuration and result registers and can be set up to run only once per

trigger or repetitively. The scan mode has priority over the single sample mode. However, if scan

sequence is running, a triggered single sample will be interleaved between two scan samples.

28.3.7.1 Single Sample Mode

The single sample mode can be used to convert a single sample either once per trigger or repetitively.

The configuration of the single sample mode is done in the ADCn_SINGLECTRL register and the

results are found in the ADCn_SINGLEDATA register. The SINGLEDV bit in ADCn_STATUS is set

high when there is valid data in the result register and is cleared when the data is read. The single

mode results can also be read through ADCn_SINGLEDATAP without SINGLEDV being cleared. DIFF

in ADCn_SINGLECTRL selects whether differential or single ended inputs are used and INPUTSEL

selects input pin(s).

28.3.7.2 Scan mode

The scan mode is used to perform sweeps of the inputs. The configuration of the scan sequence is done

in the ADCn_SCANCTRL register and the results are found in the ADCn_SCANDATA register. The

SCANDV bit in ADCn_STATUS is set high when there is valid data in the result register and is cleared

when the data is read. The scan mode results can also be read through ADCn_SCANDATAP without

SCANDV being cleared. The inputs included in the sequence are defined by a the mask in INPUTMASK

in ADCn_SCANCTRL. When the scan sequence is triggered, the sequence samples all inputs that are

included in the mask, starting at the lowest pin number. DIFF in ADCn_SCANCTRL selects whether

single ended or differential inputs are used.

28.3.7.3 Conversion Tailgating

The scan sequence has priority over the single sample mode. However, a scan trigger will not interrupt

in the middle of a single conversion. If a scan sequence is triggered by a timer on a periodic basis,

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single sample just before a scan trigger can delay the start of the scan sequence, thus causing jitter in

sample rate. To solve this, conversion tailgating can be chosen by setting TAILGATE in ADCn_CTRL.

When this bit is set, any triggered single samples will wait for the next scan sequence to finish before

activating (see Figure 28.6 (p. 694) ). The single sample will then follow immediately after the scan

sequence. In this way, the scan sequence will always start immediately when triggered, if the period

between the scan triggers is big enough to allow any single samples that might be triggered to finish

in between the scan sequences.

Figure 28.6. ADC Conversion Tailgating

SINGLESTART

SCANSTART

SCANACT

ADC action

SINGLEACT

Scan Single Scan Single Scan

28.3.7.4 Conversion Trigger

The conversion modes can be activated by writing a 1 to the SINGLESTART or SCANSTART bit

in the ADCn_CMD register. The conversions can be stopped by writing a 1 to the SINGLESTOP or

SCANSTOP bit in the ADCn_CMD register. A START command will have priority over a stop command.

When the ADC is stopped in the middle of a conversion, the result buffer is cleared. The SINGLEACT

and SCANACT bits in ADCn_STATUS are set high when the modes are actively converting or have

pending conversions.

It is also possible to trigger conversions from PRS signals. The system requires one HFPERCLK

cycle pulses to trigger conversions. Setting PRSEN in ADCn_SINGLECTRL/ADCn_SCANCTRL

enables triggering from PRS input. Which PRS channel to listen to is defined by PRSSEL in

ADCn_SINGLECTRL/ADCn_SCANCTRL. When PRS trigger is selected, it is still possible to trigger the

conversion from software. The reader is referred to the PRS datasheet for more information on how to

set up the PRS channels.

Note The conversion settings should not be changed while the ADC is running as this can lead to

unpredictable behavior.

The prescaled clock phase is always reset by a triggered conversion as long as a

conversion is not ongoing. This gives predictable latency from the time of the trigger to the

time the conversion starts, regardless of when in the prescaled clock cycle the trigger occur.

28.3.7.5 Results

The results are presented in 2’s complement form and the format for differential and single ended mode

is given in Table 28.1 (p. 694) and Table 28.2 (p. 695) . If differential mode is selected, the results

are sign extended up to 32-bit (shown in Table 28.4 (p. 696) ).

Table 28.1. ADC Single Ended Conversion

Results

Input/Reference Binary Hex value

1 111111111111 FFF

0.5 011111111111 7FF

1/4096 000000000001 001

0 000000000000 000

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Table 28.2. ADC Differential Conversion

Results

Input/Reference Binary Hex value

0.5 011111111111 7FF

0.25 001111111111 3FF

1/2048 000000000001 001

0 000000000000 000

-1/2048 111111111111 FFF

-0.25 101111111111 BFF

-0.5 100000000000 800

28.3.7.6 Resolution

The ADC gives out 12-bit results, by default. However, if full 12-bit resolution is not needed, it is possible

to speed up the conversion by selecting a lower resolution (N = 6 or 8 bits). For more information on the

accuracy of the ADC, the reader is referred to the electrical characteristics section for the device.

28.3.7.7 Oversampling

To achieve higher accuracy, hardware oversampling can be enabled individually for each mode (Set RES

in ADCn_SINGLECTRL/ADCn_SCANCTRL to 0x3). The oversampling rate (OVSRSEL in ADCn_CTRL)

can be set to any integer power of 2 from 2 to 4096 and the configuration is shared between the scan

and single sample mode (OVSRSEL field in ADCn_CTRL).

With oversampling, each selected input is sampled a number (given by the OVSR) of times, and the

results are filtered by a first order accumulate and dump filter to form the end result. The data presented in

the ADCn_SINGLEDATA and ADCn_SCANDATA registers are the direct contents of the accumulation

results are shifted to fit the MSB in bit 15 as shown in Table 28.3 (p. 695) .

Table 28.3. Oversampling Result Shifting and Resolution

Oversampling setting # right shifts Result Resolution # bits

2x 0 13

4x 0 14

8x 0 15

16x 0 16

32x 1 16

64x 2 16

128x 3 16

256x 4 16

512x 5 16

1024x 6 16

2048x 7 16

4096x 8 16

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28.3.7.8 Adjustment

By default, all results are right adjusted, with the LSB of the result in bit position 0 (zero). In differential

mode the signed bit is extended up to bit 31, but in single ended mode the bits above the result are read

as 0. By setting ADJ in ADCn_SINGLECTRL/ADCn_SCANCTRL, the results are left adjusted as shown

in Table 28.4 (p. 696) . When left adjusted, the MSB is always placed on bit 15 and sign extended to

bit 31. All bits below the conversion result are read as 0 (zero).

Table 28.4. ADC Results Representation

Bit

Adjustment

Resolution

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

12 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 10 9 8 7 6 5 4 3 2 1 0

8 77777777777777777777777776543210

6 55555555555555555555555555543210

Right

OVS 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

12 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 10 9 8 7 6 5 4 3 2 1 0 - - - -

8 777777777777777776543210- - - - - - - -

6 5555555555555555543210- - - - - - - - - -

Left

OVS 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

28.3.8 Interrupts, PRS Output

The single and scan modes have separate interrupt flags indicating finished conversions. Setting one of

these flags will result in an ADC interrupt if the corresponding interrupt enable bit is set in ADCn_IEN.

In addition to the finished conversion flags, there is a scan and single sample result overflow flag which

signalizes that a result from a scan sequence or single sample has been overwritten before being read.

A finished conversion will result in a one HFPERCLK cycle pulse which is output to the Peripheral Reflex

System (PRS).

28.3.9 DMA Request

The ADC has two DMA request lines, SINGLE and SCAN, which are set when a single or scan

conversion has completed. The request are cleared when the corresponding single or scan result register

is read.

28.3.10 Calibration

The ADC supports offset and gain calibration to correct errors due to process and temperature variations.

This must be done individually for each reference used. The ADC calibration (ADCn_CAL) register

contains four register fields for calibrating offset and gain for both single and scan mode. The gain and

offset calibration are done in single mode, but the resulting calibration values can be used for both single

and scan mode.

Gain and offset for the 1V25, 2V5 and VDD references are calibrated during production and the

calibration values for these can be found in the Device Information page. During reset, the gain and

offset calibration registers are loaded with the production calibration values for the 1V25 reference.

The SCANGAIN and SINGLEGAIN calibration fields are not used when the unbuffered differential

2xVDD reference is selected.

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The effects of changing the calibration register values are given in Table 28.5 (p. 697) . Step

by step calibration procedures for offset and gain are given in Section 28.3.10.1 (p. 697) and

Section 28.3.10.2 (p. 697) .

Table 28.5. Calibration Register Effect

Calibration Register ADC Result Calibration Binary Value Calibration Hex Value

Lowest Output 0111111 3F

Offset Highest Output 1000000 40

Lowest Output 0000000 00

Gain Highest Output 1111111 7F

The offset calibration register expects a signed 2’s complement value with negative effect. A high value

gives a low ADC reading.

The gain calibration register expects an unsigned value with positive effect. A high value gives a high

ADC reading.

28.3.10.1 Offset Calibration

Offset calibration must be performed prior to gain calibration. Follow these steps for the offset calibration

in single mode:

1. Select wanted reference by setting the REF bitfield of the ADCn_SINGLECTRL register.

2. Set the AT bitfield of the ADCn_SINGLECTRL register to 16CYCLES.

3. Set the INPUTSEL bitfield of the ADCn_SINGLECTRL register to DIFF0, and set the DIFF bitfield to

1 for enabling differential input. Since the input voltage is 0, the expected ADC output is the half of

the ADC code range as it is in differential mode.

4. A binary search is used to find the offset calibration value. Set the SINGLESTART bit in the

ADCn_CMD register and read the ADCn_SINGLEDATA register. The result of the binary search is

written to the SINGLEOFFSET field of the ADCn_CAL register.

28.3.10.2 Gain Calibration

Offset calibration must be performed prior to gain calibration. The Gain Calibration is done in the following

manner:

1. Select an external ADC channel (a differential channel can also be used).

2. Apply an external voltage on the selected ADC input channel. This voltage should correspond to the

top of the ADC range.

3. A binary search is used to find the gain calibration value. Set the SINGLESTART bit in the

ADCn_CTRL register and read the ADCn_SINGLEDATA register. The target value is ideally the top

of the ADC range, but it is recommended to use a value a couple of LSBs below in order to avoid

overshooting. The result of the binary search is written to the SINGLEGAIN field of the ADCn_CAL

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28.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 ADCn_CTRL RW Control Register

0x004 ADCn_CMD W1 Command Register

0x008 ADCn_STATUS R Status Register

0x00C ADCn_SINGLECTRL RW Single Sample Control Register

0x010 ADCn_SCANCTRL RW Scan Control Register

0x014 ADCn_IEN RW Interrupt Enable Register

0x018 ADCn_IF R Interrupt Flag Register

0x01C ADCn_IFS W1 Interrupt Flag Set Register

0x020 ADCn_IFC W1 Interrupt Flag Clear Register

0x024 ADCn_SINGLEDATA R Single Conversion Result Data

0x028 ADCn_SCANDATA R Scan Conversion Result Data

0x02C ADCn_SINGLEDATAP R Single Conversion Result Data Peek Register

0x030 ADCn_SCANDATAP R Scan Sequence Result Data Peek Register

0x034 ADCn_CAL RW Calibration Register

0x03C ADCn_BIASPROG RW Bias Programming Register

28.5 Register Description

28.5.1 ADCn_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

0x1F

0x00

0x0

Access

Name

OVSRSEL

TIMEBASE

PRESC

LPFMODE

TAILGATE

WARMUPMODE

Bit Name Reset Access Description

31:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

27:24 OVSRSEL 0x0 RW Oversample Rate Select

Select oversampling rate. Oversampling must be enabled for each mode for this setting to take effect.

Value Mode Description

0 X2 2 samples for each conversion result

1 X4 4 samples for each conversion result

2 X8 8 samples for each conversion result

3 X16 16 samples for each conversion result

4 X32 32 samples for each conversion result

5 X64 64 samples for each conversion result

6 X128 128 samples for each conversion result

7 X256 256 samples for each conversion result

8 X512 512 samples for each conversion result

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Bit Name Reset Access Description

Value Mode Description

9 X1024 1024 samples for each conversion result

10 X2048 2048 samples for each conversion result

11 X4096 4096 samples for each conversion result

23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:16 TIMEBASE 0x1F RW Time Base

Set time base used for ADC warm up sequence according to the HFPERCLK frequency. The time base is defined as a number of

HFPERCLK cycles which should be set equal to or higher than 1us.

Value Description

TIMEBASE ADC warm-up is set to TIMEBASE+1 HFPERCLK clock cycles and bandgap

warm-up is set to 5x(TIMEBASE+1) HFPERCLK cycles.

15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:8 PRESC 0x00 RW Prescaler Setting

Select clock division factor.

Value Description

PRESC Clock division factor of PRESC+1.

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 LPFMODE 0x0 RW Low Pass Filter Mode

These bits control the filtering of the ADC input. Details on the filter characteristics can be found in the device datasheets.

Value Mode Description

0 BYPASS No filter or decoupling capacitor

1 DECAP On chip decoupling capacitor selected

2 RCFILT On chip RC filter selected

3 TAILGATE 0 RW Conversion Tailgating

Enable/disable conversion tailgating.

Value Description

0 Scan sequence has priority, but can be delayed by ongoing single samples.

1 Scan sequence has priority and single samples will only start immediately after scan sequence.

2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 WARMUPMODE 0x0 RW Warm-up Mode

Select Warm-up Mode for ADC

Value Mode Description

0 NORMAL ADC is shut down after each conversion

1 FASTBG Bandgap references do not need warm up, but have reduced accuracy.

2 KEEPSCANREFWARM Reference selected for scan mode is kept warm.

3 KEEPADCWARM ADC is kept warmed up and scan reference is kept warm

28.5.2 ADCn_CMD - Command Register

Offset Bit Position

0x004

Reset

Access

Name

SCANSTOP

SCANSTART

SINGLESTOP

SINGLESTART

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Bit Name Reset Access Description

31:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3 SCANSTOP 0 W1 Scan Sequence Stop

Write a 1 to stop scan sequence.

2 SCANSTART 0 W1 Scan Sequence Start

Write a 1 to start scan sequence.

1 SINGLESTOP 0 W1 Single Conversion Stop

Write a 1 to stop single conversion.

0 SINGLESTART 0 W1 Single Conversion Start

Write to 1 to start single conversion.

28.5.3 ADCn_STATUS - Status Register

Offset Bit Position

0x008

Reset

0x0

Access

Name

SCANDATASRC

SCANDV

SINGLEDV

WARM

SCANREFWARM

SINGLEREFWARM

SCANACT

SINGLEACT

Bit Name Reset Access Description

31:27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26:24 SCANDATASRC 0x0 R Scan Data Source

This value indicates from which input channel the results in the ADCn_SCANDATA register originates.

Value Mode Description

0 CH0 Single ended mode: SCANDATA result originates from ADCn_CH0. Differential mode:

SCANDATA result originates from ADCn_CH0-ADCn_CH1

1 CH1 Single ended mode: SCANDATA result originates from ADCn_CH1. Differential mode:

SCANDATA result originates from ADCn_CH2_ADCn_CH3

2 CH2 Single ended mode: SCANDATA result originates from ADCn_CH2. Differential mode:

SCANDATA result originates from ADCn_CH4-ADCn_CH5

3 CH3 Single ended mode: SCANDATA result originates from ADCn_CH3. Differential mode:

SCANDATA result originates from ADCn_CH6-ADCn_CH7

4 CH4 SCANDATA result originates from ADCn_CH4

5 CH5 SCANDATA result originates from ADCn_CH5

6 CH6 SCANDATA result originates from ADCn_CH6

7 CH7 SCANDATA result originates from ADCn_CH7

23:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17 SCANDV 0 R Scan Data Valid

Scan conversion data is valid.

16 SINGLEDV 0 R Single Sample Data Valid

Single conversion data is valid.

15:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12 WARM 0 R ADC Warmed Up

ADC is warmed up.

11:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 SCANREFWARM 0 R Scan Reference Warmed Up

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Bit Name Reset Access Description

Reference selected for scan mode is warmed up.

8 SINGLEREFWARM 0 R Single Reference Warmed Up

Reference selected for single mode is warmed up.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SCANACT 0 R Scan Conversion Active

Scan sequence is active or has pending conversions.

0 SINGLEACT 0 R Single Conversion Active

Single conversion is active or has pending conversions.

28.5.4 ADCn_SINGLECTRL - Single Sample Control Register

Offset Bit Position

0x00C

Reset

0x0

Access

Name

PRSSEL

PRSEN

REF

INPUTSEL

RES

ADJ

DIFF

REP

Bit Name Reset Access Description

31:28 PRSSEL 0x0 RW Single Sample PRS Trigger Select

Select PRS trigger for single sample.

Value Mode Description

0 PRSCH0 PRS ch 0 triggers single sample

1 PRSCH1 PRS ch 1 triggers single sample

2 PRSCH2 PRS ch 2 triggers single sample

3 PRSCH3 PRS ch 3 triggers single sample

4 PRSCH4 PRS ch 4 triggers single sample

5 PRSCH5 PRS ch 5 triggers single sample

6 PRSCH6 PRS ch 6 triggers single sample

7 PRSCH7 PRS ch 7 triggers single sample

8 PRSCH8 PRS ch 8 triggers single sample

9 PRSCH9 PRS ch 9 triggers single sample

10 PRSCH10 PRS ch 10 triggers single sample

11 PRSCH11 PRS ch 11 triggers single sample

27:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24 PRSEN 0 RW Single Sample PRS Trigger Enable

Enabled/disable PRS trigger of single sample.

Value Description

0 Single sample is not triggered by PRS input

1 Single sample is triggered by PRS input selected by PRSSEL

23:20 AT 0x0 RW Single Sample Acquisition Time

Select the acquisition time for single sample.

Value Mode Description

0 1CYCLE 1 ADC_CLK cycle acquisition time for single sample

1 2CYCLES 2 ADC_CLK cycles acquisition time for single sample

2 4CYCLES 4 ADC_CLK cycles acquisition time for single sample

3 8CYCLES 8 ADC_CLK cycles acquisition time for single sample

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Bit Name Reset Access Description

Value Mode Description

4 16CYCLES 16 ADC_CLK cycles acquisition time for single sample

5 32CYCLES 32 ADC_CLK cycles acquisition time for single sample

6 64CYCLES 64 ADC_CLK cycles acquisition time for single sample

7 128CYCLES 128 ADC_CLK cycles acquisition time for single sample

8 256CYCLES 256 ADC_CLK cycles acquisition time for single sample

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 REF 0x0 RW Single Sample Reference Selection

Select reference to ADC single sample mode.

Value Mode Description

0 1V25 Internal 1.25 V reference

1 2V5 Internal 2.5 V reference

2 VDD Buffered VDD

3 5VDIFF Internal differential 5 V reference

4 EXTSINGLE Single ended external reference from ADCn_CH6

5 2XEXTDIFF Differential external reference, 2x(ADCn_CH6 - ADCn_CH7)

6 2XVDD Unbuffered 2xVDD

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:8 INPUTSEL 0x0 RW Single Sample Input Selection

Select input to ADC single sample mode in either single ended mode or differential mode.

DIFF = 0

Mode Value Description

CH0 0 ADCn_CH0

CH1 1 ADCn_CH1

CH2 2 ADCn_CH2

CH3 3 ADCn_CH3

CH4 4 ADCn_CH4

CH5 5 ADCn_CH5

CH6 6 ADCn_CH6

CH7 7 ADCn_CH7

TEMP 8 Temperature reference

VDDDIV3 9 VDD/3

VDD 10 VDD

VSS 11 VSS

VREFDIV2 12 VREF/2

DAC0OUT0 13 DAC0 output 0

DAC0OUT1 14 DAC0 output 1

DIFF = 1

Mode Value Description

CH0CH1 0 Positive input: ADCn_CH0 Negative input: ADCn_CH1

CH2CH3 1 Positive input: ADCn_CH2 Negative input: ADCn_CH3

CH4CH5 2 Positive input: ADCn_CH4 Negative input: ADCn_CH5

CH6CH7 3 Positive input: ADCn_CH6 Negative input: ADCn_CH7

DIFF0 4 Differential 0 (Short between positive and negative

inputs)

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 RES 0x0 RW Single Sample Resolution Select

Select single sample conversion resolution.

Value Mode Description

0 12BIT 12-bit resolution

1 8BIT 8-bit resolution

2 6BIT 6-bit resolution

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Bit Name Reset Access Description

Value Mode Description

3 OVS Oversampling enabled. Oversampling rate is set in OVSRSEL

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 ADJ 0 RW Single Sample Result Adjustment

Select single sample result adjustment.

Value Mode Description

0 RIGHT Results are right adjusted

1 LEFT Results are left adjusted

1 DIFF 0 RW Single Sample Differential Mode

Select single ended or differential input.

Value Description

0 Single ended input

1 Differential input

0 REP 0 RW Single Sample Repetitive Mode

Enable/disable repetitive single samples.

Value Description

0 Single conversion mode is deactivated after one conversion

1 Single conversion mode is converting continuously until SINGLESTOP is written

28.5.5 ADCn_SCANCTRL - Scan Control Register

Offset Bit Position

0x010

Reset

0x0

0x00

0x0

Access

Name

PRSSEL

PRSEN

REF

INPUTMASK

RES

ADJ

DIFF

REP

Bit Name Reset Access Description

31:28 PRSSEL 0x0 RW Scan Sequence PRS Trigger Select

Select PRS trigger for scan sequence.

Value Mode Description

0 PRSCH0 PRS ch 0 triggers scan sequence

1 PRSCH1 PRS ch 1 triggers scan sequence

2 PRSCH2 PRS ch 2 triggers scan sequence

3 PRSCH3 PRS ch 3 triggers scan sequence

4 PRSCH4 PRS ch 4 triggers scan sequence

5 PRSCH5 PRS ch 5 triggers scan sequence

6 PRSCH6 PRS ch 6 triggers scan sequence

7 PRSCH7 PRS ch 7 triggers scan sequence

8 PRSCH8 PRS ch 8 triggers scan sequence

9 PRSCH9 PRS ch 9 triggers scan sequence

10 PRSCH10 PRS ch 10 triggers scan sequence

11 PRSCH11 PRS ch 11 triggers scan sequence

27:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24 PRSEN 0 RW Scan Sequence PRS Trigger Enable

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Bit Name Reset Access Description

Enabled/disable PRS trigger of scan sequence.

Value Description

0 Scan sequence is not triggered by PRS input

1 Scan sequence is triggered by PRS input selected by PRSSEL

23:20 AT 0x0 RW Scan Sample Acquisition Time

Select the acquisition time for scan samples.

Value Mode Description

0 1CYCLE 1 ADC_CLK cycle acquisition time for scan samples

1 2CYCLES 2 ADC_CLK cycles acquisition time for scan samples

2 4CYCLES 4 ADC_CLK cycles acquisition time for scan samples

3 8CYCLES 8 ADC_CLK cycles acquisition time for scan samples

4 16CYCLES 16 ADC_CLK cycles acquisition time for scan samples

5 32CYCLES 32 ADC_CLK cycles acquisition time for scan samples

6 64CYCLES 64 ADC_CLK cycles acquisition time for scan samples

7 128CYCLES 128 ADC_CLK cycles acquisition time for scan samples

8 256CYCLES 256 ADC_CLK cycles acquisition time for scan samples

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 REF 0x0 RW Scan Sequence Reference Selection

Select reference to ADC scan sequence.

Value Mode Description

0 1V25 Internal 1.25 V reference

1 2V5 Internal 2.5 V reference

2 VDD VDD

3 5VDIFF Internal differential 5 V reference

4 EXTSINGLE Single ended external reference from ADCn_CH6

5 2XEXTDIFF Differential external reference, 2x(ADCn_CH6 - ADCn_CH7)

6 2XVDD Unbuffered 2xVDD

15:8 INPUTMASK 0x00 RW Scan Sequence Input Mask

Set one or more bits in this mask to select which inputs are included the scan sequence in either single ended or differential mode.

DIFF = 0

Mode Value Description

CH0 00000001 ADCn_CH0 included in mask

CH1 00000010 ADCn_CH1 included in mask

CH2 00000100 ADCn_CH2 included in mask

CH3 00001000 ADCn_CH3 included in mask

CH4 00010000 ADCn_CH4 included in mask

CH5 00100000 ADCn_CH5 included in mask

CH6 01000000 ADCn_CH6 included in mask

CH7 10000000 ADCn_CH7 included in mask

DIFF = 1

Mode Value Description

CH0CH1 00000001 (Positive input: ADCn_CH0 Negative input: ADCn_CH1) included

in mask

CH2CH3 00000010 (Positive input: ADCn_CH2 Negative input: ADCn_CH3) included

in mask

CH4CH5 00000100 (Positive input: ADCn_CH4 Negative input: ADCn_CH5) included

in mask

CH6CH7 00001000 (Positive input: ADCn_CH6 Negative input: ADCn_CH7) included

in mask

0001xxxx-1111xxxx Reserved

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 RES 0x0 RW Scan Sequence Resolution Select

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Bit Name Reset Access Description

Select scan sequence conversion resolution.

Value Mode Description

0 12BIT 12-bit resolution

1 8BIT 8-bit resolution

2 6BIT 6-bit resolution

3 OVS Oversampling enabled. Oversampling rate is set in OVSRSEL

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 ADJ 0 RW Scan Sequence Result Adjustment

Select scan sequence result adjustment.

Value Mode Description

0 RIGHT Results are right adjusted

1 LEFT Results are left adjusted

1 DIFF 0 RW Scan Sequence Differential Mode

Select single ended or differential input.

Value Description

0 Single ended input

1 Differential input

0 REP 0 RW Scan Sequence Repetitive Mode

Enable/disable repetitive scan sequence.

Value Description

0 Scan conversion mode is deactivated after one sequence

1 Scan conversion mode is converting continuously until SCANSTOP is written

28.5.6 ADCn_IEN - Interrupt Enable Register

Offset Bit Position

0x014

Reset

Access

Name

SCANOF

SINGLEOF

SCAN

SINGLE

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 SCANOF 0 RW Scan Result Overflow Interrupt Enable

Enable/disable scan result overflow interrupt.

8 SINGLEOF 0 RW Single Result Overflow Interrupt Enable

Enable/disable single result overflow interrupt.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SCAN 0 RW Scan Conversion Complete Interrupt Enable

Enable/disable scan conversion complete interrupt.

0 SINGLE 0 RW Single Conversion Complete Interrupt Enable

Enable/disable single conversion complete interrupt.

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28.5.7 ADCn_IF - Interrupt Flag Register

Offset Bit Position

0x018

Reset

Access

Name

SCANOF

SINGLEOF

SCAN

SINGLE

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 SCANOF 0 R Scan Result Overflow Interrupt Flag

Indicates scan result overflow when this bit is set.

8 SINGLEOF 0 R Single Result Overflow Interrupt Flag

Indicates single result overflow when this bit is set.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SCAN 0 R Scan Conversion Complete Interrupt Flag

Indicates scan conversion complete when this bit is set.

0 SINGLE 0 R Single Conversion Complete Interrupt Flag

Indicates single conversion complete when this bit is set.

28.5.8 ADCn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x01C

Reset

Access

Name

SCANOF

SINGLEOF

SCAN

SINGLE

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 SCANOF 0 W1 Scan Result Overflow Interrupt Flag Set

Write to 1 to set scan result overflow interrupt flag

8 SINGLEOF 0 W1 Single Result Overflow Interrupt Flag Set

Write to 1 to set single result overflow interrupt flag.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SCAN 0 W1 Scan Conversion Complete Interrupt Flag Set

Write to 1 to set scan conversion complete interrupt flag.

0 SINGLE 0 W1 Single Conversion Complete Interrupt Flag Set

Write to 1 to set single conversion complete interrupt flag.

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28.5.9 ADCn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x020

Reset

Access

Name

SCANOF

SINGLEOF

SCAN

SINGLE

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9 SCANOF 0 W1 Scan Result Overflow Interrupt Flag Clear

Write to 1 to clear scan result overflow interrupt flag.

8 SINGLEOF 0 W1 Single Result Overflow Interrupt Flag Clear

Write to 1 to clear single result overflow interrupt flag.

7:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 SCAN 0 W1 Scan Conversion Complete Interrupt Flag Clear

Write to 1 to clear scan conversion complete interrupt flag.

0 SINGLE 0 W1 Single Conversion Complete Interrupt Flag Clear

Write to 1 to clear single conversion complete interrupt flag.

28.5.10 ADCn_SINGLEDATA - Single Conversion Result Data

Offset Bit Position

0x024

Reset

0x00000000

Access

Name

DATA

Bit Name Reset Access Description

31:0 DATA 0x00000000 R Single Conversion Result Data

The register holds the results from the last single conversion. Reading this field clears the SINGLEDV bit in the ADCn_STATUS

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28.5.11 ADCn_SCANDATA - Scan Conversion Result Data

Offset Bit Position

0x028

Reset

0x00000000

Access

Name

DATA

Bit Name Reset Access Description

31:0 DATA 0x00000000 R Scan Conversion Result Data

The register holds the results from the last scan conversion. Reading this field clears the SCANDV bit in the ADCn_STATUS register.

28.5.12 ADCn_SINGLEDATAP - Single Conversion Result Data Peek

Offset Bit Position

0x02C

Reset

0x00000000

Access

Name

DATAP

Bit Name Reset Access Description

31:0 DATAP 0x00000000 R Single Conversion Result Data Peek

The register holds the results from the last single conversion. Reading this field will not clear SINGLEDV in ADCn_STATUS or

SINGLE DMA request.

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28.5.13 ADCn_SCANDATAP - Scan Sequence Result Data Peek Register

Offset Bit Position

0x030

Reset

0x00000000

Access

Name

DATAP

Bit Name Reset Access Description

31:0 DATAP 0x00000000 R Scan Conversion Result Data Peek

The register holds the results from the last scan conversion. Reading this field will not clear SCANDV in ADCn_STATUS or single

DMA request.

28.5.14 ADCn_CAL - Calibration Register

Offset Bit Position

0x034

Reset

0x3F

0x00

0x3F

0x00

Access

Name

SCANGAIN

SCANOFFSET

SINGLEGAIN

SINGLEOFFSET

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:24 SCANGAIN 0x3F RW Scan Mode Gain Calibration Value

This register contains the gain calibration value used with scan conversions. This field is set to the production gain calibration value

for the 1V25 internal reference during reset, hence the reset value might differ from device to device. The field is unsigned. Higher

values lead to higher ADC results.

23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:16 SCANOFFSET 0x00 RW Scan Mode Offset Calibration Value

This register contains the offset calibration value used with scan conversions. This field is set to the production offset calibration

value for the 1V25 internal reference during reset, hence the reset value might differ from device to device. The field is encoded as

a signed 2's complement number. Higher values lead to lower ADC results.

15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:8 SINGLEGAIN 0x3F RW Single Mode Gain Calibration Value

This register contains the gain calibration value used with single conversions. This field is set to the production gain calibration value

for the 1V25 internal reference during reset, hence the reset value might differ from device to device. The field is unsigned. Higher

values lead to higher ADC results.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:0 SINGLEOFFSET 0x00 RW Single Mode Offset Calibration Value

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Bit Name Reset Access Description

This register contains the offset calibration value used with single conversions. This field is set to the production offset calibration

value for the 1V25 internal reference during reset, hence the reset value might differ from device to device. The field is encoded as

a signed 2's complement number. Higher values lead to lower ADC results.

28.5.15 ADCn_BIASPROG - Bias Programming Register

Offset Bit Position

0x03C

Reset

0x7

Access

Name

COMPBIAS

HALFBIAS

BIASPROG

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:8 COMPBIAS 0x7 RW Comparator Bias Value

These bits are used to adjust the bias current to the ADC Comparator.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 HALFBIAS 1 RW Half Bias Current

Set this bit to halve the bias current.

5:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 BIASPROG 0x7 RW Bias Programming Value

These bits are used to adjust the bias current.

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29 DAC - Digital to Analog Converter

01 2 3 4

DAC

...0100010...

...0101110...

Quick Facts

What?

The DAC is designed for low energy

consumption, but can also provide very good

performance. It can convert digital values

to analog signals at up to 500 kilo samples/

second and with 12-bit accuracy.

Why?

The DAC is able to generate accurate analog

signals using only a limited amount of energy.

How?

The DAC can generate high-resolution

analog signals while the MCU is operating

at low frequencies and with low total power

consumption. Using DMA and a timer, the

DAC can be used to generate waveforms

without any CPU intervention.

29.1 Introduction

The Digital to Analog Converter (DAC) can convert a digital value to an analog output voltage. The DAC

is fully differential rail-to-rail, with 12-bit resolution. It has two single ended output buffers which can be

combined into one differential output. The DAC may be used for a number of different applications such

as sensor interfaces or sound output.

29.2 Features

• 500 ksamples/s operation

• Two single ended output channels

• Can be combined into one differential output

• Integrated prescaler with division factor selectable between 1-128

• Selectable voltage reference

• Internal 2.5V

• Internal 1.25V

• VDD

• Conversion triggers

• Data write

• PRS input

• Automatic refresh timer

• Selection from 16-64 prescaled HFPERCLK cycles

• Individual refresh enable for each channel

• Interrupt generation on finished conversion

• Separate interrupt flag for each channel

• PRS output pulse on finished conversion

• Separate line for each channel

• DMA request on finished conversion

• Separate request for each channel

• Support for offset and gain calibration

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• Output to ADC

• Sine generation mode

• Optional high strength line driver

29.3 Functional Description

An overview of the DAC module is shown in Figure 29.1 (p. 712) .

Figure 29.1. DAC Overview

DACn_OUT0

DACn_OUT1

Ch 1

VDD

1.25 V

2.5 V

CH0DATA

CH1DATA

ADC and ACMP

REFSEL

Ch 0

29.3.1 Conversions

The DAC consists of two channels (Channel 0 and 1) with separate 12-bit data registers

(DACn_CH0DATA and DACn_CH1DATA). These can be used to produce two independent single ended

outputs or the channel 0 register can be used to drive both outputs in differential mode. The DAC supports

three conversion modes, continuous, sample/hold, sample/off.

29.3.1.1 Continuous Mode

In continuous mode the DAC channels will drive their outputs continuously with the data in the

DACn_CHxDATA registers. This mode will maintain the output voltage and refresh is therefore not

needed.

29.3.1.2 Sample/Hold Mode

In sample/hold mode, the DAC core converts data on a triggered conversion and then holds the output

in a sample/hold element. When not converting, the DAC core is turned off between samples, which

reduces the power consumption. Because of output voltage drift the sample/hold element will only hold

the output for a certain period without a refresh conversion. The reader is referred to the electrical

characteristics for the details on the voltage drift. The sampling period in this mode is set to the length

of one prescaled clock cycle.

29.3.1.3 Sample/Off Mode

In sample/off mode the DAC and the sample/hold element is turned completely off between samples,

tri-stating the DAC output. This requires the DAC output voltage to be held externally. The references

are also turned off between samples, which means that a new warm-up period is needed before each

conversion. The sampling period in this mode is set to the length of one prescaled clock cycle.

29.3.1.4 Conversion Start

The DAC channel must be enabled before it can be used. When the channel is enabled, a conversion

can be started by writing to the DACn_CHxDATA register. These data registers are also mapped into

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a combined data register, DACn_COMBDATA, where the data values for both channels can be written

simultaneously. Writing to this register will start all enabled channels.

If the PRSEN bit in DACn_CHxCTRL is set, a DAC conversion on channel x will not be started by data

write, but when a positive one HFPERCLK cycle pulse is received on the PRS input selected by PRSSEL

in DACn_CHxCTRL.

The CH0DV and CH1DV bits in DACn_STATUS indicate that the corresponding channel contains data

that has not yet been converted.

When entering Energy Mode 4, both DAC channels must be stopped.

29.3.1.5 Clock Prescaling

The DAC has an internal clock prescaler, which can divide the HFPERCLK by any factor between 1 and

128, by setting the PRESC bits in DACnCTRL. The resulting DAC_CLK is used by the converter core

and the frequency is given by Equation 29.1 (p. 713) :

DAC Clock Prescaling

fDAC_CLK = fHFPERCLK / 2PRESC (29.1)

where fHFPERCLK is the HFPERCLK frequency. One conversion takes 2 DAC_CLK cycles and the

DAC_CLK should not be set higher than 1 MHz.

Normally the PRESCALER runs continuously when either of the channels are enabled. When running

with a prescaler setting higher than 0, there will be an unpredictable delay from the time the conversion

was triggered to the time the actual conversion takes place. This is because the conversions is controlled

by the prescaled clock and the conversion can arrive at any time during a prescaled clock (DAC_CLK)

period. However, if the CH0PRESCRST bit in DACn_CTRL is set, the prescaler will be reset every time

a conversion is triggered on channel 0. This leads to a predictable latency between channel 0 trigger

and conversion.

29.3.2 Reference Selection

Three internal voltage references are available and are selected by setting the REFSEL bits in

DACn_CTRL:

• Internal 2.5V

• Internal 1.25V

• VDD

The reference selection can only be changed while both channels are disabled. The references for the

DAC need to be enabled for some time before they can be used. This is called the warm-up period, and

starts when one of the channels is enabled. For a bandgap reference, this period is 5 DAC_CLK cycles

while the VDD reference needs 1 DAC_CLK cycle. The DAC will time this period automatically(given that

the prescaler is set correctly) and delay any conversion triggers received during the warm-up until the

references have stabilized.

29.3.3 Programming of Bias Current

The bias current of the bandgap reference and the DAC output buffer can be scaled by the BIASPROG

and HALFBIAS bit fields of the DACn_BIASPROG register as illustrated in Figure 29.2 (p. 714) .

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Figure 29.2. DAC Bias Programming

BIASPROG

HALFBIAS

Reference

Current

Internal

bandgap

reference

DAC output

buffer

The minimum value of the BIASPROG bit-field of the DACn_BIASPROG register (i.e.

BIASPROG=0b0000) represents the minimum bias current. Similarly BIASPROG=0b1111 represents

the maximum bias current. The bias current defined by the BIASPROG setting can be halved by setting

the HALFBIAS bit of the DACn_BIASPROG register.

The bias current settings should only be changed while both DAC channels are disabled. The electrical

characteristics given in the datasheet require the bias configuration to be set to the default values, where

no other bias values are given.

29.3.4 Mode

The two DAC channels can act as two separate single ended channels or be combined into one

differential channel. This is selected through the DIFF bit in DACn_CTRL.

29.3.4.1 Single Ended Output

When operating in single ended mode, the channel 0 output is on DACn_OUT0 and the channel 1 output

is on DACn_OUT1. The output voltage can be calculated using Equation 29.2 (p. 714)

DAC Single Ended Output Voltage

VOUT = VDACn_OUTx - VSS= Vref x CHxDATA/4095 (29.2)

where CHxDATA is a 12-bit unsigned integer.

29.3.4.2 Differential Output

When operating in differential mode, both DAC outputs are used as output for the bipolar voltage. The

differential conversion uses DACn_CH0DATA as source. The positive output is on DACn_OUT1 and

the negative output is on DACn_OUT0. Since the output can be negative, it is expected that the data is

written in 2’s complement form with the MSB of the 12-bit value being the signed bit. The output voltage

can be calculated using Equation 29.3 (p. 714) :

DAC Differential Output Voltage

VOUT = VDACn_OUT1 - VDACn_OUT0= Vref x CH0DATA/2047 (29.3)

where CH0DATA is a 12-bit signed integer. The common mode voltage is VDD/2.

29.3.5 Sine Generation Mode

The DAC contains an automatic sine-generation mode, which is enabled by setting the SINEMODE bit in

DACn_CTRL. In this mode, the DAC data is overridden with a conversion data taken from a sine lookup

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table. The sine signal is controlled by the PRS line selected by CH0PRSSEL in DACn_CH0CTRL. When

the PRS line is low, a voltage of Vref/2 will be produced. When the line is high, a sine wave will be

produced. Each period, starting at 0 degrees, is made up of 16 samples and the frequency is given by

Equation 29.4 (p. 715) :

DAC Sine Generation

fsine = fHFPERCLK / 32 x 2PRESC (29.4)

The SINE wave will be output on channel 0. If DIFF is set in DACn_CTRL, the sine wave will be output

on both channels (if enabled), but inverted (see Figure 29.1 (p. 712) ). Note that when OUTENPRS

in DACn_CTRL is set, the sine output will be reset to 0 degrees when the PRS line selected by

CH1PRSSEL is low.

Figure 29.3. DAC Sine Mode

CH1 PRS

DACn_OUT1

DACn_OUT0

Hi-Z

CH0 PRS

Vref

Vref/2

Vref

Vref/2

29.3.6 Interrupts and PRS Output

Both DAC channels have separate interrupt flags (in DACn_IF) indicating that a conversion has finished

on the channel and that new data can be written to the data registers. Setting one of these flags will result

in a DAC interrupt if the corresponding interrupt enable bit is set in DACn_IEN. All generated interrupts

from the DAC will activate the same interrupt vector when enabled.

The DAC has two PRS outputs which will carry a one cycle (HFPERCLK) high pulse when the

corresponding channel has finished a conversion.

29.3.7 DMA Request

The DAC sends out a DMA request when a conversion on a channel is complete. This request is cleared

when the corresponding channel’s data register is written.

29.3.8 Analog Output

Each DAC channel has its own output pin (DACn_OUT0 and DACn_OUT1) in addition to an internal

loopback to the ADC and ACMP. These outputs can be enabled and disabled individually in the EN

field in DACn_CHxCTRL registers in combination with OUTPUTSEL in DACn_CTRL. The DAC outputs

can also be directed to the ADC and ACMP, which is also configurable in the OUTPUTSEL field in

DACn_CTRL.

The DAC outputs are tri-stated when the channels are not enabled. By setting the OUTENPRS

bit in DACn_CTRL, the outputs are also tri-stated when the PRS line selected by CH1PRSSEL in

DACn_CH1CTRL is low. When the PRS signal is high, the outputs are enabled as normal.

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The DAC channels can also drive an alternative output network, which is described in the Opamp

chapter in Section 30.3.1.2 (p. 734) . To enable this network, OUTMODE must be configured to ADC

in DACn_CTRL. The actual output network can be configred by configuring DACn_OPAxMUX registers.

29.3.9 Calibration

The DAC contains a calibration register, DACn_CAL, where calibration values for both offset and gain

correction can be written. Offset calibration is done separately for each channel through the CHxOFFSET

bit-fields. Gain is calibrated in one common register field, GAIN. The gain calibration is linked to the

reference and when the reference is changed, the gain must be re-calibrated. Gain and offset for the

1V25, 2V5 and VDD references are calibrated during production and the calibration values for these

can be found in the Device Information page. During reset, the gain and offset calibration registers are

loaded with the production calibration values for the 1V25 reference.

29.3.10 Opamps

The DAC includes a set of three highly configurable opamps that can be accessed in the DAC module.

Two of the opamps are located in the DAC, while the third opamp is a standalone opamp. For detailed

description see the OPAMP chapter. The register description can be found Section 29.5 (p. 717)

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29.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 DACn_CTRL RW Control Register

0x004 DACn_STATUS R Status Register

0x008 DACn_CH0CTRL RW Channel 0 Control Register

0x00C DACn_CH1CTRL RW Channel 1 Control Register

0x010 DACn_IEN RW Interrupt Enable Register

0x014 DACn_IF R Interrupt Flag Register

0x018 DACn_IFS W1 Interrupt Flag Set Register

0x01C DACn_IFC W1 Interrupt Flag Clear Register

0x020 DACn_CH0DATA RW Channel 0 Data Register

0x024 DACn_CH1DATA RW Channel 1 Data Register

0x028 DACn_COMBDATA W Combined Data Register

0x02C DACn_CAL RW Calibration Register

0x030 DACn_BIASPROG RW Bias Programming Register

0x054 DACn_OPACTRL RW Operational Amplifier Control Register

0x058 DACn_OPAOFFSET RW Operational Amplifier Offset Register

0x05C DACn_OPA0MUX RW Operational Amplifier Mux Configuration Register

0x060 DACn_OPA1MUX RW Operational Amplifier Mux Configuration Register

0x064 DACn_OPA2MUX RW Operational Amplifier Mux Configuration Register

29.5 Register Description

29.5.1 DACn_CTRL - Control Register

Offset Bit Position

0x000

Reset

0x0

0x1

0x0

Access

Name

REFRSEL

PRESC

REFSEL

CH0PRESCRST

OUTENPRS

OUTMODE

CONVMODE

SINEMODE

DIFF

Bit Name Reset Access Description

31:22 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

21:20 REFRSEL 0x0 RW Refresh Interval Select

Select refresh counter timeout value. A channel x will be refreshed with the interval set in this register if the REFREN bit in

DACn_CHxCTRL is set.

Value Mode Description

0 8CYCLES All channels with enabled refresh are refreshed every 8 prescaled cycles

1 16CYCLES All channels with enabled refresh are refreshed every 16 prescaled cycles

2 32CYCLES All channels with enabled refresh are refreshed every 32 prescaled cycles

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Bit Name Reset Access Description

Value Mode Description

3 64CYCLES All channels with enabled refresh are refreshed every 64 prescaled cycles

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 PRESC 0x0 RW Prescaler Setting

Select clock division factor.

Value Description

PRESC Clock division factor of 2^PRESC.

15:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 REFSEL 0x0 RW Reference Selection

Select reference.

Value Mode Description

0 1V25 Internal 1.25 V bandgap reference

1 2V5 Internal 2.5 V bandgap reference

2 VDD VDD reference

7 CH0PRESCRST 0 RW Channel 0 Start Reset Prescaler

Select if prescaler is reset on channel 0 start.

Value Description

0 Prescaler not reset on channel 0 start

1 Prescaler reset on channel 0 start

6 OUTENPRS 0 RW PRS Controlled Output Enable

Enable PRS Control of DAC output enable.

Value Description

0 DAC output enable always on

1 DAC output enable controlled by PRS signal selected for CH1.

5:4 OUTMODE 0x1 RW Output Mode

Select output mode.

Value Mode Description

0 DISABLE DAC output to pin and ADC disabled

1 PIN DAC output to pin enabled. DAC output to ADC and ACMP disabled

2 ADC DAC output to pin disabled. DAC output to ADC and ACMP enabled

3 PINADC DAC output to pin, ADC, and ACMP enabled

3:2 CONVMODE 0x0 RW Conversion Mode

Configure conversion mode.

Value Mode Description

0 CONTINUOUS DAC is set in continuous mode

1 SAMPLEHOLD DAC is set in sample/hold mode

2 SAMPLEOFF DAC is set in sample/shut off mode

1 SINEMODE 0 RW Sine Mode

Enable/disable sine mode.

Value Description

0 Sine mode disabled. Sine reset to 0 degrees

1 Sine mode enabled

0 DIFF 0 RW Differential Mode

Select single ended or differential mode.

Value Description

0 Single ended output

1 Differential output

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29.5.2 DACn_STATUS - Status Register

Offset Bit Position

0x004

Reset

Access

Name

CH1DV

CH0DV

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 CH1DV 0 R Channel 1 Data Valid

This bit is set high when CH1DATA is written and is set low when CH1DATA is used in conversion.

0 CH0DV 0 R Channel 0 Data Valid

This bit is set high when CH0DATA is written and is set low when CH0DATA is used in conversion.

29.5.3 DACn_CH0CTRL - Channel 0 Control Register

Offset Bit Position

0x008

Reset

0x0

Access

Name

PRSSEL

PRSEN

REFREN

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:4 PRSSEL 0x0 RW Channel 0 PRS Trigger Select

Select Channel 0 PRS input channel.

Value Mode Description

0 PRSCH0 PRS ch 0 triggers channel 0 conversion.

1 PRSCH1 PRS ch 1 triggers channel 0 conversion.

2 PRSCH2 PRS ch 2 triggers channel 0 conversion.

3 PRSCH3 PRS ch 3 triggers channel 0 conversion.

4 PRSCH4 PRS ch 4 triggers channel 0 conversion.

5 PRSCH5 PRS ch 5 triggers channel 0 conversion.

6 PRSCH6 PRS ch 6 triggers channel 0 conversion.

7 PRSCH7 PRS ch 7 triggers channel 0 conversion.

8 PRSCH8 PRS ch 8 triggers channel 0 conversion.

9 PRSCH9 PRS ch 9 triggers channel 0 conversion.

10 PRSCH10 PRS ch 10 triggers channel 0 conversion.

11 PRSCH11 PRS ch 11 triggers channel 0 conversion.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 PRSEN 0 RW Channel 0 PRS Trigger Enable

Select Channel 0 conversion trigger.

Value Description

0 Channel 0 is triggered by CH0DATA or COMBDATA write

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Bit Name Reset Access Description

Value Description

1 Channel 0 is triggered by PRS input

1 REFREN 0 RW Channel 0 Automatic Refresh Enable

Set to enable automatic refresh of channel 0. Refresh period is set by REFRSEL in DACn_CTRL.

Value Description

0 Channel 0 is not refreshed automatically

1 Channel 0 is refreshed automatically

0 EN 0 RW Channel 0 Enable

Enable/disable channel 0.

29.5.4 DACn_CH1CTRL - Channel 1 Control Register

Offset Bit Position

0x00C

Reset

0x0

Access

Name

PRSSEL

PRSEN

REFREN

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:4 PRSSEL 0x0 RW Channel 1 PRS Trigger Select

Select Channel 1 PRS input channel.

Value Mode Description

0 PRSCH0 PRS ch 0 triggers channel 1 conversion.

1 PRSCH1 PRS ch 1 triggers channel 1 conversion.

2 PRSCH2 PRS ch 2 triggers channel 1 conversion.

3 PRSCH3 PRS ch 3 triggers channel 1 conversion.

4 PRSCH4 PRS ch 4 triggers channel 1 conversion.

5 PRSCH5 PRS ch 5 triggers channel 1 conversion.

6 PRSCH6 PRS ch 6 triggers channel 1 conversion.

7 PRSCH7 PRS ch 7 triggers channel 1 conversion.

8 PRSCH8 PRS ch 8 triggers channel 1 conversion.

9 PRSCH9 PRS ch 9 triggers channel 1 conversion.

10 PRSCH10 PRS ch 10 triggers channel 1 conversion.

11 PRSCH11 PRS ch 11 triggers channel 1 conversion.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 PRSEN 0 RW Channel 1 PRS Trigger Enable

Select Channel 1 conversion trigger.

Value Description

0 Channel 1 is triggered by CH1DATA or COMBDATA write

1 Channel 1 is triggered by PRS input

1 REFREN 0 RW Channel 1 Automatic Refresh Enable

Set to enable automatic refresh of channel 1. Refresh period is set by REFRSEL in DACn_CTRL.

Value Description

0 Channel 1 is not refreshed automatically

1 Channel 1 is refreshed automatically

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Bit Name Reset Access Description

0 EN 0 RW Channel 1 Enable

Enable/disable channel 1.

29.5.5 DACn_IEN - Interrupt Enable Register

Offset Bit Position

0x010

Reset

Access

Name

CH1UF

CH0UF

CH1

CH0

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 CH1UF 0 RW Channel 1 Conversion Data Underflow Interrupt Enable

Enable/disable channel 1 data underflow interrupt.

4 CH0UF 0 RW Channel 0 Conversion Data Underflow Interrupt Enable

Enable/disable channel 0 data underflow interrupt.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 CH1 0 RW Channel 1 Conversion Complete Interrupt Enable

Enable/disable channel 1 conversion complete interrupt.

0 CH0 0 RW Channel 0 Conversion Complete Interrupt Enable

Enable/disable channel 0 conversion complete interrupt.

29.5.6 DACn_IF - Interrupt Flag Register

Offset Bit Position

0x014

Reset

Access

Name

CH1UF

CH0UF

CH1

CH0

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 CH1UF 0 R Channel 1 Data Underflow Interrupt Flag

Indicates channel 1 data underflow.

4 CH0UF 0 R Channel 0 Data Underflow Interrupt Flag

Indicates channel 0 data underflow.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 CH1 0 R Channel 1 Conversion Complete Interrupt Flag

Indicates channel 1 conversion complete and that new data can be written to the data register.

0 CH0 0 R Channel 0 Conversion Complete Interrupt Flag

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Bit Name Reset Access Description

Indicates channel 0 conversion complete and that new data can be written to the data register.

29.5.7 DACn_IFS - Interrupt Flag Set Register

Offset Bit Position

0x018

Reset

Access

Name

CH1UF

CH0UF

CH1

CH0

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 CH1UF 0 W1 Channel 1 Data Underflow Interrupt Flag Set

Write to 1 to set channel 1 Data Underflow interrupt flag.

4 CH0UF 0 W1 Channel 0 Data Underflow Interrupt Flag Set

Write to 1 to set channel 0 Data Underflow interrupt flag.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 CH1 0 W1 Channel 1 Conversion Complete Interrupt Flag Set

Write to 1 to set channel 1 conversion complete interrupt flag.

0 CH0 0 W1 Channel 0 Conversion Complete Interrupt Flag Set

Write to 1 to set channel 0 conversion complete interrupt flag.

29.5.8 DACn_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x01C

Reset

Access

Name

CH1UF

CH0UF

CH1

CH0

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5 CH1UF 0 W1 Channel 1 Data Underflow Interrupt Flag Clear

Write to 1 to clear channel 1 data underflow interrupt flag.

4 CH0UF 0 W1 Channel 0 Data Underflow Interrupt Flag Clear

Write to 1 to clear channel 0 data underflow interrupt flag.

3:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 CH1 0 W1 Channel 1 Conversion Complete Interrupt Flag Clear

Write to 1 to clear channel 1 conversion complete interrupt flag.

0 CH0 0 W1 Channel 0 Conversion Complete Interrupt Flag Clear

Write to 1 to clear channel 0 conversion complete interrupt flag.

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29.5.9 DACn_CH0DATA - Channel 0 Data Register

Offset Bit Position

0x020

Reset

0x000

Access

Name

DATA

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 DATA 0x000 RW Channel 0 Data

This register contains the value which will be converted by channel 0.

29.5.10 DACn_CH1DATA - Channel 1 Data Register

Offset Bit Position

0x024

Reset

0x000

Access

Name

DATA

Bit Name Reset Access Description

31:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 DATA 0x000 RW Channel 1 Data

This register contains the value which will be converted by channel 1.

29.5.11 DACn_COMBDATA - Combined Data Register

Offset Bit Position

0x028

Reset

0x000

Access

Name

CH1DATA

CH0DATA

Bit Name Reset Access Description

31:28 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

27:16 CH1DATA 0x000 W Channel 1 Data

Data written to this register will be written to DATA in DACn_CH1DATA.

15:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:0 CH0DATA 0x000 W Channel 0 Data

Data written to this register will be written to DATA in DACn_CH0DATA.

29.5.12 DACn_CAL - Calibration Register

Offset Bit Position

0x02C

Reset

0x40

0x00

Access

Name

GAIN

CH1OFFSET

CH0OFFSET

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:16 GAIN 0x40 RW Gain Calibration Value

This register contains the gain calibration value. This field is set to the production gain calibration value for the 1V25 internal reference

during reset, hence the reset value might differ from device to device. The field is unsigned. Higher values lead to lower DAC results.

15:14 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

13:8 CH1OFFSET 0x00 RW Channel 1 Offset Calibration Value

This register contains the offset calibration value used with channel 1 conversions. This field is set to the production channel 1 offset

calibration value for the 1V25 internal reference during reset, hence the reset value might differ from device to device. The field is

sign-magnitude encoded. Higher values lead to lower DAC results.

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 CH0OFFSET 0x00 RW Channel 0 Offset Calibration Value

This register contains the offset calibration value used with channel 0 conversions. This field is set to the production channel 0 offset

calibration value for the 1V25 internal reference during reset, hence the reset value might differ from device to device. The field is

sign-magnitude encoded. Higher values lead to lower DAC results.

29.5.13 DACn_BIASPROG - Bias Programming Register

Offset Bit Position

0x030

Reset

0x7

Access

Name

OPA2HALFBIAS

OPA2BIASPROG

HALFBIAS

BIASPROG

Bit Name Reset Access Description

31:15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14 OPA2HALFBIAS 1 RW Half Bias Current

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Bit Name Reset Access Description

Set this bit to halve the bias current.

13:12 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

11:8 OPA2BIASPROG 0x7 RW Bias Programming Value for OPA2

These bits control the bias current level.

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 HALFBIAS 1 RW Half Bias Current

Set this bit to halve the bias current.

5:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 BIASPROG 0x7 RW Bias Programming Value

These bits control the bias current level.

29.5.14 DACn_OPACTRL - Operational Amplifier Control Register

Offset Bit Position

0x054

Reset

0x0

Access

Name

OPA2SHORT

OPA1SHORT

OPA0SHORT

OPA2LPFDIS

OPA1LPFDIS

OPA0LPFDIS

OPA2HCMDIS

OPA1HCMDIS

OPA0HCMDIS

OPA2EN

OPA1EN

OPA0EN

Bit Name Reset Access Description

31:25 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

24 OPA2SHORT 0 RW Short the non-inverting and inverting input.

Set to short the non-inverting and inverting input.

23 OPA1SHORT 0 RW Short the non-inverting and inverting input.

Set to short the non-inverting and inverting input.

22 OPA0SHORT 0 RW Short the non-inverting and inverting input.

Set to short the non-inverting and inverting input.

21:18 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

17:16 OPA2LPFDIS 0x0 RW Disables Low Pass Filter.

Disables the low pass filter between pad and the positive and negative input mux.

LPF DISABLE VALUE Description

PLPFDIS x1 Disables the low pass filter between positive pad and positive

input.

NLPFDIS 1x Disables the low pass filter between negative pad and

negative input.

15:14 OPA1LPFDIS 0x0 RW Disables Low Pass Filter.

Disables the low pass filter between pad and the positive and negative input mux.

LPF DISABLE VALUE Description

PLPFDIS x1 Disables the low pass filter between positive pad and positive

input.

NLPFDIS 1x Disables the low pass filter between negative pad and

negative input.

13:12 OPA0LPFDIS 0x0 RW Disables Low Pass Filter.

Disables the low pass filter between pad and the positive and negative input mux.

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Bit Name Reset Access Description

LPF DISABLE VALUE Description

PLPFDIS x1 Disables the low pass filter between positive pad and positive

input.

NLPFDIS 1x Disables the low pass filter between negative pad and

negative input.

11:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 OPA2HCMDIS 0 RW High Common Mode Disable.

Set to disable high common mode. Disables rail-to-rail on input, while output still remains rail-to-rail. The input voltage to the opamp

while HCM is disabled is restricted between VSS and VDD-1.2V.

7 OPA1HCMDIS 0 RW High Common Mode Disable.

Set to disable high common mode. Disables rail-to-rail on input, while output still remains rail-to-rail. The input voltage to the opamp

while HCM is disabled is restricted between VSS and VDD-1.2V.

6 OPA0HCMDIS 0 RW High Common Mode Disable.

Set to disable high common mode. Disables rail-to-rail on input, while output still remains rail-to-rail. The input voltage to the opamp

while HCM is disabled is restricted between VSS and VDD-1.2V.

5:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 OPA2EN 0 RW OPA2 Enable

Set to enable OPA2, clear to disable.

1 OPA1EN 0 RW OPA1 Enable

Set to enable OPA1, clear to disable. CH1EN in DAC_CH1CTRL must also be set.

0 OPA0EN 0 RW OPA0 Enable

Set to enable OPA0, clear to disable. CH0EN in DAC_CH0CTRL must also be set.

29.5.15 DACn_OPAOFFSET - Operational Amplifier Offset Register

Offset Bit Position

0x058

Reset

0x20

Access

Name

OPA2OFFSET

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 OPA2OFFSET 0x20 RW OPA2 Offset Configuration Value

This register contains the offset calibration value for OPA2. This field is set to the production OPA2 offset calibration value, hence

the reset value might differ from device to device. The field is sign-magnitude encoded. Higher values lead to lower OPA results.

The resolution of the LSB is 1.6mV/LSB

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29.5.16 DACn_OPA0MUX - Operational Amplifier Mux Configuration

Offset Bit Position

0x05C

Reset

0x0

0x1

0x00

0x0

Access

Name

RESSEL

NEXTOUT

OUTMODE

OUTPEN

NPEN

PPEN

RESINMUX

NEGSEL

POSSEL

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:28 RESSEL 0x0 RW OPA0 Resistor Ladder Select

Configures the resistor ladder tap for OPA0.

Value Mode Resistor Value Inverting Mode Gain (-R2/R1) Non-inverting Mode Gain (1+(R2/

R1)

0 RES0 R2 = 1/3 x R1 -1/3 1 1/3

1 RES1 R2 = R1 -1 2

2 RES2 R2 = 1 2/3 x R1 -1 2/3 2 2/3

3 RES3 R2 = 2 x R1 -2 1/5 3 1/5

4 RES4 R2 = 3 x R1 -3 4

5 RES5 R2 = 4 1/3 x R1 -4 1/3 5 1/3

6 RES6 R2 = 7 x R1 -7 8

7 RES7 R2 = 15 x R1 -15 16

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 NEXTOUT 0 RW OPA0 Next Enable

Makes output of OPA0 available to OPA1.

25:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:22 OUTMODE 0x1 RW Output Select

Select output channel.

Value Mode Description

0 DISABLE OPA0 output is disabled

1 MAIN Main OPA0 output to pin enabled

2 ALT OPA0 alternative output enabled.

3 ALL Main OPA0 output drives both main and alternative outputs.

21:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:14 OUTPEN 0x00 RW OPA0 Output Enable Value

Set to enable output, clear to disable output

OUT ENABLE VALUE Description

OUT0 xxxx1 Alternate Output 0

OUT1 xxx1x Alternate Output 1

OUT2 xx1xx Alternate Output 2

OUT3 x1xxx Alternate Output 3

OUT4 1xxxx Alternate Output 4

13 NPEN 0 RW OPA0 Negative Pad Input Enable

Connects pad to the negative input mux

12 PPEN 0 RW OPA0 Positive Pad Input Enable

Connects pad to the positive input mux

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Bit Name Reset Access Description

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 RESINMUX 0x0 RW OPA0 Resistor Ladder Input Mux

These bits selects the source for the input mux to the resistor ladder

Value Mode Description

0 DISABLE Set for Unity Gain

1 OPA0INP Set for OPA0 input

2 NEGPAD NEG pad connected

3 POSPAD POS pad connected

4 VSS VSS connected

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 NEGSEL 0x0 RW OPA0 inverting Input Mux

These bits selects the source for the inverting input on OPA0

Value Mode Description

0 DISABLE Input disabled

1 UG Unity Gain feedback path

2 OPATAP OPA0 Resistor ladder as input

3 NEGPAD Input from NEG PAD

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 POSSEL 0x0 RW OPA0 non-inverting Input Mux

These bits selects the source for the non-inverting input on OPA0

Value Mode Description

0 DISABLE Input disabled

1 DAC DAC as input

2 POSPAD POS PAD as input

3 OPA0INP OPA0 as input

4 OPATAP OPA0 Resistor ladder as input

29.5.17 DACn_OPA1MUX - Operational Amplifier Mux Configuration

Offset Bit Position

0x060

Reset

0x0

0x00

0x0

Access

Name

RESSEL

NEXTOUT

OUTMODE

OUTPEN

NPEN

PPEN

RESINMUX

NEGSEL

POSSEL

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:28 RESSEL 0x0 RW OPA1 Resistor Ladder Select

Configures the resistor ladder tap for OPA1.

Value Mode Resistor Value Inverting Mode Gain (-R2/R1) Non-inverting Mode Gain (1+(R2/

R1)

0 RES0 R2 = 1/3 x R1 -1/3 1 1/3

1 RES1 R2 = R1 -1 2

2 RES2 R2 = 1 2/3 x R1 -1 2/3 2 2/3

3 RES3 R2 = 2 x R1 -2 1/5 3 1/5

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Bit Name Reset Access Description

Value Mode Resistor Value Inverting Mode Gain (-R2/R1) Non-inverting Mode Gain (1+(R2/

R1)

4 RES4 R2 = 3 x R1 -3 4

5 RES5 R2 = 4 1/3 x R1 -4 1/3 5 1/3

6 RES6 R2 = 7 x R1 -7 8

7 RES7 R2 = 15 x R1 -15 16

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 NEXTOUT 0 RW OPA1 Next Enable

Makes output of OPA1 available to OPA2.

25:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:22 OUTMODE 0x0 RW Output Select

Select output channel.

Value Mode Description

0 DISABLE OPA0 output is disabled

1 MAIN Main OPA1 output to pin enabled

2 ALT OPA1 alternative output enabled.

3 ALL Main OPA1 output drives both main and alternative outputs.

21:19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:14 OUTPEN 0x00 RW OPA1 Output Enable Value

Set to enable output, clear to disable output

OUT ENABLE VALUE Description

OUT0 xxxx1 Alternate Output 0

OUT1 xxx1x Alternate Output 1

OUT2 xx1xx Alternate Output 2

OUT3 x1xxx Alternate Output 3

OUT4 1xxxx Alternate Output 4

13 NPEN 0 RW OPA1 Negative Pad Input Enable

Connects pad to the negative input mux

12 PPEN 0 RW OPA1 Positive Pad Input Enable

Connects pad to the positive input mux

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 RESINMUX 0x0 RW OPA1 Resistor Ladder Input Mux

These bits selects the source for the input mux to the resistor ladder

Value Mode Description

0 DISABLE Set for Unity Gain

1 OPA0INP Set for OPA0 input

2 NEGPAD NEG PAD connected

3 POSPAD POS PAD connected

4 VSS VSS connected

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 NEGSEL 0x0 RW OPA1 inverting Input Mux

These bits selects the source for the inverting input on OPA1

Value Mode Description

0 DISABLE Input disabled

1 UG Unity Gain feedback path

2 OPATAP OPA1 Resistor ladder as input

3 NEGPAD Input from NEG PAD

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

2:0 POSSEL 0x0 RW OPA1 non-inverting Input Mux

These bits selects the source for the non-inverting input on OPA1

Value Mode Description

0 DISABLE Input disabled

1 DAC DAC as input

2 POSPAD POS PAD as input

3 OPA0INP OPA0 as input

4 OPATAP OPA 1 Resistor ladder as input

29.5.18 DACn_OPA2MUX - Operational Amplifier Mux Configuration

Offset Bit Position

0x064

Reset

0x0

Access

Name

RESSEL

NEXTOUT

OUTMODE

OUTPEN

NPEN

PPEN

RESINMUX

NEGSEL

POSSEL

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:28 RESSEL 0x0 RW OPA2 Resistor Ladder Select

Configures the resistor ladder tap for OPA2.

Value Mode Resistor Value Inverting Mode Gain (-R2/R1) Non-inverting Mode Gain (1+(R2/

R1)

0 RES0 R2 = 1/3 x R1 -1/3 1 1/3

1 RES1 R2 = R1 -1 2

2 RES2 R2 = 1 2/3 x R1 -1 2/3 2 2/3

3 RES3 R2 = 2 x R1 -2 1/5 3 1/5

4 RES4 R2 = 3 x R1 -3 4

5 RES5 R2 = 4 1/3 x R1 -4 1/3 5 1/3

6 RES6 R2 = 7 x R1 -7 8

7 RES7 R2 = 15 x R1 -15 16

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26 NEXTOUT 0 RW OPA2 Next Enable

OPA2 does not have an next output.

25:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 OUTMODE 0 RW Output Select

Enables OPA2 main output.

21:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:14 OUTPEN 0x0 RW OPA2 Output Location

Select location for main output

Value Mode Description

1 OUT0 Main Output 0

2 OUT1 Main Output 1

13 NPEN 0 RW OPA2 Negative Pad Input Enable

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Bit Name Reset Access Description

Connects pad to the negative input mux

12 PPEN 0 RW OPA2 Positive Pad Input Enable

Connects pad to the positive input mux

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 RESINMUX 0x0 RW OPA2 Resistor Ladder Input Mux

These bits selects the source for the input mux to the resistor ladder

Value Mode Description

0 DISABLE Set for Unity Gain

1 OPA1INP Set for OPA1 input

2 NEGPAD NEG PAD connected

3 POSPAD POS PAD connected

4 VSS VSS connected

7:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:4 NEGSEL 0x0 RW OPA2 inverting Input Mux

These bits selects the source for the inverting input on OPA2

Value Mode Description

0 DISABLE Input disabled

1 UG Unity Gain feedback path

2 OPATAP OPA2 Resistor ladder as input

3 NEGPAD Input from NEG PAD

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 POSSEL 0x0 RW OPA2 non-inverting Input Mux

These bits selects the source for the non-inverting input on OPA2

Value Mode Description

0 DISABLE Input disabled

2 POSPAD POS PAD as input

3 OPA1INP OPA1 as input

4 OPATAP OPA0 Resistor ladder as input

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30 OPAMP - Operational Amplifier

01 2 3 4

VIN

VOUT

Quick Facts

What?

The opamps are low power amplifiers with

a high degree of flexibility targeting a wide

variety of standard opamp application areas.

With flexible gain and interconnection built-

in programming they can be configured to

support multiple common opamp functions,

with all pins available externally for filter

configurations. Each opamp has a rail to rail

input and a rail to rail output.

Why?

The opamps are included to save energy on

a pcb compared to standalone opamps, but

also reduce system cost by replacing external

opamps.

How?

Two of the opamps are made available

as part of the DAC, while the third opamp

is standalone. An ADC unity gain buffer

mode configuration makes it possible to

isolate kickback noise, in addition to popular

differential to single ended and differential

to differential driver modes. The opamps

can also be configured as a one, two- or

three-step cascaded PGA, and for all of the

built-in modes no external components are

necessary.

30.1 Introduction

The opamps are highly configurable general purpose opamps, suitable for simple filters and buffer

applications. The three opamps can be configured to support various operational amplifier functions

through a network of muxes, with possibilities of selecting ranges of on-chip non-inverting and inverting

gain configurations, and selecting between outputs to various destinations. The opamps can also be

configured with external feedback in addition to supporting cascade connections between two or three

opamps. The opamps are rail-to-rail in and out. A user selectable mode has been added to optimize

linearity, in which case the input voltage to the opamp is restricted between VSS and VDD-1.2V.

30.2 Features

• 3 individually configurable opamps

• Opamps support rail-to-rail inputs and outputs

• Supports the following functions

• General Opamp Mode

• Voltage Follower Unity Gain

• Inverting Input PGA

• Non-inverting PGA

• Cascaded Inverting PGA

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• Cascaded Non-inverting PGA

• Two Opamp Differential Amplifier

• Three Opamp Differential Amplifier

• Dual Buffer ADC Driver

• Programmable gain

30.3 Functional Description

The three opamps can be configured to perform various opamp functions through a network of muxes.

An overview of the opamps are shown in Figure 30.1 (p. 733) . Two of the three opamps are part of the

DAC, while the third opamp is standalone. The output of OPA0 can be routed to ADC CH0, OPA1 and

various pin outputs. The output of OPA1 can be routed to ADC CH1, OPA2, and various pin outputs. The

output of OPA2 can be routed to ADC CH0, CH5, and various pin output destinations. All three opamps

can also take input from pins. Since OPA0 and OPA1 are part of the DAC, special considerations needs

to be taken when both the DAC Ch0/Ch1 and OPA0/OPA1 are being used. For detailed explanation the

reader is referred to Section 30.3.3 (p. 742) .

Figure 30.1. OPAMP System Overview

OPA0

DAC OPA0 Alternative

outputs

OPA0 Main

output

OPA0NEXT

OPA1

OPA1 Alternative

outputs

OPA1 Main

output

OPA1NEXT

OPA2

OPA2 Main

outputs

ADC CH5

input mux

POS0

NEG0

POS1

NEG1

POS2

NEG2

ADC CH0

input mux

ADC CH1

input mux

ADC CH0

input mux

A more detailed view of the three opamps, including the mux network is shown in Figure 30.2 (p. 734)

. There is a set of input muxes for each opamp, making it possible to select various input sources. The

POSSEL mux connected to the positive input makes it possible to select pin, another opamp output,

or tap from the resistor network. Similarly, the NEGSEL mux on the negative input makes it possible

to select pin or a feedback path as its source. The feedback path can be a unity gain configuration, or

selected from the resistor network for programmable gain. The output of the opamp have different sets of

outputs, a main output, an alternative output network and a next output. These outputs make it possible

to route the output to pin, another opamp input, ADC, or into the feedback path. For details regarding

configuring the outputs, the reader is referred to Section 30.3.1.2 (p. 734) . In addition, there is also a

mux to configure the resistor ladder to be connected to vss, pin, or another opamp output.

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Figure 30.2. OPAMP Overview

OPA0TAP

NEXTOUT0

VSS

OPA0

POSSEL[2:0]

NEGSEL[1:0]

POS0

NEG0

PPEN

NPEN

Main output

Alternative output network

R1 R2

Unity gain

POSPAD

NEXTOUT0

NEGPAD

RESINMUX[3:0]

OPA1TAP

NEXTOUT0

VSS

OPA1

POSSEL[2:0]

NEGSEL[1:0]

POS1

NEG1

PPEN

NPEN

Main output

Alternative output network

R1 R2

Unity gain

POSPAD

NEXTOUT1

NEGPAD

RESINMUX[3:0]

OPA2TAP

OPA0TAP

NEXTOUT1

VSS

OPA2

POSSEL[2:0]

NEGSEL[1:0]

POS2

NEG2

PPEN

NPEN

Main output

R1 R2

Unity gain

POSPAD

NEGPAD

RESINMUX[3:0]

30.3.1 Opamp Configuration

Since two of the three opamps (OPA0, OPA1) are part of the DAC, the opamp configuration registers

are located in the DAC. The mux registers for OPA0/OPA1 together with OPA2 registers are separate

registers, also located under the DAC module. OPA0 and OPA1 can be enabled by setting OPAxEN

in DACn_OPACTRL and CHxEN in CHxCTRL. OPA2 can be enabled by only setting OPA2EN in

DACn_OPACTRL.

30.3.1.1 Input Configuration

The inputs to the opamps are controlled through a set of input muxes. The mux connected to the

positive input is configured by the POSSEL bit-field in the DACn_OPAxMUX register. Similarly, the mux

connected to the negative input is configured by setting the NEGSEL bit-field in DACn_OPAxMUX. To

connect the pins to the input muxes, the pin switches must also be enabled. Setting the PPEN bit-

field enables to POSPADx, while setting the NPEN bit-field enables the NEGPADx, both located in

DACn_OPAxMUX. The input into the resistor ladder can be configured by setting the RESINMUX bit-

field in DACn_OPAxMUX.

30.3.1.2 Output Configuration

The opamp have two outputs, one main output and one alternative output with lower drive strength.

These two outputs can be used to drive the different outputs as shown in Figure 30.3 (p. 735) . The main

opamp output can be used to drive the main output by setting OUTMODE to MAIN in DACn_OPAxMUX.

The alternative opamp output can drive the alternative output network by setting OUTMODE to ALT in

DACn_OPAxMUX. In addition, it is also possible to use the main opamp output to drive both the main

output and the alternative output network by setting OUTMODE to ALL in DACn_OPAxMUX.

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Figure 30.3. Opamp Output Stage Overview

OPA0

output MAIN/ALL

OPA0 Alternative

output network

ALT/ALL

OUT0

OUT1

OUT2

OUT3

OUT4

NEXTOUT

OPA0 Main output

ADC CH0

input mux

OPA1

output MAIN/ALL

OPA1 Alternative

output network

ALT/ALL

OUT0

OUT1

OUT2

OUT3

OUT4

NEXTOUT

OPA1 Main output

ADC CH1

input mux

OPA2

output OUT0

OUT1

OPA2 Main outputs ADC CH5

input mux

ADC CH0

input mux

MAIN

The alternative output network consists of connections to pins, ADC, and a connection to the next opamp

(OPA0 to OPA1, and OPA1 to OPA2). The connections to pins can be individually enabled by configuring

OUTPEN in DACn_OPAxMUX register. To enable cascaded opamp configurations, each opamp has a

NEXTOUT connection. This output makes it possible to connect OPA0 to OPA1, and OPA1 to OPA2.

This output connection is enabled by setting NEXTOUT in DACn_OPAxMUX.

The opamps can also be routed to the ADC. OPA0 can be connected to ADC CH0, OPA1 to ADC CH1

and OPA2 can be connected to both ADC CH1 and CH5. The ADC connections are created by routing

the OPA output by setting corresponding bits in OUTPEN in DACn_OPAxMUX. For OPA0 alternative

output 4 is connected to ADC input mux CH0 when enabled. OPA1's alternative output 4 is connected

to ADC input mux CH1 when enabled. For OPA2, the two main outputs can be connected to ADC input

mux CH0 and ADC input mux CH5 respectively when enabled. See Section 28.3.4 (p. 691) , in the ADC

chapter for information on how to configure the ADC input mux.

30.3.1.3 Gain Programming

The feedback path of each mux includes a resistor ladder, which can be used to select a set of gain

values. The gain can be selected by the RESSEL bit-field located in DACn_OPAxMUX register. The

gain values are taken from tappings of the resistor ladder based on ratio of R2/R1. It is also possible to

bypass the resistor ladder in Unity Gain (UG) mode.

30.3.1.4 Offset Calibration

The offset calibration registers are located in different registers for the opamps. OPA0 and OPA1's offset

can be set through the CH0OFFSET and CH1OFFSET bit-fields respectively in DACn_CAL. The offset

for OPA2 can be set through OPA2OFFSET in DACn_OPAOFFSET.

30.3.1.5 Shorting Non-inverting and Inverting Input

Functionality for offset calibration of the opamps has been added, this functionality is enabled by

setting the OPAxSHORT bit-field in DACn_OPAxCTRL. Setting this bit-field enables a switch that shorts

between the inverting and non-inverting input of the OPA, effectively driving the offset voltage of the

opamp to the output. Using the ADC to measure this offset, the calibration register can be adjusted to

minimize the output offset.

30.3.1.6 Low Pass Filter

The low pass filter is located between the pad and the positive input. The low-pass filter is designed to

couple the input signal to local VSS for high frequencies and has a 3 dB frequency of approximately 130

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MHz when driven from a 50 ohm source. The filter adds a parasitic capacitance of approximately 1.2

pF towards local VSS when enabled. The filter is enabled out of reset and can be disabled by setting

OPAxLPFDIS in DACn_OPAxCTRL.

30.3.1.7 Disabling of rail-to-rail Operation

Each opamp can have the input rail-to-rail stage disabled by setting the OPAxHCMDIS bit-field in

DACn_OPACTRL. Disabling the rail-to-rail input stage improves linearity of the opamp, thus improving

the Total Harmonic Distortion, THD, at the cost of reduced input signal swing.

30.3.2 Opamp Modes

The opamp can be configured to perform different Operational Amplifier functions by configuring the

internal signal routing between the opamps. The modes available are described in the following sections.

30.3.2.1 General Opamp Mode

In this mode the resistor ladder is isolated from the feedback path and input signal routing is defined

by OPAxPOSSEL and OPAxNEGSEL in DACn_OPAxMUX. The output signal routing is defined by

OUTPEN in DACn_OPAxMUX

Table 30.1. General Opamp Mode Configuration

OPA bit-fields OPA Configuration

OPAx POSSEL POSPADx

OPAx NEGSEL OPATAP, UG, NEGPADx

OPAx RESINMUX NEXTOUT, POSPADx, NEGPADx VSS

30.3.2.2 Voltage Follower Unity Gain

In this mode the unity gain feedback path is selected for the negative input by setting the OPAxNEGSEL

bit-field to UG in the DACn_OPAxMUX register as shown in Figure 30.4 (p. 736) . The positive input

is selected by the OPAxPOSSEL bit-field, and the output is configured by the OUTPEN bit-field, both

in the DACn_OPAxMUX register.

Figure 30.4. Voltage Follower Unity Gain Overview

VIN

VOUT

Table 30.2. Voltage Follower Unity Gain Configuration

OPA bit-fields OPA Configuration

OPAx POSSEL OPATAP, NEXTOUT, POSPADx

OPAx NEGSEL UG

OPAx RESINMUX DISABLE

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30.3.2.3 Inverting input PGA

Figure 30.5 (p. 737) shows the inverting input PGA configuration. In this mode the negative

input is connected to the resistor ladder by setting the OPAxNEGSEL bit-field to OPATAP in the

DACn_OPAxMUX register. This setting provides a programmable gain on the negative input, which

can be set by choosing the wanted gain value in the RESSEL bit-field in DACn_OPAxMUX. Signal

ground for the positive input can be generated off-chip through the pad by setting OPAxPOSSEL bit-

field to PAD in DACn_OPAxMUX. In addition the output is configured by the OUTPEN bit-field, located

in DACn_OPAxMUX.

Figure 30.5. Inverting input PGA Overview

VOUT

VOUT=-(VIN-POS) R2/R1 + POS

R1 R2

POS

VIN

Table 30.3. Inverting input PGA Configuration

OPA bit-fields OPA Configuration

OPAx POSSEL POSPADx

OPAx NEGSEL OPATAP

OPAx RESINMUX NEXTOUT, NEGPADx, POSPADx

30.3.2.4 Non-inverting PGA

Figure 30.6 (p. 737) shows the non-inverting input configuration. In this mode the negative input is

connected to the resistor ladder by setting the OPAxNEGSEL bit-field to OPATAP in DACn_OPAxMUX.

This setting provides a programmable gain on the negative input, which can be set by choosing the

wanted gain value in the RESSEL bit-field in DACn_OPAxMUX. In addition the OPAxRESINMUX

bit-field must be set to VSS or NEGPAD in DACn_OPAxMUX. The positive input is selected by

the OPAxPOSSEL bit-field, and the output is configured by the OUTPEN bit-field, both located in

DACn_OPAxMUX.

Figure 30.6. Non-inverting PGA Overview

R1 R2

VIN

+VOUT

VOUT=VIN(1+ R2/R1)

Table 30.4. Non-inverting PGA Configuration

OPA bit-fields OPA Configuration

OPAx POSSEL NEXTOUT, POSPADx

OPAx NEGSEL OPATAP

OPAx RESINMUX VSS, NEGPAD

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30.3.2.5 Cascaded Inverting PGA

This mode enables the opamp signals to be internally configured to cascade two or three opamps in

inverting mode as shown in Figure 30.7 (p. 738) . In both cases the positive input will be configured

to signal ground by setting OPAxPOSSEL bit-field to PAD in DACn_OPAx_MUX. When cascaded, the

negative input is connected to the resistor ladder by setting the OPAxNEGSEL bit-field to OPATAP in

DACn_OPAxMUX. The input to the resistor ladder can be configured in the OPAxRESINMUX bit-field

in DAC_nOPAxMUX. The output from OPA0 can be connected to OPA1 to create the second stage

by setting the NEXTOUT bit-field in DACn_OPAxMUX. To complete the stage, OPA1RESINMUX field

must be set to OPA0INP. Similarly, the last stage can be created by setting the NEXTOUT bit-field in

DACn_OPA1MUX and OPA2RESINMUX bit-field to OPA1INP in DACn_OPA2MUX.

Figure 30.7. Cascaded Inverting PGA Overview

R1 R2

VIN

POS0

VOUT1=-(VIN-POS0) x R2/R1 + POS0

VOUT2=-(VOUT1-POS1) x R2/R1 + POS1

VOUT3=-(VOUT2-POS3) x R2/R1 + POS3

R1 R2

POS1

R1 R2

POS2

Table 30.5. Cascaded Inverting PGA Configuration

OPA OPA bit-fields OPA Configuration

OPA0 POSSEL POSPAD0

OPA0 NEGSEL OPA0TAP

OPA0 RESINMUX NEGPAD0

OPA0 NEXTOUT 1

OPA1 POSSEL POSPAD1

OPA1 NEGSEL OPATAP

OPA1 RESINMUX OPA0INP

OPA1 NEXTOUT 1

OPA2 POSSEL POSPAD2

OPA2 NEGSEL OPATAP

OPA2 RESINMUX OPA1INP

30.3.2.6 Cascaded Non-inverting PGA

This mode enables the opamp signals to be internally configured to cascade two or three opamps in non-

inverting mode as shown in Figure 30.8 (p. 739) . In both cases the negative input for all opamps will be

connected to the resistor ladder by setting the OPAxNEGSEL bit-field to OPATAP. In addition the resistor

ladder input must be set to VSS or NEGPADx in the OPAxRESINMUX in DACn_OPAxMUX. When

cascaded, the positive input on OPA0 is configured by the OPA0POSSEL bit-field. The output from OPA0

can be connected to OPA1 to create the second stage by setting NEXTOUT in DACn_OPA0MUX. To

complete the stage, the OPA1POSSEL bit-field must be set to OPA0INP in DACn_OPA1MUX. Similarly,

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the last stage can be created by setting NEXTOUT in DACn_OPA1MUX and OPA2POSSEL bit-field to

OPA1INP in DACn_OPA2MUX.

Figure 30.8. Cascaded Non-inverting PGA Overview

R1 R2

VIN

+VOUT1=VIN(1+ R2/R1) VOUT2=VIN(1+ R2/R1) VOUT3=VIN(1+ R2/R1)

R1 R2

Table 30.6. Cascaded Non-inverting PGA Configuration

OPA OPA bit-fields OPA Configuration

OPA0 POSSEL POSPAD0

OPA0 NEGSEL OPATAP

OPA0 RESINMUX VSS, NEGPAD0

OPA0 NEXTOUT 1

OPA1 POSSEL OPA0INP

OPA1 NEGSEL OPATAP

OPA1 RESINMUX VSS, NEGPAD1

OPA1 NEXTOUT 1

OPA2 POSSEL OPA1INP

OPA2 NEGSEL OPATAP

OPA2 RESINMUX VSS, NEGPAD2

30.3.2.7 Two Opamp Differential Amplifier

This mode enables OPA0 and OPA1 or OPA1 and OPA2 to be internally configured to form a two opamp

differential amplifier as shown in Figure 30.9 (p. 740) . When using OPA0 and OPA1, the positive input

of OPA0 can be connected to any input by configuring the OPA0POSSEL bit-field in DACn_OPA0MUX.

The OPA0 feedback path must be configured to unity gain by setting the OPA0NEGSEL bit-field to UG in

DACn_OPA0MUX. In addition, the OPA0RESINMUX bit-field must be set to DISABLED. The OPA0OUT

must be connected to OPA1 by setting NEXTOUT in DACn_OPA0MUX, and OPA1RESINMUX to

OPA0INP. The positive input on OPA1 can be set by configuring OPA1POSSEL. The OPA1 output can

be configured by configuring the OUTPEN and OUTMODE bit-field.

When using OPA1 and OPA2, the positive input of OPA1 can be connected to any input by configuring

the OPA1POSSEL bit-field in DACn_OPA1MUX. The OPA1 feedback path must be configured to unity

gain by setting the OPA1NEGSEL bit-field to UG in DACn_OPA1MUX. In addition, the OPA1RESINMUX

bit-field must be set to DISABLED. The OPA1OUT must be connected to OPA2 by setting NEXTOUT

in DACn_OPA1MUX, and OPA2RESINMUX to OPA1INP. The positive input on OPA2 can be set

by configuring OPA2POSSEL. The OPA2 output can be configured by configuring the OUTPEN and

OUTMODE bit-field.

Note When making a differential connection with the ADC, only OPA1 and OPA2 can be used

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Figure 30.9. Two Op-amp Differential Amplifier Overview

R1 R2

V1 VDIFF=(V2-V1)R2/R1

OPA0

OPA1

R1 R2

V1 VDIFF=(V2-V1)R2/R1

OPA1

OPA2

Table 30.7. OPA0/OPA1 Differential Amplifier Configuration

OPA OPA bit-fields OPA Configuration

OPA0 POSSEL POSPAD1

OPA0 NEGSEL UG

OPA0 RESINMUX DISABLE

OPA0 NEXTOUT 1

OPA1 POSSEL POSPAD1

OPA1 NEGSEL OPATAP

OPA1 RESINMUX OPA1INP

Table 30.8. OPA1/OPA2 Differential Amplifier Configuration

OPA OPA bit-fields OPA Configuration

OPA1 POSSEL POSPAD1

OPA1 NEGSEL UG

OPA1 RESINMUX DISABLE

OPA1 NEXTOUT 1

OPA2 POSSEL POSPAD1

OPA2 NEGSEL OPATAP

OPA2 RESINMUX OPA1INP

30.3.2.8 Three Opamp Differential Amplifier

This mode enables the three opamps to be internally configured to form a three opamp differential

amplifier as shown in Figure 30.10 (p. 741) . Both OPA0 and OPA1 can be configured in the same

unity gain mode. For both OPA0/OPA1 the positive input can be connected to any input by configuring

the OPA0POSSEL/OPA1POSSEL bit-field. The OPA0/OPA1 feedback path must be configured to unity

gain by setting the OPA0NEGSEL/OPA1NEGSEL bit-field to UG. In addition the OPA0RESINMUX/

OPA1RESINMUX bit-fields must be set to DISABLED. The OPA1 output must be connected to

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OPA2 by setting the NEXTOUT bit-field in DACn_OPA1MUX and OPA2RESINMUX to OPA1INP in

DACn_OPA2MUX. In addition the OPA2POSSEL must be set to 0PATAP. The OPA2 output can be

configured by configuring the OUTPEN and OUTMODE bit-field.

Figure 30.10. Three Op-amp Differential Amplifier Overview

R1 R2

+VOUT

VOUT=(V2-V1)R2/R1

R1 R2

V1 OPA1

OPA0

OPA2

The gain values for the Three Opamp Differential Amplifier is determined by the combination of the gain

settings of OPA0 and OPA2. The 3 different gain values available, 1/3, 1 and 3, can be programmed

as shown in the table below.

Table 30.9. Three Opamp Differential Amplifier Gain Programming

Gain OPA0 RESSEL OPA2 RESSEL

1/3 4 0

1 1 1

3 0 4

Table 30.10. Three Opamp Differential Amplifier Configuration

OPA OPA bit-fields OPA Configuration

OPA0 POSSEL POSPAD

OPA0 NEGSEL UG

OPA0 RESINMUX DISABLE

OPA1 POSSEL POSPAD

OPA1 NEGSEL UG

OPA1 RESINMUX DISABLE

OPA1 NEXTOUT 1

OPA2 POSSEL OPATAP

OPA2 NEGSEL OPATAP

OPA2 RESINMUX OPA1INP

30.3.2.9 Dual Buffer ADC Driver

It is possible to use OPA0 and OPA1 to form a Dual Buffer ADC driver as shown in Figure 30.11 (p.

742) . Both opamps used can be configured in the same way. The positive input is configured by

setting the 0PAxPOSSEL to PAD and the negative input can be connected to the resistor ladder by

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setting OPATAP in DACn_OPAxMUX. The output from the opamps can be configured to connect to the

ADC by setting OUTMODE to ALT or ALL in DACn_OPAxMUX.

Figure 30.11. Dual Buffer ADC Driver Overview

R1 R2

VIP

VOUTP=VIP(1+ R2/R1)

VOUTP = VIP (Unity Gain)

VOUTN=VIN(1+ R2/R1)

VOUTN = VIN (Unity Gain)

R1 R2

VIN

Table 30.11. Dual Buffer ADC Driver Configuration

OPA OPA bit-fields OPA Configuration

OPA0 POSSEL POSPAD0

OPA0 NEGSEL OPATAP

OPA0 RESINMUX VSS

OPA1 POSSEL POSPAD1

OPA1 NEGSEL OPATAP

OPA1 RESINMUX VSS

30.3.3 Opamp DAC Combination

Since two of the opamps are part of the DAC it is not possible to use both DAC channels and all three

opamps at the same time. If both DAC channels are used, only OPA2 is available out of the 3 opamps.

However, it is possible to use one of the DAC channels in combination with OPA0/OPA1. OPA1 is

available when DAC channel 0 is in use and OPA0 is available when DAC channel 1 is used. When using

the opamp DAC combination, the DAC CONVMODE can only be configured to either CONTINUOUS

or SAMPLEHOLD mode. The CONVMODE bitfield can be configured in DACn_CTRL register. In the

opamp/DAC combination, the DAC channel enabled is configured through the DAC registers while the

opamp is controlled through the opamp registers.

30.4 Register Description

The register description of the opamp can be found in Section 29.4 (p. 717) in the DAC chapter.

30.5 Register Map

The register map of the opamp can be found in Section 29.4 (p. 717) in the DAC chapter.

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31 AES - Advanced Encryption Standard Accelerator

01 2 3 4

How are you? AES &G#%5

!T4/#2I am fine AES

Quick Facts

What?

A fast and energy efficient hardware

accelerator for AES-128 and AES-256

encryption and decryption.

Why?

Efficient encryption/decryption with little or

no CPU intervention helps to meet the speed

and energy demands of the application.

How?

High AES throughput allows the EFM32LG

to spend more time in lower energy modes.

In addition, specialized data access functions

allow autonomous DMA/AES operation in

both EM0 and EM1.

31.1 Introduction

The Advanced Encryption Standard (FIPS-197) is a symmetric block cipher operating on 128-bit blocks

of data and 128-, 192- or 256-bit keys.

The AES accelerator performs AES encryption and decryption with 128-bit or 256-bit keys. Encrypting or

decrypting one 128-bit data block takes 54 HFCORECLK cycles with 128-bit keys and 75 HFCORECLK

cycles with 256-bit keys. The AES module is an AHB slave which enables efficient access to the data

and key registers. All write accesses to the AES module must be 32-bit operations, i.e. 8- or 16-bit

operations are not supported.

31.2 Features

• AES hardware encryption/decryption

• 128-bit key (54 HFCORECLK cycles)

• 256-bit key (75 HFCORECLK cycles)

• Efficient CPU/DMA support

• Interrupt on finished encryption/decryption

• DMA request on finished encryption/decryption

• Key buffer in AES128 mode

• Optional XOR on Data write

• Configurable byte ordering

31.3 Functional Description

Some data and a key must be loaded into the KEY and DATA registers before an encryption or decryption

can take place. The input data before encryption is called the PlainText and output from the encryption

is called CipherText. For encryption, the key is called PlainKey. After one encryption, the resulting key

in the KEY registers is the CipherKey. This key must be loaded into the KEY registers before every

decryption. After one decryption, the resulting key will be the PlainKey. The resulting PlainKey/CipherKey

is only dependent on the value in the KEY registers before encryption/decryption. The resulting keys

and data are shown in Figure 31.1 (p. 744) .

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Figure 31.1. AES Key and Data Definitions

PlainText CipherText

PlainKey CipherKey

Encryption

Decryption

Encryption

Decryption

31.3.1 Encryption/Decryption

The AES module can be set to encrypt or decrypt by clearing/setting the DECRYPT bit in AES_CTRL.

The AES256 bit in AES_CTRL configures the size of the key used for encryption/decryption. The

AES_CTRL register should not be altered while AES is running, as this may lead to unpredictable

behaviour.

An AES encryption/decryption can be started in the following ways:

• Writing a 1 to the START bit in AES_CMD

• Writing 4 times 32 bits to AES_DATA when the DATASTART control bit is set

• Writing 4 times 32 bits to AES_XORDATA when the XORSTART control bit is set

An AES encryption/decryption can be stopped by writing a 1 to the STOP bit in AES_CMD. The

RUNNING bit in AES_STATUS indicates that an AES encryption/decryption is ongoing.

31.3.2 Data and Key Access

The AES module contains a 128-bit DATA (State) register and two 128-bit KEY registers defined as

DATA3-DATA0, KEY3-KEY0 (KEYL) and KEY7-KEY4 (KEYH). In AES128 mode, the 128-bit key is read

from KEYL, while both KEYH and KEYL are used in AES256 mode. The AES module has configurable

byte ordering which is configured in BYTEORDER in AES_CTRL. Figure 31.2 (p. 744) illustrates how

data written to the AES registers is mapped to the key and state defined in the Advanced Encryption

Standard (FIPS-197). The figure presents the key byte order for 256-bit keys. In 128-bit mode with

BYTEORDER cleared, a16 represents the first byte of the 128-bit key. When BYTEORDER is set, a0

represents the first byte in the key. AES encryption/decryption takes two extra cycles when BYTEORDER

is set. BYTEORDER has to be set prior to loading the data and key registers.

Figure 31.2. AES Data and Key Orientation as Defined in the Advanced Encryption Standard

DATA0

DATA1

DATA2

DATA3

KEY3

KEY2

KEY1

KEY0

DATA KEYL

[31:24]

[23:16]

[15:8]

[7:0]

a0a4

a1a5

a2a6

a8a12

a9a13

a10 a14

a11 a15

a3a7

Byte order in word

S0,0 S0,1

S1,0 S1,1

S2,0 S2,1

S0,2 S0,3

S1,2 S1,3

S2,2 S2,3

S3,2 S3,3

S3,0 S3,1

KEY7

KEY6

KEY5

KEY4

KEYH

a16 a20

a17 a21

a18 a22

a24 a28

a25 a29

a26 a30

a27 a31

a19 a23

BYTEORDER = 0 BYTEORDER = 1

DATA3

DATA2

DATA1

DATA0

KEY4

KEY5

KEY6

KEY7

DATA KEYH

[7:0]

[15:8]

[23:16]

[31:24]

a0a4

a1a5

a2a6

a8a12

a9a13

a10 a14

a11 a15

a3a7

Byte order in word

S0,0 S0,1

S1,0 S1,1

S2,0 S2,1

S0,2 S0,3

S1,2 S1,3

S2,2 S2,3

S3,2 S3,3

S3,0 S3,1

KEY0

KEY1

KEY2

KEY3

KEYL

a16 a20

a17 a21

a18 a22

a24 a28

a25 a29

a26 a30

a27 a31

a19 a23

The registers DATA3-DATA0, are not memory mapped directly, but can be written/read by accessing

AES_DATA or AES_XORDATA. The same applies for the key registers, KEY3-KEY0 which are

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accessed through AES_KEYLn (n=A, B, C or D), while KEY7-KEY4 are accessed through KEYHn

(n=A, B, C or D). Writing DATA3-DATA0 is then done through 4 consecutive writes to AES_DATA (or

AES_XORDATA), starting with the word which is to be written to DATA0. For each write, the words will

be word wise barrel shifted towards the least significant word. Accessing the KEY registers are done in

the same fashion through KEYLn and KEYHn. See Figure 31.3 (p. 745) . Note that KEYHA, KEYHB,

KEYHC and KEYHD are really the same register, just mapped to four different addresses. You can

then choose freely which of these addresses you want to use to update the KEY7-KEY4 registers. The

same principle applies to the KEYLn registers. Mapping the same registers to multiple addresses like

this, allows the DMA controller to write a full 256-bit key in one sweep, when incrementing the address

between each word write.

Figure 31.3. AES Data and Key Register Operation

DATA3Write data Read data

Shift on write and read

DATA2 DATA1 DATA0

AES_DATA/

AES_XORDATA

KEY3Write data Read data

Shift on write and read

KEY2 KEY1 KEY0

AES_KEYLn

KEY7Write data Read data

Shift on write and read

KEY6 KEY5 KEY4

AES_KEYHn

31.3.2.1 Key Buffer

When encrypting multiple blocks of data in a row, the PlainKey must be written to the key register

between each encryption, since the contents of the key registers will be turned into the CipherKey during

the encryption. The opposite applies when decrypting, where you have to re-supply the CipherKey

between each block. However, in AES128 mode, KEY4-KEY7 can be used as a buffer register, to hold

an extra copy of the KEY3-KEY0 registers. When KEYBUFEN is set in AES_CTRL, the contents of

KEY7-KEY4 are copied to KEY3-KEY0, when an encryption/decryption is started. This eliminates the

need for re-loading the KEY for every encrypted/decrypted block when running in AES128 mode.

31.3.2.2 Data Write XOR

The AES module contains an array of XOR gates connected to the DATA registers, which can be used

during a data write to XOR the existing contents of the registers with the new data written. To use the

XOR function, the data must be written to AES_XORDATA location.

Reading data from AES_XORDATA is equivalent to reading data from AES_DATA.

31.3.2.3 Start on Data Write

The AES module can be configured to start an encryption/decryption when the new data has been written

to AES_DATA and/or AES_XORDATA. A 2-bit counter is incremented each time the AES_DATA or

AES_XORDATA registers are written. This counter indicates which data word is written. If DATASTART/

XORSTART in AES_CTRL is set, an encryption will start each time the counter overflows (DATA3 is

written). Writing to the AES_CTRL register will reset the counter to 0.

31.3.3 Interrupt Request

The DONE interrupt flag is set when an encryption/ decryption has finished.

31.3.4 DMA Request

The AES module has 4 DMA requests which are all set on a finished encryption/decryption and cleared

on the following conditions:

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• DATAWR: Cleared on a AES_DATA write or AES_CTRL write

• XORDATAWR: Cleared on a AES_XORDATA write or AES_CTRL write

• DATARD: Cleared on a AES_DATA read or AES_CTRL write

• KEYWR: Cleared on a AES_KEYHn write or AES_CTRL write

31.3.5 Block Chaining Example

Example 31.1 (p. 746) below illustrates how the AES module could be configured to perform Cipher

Block Chaining with 128-bit keys.

Example 31.1. AES Cipher Block Chaining

1. Configure module to encryption, key buffer enabled and XORSTART in AES_CTRL.

2. Write 128-bit initialization vector to AES_DATA, starting with least significant word.

3. Write PlainKey to AES_KEYHn, starting with least significant word.

4. Write PlainText to AES_XORDATA, starting with least significant word. Encryption will be started

when the DATA3 is written. KEYH (PlainKey) will be copied to KEYL before encryption starts.

5. When encryption is finished, read CipherText from AES_DATA, starting with least significant word.

6. Loop to step 4, if new PlainText is available.

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31.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 AES_CTRL RW Control Register

0x004 AES_CMD W1 Command Register

0x008 AES_STATUS R Status Register

0x00C AES_IEN RW Interrupt Enable Register

0x010 AES_IF R Interrupt Flag Register

0x014 AES_IFS W1 Interrupt Flag Set Register

0x018 AES_IFC W1 Interrupt Flag Clear Register

0x01C AES_DATA RW DATA Register

0x020 AES_XORDATA RW XORDATA Register

0x030 AES_KEYLA RW KEY Low Register

0x034 AES_KEYLB RW KEY Low Register

0x038 AES_KEYLC RW KEY Low Register

0x03C AES_KEYLD RW KEY Low Register

0x040 AES_KEYHA RW KEY High Register

0x044 AES_KEYHB RW KEY High Register

0x048 AES_KEYHC RW KEY High Register

0x04C AES_KEYHD RW KEY High Register

31.5 Register Description

31.5.1 AES_CTRL - Control Register

Offset Bit Position

0x000

Reset

Access

Name

BYTEORDER

XORSTART

DATASTART

KEYBUFEN

AES256

DECRYPT

Bit Name Reset Access Description

31:7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6 BYTEORDER 0 RW Configure byte order in data and key registers

When set, the byte orders in the data and key registers are swapped before and after encryption/decryption.

5 XORSTART 0 RW AES_XORDATA Write Start

Set this bit to start encryption/decryption when DATA3 is written through AES_XORDATA.

4 DATASTART 0 RW AES_DATA Write Start

Set this bit to start encryption/decryption when DATA3 is written through AES_DATA.

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 KEYBUFEN 0 RW Key Buffer Enable

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Bit Name Reset Access Description

Enable/disable key buffer in AES-128 mode.

1 AES256 0 RW AES-256 Mode

Select AES-128 or AES-256 mode.

Value Description

0 AES-128 mode

1 AES-256 mode

0 DECRYPT 0 RW Decryption/Encryption Mode

Select encryption or decryption.

Value Description

0 AES Encryption

1 AES Decryption

31.5.2 AES_CMD - Command Register

Offset Bit Position

0x004

Reset

Access

Name

STOP

START

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 STOP 0 W1 Encryption/Decryption Stop

Set to stop encryption/decryption.

0 START 0 W1 Encryption/Decryption Start

Set to start encryption/decryption.

31.5.3 AES_STATUS - Status Register

Offset Bit Position

0x008

Reset

Access

Name

RUNNING

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 RUNNING 0 R AES Running

This bit indicates that the AES module is running an encryption/decryption.

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31.5.4 AES_IEN - Interrupt Enable Register

Offset Bit Position

0x00C

Reset

Access

Name

DONE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 DONE 0 RW Encryption/Decryption Done Interrupt Enable

Enable/disable interrupt on encryption/decryption done.

31.5.5 AES_IF - Interrupt Flag Register

Offset Bit Position

0x010

Reset

Access

Name

DONE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 DONE 0 R Encryption/Decryption Done Interrupt Flag

Set when an encryption/decryption has finished.

31.5.6 AES_IFS - Interrupt Flag Set Register

Offset Bit Position

0x014

Reset

Access

Name

DONE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 DONE 0 W1 Encryption/Decryption Done Interrupt Flag Set

Write to 1 to set encryption/decryption done interrupt flag

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31.5.7 AES_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x018

Reset

Access

Name

DONE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 DONE 0 W1 Encryption/Decryption Done Interrupt Flag Clear

Write to 1 to clear encryption/decryption done interrupt flag

31.5.8 AES_DATA - DATA Register

Offset Bit Position

0x01C

Reset

0x00000000

Access

Name

DATA

Bit Name Reset Access Description

31:0 DATA 0x00000000 RW Data Access

Access data through this register.

31.5.9 AES_XORDATA - XORDATA Register

Offset Bit Position

0x020

Reset

0x00000000

Access

Name

XORDATA

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Bit Name Reset Access Description

31:0 XORDATA 0x00000000 RW XOR Data Access

Access data with XOR function through this register.

31.5.10 AES_KEYLA - KEY Low Register

Offset Bit Position

0x030

Reset

0x00000000

Access

Name

KEYLA

Bit Name Reset Access Description

31:0 KEYLA 0x00000000 RW Key Low Access A

Access the low key words through this register.

31.5.11 AES_KEYLB - KEY Low Register

Offset Bit Position

0x034

Reset

0x00000000

Access

Name

KEYLB

Bit Name Reset Access Description

31:0 KEYLB 0x00000000 RW Key Low Access B

Access the low key words through this register.

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31.5.12 AES_KEYLC - KEY Low Register

Offset Bit Position

0x038

Reset

0x00000000

Access

Name

KEYLC

Bit Name Reset Access Description

31:0 KEYLC 0x00000000 RW Key Low Access C

Access the low key words through this register.

31.5.13 AES_KEYLD - KEY Low Register

Offset Bit Position

0x03C

Reset

0x00000000

Access

Name

KEYLD

Bit Name Reset Access Description

31:0 KEYLD 0x00000000 RW Key Low Access D

Access the low key words through this register.

31.5.14 AES_KEYHA - KEY High Register

Offset Bit Position

0x040

Reset

0x00000000

Access

Name

KEYHA

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Bit Name Reset Access Description

31:0 KEYHA 0x00000000 RW Key High Access A

Access the high key words through this register.

31.5.15 AES_KEYHB - KEY High Register

Offset Bit Position

0x044

Reset

0x00000000

Access

Name

KEYHB

Bit Name Reset Access Description

31:0 KEYHB 0x00000000 RW Key High Access B

Access the high key words through this register.

31.5.16 AES_KEYHC - KEY High Register

Offset Bit Position

0x048

Reset

0x00000000

Access

Name

KEYHC

Bit Name Reset Access Description

31:0 KEYHC 0x00000000 RW Key High Access C

Access the high key words through this register.

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31.5.17 AES_KEYHD - KEY High Register

Offset Bit Position

0x04C

Reset

0x00000000

Access

Name

KEYHD

Bit Name Reset Access Description

31:0 KEYHD 0x00000000 RW Key High Access D

Access the high key words through this register.

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32 GPIO - General Purpose Input/Output

01 2 3 4

GPIO

Peripherals

ARM

Cortex-M3

EFM32 MCU

Quick Facts

What?

The GPIO (General Purpose Input/Output)

is used for pin configuration and direct pin

manipulation and sensing as well as routing

for peripheral pin connections.

Why?

Easy to use and highly configurable input/

output pins are important to fit many

communication protocols as well as

minimizing software control overhead.

Flexible routing of peripheral functions helps

to ease PCB layout.

How?

Each pin on the device can be individually

configured as either an input or an output with

several different drive modes. Also, individual

bit manipulation registers minimizes control

overhead. Peripheral connections to pins

can be routed to several different locations,

thus solving congestion issues that may

arise with multiple functions on the same pin.

Fully asynchronous interrupts can also be

generated from any pin.

32.1 Introduction

In the EFM32LG devices the General Purpose Input/Output (GPIO) pins are organized into ports with up

to 16 pins each. These pins can individually be configured as either an output or input. More advanced

configurations like open-drain, filtering and drive strength can also be configured individually for the pins.

The GPIO pins can also be overridden by peripheral pin connections, like Timer PWM outputs or USART

communication, which can be routed to several locations on the device. The GPIO supports up to 16

asynchronous external pin interrupts, which enables interrupts from any pin on the device. Also, the

input value of a pin can be routed through the Peripheral Reflex System to other peripherals.

32.2 Features

• Individual configuration for each pin

• Tristate (reset state)

• Push-pull

• Open-drain

• Pull-up resistor

• Pull-down resistor

• Four drive strength modes

• HIGH

• STANDARD

• LOW

• LOWEST

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• EM4 IO pin retention. This includes

• Output enable

• Output value

• Pull enable

• Pull direction

• EM4 wake-up on selected GPIO pins

• Glitch suppression input filter.

• Analog connection to e.g. ADC.

• Alternate functions (e.g. peripheral outputs and inputs)

• Routed to several locations on the device

• Pin connections can be enabled individually

• Output data can be overridden by peripheral

• Output enable can be overridden by peripheral

• Toggle, set and clear registers for output data

• Dedicated data input register (read-only)

• Interrupts

• 2 interrupt lines from up to 16 pending sources

• All GPIO pins are selectable

• Separate enable, status, set and clear registers

• Asynchronous sensing

• Rising, falling or both edges

• Wake up from EM0-EM3

• Peripheral Reflex System producer

• All GPIO pins are selectable

• Configuration lock functionality to avoid accidental changes

32.3 Functional Description

An overview of the GPIO module is shown in Figure 32.1 (p. 757) .The GPIO pins are grouped into 16-

pin ports. Each individual GPIO pin is called Pxn where x indicates the port (A, B, C ...) and n indicates

the pin number (0,1,....,15). Fewer than 16 bits may be available on some ports, depending on the total

number of I/O pins on the package. After a reset both input and output is disabled for all pins on the

device, except for debug pins. To use a pin, the port GPIO_Px_MODEL/GPIO_Px_MODEH registers

must be configured for the pin to make it an input or output. These registers can also do more advanced

configuration, which is covered in Section 32.3.1 (p. 757) . When the port is either configured as an

input or an output, the Data In Register (GPIO_Px_DIN) can be used to read the level of each pin in the

port (bit n in the register is connected to pin n on the port). When configured as an output, the value of

the Data Out Register (GPIO_Px_DOUT) will be driven to the pin.

The DOUT value can be changed in 4 different ways

• Writing to the GPIO_Px_DOUT register.

• Writing a 1 to a bit in the GPIO_Px_DOUTSET register sets the corresponding DOUT bit

• Writing a 1 to a bit in the GPIO_Px_DOUTCLR register clears the corresponding DOUT bit

• Writing a 1 to a bit in the GPIO_Px_DOUTTGL register toggles the corresponding DOUT bit

Reading the GPIO_Px_DOUT register will return its contents. Reading the GPIO_Px_DOUTSET,

GPIO_Px_CLR or GPIO_Px_TGL will return 0.

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Figure 32.1. Pin Configuration

Port Control

VSS

MODEn[3:0]

DOUT

Analog connection

VDD

Output enable

Input enable

Interrupt input

Alternate function override

Alternate function input

Alternate function output enable

Alternate function data out

Data out

DIN

Pull-down enable

Pull-up enable

Output enable

Output value

Glitch

suppression

filter

Filter enable

PRS

ESD

protection

ESD

protection

32.3.1 Pin Configuration

In addition to setting the pins as either outputs or inputs, the GPIO_Px_MODEL and GPIO_Px_MODEH

registers can be used for more advanced configurations. GPIO_Px_MODEL contains 8 bit fields

named MODEn (n=0,1,..7) which control pins 0-7, while GPIO_Px_MODEH contains 8 bit fields named

MODEn (n=8,9,..15) which control pins 8-15. In some modes GPIO_Px_DOUT is also used for extra

configurations like pull-up/down and glitch suppression filter enable. Table 32.1 (p. 757) shows the

available configurations.

Table 32.1. Pin Configuration

MODEn Input Output DOUT Pull-

down Pull-

up Alt.

strength Input

Filter Description

0 Input disabled0b0000 Disabled

1 On Input disabled with pull-up

0 Input enabled0b0001

1 On Input enabled with filter

0 On Input enabled with pull-down0b0010

Enabled

Disabled

1 On Input enabled with pull-up

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MODEn Input Output DOUT Pull-

down Pull-

up Alt.

strength Input

Filter Description

0 On On Input enabled with pull-down and

filter

0b0011

1 On On Input enabled with pull-up and filter

0b0100 x Push-pull

0b0101

Push-pull

x On Push-pull with alt. drive strength

0b0110 x Open-source

0b0111

Open

Source

(Wired-OR) x On Open-source with pull-down

0b1000 x Open-drain

0b1001 x On Open-drain with filter

0b1010 x On Open-drain with pull-up

0b1011 x On On Open-drain with pull-up and filter

0b1100 x On Open-drain with alt. drive strength

0b1101 x On On Open-drain with alt. drive strength

and filter

0b1110 x On On Open-drain with alt. drive strength

and pull-up

0b1111

Open Drain

(Wired-

AND)

x On On On Open-drain with alt. drive strength,

pull-up and filter

MODEn determines which mode the pin is in at a given time. Setting MODEn to 0b0000 disables the

pin, reducing power consumption to a minimum. When the output driver is disabled, the pin can be used

as a connection for an analog module (e.g. ADC). Input is enabled by setting MODEn to any value

other than 0b0000. The pull-up, pull-down and filter function can optionally be applied to the input, see

Figure 32.2 (p. 758) .

The internal pull-up resistance, RPU, and pull-down resistance, RPD, are defined in the device datasheet.

When the filter is enabled it suppresses glitches with pulse widths as defined by the parameter tIOGLITCH

in the device datasheet.

Figure 32.2. Tristated Output with Optional Pull-up or Pull-down

VDD

DIN

Optional

pull-up

VSS

Optional

pull-down

Input enable

Analog connection

Glitch

suppression

filter

Filter enable

When MODEn=0b0100 or MODEn=0b0101, the pin operates in push-pull mode. In this mode, the pin

is driven either high or low, dependent on the value of GPIO_Px_DOUT. The push-pull configuration is

shown in Figure 32.3 (p. 759) .

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Figure 32.3. Push-Pull Configuration

Input Enable

DOUT

DIN

Output Enable

When MODEn is 0110 or 0111, the pin operates in open-source mode, the latter with a pull-down resistor.

When driving a high value in open-source mode, the pull-down is disconnected to save power.

For the remaining MODEn values, i.e. MODEn >= 1000, the pin operates in open-drain mode as shown

in Figure 32.4 (p. 759) . In open-drain mode, the pin can have an input filter, a pull-up, different driver

strengths or any combination of these. When driving a low value in open-drain mode, the pull-up is

disconnected to save power.

Figure 32.4. Open-drain

VSS

DOUT

VDD

DIN

Optional

pull-up

Glitch

suppression

filter

Filter enable

When MODEn=0b0101 or 0b11xx, the output driver uses the drive strength specified in DRIVEMODE

in GPIO_Px_CTRL. In all other output modes, the drive strength is set to STANDARD.

32.3.1.1 Configuration Lock

GPIO_Px_MODEL, GPIO_Px_MODEH, GPIO_Px_CTRL, GPIO_Px_PINLOCKN, GPIO_EXTIPSELL,

GPIO_EXTIPSELH, GPIO_INSENSE and GPIO_ROUTE can be locked by writing any other value

than 0xA534 to GPIO_LOCK. Writing the value 0xA534 to the GPIOx_LOCK register unlocks the

configuration registers.

In addition to configuration lock, GPIO_Px_MODEL, GPIO_Px_MODEH, GPIO_Px_DOUT,

GPIO_Px_DOUTSET, GPIO_Px_DOUTCLR, and GPIO_Px_DOUTTGL can be locked individually for

each pin by clearing the corresponding bit in GPIO_Px_PINLOCKN. Bits in the GPIO_Px_PINLOCKN

32.3.2 EM4 Wake-up

It is possible to wake-up from EM4 through reset triggered from any of up to 6 selectable GPIO pins.

For the wake-up logic to work correctly, EM4 retention needs to be enabled before entering EM4, as

described in Section 32.3.3 (p. 760) The wake-up request can be triggered through the pins by

enabling the corresponding bit in the GPIO_EM4WUEN register. When EM4 wake-up is enabled for the

pin, the input filter is enabled during EM4. This is done to avoid false wake-up caused by glitches. In

addition, the polarity of the EM4 wake-up request can be selected using the GPIO_EM4WUPOL register.

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Figure 32.5. EM4 Wake-up Logic

GPIO_EM4WUPOL

Wake-up Logic

GPIO_EM4WUEN

GPIO_EM4WUCAUSE

Wake-up request

GPIO_CMD

The pins used for EM4 wake-up must be configured as inputs using the GPIO_Px_MODEL/

GPIO_Px_MODEH register. Before going down to EM4, it is important to clear the wake-up logic

by setting the EM4WUCLR bitfield in the GPIO_CMD register, which clears the complete wake-up

logic, including the GPIO_EM4WUCAUSE register. When the chip comes out of reset, it is possible

to determine what caused the reset by reading the RMU_RSTCAUSE register. If an EM4 wake-up

reset occurred, the EM4RST (indicating the chip was in EM4) and the EM4WU (indicating the EM4

wake-up reset) bits should be set. It is possible to determine which pin caused the reset by reading

the GPIO_EM4WUCAUSE register. The mapping between pins and the bits in the GPIO_EM4WUEN,

GPIO_EM4WUPOL, and GPIO_EM4WUCAUSE registers are described in Table 32.2 (p. 760)

Table 32.2. EM4 WU Register bits to pin mapping

Wake-up Registers Bits Pin

bit 0 A0

bit 1 A6

bit 2 C9

bit 3 F1

bit 4 F2

bit 5 E13

32.3.3 EM4 Retention

It is possible to enable retention of output enable, output value, pull enable and pull direction when

in EM4. EM4 retention also makes it possible to wake up from EM4 on pin reset as described in

Section 32.3.2 (p. 759) EM4 retention can be enabled by setting the EM4RET field in GPIO_CTRL

32.3.4 Alternate Functions

Alternate functions are connections to pins from Timers, USARTs etc. These modules contain route

registers, where the pin connections are enabled. In addition, these registers contain a location bit

field, which configures which pins the outputs of that module will be connected to if they are enabled.

If an alternate signal output is enabled for a pin and output is enabled for the pin, the alternate

function’s output data and output enable signals override the data output and output enable signals

from the GPIO. However, the pin configuration stays as set in GPIO_Px_MODEL, GPIO_Px_MODEH

and GPIO_Px_DOUT registers. I.e. the pin configuration must be set to output enable in GPIO for a

peripheral to be able to use the pin as an output.

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It is possible, but not recommended to select two or more peripherals as output on the same pin. These

signals will then be OR'ed together. However, TIMER CCx and CDTIx outputs, which are routed as

alternate functions, have priority, and will never be OR'ed with other alternate functions. The reader is

referred to the pin map section of the device datasheet for more information on the possible locations

of each alternate function and any priority settings.

32.3.4.1 Serial Wire Debug Port Connection

The SW Debug Port is routed as an alternate function and the SWDIO and SWCLK pin connections

are enabled by default with internal pull-up and pull-down resistors, respectively. It is possible to disable

these pin connections (and disable the pull resistors) by setting the SWDIOPEN and SWCLKPEN bits

in GPIO_ROUTE to 0.

WARNING: When the debug pins are disabled, the device can no longer be accessed by a debugger. A

reset will set the debug pins back to their default state as enabled. If you do disable the debug pins, make

sure you have at least a 3 second timeout at the start of your program code before you disable the debug

pins. This way the debugger will have time to halt the device after a reset before the pins are disabled.

The Serial Wire Viewer Output pin (SWO) can be enabled by setting the SWOPEN bit in GPIO_ROUTE.

This bit can also be routed to alternate locations by configuring the LOCATION bitfield in GPIO_ROUTE.

32.3.4.2 ETM Trace Ports

There are five trace pins available on the device. One trace clock which can be enabled by setting the

TCLKPEN bitfield in GPIO_ROUTE. The four data pins can be enabled individually by setting TD0PEN,

TD1PEN, TD2PEN, and TD3PEN respectively in GPIO_ROUTE. It is possible to choose which pins

the trace data will be exported to. The lowest trace bit will be routed to the first enabled trace pin. For

example, if the ETM data port size is 2 bits and TD0 and TD3 are enabled, will make bit 0 be routed

to TD0 while bit 1 will be routed to TD3.

Both the TCLK and all the TD pins can also be routed to alternate locations by configuring the

ETMLOCATION bitifeld in GPIO_ROUTE.

32.3.4.3 Analog Connections

When using the GPIO pin for analog functionality, it is recommended to disable the digital output and

set the MODEn in GPIO_Px_MODEL/GPIO_Px_MODEH equal to 0b0000 to disable the input sense

and pull resistors.

32.3.5 Interrupt Generation

The GPIO can generate an interrupt from the input of any GPIO pin on a device. The interrupts have

asynchronous sense capability, enabling wake-up from energy modes as low as EM3, see Figure 32.6 (p.

761) .

Figure 32.6. Pin n Interrupt Generation

IRQ_GPIO_EVEN/

IRQ_GPIO_ODD

PAn

EXTIRISE[n] IEN[n]EXTIPSELn[2:0]

PBn

PCn

PDn

PEn

IF[n]

set clear

IFS[n] IFC[n]

wakeup

PFn

EXTIFALL[n]

PRS

Odd/even inputs

Synch

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All pins with the same pin number (n) are grouped together to trigger one interrupt flag (EXT[n] in

GPIO_IF). The EXTIPSELn[2:0] bits in GPIO_EXTIPSELL or GPIO_EXTIPSELH select which port will

trigger the interrupt flag. The GPIO_EXTIRISE[n] and GPIO_EXTIFALL[n] registers enables sensing of

rising and falling edges. By setting the EXT[n] bit in GPIO_IEN, a high interrupt flag n, will trigger one

of two interrupt lines. The even interrupt line is triggered by any enabled even numbered interrupt flag,

while the odd is triggered by odd flags. The interrupt flags can be set and cleared by software by writing

the GPIO_IFS and GPIO_IFC registers, see Example 32.1 (p. 762) . Since the external interrupts

are asynchronous, they are sensitive to noise. To increase noise tolerance, the MODEL and MODEH

fields in the GPIO_Px_MODEL and GPIO_Px_MODEH registers, respectively, should be set to include

filtering for pins that have external interrupts enabled.

Example 32.1. GPIO Interrupt Example

Setting EXTIPSEL3 in GPIO_EXTIPSELL to 2 (Port C) and setting the GPIO_EXTIRISE[3] bit, the

interrupt flag EXT[3] in GPIO_IF will be triggered by a rising edge on pin 3 on PORT C. If EXT[3] in

GPIO_IEN is set as well, a interrupt request will be sent on IRQ_GPIO_ODD.

32.3.6 Output to PRS

All pins with the same pin number (n) are grouped together to form one PRS producer output, giving

a total of 16 outputs to the PRS. The port on which the output n should be taken is selected by the

EXTIPSELn[3:0] bits in the GPIO_EXTIPSELL or the GPIO_EXTIPSELH registers.

32.3.7 Synchronization

To avoid metastability in synchronous logic connected to the pins, all inputs are synchronized with

double flip-flops. The flip-flops for the input data run on the HFCORECLK. Consequently, when a pin

changes state, the change will have propagated to GPIO_Px_DIN after 2 positive HFCORECLK edges,

or maximum 2 HFCORECLK cycles.

Synchronization (also running on the HFCORECLK) is also added for interrupt input. The input to the

PRS generation is also synchronized, but these flip-flops run on the HFPERCLK. To save power when

the external interrupts or PRS generation is not used, the synchronization flip-flops for these can be

turned off by clearing the INTSENSE or PRSSENSE, respectively, in GPIO_INSENSE register.

Note To use the GPIO, the GPIO clock must first be enabled in CMU_HFPERCLKEN0. Setting

this bit enables the HFCORECLK and the HFPERCLK for the GPIO. HFCORECLK is used

for updating registers, while HFPERCLK is only used to synchronize PRS and interrupts.

The PRS and interrupt synchronization can also be disabled through GPIO_INSENSE, if

these are not used.

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32.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 GPIO_PA_CTRL RW Port Control Register

0x004 GPIO_PA_MODEL RW Port Pin Mode Low Register

0x008 GPIO_PA_MODEH RW Port Pin Mode High Register

0x00C GPIO_PA_DOUT RW Port Data Out Register

0x010 GPIO_PA_DOUTSET W1 Port Data Out Set Register

0x014 GPIO_PA_DOUTCLR W1 Port Data Out Clear Register

0x018 GPIO_PA_DOUTTGL W1 Port Data Out Toggle Register

0x01C GPIO_PA_DIN R Port Data In Register

0x020 GPIO_PA_PINLOCKN RW Port Unlocked Pins Register

0x024 GPIO_PB_CTRL RW Port Control Register

0x028 GPIO_PB_MODEL RW Port Pin Mode Low Register

0x02C GPIO_PB_MODEH RW Port Pin Mode High Register

0x030 GPIO_PB_DOUT RW Port Data Out Register

0x034 GPIO_PB_DOUTSET W1 Port Data Out Set Register

0x038 GPIO_PB_DOUTCLR W1 Port Data Out Clear Register

0x03C GPIO_PB_DOUTTGL W1 Port Data Out Toggle Register

0x040 GPIO_PB_DIN R Port Data In Register

0x044 GPIO_PB_PINLOCKN RW Port Unlocked Pins Register

0x048 GPIO_PC_CTRL RW Port Control Register

0x04C GPIO_PC_MODEL RW Port Pin Mode Low Register

0x050 GPIO_PC_MODEH RW Port Pin Mode High Register

0x054 GPIO_PC_DOUT RW Port Data Out Register

0x058 GPIO_PC_DOUTSET W1 Port Data Out Set Register

0x05C GPIO_PC_DOUTCLR W1 Port Data Out Clear Register

0x060 GPIO_PC_DOUTTGL W1 Port Data Out Toggle Register

0x064 GPIO_PC_DIN R Port Data In Register

0x068 GPIO_PC_PINLOCKN RW Port Unlocked Pins Register

0x06C GPIO_PD_CTRL RW Port Control Register

0x070 GPIO_PD_MODEL RW Port Pin Mode Low Register

0x074 GPIO_PD_MODEH RW Port Pin Mode High Register

0x078 GPIO_PD_DOUT RW Port Data Out Register

0x07C GPIO_PD_DOUTSET W1 Port Data Out Set Register

0x080 GPIO_PD_DOUTCLR W1 Port Data Out Clear Register

0x084 GPIO_PD_DOUTTGL W1 Port Data Out Toggle Register

0x088 GPIO_PD_DIN R Port Data In Register

0x08C GPIO_PD_PINLOCKN RW Port Unlocked Pins Register

0x090 GPIO_PE_CTRL RW Port Control Register

0x094 GPIO_PE_MODEL RW Port Pin Mode Low Register

0x098 GPIO_PE_MODEH RW Port Pin Mode High Register

0x09C GPIO_PE_DOUT RW Port Data Out Register

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Offset Name Type Description

0x0A0 GPIO_PE_DOUTSET W1 Port Data Out Set Register

0x0A4 GPIO_PE_DOUTCLR W1 Port Data Out Clear Register

0x0A8 GPIO_PE_DOUTTGL W1 Port Data Out Toggle Register

0x0AC GPIO_PE_DIN R Port Data In Register

0x0B0 GPIO_PE_PINLOCKN RW Port Unlocked Pins Register

0x0B4 GPIO_PF_CTRL RW Port Control Register

0x0B8 GPIO_PF_MODEL RW Port Pin Mode Low Register

0x0BC GPIO_PF_MODEH RW Port Pin Mode High Register

0x0C0 GPIO_PF_DOUT RW Port Data Out Register

0x0C4 GPIO_PF_DOUTSET W1 Port Data Out Set Register

0x0C8 GPIO_PF_DOUTCLR W1 Port Data Out Clear Register

0x0CC GPIO_PF_DOUTTGL W1 Port Data Out Toggle Register

0x0D0 GPIO_PF_DIN R Port Data In Register

0x0D4 GPIO_PF_PINLOCKN RW Port Unlocked Pins Register

0x100 GPIO_EXTIPSELL RW External Interrupt Port Select Low Register

0x104 GPIO_EXTIPSELH RW External Interrupt Port Select High Register

0x108 GPIO_EXTIRISE RW External Interrupt Rising Edge Trigger Register

0x10C GPIO_EXTIFALL RW External Interrupt Falling Edge Trigger Register

0x110 GPIO_IEN RW Interrupt Enable Register

0x114 GPIO_IF R Interrupt Flag Register

0x118 GPIO_IFS W1 Interrupt Flag Set Register

0x11C GPIO_IFC W1 Interrupt Flag Clear Register

0x120 GPIO_ROUTE RW I/O Routing Register

0x124 GPIO_INSENSE RW Input Sense Register

0x128 GPIO_LOCK RW Configuration Lock Register

0x12C GPIO_CTRL RW GPIO Control Register

0x130 GPIO_CMD W1 GPIO Command Register

0x134 GPIO_EM4WUEN RW EM4 Wake-up Enable Register

0x138 GPIO_EM4WUPOL RW EM4 Wake-up Polarity Register

0x13C GPIO_EM4WUCAUSE R EM4 Wake-up Cause Register

32.5 Register Description

32.5.1 GPIO_Px_CTRL - Port Control Register

Offset Bit Position

0x000

Reset

0x0

Access

Name

DRIVEMODE

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Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1:0 DRIVEMODE 0x0 RW Drive Mode Select

Select drive mode for all pins on port configured with alternate drive strength.

Value Mode Description

0 STANDARD 6 mA drive current

1 LOWEST 0.1 mA drive current

2 HIGH 20 mA drive current

3 LOW 1 mA drive current

32.5.2 GPIO_Px_MODEL - Port Pin Mode Low Register

Offset Bit Position

0x004

Reset

0x0

Access

Name

MODE7

MODE6

MODE5

MODE4

MODE3

MODE2

MODE1

MODE0

Bit Name Reset Access Description

31:28 MODE7 0x0 RW Pin 7 Mode

Configure mode for pin 7. Enumeration is equal to MODE0.

27:24 MODE6 0x0 RW Pin 6 Mode

Configure mode for pin 6. Enumeration is equal to MODE0.

23:20 MODE5 0x0 RW Pin 5 Mode

Configure mode for pin 5. Enumeration is equal to MODE0.

19:16 MODE4 0x0 RW Pin 4 Mode

Configure mode for pin 4. Enumeration is equal to MODE0.

15:12 MODE3 0x0 RW Pin 3 Mode

Configure mode for pin 3. Enumeration is equal to MODE0.

11:8 MODE2 0x0 RW Pin 2 Mode

Configure mode for pin 2. Enumeration is equal to MODE0.

7:4 MODE1 0x0 RW Pin 1 Mode

Configure mode for pin 1. Enumeration is equal to MODE0.

3:0 MODE0 0x0 RW Pin 0 Mode

Configure mode for pin 0.

Value Mode Description

0 DISABLED Input disabled. Pullup if DOUT is set.

1 INPUT Input enabled. Filter if DOUT is set

2 INPUTPULL Input enabled. DOUT determines pull direction

3 INPUTPULLFILTER Input enabled with filter. DOUT determines pull direction

4 PUSHPULL Push-pull output

5 PUSHPULLDRIVE Push-pull output with drive-strength set by DRIVEMODE

6 WIREDOR Wired-or output

7 WIREDORPULLDOWN Wired-or output with pull-down

8 WIREDAND Open-drain output

9 WIREDANDFILTER Open-drain output with filter

10 WIREDANDPULLUP Open-drain output with pullup

11 WIREDANDPULLUPFILTER Open-drain output with filter and pullup

12 WIREDANDDRIVE Open-drain output with drive-strength set by DRIVEMODE

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Bit Name Reset Access Description

Value Mode Description

13 WIREDANDDRIVEFILTER Open-drain output with filter and drive-strength set by DRIVEMODE

14 WIREDANDDRIVEPULLUP Open-drain output with pullup and drive-strength set by DRIVEMODE

15 WIREDANDDRIVEPULLUPFILTER Open-drain output with filter, pullup and drive-strength set by DRIVEMODE

32.5.3 GPIO_Px_MODEH - Port Pin Mode High Register

Offset Bit Position

0x008

Reset

0x0

Access

Name

MODE15

MODE14

MODE13

MODE12

MODE11

MODE10

MODE9

MODE8

Bit Name Reset Access Description

31:28 MODE15 0x0 RW Pin 15 Mode

Configure mode for pin 15. Enumeration is equal to MODE8.

27:24 MODE14 0x0 RW Pin 14 Mode

Configure mode for pin 14. Enumeration is equal to MODE8.

23:20 MODE13 0x0 RW Pin 13 Mode

Configure mode for pin 13. Enumeration is equal to MODE8.

19:16 MODE12 0x0 RW Pin 12 Mode

Configure mode for pin 12. Enumeration is equal to MODE8.

15:12 MODE11 0x0 RW Pin 11 Mode

Configure mode for pin 11. Enumeration is equal to MODE8.

11:8 MODE10 0x0 RW Pin 10 Mode

Configure mode for pin 10. Enumeration is equal to MODE8.

7:4 MODE9 0x0 RW Pin 9 Mode

Configure mode for pin 9. Enumeration is equal to MODE8.

3:0 MODE8 0x0 RW Pin 8 Mode

Configure mode for pin 8.

Value Mode Description

0 DISABLED Input disabled. Pullup if DOUT is set.

1 INPUT Input enabled. Filter if DOUT is set

2 INPUTPULL Input enabled. DOUT determines pull direction

3 INPUTPULLFILTER Input enabled with filter. DOUT determines pull direction

4 PUSHPULL Push-pull output

5 PUSHPULLDRIVE Push-pull output with drive-strength set by DRIVEMODE

6 WIREDOR Wired-or output

7 WIREDORPULLDOWN Wired-or output with pull-down

8 WIREDAND Open-drain output

9 WIREDANDFILTER Open-drain output with filter

10 WIREDANDPULLUP Open-drain output with pullup

11 WIREDANDPULLUPFILTER Open-drain output with filter and pullup

12 WIREDANDDRIVE Open-drain output with drive-strength set by DRIVEMODE

13 WIREDANDDRIVEFILTER Open-drain output with filter and drive-strength set by DRIVEMODE

14 WIREDANDDRIVEPULLUP Open-drain output with pullup and drive-strength set by DRIVEMODE

15 WIREDANDDRIVEPULLUPFILTER Open-drain output with filter, pullup and drive-strength set by DRIVEMODE

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32.5.4 GPIO_Px_DOUT - Port Data Out Register

Offset Bit Position

0x00C

Reset

0x0000

Access

Name

DOUT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DOUT 0x0000 RW Data Out

Data output on port.

32.5.5 GPIO_Px_DOUTSET - Port Data Out Set Register

Offset Bit Position

0x010

Reset

0x0000

Access

Name

DOUTSET

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DOUTSET 0x0000 W1 Data Out Set

Write bits to 1 to set corresponding bits in GPIO_Px_DOUT. Bits written to 0 will have no effect.

32.5.6 GPIO_Px_DOUTCLR - Port Data Out Clear Register

Offset Bit Position

0x014

Reset

0x0000

Access

Name

DOUTCLR

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Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DOUTCLR 0x0000 W1 Data Out Clear

Write bits to 1 to clear corresponding bits in GPIO_Px_DOUT. Bits written to 0 will have no effect.

32.5.7 GPIO_Px_DOUTTGL - Port Data Out Toggle Register

Offset Bit Position

0x018

Reset

0x0000

Access

Name

DOUTTGL

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DOUTTGL 0x0000 W1 Data Out Toggle

Write bits to 1 to toggle corresponding bits in GPIO_Px_DOUT. Bits written to 0 will have no effect.

32.5.8 GPIO_Px_DIN - Port Data In Register

Offset Bit Position

0x01C

Reset

0x0000

Access

Name

DIN

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 DIN 0x0000 R Data In

Port data input.

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32.5.9 GPIO_Px_PINLOCKN - Port Unlocked Pins Register

Offset Bit Position

0x020

Reset

0xFFFF

Access

Name

PINLOCKN

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 PINLOCKN 0xFFFF RW Unlocked Pins

Shows unlocked pins in the port. To lock pin n, clear bit n. The pin is then locked until reset.

32.5.10 GPIO_EXTIPSELL - External Interrupt Port Select Low Register

Offset Bit Position

0x100

Reset

0x0

Access

Name

EXTIPSEL7

EXTIPSEL6

EXTIPSEL5

EXTIPSEL4

EXTIPSEL3

EXTIPSEL2

EXTIPSEL1

EXTIPSEL0

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:28 EXTIPSEL7 0x0 RW External Interrupt 7 Port Select

Select input port for external interrupt 7.

Value Mode Description

0 PORTA Port A pin 7 selected for external interrupt 7

1 PORTB Port B pin 7 selected for external interrupt 7

2 PORTC Port C pin 7 selected for external interrupt 7

3 PORTD Port D pin 7 selected for external interrupt 7

4 PORTE Port E pin 7 selected for external interrupt 7

5 PORTF Port F pin 7 selected for external interrupt 7

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26:24 EXTIPSEL6 0x0 RW External Interrupt 6 Port Select

Select input port for external interrupt 6.

Value Mode Description

0 PORTA Port A pin 6 selected for external interrupt 6

1 PORTB Port B pin 6 selected for external interrupt 6

2 PORTC Port C pin 6 selected for external interrupt 6

3 PORTD Port D pin 6 selected for external interrupt 6

4 PORTE Port E pin 6 selected for external interrupt 6

5 PORTF Port F pin 6 selected for external interrupt 6

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Bit Name Reset Access Description

23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:20 EXTIPSEL5 0x0 RW External Interrupt 5 Port Select

Select input port for external interrupt 5.

Value Mode Description

0 PORTA Port A pin 5 selected for external interrupt 5

1 PORTB Port B pin 5 selected for external interrupt 5

2 PORTC Port C pin 5 selected for external interrupt 5

3 PORTD Port D pin 5 selected for external interrupt 5

4 PORTE Port E pin 5 selected for external interrupt 5

5 PORTF Port F pin 5 selected for external interrupt 5

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 EXTIPSEL4 0x0 RW External Interrupt 4 Port Select

Select input port for external interrupt 4.

Value Mode Description

0 PORTA Port A pin 4 selected for external interrupt 4

1 PORTB Port B pin 4 selected for external interrupt 4

2 PORTC Port C pin 4 selected for external interrupt 4

3 PORTD Port D pin 4 selected for external interrupt 4

4 PORTE Port E pin 4 selected for external interrupt 4

5 PORTF Port F pin 4 selected for external interrupt 4

15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:12 EXTIPSEL3 0x0 RW External Interrupt 3 Port Select

Select input port for external interrupt 3.

Value Mode Description

0 PORTA Port A pin 3 selected for external interrupt 3

1 PORTB Port B pin 3 selected for external interrupt 3

2 PORTC Port C pin 3 selected for external interrupt 3

3 PORTD Port D pin 3 selected for external interrupt 3

4 PORTE Port E pin 3 selected for external interrupt 3

5 PORTF Port F pin 3 selected for external interrupt 3

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 EXTIPSEL2 0x0 RW External Interrupt 2 Port Select

Select input port for external interrupt 2.

Value Mode Description

0 PORTA Port A pin 2 selected for external interrupt 2

1 PORTB Port B pin 2 selected for external interrupt 2

2 PORTC Port C pin 2 selected for external interrupt 2

3 PORTD Port D pin 2 selected for external interrupt 2

4 PORTE Port E pin 2 selected for external interrupt 2

5 PORTF Port F pin 2 selected for external interrupt 2

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:4 EXTIPSEL1 0x0 RW External Interrupt 1 Port Select

Select input port for external interrupt 1.

Value Mode Description

0 PORTA Port A pin 1 selected for external interrupt 1

1 PORTB Port B pin 1 selected for external interrupt 1

2 PORTC Port C pin 1 selected for external interrupt 1

3 PORTD Port D pin 1 selected for external interrupt 1

4 PORTE Port E pin 1 selected for external interrupt 1

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Bit Name Reset Access Description

Value Mode Description

5 PORTF Port F pin 1 selected for external interrupt 1

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 EXTIPSEL0 0x0 RW External Interrupt 0 Port Select

Select input port for external interrupt 0.

Value Mode Description

0 PORTA Port A pin 0 selected for external interrupt 0

1 PORTB Port B pin 0 selected for external interrupt 0

2 PORTC Port C pin 0 selected for external interrupt 0

3 PORTD Port D pin 0 selected for external interrupt 0

4 PORTE Port E pin 0 selected for external interrupt 0

5 PORTF Port F pin 0 selected for external interrupt 0

32.5.11 GPIO_EXTIPSELH - External Interrupt Port Select High Register

Offset Bit Position

0x104

Reset

0x0

Access

Name

EXTIPSEL15

EXTIPSEL14

EXTIPSEL13

EXTIPSEL12

EXTIPSEL11

EXTIPSEL10

EXTIPSEL9

EXTIPSEL8

Bit Name Reset Access Description

31 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

30:28 EXTIPSEL15 0x0 RW External Interrupt 15 Port Select

Select input port for external interrupt 15.

Value Mode Description

0 PORTA Port A pin 15 selected for external interrupt 15

1 PORTB Port B pin 15 selected for external interrupt 15

2 PORTC Port C pin 15 selected for external interrupt 15

3 PORTD Port D pin 15 selected for external interrupt 15

4 PORTE Port E pin 15 selected for external interrupt 15

5 PORTF Port F pin 15 selected for external interrupt 15

27 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

26:24 EXTIPSEL14 0x0 RW External Interrupt 14 Port Select

Select input port for external interrupt 14.

Value Mode Description

0 PORTA Port A pin 14 selected for external interrupt 14

1 PORTB Port B pin 14 selected for external interrupt 14

2 PORTC Port C pin 14 selected for external interrupt 14

3 PORTD Port D pin 14 selected for external interrupt 14

4 PORTE Port E pin 14 selected for external interrupt 14

5 PORTF Port F pin 14 selected for external interrupt 14

23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22:20 EXTIPSEL13 0x0 RW External Interrupt 13 Port Select

Select input port for external interrupt 13.

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Bit Name Reset Access Description

Value Mode Description

0 PORTA Port A pin 13 selected for external interrupt 13

1 PORTB Port B pin 13 selected for external interrupt 13

2 PORTC Port C pin 13 selected for external interrupt 13

3 PORTD Port D pin 13 selected for external interrupt 13

4 PORTE Port E pin 13 selected for external interrupt 13

5 PORTF Port F pin 13 selected for external interrupt 13

19 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

18:16 EXTIPSEL12 0x0 RW External Interrupt 12 Port Select

Select input port for external interrupt 12.

Value Mode Description

0 PORTA Port A pin 12 selected for external interrupt 12

1 PORTB Port B pin 12 selected for external interrupt 12

2 PORTC Port C pin 12 selected for external interrupt 12

3 PORTD Port D pin 12 selected for external interrupt 12

4 PORTE Port E pin 12 selected for external interrupt 12

5 PORTF Port F pin 12 selected for external interrupt 12

15 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

14:12 EXTIPSEL11 0x0 RW External Interrupt 11 Port Select

Select input port for external interrupt 11.

Value Mode Description

0 PORTA Port A pin 11 selected for external interrupt 11

1 PORTB Port B pin 11 selected for external interrupt 11

2 PORTC Port C pin 11 selected for external interrupt 11

3 PORTD Port D pin 11 selected for external interrupt 11

4 PORTE Port E pin 11 selected for external interrupt 11

5 PORTF Port F pin 11 selected for external interrupt 11

11 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

10:8 EXTIPSEL10 0x0 RW External Interrupt 10 Port Select

Select input port for external interrupt 10.

Value Mode Description

0 PORTA Port A pin 10 selected for external interrupt 10

1 PORTB Port B pin 10 selected for external interrupt 10

2 PORTC Port C pin 10 selected for external interrupt 10

3 PORTD Port D pin 10 selected for external interrupt 10

4 PORTE Port E pin 10 selected for external interrupt 10

5 PORTF Port F pin 10 selected for external interrupt 10

7 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

6:4 EXTIPSEL9 0x0 RW External Interrupt 9 Port Select

Select input port for external interrupt 9.

Value Mode Description

0 PORTA Port A pin 9 selected for external interrupt 9

1 PORTB Port B pin 9 selected for external interrupt 9

2 PORTC Port C pin 9 selected for external interrupt 9

3 PORTD Port D pin 9 selected for external interrupt 9

4 PORTE Port E pin 9 selected for external interrupt 9

5 PORTF Port F pin 9 selected for external interrupt 9

3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:0 EXTIPSEL8 0x0 RW External Interrupt 8 Port Select

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Bit Name Reset Access Description

Select input port for external interrupt 8.

Value Mode Description

0 PORTA Port A pin 8 selected for external interrupt 8

1 PORTB Port B pin 8 selected for external interrupt 8

2 PORTC Port C pin 8 selected for external interrupt 8

3 PORTD Port D pin 8 selected for external interrupt 8

4 PORTE Port E pin 8 selected for external interrupt 8

5 PORTF Port F pin 8 selected for external interrupt 8

32.5.12 GPIO_EXTIRISE - External Interrupt Rising Edge Trigger Register

Offset Bit Position

0x108

Reset

0x0000

Access

Name

EXTIRISE

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 EXTIRISE 0x0000 RW External Interrupt n Rising Edge Trigger Enable

Set bit n to enable triggering of external interrupt n on rising edge.

Value Description

EXTIRISE[n] = 0 Rising edge trigger disabled

EXTIRISE[n] = 1 Rising edge trigger enabled

32.5.13 GPIO_EXTIFALL - External Interrupt Falling Edge Trigger Register

Offset Bit Position

0x10C

Reset

0x0000

Access

Name

EXTIFALL

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 EXTIFALL 0x0000 RW External Interrupt n Falling Edge Trigger Enable

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Bit Name Reset Access Description

Set bit n to enable triggering of external interrupt n on falling edge.

Value Description

EXTIFALL[n] = 0 Falling edge trigger disabled

EXTIFALL[n] = 1 Falling edge trigger enabled

32.5.14 GPIO_IEN - Interrupt Enable Register

Offset Bit Position

0x110

Reset

0x0000

Access

Name

EXT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 EXT 0x0000 RW External Interrupt n Enable

Set bit n to enable external interrupt from pin n.

Value Description

EXT[n] = 0 Pin n external interrupt disabled

EXT[n] = 1 Pin n external interrupt enabled

32.5.15 GPIO_IF - Interrupt Flag Register

Offset Bit Position

0x114

Reset

0x0000

Access

Name

EXT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 EXT 0x0000 R External Interrupt Flag n

Pin n external interrupt flag.

Value Description

EXT[n] = 0 Pin n external interrupt flag cleared

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Bit Name Reset Access Description

Value Description

EXT[n] = 1 Pin n external interrupt flag set

32.5.16 GPIO_IFS - Interrupt Flag Set Register

Offset Bit Position

0x118

Reset

0x0000

Access

Name

EXT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 EXT 0x0000 W1 External Interrupt Flag n Set

Write bit n to 1 to set interrupt flag n.

Value Description

EXT[n] = 0 Pin n external interrupt flag unchanged

EXT[n] = 1 Pin n external interrupt flag set

32.5.17 GPIO_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x11C

Reset

0x0000

Access

Name

EXT

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 EXT 0x0000 W1 External Interrupt Flag Clear

Write bit n to 1 to clear external interrupt flag n.

Value Description

EXT[n] = 0 Pin n external interrupt flag unchanged

EXT[n] = 1 Pin n external interrupt flag cleared

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32.5.18 GPIO_ROUTE - I/O Routing Register

Offset Bit Position

0x120

Reset

0x0

Access

Name

ETMLOCATION

TD3PEN

TD2PEN

TD1PEN

TD0PEN

TCLKPEN

SWLOCATION

SWOPEN

SWDIOPEN

SWCLKPEN

Bit Name Reset Access Description

31:26 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

25:24 ETMLOCATION 0x0 RW I/O Location

Decides the location of the TCLK and TD pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

23:17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 TD3PEN 0 RW ETM Trace Data Pin Enable

Enable ETM Trace Data Output 3 connection to pin.

15 TD2PEN 0 RW ETM Trace Data Pin Enable

Enable ETM Trace Data Output 2 connection to pin.

14 TD1PEN 0 RW ETM Trace Data Pin Enable

Enable ETM Trace Data Output 1 connection to pin.

13 TD0PEN 0 RW ETM Trace Data Pin Enable

Enable ETM Trace Data Output 0 connection to pin.

12 TCLKPEN 0 RW ETM Trace Clock Pin Enable

Enable ETM Trace Clock Output connection to pin.

11:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:8 SWLOCATION 0x0 RW I/O Location

Decides the location of the SW pins.

Value Mode Description

0 LOC0 Location 0

1 LOC1 Location 1

2 LOC2 Location 2

3 LOC3 Location 3

7:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2 SWOPEN 0 RW Serial Wire Viewer Output Pin Enable

Enable Serial Wire Viewer Output connection to pin.

1 SWDIOPEN 1 RW Serial Wire Data Pin Enable

Enable Serial Wire Data connection to pin. WARNING: When this pin is disabled, the device can no longer be accessed by a debugger.

A reset will set the pin back to a default state as enabled. If you disable this pin, make sure you have at least a 3 second timeout

at the start of you program code before you disable the pin. This way, the debugger will have time to halt the device after a reset

before the pin is disabled.

0 SWCLKPEN 1 RW Serial Wire Clock Pin Enable

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Bit Name Reset Access Description

Enable Serial Wire Clock connection to pin. WARNING: When this pin is disabled, the device can no longer be accessed by a

debugger. A reset will set the pin back to a default state as enabled. If you disable this pin, make sure you have at least a 3 second

timeout at the start of you program code before you disable the pin. This way, the debugger will have time to halt the device after

a reset before the pin is disabled.

32.5.19 GPIO_INSENSE - Input Sense Register

Offset Bit Position

0x124

Reset

Access

Name

PRS

INT

Bit Name Reset Access Description

31:2 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

1 PRS 1 RW PRS Sense Enable

Set this bit to enable input sensing for PRS.

0 INT 1 RW Interrupt Sense Enable

Set this bit to enable input sensing for interrupts.

32.5.20 GPIO_LOCK - Configuration Lock Register

Offset Bit Position

0x128

Reset

0x0000

Access

Name

LOCKKEY

Bit Name Reset Access Description

31:16 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

15:0 LOCKKEY 0x0000 RW Configuration Lock Key

Write any other value than the unlock code to lock MODEL, MODEH, CTRL, PINLOCKN, EPISELL, EIPSELH, INSENSE and

SWDPROUTE from editing. Write the unlock code to unlock. When reading the register, bit 0 is set when the lock is enabled.

Mode Value Description

Read Operation

UNLOCKED 0 GPIO registers are unlocked

LOCKED 1 GPIO registers are locked

Write Operation

LOCK 0 Lock GPIO registers

UNLOCK 0xA534 Unlock GPIO registers

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32.5.21 GPIO_CTRL - GPIO Control Register

Offset Bit Position

0x12C

Reset

Access

Name

EM4RET

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 EM4RET 0 RW Enable EM4 retention

Set to enable EM4 retention of output enable, output value and pull enable.

32.5.22 GPIO_CMD - GPIO Command Register

Offset Bit Position

0x130

Reset

Access

Name

EM4WUCLR

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 EM4WUCLR 0 W1 EM4 Wake-up clear

Write 1 to clear all wake-up requests.

32.5.23 GPIO_EM4WUEN - EM4 Wake-up Enable Register

Offset Bit Position

0x134

Reset

0x00

Access

Name

EM4WUEN

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 EM4WUEN 0x00 RW EM4 Wake-up enable

Write 1 to enable wake-up request, write 0 to disable wake-up request.

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Bit Name Reset Access Description

Value Mode Description

0x01 A0 Enable em4 wakeup on pin A0

0x02 A6 Enable em4 wakeup on pin A6

0x04 C9 Enable em4 wakeup on pin C9

0x08 F1 Enable em4 wakeup on pin F1

0x10 F2 Enable em4 wakeup on pin F2

0x20 E13 Enable em4 wakeup on pin E13

32.5.24 GPIO_EM4WUPOL - EM4 Wake-up Polarity Register

Offset Bit Position

0x138

Reset

0x00

Access

Name

EM4WUPOL

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 EM4WUPOL 0x00 RW EM4 Wake-up Polarity

Write bit n to 1 for high wake-up request. Write bit n to 0 for low wake-up request

Value Mode Description

0x01 A0 Determines polarity on pin A0

0x02 A6 Determines polarity on pin A6

0x04 C9 Determines polarity on pin C9

0x08 F1 Determines polarity on pin F1

0x10 F2 Determines polarity on pin F2

0x20 E13 Determines polarity on pin E13

32.5.25 GPIO_EM4WUCAUSE - EM4 Wake-up Cause Register

Offset Bit Position

0x13C

Reset

0x00

Access

Name

EM4WUCAUSE

Bit Name Reset Access Description

31:6 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

5:0 EM4WUCAUSE 0x00 R EM4 wake-up cause

Bit n indicates which pin the wake-up request occurred.

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Bit Name Reset Access Description

Value Mode Description

0x01 A0 This bit indicates an em4 wake-up request occurred on pin A0

0x02 A6 This bit indicates an em4 wake-up request occurred on pin A6

0x04 C9 This bit indicates an em4 wake-up request occurred on pin C9

0x08 F1 This bit indicates an em4 wake-up request occurred on pin F1

0x10 F2 This bit indicates an em4 wake-up request occurred on pin F2

0x20 E13 This bit indicates an em4 wake-up request occurred on pin E13

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33 LCD - Liquid Crystal Display Driver

01 2 3 4

LCD

Driver

EFM32

Quick Facts

What?

The LCD driver can drive up to 8x36

segmented LCD directly. The LCD driver

consumes less than 900 nA in EM2. The

animation feature makes it possible to have

active animations without CPU intervention.

Why?

Segmented LCD displays are common way to

display information. The extreme low-power

LCD driver enables a lot of applications to

utilize an LCD display even in energy critical

systems.

How?

The low frequency clock signal, low-power

waveform, animation and blink capabilities

enable the LCD driver to run autonomously

in EM2 for long periods. Adding the flexible

frame rate setting, contrast control, and

different multiplexing modes make the

EFM32LG the optimal choice for battery-

driven systems with LCD panels.

33.1 Introduction

The LCD driver is capable of driving a segmented LCD display combination of: 1x40, 2x40, 3x40, 4x40,

6x38 or 8x36 segments. A voltage boost function enables it to provide the LCD display with higher voltage

than the supply voltage for the device. In addition, an animation feature can run custom animations on

the LCD display without any CPU intervention. The LCD driver can also remain active even in Energy

Mode 2 and provides a Frame Counter interrupt that can wake-up the device on a regular basis for

updating data.

33.2 Features

• Up to 8x36 segments.

• Configurable multiplexing (1, 2, 3, 4, 6, 8)

• LCD supports the following COM/SEG combinations

• 1x40, 2x40, 3x40, 4x40, 6x38, 8x36

• Configurable bias/voltage levels settings

• Configurable clock source prescaler

• Configurable Frame rate

• Segment lines can be enabled or disabled individually

• Blink capabilities

• Integrated animation functionality

• Available on SEG0-SEG7 or SEG8-SEG15

• Voltage boost capabilities

• Possible to run on external power

• Programmable contrast

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• Frame Counter

• LCD frame interrupt

• Direct segment control

33.3 Functional Description

An overview of the LCD module is shown in Figure 33.1 (p. 782) . In its simplest form, an LCD driver

would apply a voltage above a certain threshold voltage in order to darken a segment and a voltage below

threshold to make a segment clear. However, the LCD display segment will degrade if the applied voltage

has a DC-component. To avoid this, the applied waveforms are arranged such that the differential voltage

seen by each segment has an average value of zero, and such that the RMS voltage (or differential sum

of the two waveforms for fast response LCDs) is below the segment threshold voltage if the segment

shall be transparent, and above the segment threshold voltage when the segment shall be dark.

The waveforms are multiplexed between eight (1-8) different common lines and 20-36 segment lines

to support up to 288 different LCD segments. The common lines and segment lines can be enabled or

disabled individually to prevent the LCD driver from occupying more I/O resources than required.

Figure 33.1. LCD Block Diagram

LCD

voltage

generator

VINT VEXT

VBOOST

VLC1

VLC0

VLC1

VLC0

Disable

SEG out

Disable

COM out

LCD_SEGx

LCD_COMx

VLCDSEL

LCD control and

status

LCD segment

data register

LCD animation

registers

LCD

sequence

generator

Contrast and bias setting

Mux and framerate setting

Display data

Special

effects

LCD_BEXT

Data bus

LFACLKLCD

LCD_BCAP_P

LCD_BCAP_N

VLC2

VLC4

VLC3

VLC2

VLC3

VLC4 4x

32x SEG

4x SEG/COM

For simplicity, only one segment pin and one common terminal is shown in the figure.

33.3.1 LCD Driver Enable

Setting the EN bit in LCD_CTRL enables the LCD driver. The MUX bit-field in LCD_DISPCTRL

determines which COM lines are driven by the LCD driver. By default, LCD_COM0 is driven whenever

the LCD driver is enabled.

The LCD_SEGEN register determines which segment lines are enabled. Segment lines can be enabled

in groups of 4 and disabled in groups of 4 or individually disabled. To enable output on segment lines

0-7 for instance, the two lowest segment groups, set the two lowest bits in LCD_SEGEN. Each LCD

segment pin can also be individually disabled by setting the pin to any other state than DISABLED in

the GPIO pin configuration.

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Each LCD segment pin can also be individually disabled by setting the pin to any other state than

DISABLED in the GPIO pin configuration.

33.3.2 Multiplexing, Bias, and Wave Settings

The LCD driver supports different multiplexing and bias settings, and these can be set individually in

the MUX and BIAS bits in LCD_DISPCTRL respectively, see Table 33.1 (p. 783) and Table 33.2 (p.

783) .

Note If the MUX and BIAS settings in LCD_DISPCTRL are changed while the LCD driver is

enabled, the output waveform is unpredictable and may lead to a DC-component for one

LCD frame.

The MUX setting determines the number of LCD COM lines that are enabled. When using octaplex or

sextaplex multiplexing, the additional COM lines used (COM4-COM7) are actually located on the SEG

(SEG20-SEG23) lines. When static multiplexing is selected, LCD output is enabled on LCD_COM0,

when duplex multiplexing is used, LCD_COM0-LCD_COM1 are used, when triplex multiplexing is

selected, LCD_COM0-LCD_COM2 are used, when quadruplex multiplexing is selected, LCD_COM0-

LCD_COM3 are used, when sextaplex multiplexing is selected, LCD_COM0-LCD_COM3 together with

SEG20-SEG21 as LCD_COM4-LCD_COM5 are used, making 38 segments available, located in SEG0-

SEG19, and SEG22-SEG39. Finally when octaplex multiplexing is selected, LCD_COM0-LCD_COM3

together with SEG20-SEG23 as LCD_COM4-LCD_COM7 are used, making the 36 segments available,

located in SEG0-SEG19, and SEG24-SEG39.

See Section 33.3.3 (p. 784) for waveforms for the different bias and multiplexing settings.

The waveforms generated by the LCD controller can be generated in two different versions, regular

and low-power. The low power mode waveforms have a lower switching frequency than the regular

waveforms, and thus consume less power. The WAVE bit in LCD_DISPCTRL decides which waveforms

to generate. An example of a low-power waveform is shown in Figure 33.2 (p. 784) , and an example

of a regular waveform is shown in Figure 33.3 (p. 784) .

Table 33.1. LCD Mux Settings

MUXE MUX Mode Multiplexing

0 00 Static Static (segments can be multiplexed with LCD_COM[0])

0 01 Duplex Duplex (segments can be multiplexed with LCD_COM[1:0])

0 10 Triplex Triplex (segments can be multiplexed with LCD_COM[2:0])

0 11 Quadruplex Quadruplex (segments can be multiplexed with

LCD_COM[3:0])

1 01 Sextaplex Sextaplex (segments can be multiplexed with LCD_COM[3:0]

and SEG[21:20])

1 11 Octaplex Octaplex (segments can be multiplexed with LCD_COM[3:0])

and SEG[23:20]

Table 33.2. LCD BIAS Settings

BIAS Mode Bias setting

00 Static Static (2 levels)

01 Half Bias 1/2 Bias (3 levels)

10 Third Bias 1/3 Bias (4 levels)

11 Fourth Bias 1/4 Bias (5 levels)

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Table 33.3. LCD Wave Settings

WAVE Mode Wave mode

0 LowPower Low power optimized waveform output

1 Normal Regular waveform output

Figure 33.2. LCD Low-power Waveform for LCD_COM0 in Quadruples Multiplex Mode, 1/3 Bias

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.3. LCD Normal Waveform for LCD_COM0 in Quadruples Multiplex Mode, 1/3 Bias

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

33.3.3 Waveform Examples

The numbers on the illustration's y-axes in the following sections only indicate different voltage levels.

All examples are shown with low-power waveforms.

33.3.3.1 Waveforms with Static Bias and Multiplexing

• With static bias and multiplexing, each segment line can be connected to LCD_COM0. When the

segment line has the same waveform as LCD_COM0, the LCD panel pixel is turned off, while when

the segment line has the opposite waveform, the LCD panel pixel is turned on.

• DC voltage = 0 (over one frame)

• VRMS (on) = VLCD_OUT

• VRMS (off) = 0 (VSS)

Figure 33.4. LCD Static Bias and Multiplexing - LCD_COM0

Frame Start Frame End

VLC0 (VLCD)

VLC3 (VSS)

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33.3.3.2 Waveforms with 1/2 Bias and Duplex Multiplexing

In this mode, each frame is divided into 4 periods. LCD_COM[1:0] lines can be multiplexed with all

segment lines. Figures show 1/2 bias and duplex multiplexing (waveforms show two frames)

Figure 33.5. LCD 1/2 Bias and Duplex Multiplexing - LCD_COM0

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

Figure 33.6. LCD 1/2 Bias and Duplex Multiplexing - LCD_COM1

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

1/2 bias and duplex multiplexing - LCD_SEG0

The LCD_SEG0 waveform on the left is just an example to illustrate how different segment waveforms

can be multiplexed with the LCD_COM lines in order to turn on and off LCD pixels. As illustrated in the

figures below, this waveform will turn ON pixels connected to LCD_COM0, while pixels connected to

LCD_COM1 will be turned OFF.

Figure 33.7. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

Figure 33.8. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0 Connection

com1

com0

seg0

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1/2 bias and duplex multiplexing - LCD_SEG0-LCD_COM0

• DC voltage = 0 (over one frame)

• VRMS = 0.79 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM0 will be ON with this waveform.

Figure 33.9. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM0

VLC0 (VLCD)

VLC3 (VSS)

-VLC0 (VLCD)

Frame Start Frame End

VLC1 (1/2VLCD)

-VLC1 (1/2VLCD)

1/2 bias and duplex multiplexing - LCD_SEG0-LCD_COM1

• DC voltage = 0 (over one frame)

• VRMS = 0.35 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM0 will be OFF with this waveform

Figure 33.10. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM1

VLC0 (VLCD)

VLC3 (VSS)

-VLC0 (VLCD)

Frame Start Frame End

VLC1 (1/2VLCD)

-VLC1 (1/2VLCD)

33.3.3.3 Waveforms with 1/3 Bias and Duplex Multiplexing

In this mode, each frame is divided into 4 periods. LCD_COM[1:0] lines can be multiplexed with all

segment lines. Figures show 1/3 bias and duplex multiplexing (waveforms show two frames).

Figure 33.11. LCD 1/3 Bias and Duplex Multiplexing - LCD_COM0

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

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Figure 33.12. LCD 1/3 Bias and Duplex Multiplexing - LCD_COM1

VLC0 (VLCD)

VLC3 (VSS)

Frame Start Frame End

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

1/3 bias and duplex multiplexing - LCD_SEG0

The LCD_SEG0 waveform on the left is just an example to illustrate how different segment waveforms

can be multiplexed with the COM lines in order to turn on and off LCD pixels. As illustrated in the

figures below, this waveform will turn ON pixels connected to LCD_COM0, while pixels connected to

LCD_COM1 will be turned OFF.

Figure 33.13. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0

VLC0 (VLCD)

VLC3 (VSS)

Frame Start Frame End

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

Figure 33.14. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0 Connection

com1

com0

seg0

1/3 bias and duplex multiplexing - LCD_SEG0-LCD_COM0

• DC voltage = 0 (over one frame)

• VRMS = 0.75 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM0 will be ON with this waveform

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Figure 33.15. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM0

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and duplex multiplexing - LCD_SEG0-LCD_COM0

• DC voltage = 0 (over one frame)

• VRMS = 0.33 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM1 will be OFF with this waveform

Figure 33.16. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM1

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

33.3.3.4 Waveforms with 1/2 Bias and Triplex Multiplexing

In this mode, each frame is divided into 6 periods. LCD_COM[2:0] lines can be multiplexed with all

segment lines. Figures show 1/2 bias and triplex multiplexing (waveforms show two frames).

Figure 33.17. LCD 1/2 Bias and Triplex Multiplexing - LCD_COM0

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

Figure 33.18. LCD 1/2 Bias and Triplex Multiplexing - LCD_COM1

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

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Figure 33.19. LCD 1/2 Bias and Triplex Multiplexing - LCD_COM2

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

1/2 bias and triplex multiplexing - LCD_SEG0

The LCD_SEG0 waveform on the left is just an example to illustrate how different segment waveforms

can be multiplexed with the COM lines in order to turn on and off LCD pixels. As illustrated in the

figures below, this waveform will turn ON pixels connected to LCD_COM1, while pixels connected to

LCD_COM0 and LCD_COM2 will be turned OFF.

Figure 33.20. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0

VLC0 (VLCD)

VLC1 (1/2VLCD)

VLC3 (VSS)

Frame Start Frame End

Figure 33.21. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0 Connection

com1

com2

com0

seg0

1/2 bias and triplex multiplexing - LCD_SEG0-LCD_COM0

• DC voltage = 0 (over one frame)

• VRMS = 0.4 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM0 will be OFF with this waveform

Figure 33.22. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM0

VLC0 (VLCD)

VLC3 (VSS)

-VLC0 (VLCD)

VLC1 (1/2VLCD)

-VLC1 (1/2VLCD)

Frame Start Frame End

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1/2 bias and triplex multiplexing - LCD_SEG0-LCD_COM1

• DC voltage = 0 (over one frame)

• VRMS = 0.7 VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM1 will be ON with this waveform

Figure 33.23. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM1

VLC0 (VLCD)

VLC3 (VSS)

-VLC0 (VLCD)

VLC1 (1/2VLCD)

-VLC1 (1/2VLCD)

Frame Start Frame End

1/2 bias and triplex multiplexing - LCD_SEG0-LCD_COM2

• DC voltage = 0 (over one frame)

• VRMS = 0.4 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM2 will be OFF with this waveform

Figure 33.24. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM2

VLC0 (VLCD)

VLC3 (VSS)

-VLC0 (VLCD)

VLC1 (1/2VLCD)

-VLC1 (1/2VLCD)

Frame Start Frame End

33.3.3.5 Waveforms with 1/3 Bias and Triplex Multiplexing

In this mode, each frame is divided into 6 periods. LCD_COM[2:0] lines can be multiplexed with all

segment lines. Figures show 1/3 bias and triplex multiplexing (waveforms show two frames).

Figure 33.25. LCD 1/3 Bias and Triplex Multiplexing - LCD_COM0

VLC0 (VLCD)

VLC3 (VSS)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

Frame Start Frame End

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Figure 33.26. LCD 1/3 Bias and Triplex Multiplexing - LCD_COM1

VLC0 (VLCD)

VLC3 (VSS)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.27. LCD 1/3 Bias and Triplex Multiplexing - LCD_COM2

VLC0 (VLCD)

VLC3 (VSS)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and triplex multiplexing - LCD_SEG0

The LCD_SEG0 waveform illustrates how different segment waveforms can be multiplexed with the

COM lines in order to turn on and off LCD pixels. As illustrated in the figures below, this waveform will

turn ON pixels connected to LCD_COM1, while pixels connected to LCD_COM0 and LCD_COM2 will

be turned OFF.

Figure 33.28. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0

VLC0 (VLCD)

VLC3 (VSS)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.29. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0 Connection

com1

com2

com0

seg0

1/3 bias and triplex multiplexing - LCD_SEG0-LCD_COM0

• DC voltage = 0 (over one frame)

• VRMS = 0.33 VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM0 will be OFF with this waveform

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Figure 33.30. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM0

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and triplex multiplexing - LCD_SEG0-LCD_COM1

• DC voltage = 0 (over one frame)

• VRMS = 0.64 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM1 will be ON with this waveform

Figure 33.31. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM1

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and triplex multiplexing - LCD_SEG0-LCD_COM2

• DC voltage = 0 (over one frame)

• VRMS = 0.33 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM2 will be OFF with this waveform

Figure 33.32. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM2

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

33.3.3.6 Waveforms with 1/3 Bias and Quadruplex Multiplexing

In this mode, each frame is divided into 8 periods. All COM lines can be multiplexed with all segment

lines. Figures show 1/3 bias and quadruplex multiplexing (waveforms show two frames).

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Figure 33.33. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM0

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.34. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM1

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.35. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM2

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.36. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM3

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and quadruplex multiplexing - LCD_SEG0

The LCD_SEG0 waveform on the left is just an example to illustrate how different segment waveforms

can be multiplexed with the COM lines in order to turn on and off LCD pixels. As illustrated in the

figures below, this wave form will turn ON pixels connected to LCD_COM0 and LCD_COM2, while pixels

connected to LCD_COM1 and LCD_COM3 will be turned OFF.

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Figure 33.37. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC3 (VSS)

VLC2 (1/3VLCD)

Frame Start Frame End

Figure 33.38. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0 Connection

com1

com2

com3

com0

seg0

1/3 bias and quadruplex multiplexing - LCD_SEG0-LCD_COM0

• DC voltage = 0 (over one frame)

• VRMS = 0.58 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM0 will be ON with this waveform

Figure 33.39. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0-LCD_COM0

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and quadruplex multiplexing - LCD_SEG0-LCD_COM1

• DC voltage = 0 (over one frame)

• VRMS = 0.33 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM1 will be OFF with this waveform

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Figure 33.40. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0-LCD_COM1

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and quadruplex multiplexing - LCD_SEG0-LCD_COM2

• DC voltage = 0 (over one frame)

• VRMS = 0.58 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM2 will be ON with this waveform

Figure 33.41. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0-LCD_COM2

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

1/3 bias and quadruplex multiplexing - LCD_SEG0-LCD_COM2

• DC voltage = 0 (over one frame)

• VRMS = 0.33 × VLCD_OUT

• The LCD display pixel that is connected to LCD_SEG0 and LCD_COM3 will be OFF with this waveform

Figure 33.42. LCD 1/3 Bias and Quadruplex Multiplexing- LCD_SEG0-LCD_COM3

VLC3 (VSS)

VLC0 (VLCD)

VLC1 (2/3VLCD)

VLC2 (1/3VLCD)

-VLC0 (VLCD)

-VLC1 (2/3VLCD)

-VLC2 (1/3VLCD)

Frame Start Frame End

33.3.4 LCD Contrast

Different LCD panels have different characteristics and also temperature may affect the characteristics

of the LCD panels. To compensate for such variations, the LCD driver has a programmable contrast that

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adjusts the VLCD_OUT. The contrast is set by CONLEV in LCD_DISPCTRL, and can be adjusted relative

to either VDD (VLCD) or Ground using CONCONF in LCD_DISPCTRL. See Table 33.4 (p. 796) and

Table 33.5 (p. 796) , Table 33.5 (p. 796) and Table 33.6 (p. 797) .

Table 33.4. LCD Contrast

BIAS CONLEV Equation Range

00 00000-11111 VLCD_OUT = VLCD x (0.61 x (1 + CONLEV/(25 - 1))) CONLEV = 0 => VLCD_OUT = 0.61VLCD

CONLEV = 31 => VLCD_OUT = VLCD

01 00000-11111 VLCD_OUT = VLCD x (0.53 x (1 + CONLEV/(25 - 1))) CONLEV = 0 => VLCD_OUT = 0.53VLCD

CONLEV = 31 => VLCD_OUT = VLCD

10 00000-11111 VLCD_OUT = VLCD x (0.61 x (1 + CONLEV/(25 - 1))) CONLEV = 0 => VLCD_OUT = 0.61VLCD

CONLEV = 31 => VLCD_OUT = VLCD

11 00000-11111 VLCD_OUT = VLCD x (0.61 x (1 + CONLEV/(25 - 1))) CONLEV = 0 => VLCD_OUT = 0.61VLCD

CONLEV = 31 => VLCD_OUT = VLCD

Note Reset value is maximum contrast

Table 33.5. LCD Contrast Function

CONCONF Function

0 Contrast is adjusted relative to VDD (VLCD)

1 Contrast is adjusted relative to Ground

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Table 33.6. LCD Principle of Contrast Adjustment for Different Bias Settings.

Contrast adjustment

relative to VDD (VLCD)

(CONCONF = 0)

Contrast adjustment

relative to GND

(CONCONF = 1)

No contrast adjustment

(CONLEV = 11111)

1/4 bias

VLC0

VLC1

VLC2

VLC3

VLCD_OUT

VLCD

VLC4

VLC0

VLC1

VLC2

VLC3

VLCD

VLCD_OUT

VLC4

VLC0

VLC1

VLC2

VLC3

VLCD

VLCD_OUT

R3 VLC4

1/3 bias

VLC0

VLC1

VLC2

VLC3

VLCD_OUT

VLCD

VLC0

VLC1

VLC2

VLC3

VLCD

VLCD_OUT

VLC0

VLC1

VLC2

VLC3

VLCD

VLCD_OUT

1/2 bias

VLC0

VLC1

VLC3

VLCD

VLCD_OUT

VLC0

VLC1

VLC3

VLCD

VLCD_OUT

VLC0

VLC1

VLC3

VLCD

R1 VLCD_OUT

Static

VLC0

VLC3

VLCD

VLCD_OUT

VLC0

VLC3

VLCD

VLCD_OUT

VLC0

VLC3

VLCD

VLCD_OUT

R0 = R1 = R2 = R3 in the figure, while Rx is adjusted by changing the CONLEV bits.

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33.3.5 VLCD Selection

By default, the LCD driver runs on main external power (VLCD = VDD), see Table 33.7 (p. 798) .

An internal boost circuit can be enabled by setting VBOOSTEN in CMU_LCDCTRL and selecting the

boosted voltage by setting VLCDSEL in LCD_DISPCTRL. This will boosts VLCD to VBOOST. VBOOST can

be selected in the range of 3.0 V – 3.6 V by configuring VBLEV in LCD_DISPCTRL. Note that the boost

circuit is not designed to operate with the selected boost voltage, VBOOST, smaller than VDD. The boost

circuit can boost the VLCD up to 3.6 V when VDD is as low as 2.0 V.

When using the voltage booster, the LCD_BEXT pin must be connected through a 1 µF capacitor to

VSS, and the LCD_BCAP_P and LCD_BCAP_N pins must be connected to each other through a 22

nF capacitor.

It is also possible to connect a dedicated power supply to the LCD module. The LCD external power

supply must be connected to the LCD_BEXT pin and VLCDSEL in LCD_DISPCTRL must be set. In this

mode, the voltage booster should be disabled.

Table 33.7. LCD VLCD

VLCDSEL Mode VLCD

0 VDD VDD (same as main external power)

1 VBOOST Voltage booster/External VDD

33.3.6 VBOOST Control

The boost voltage is configurable. By programming the VBLEV bits in LCD_DISPCTRL, the boost voltage

level can be adjusted between 3.0V and 3.6V.

The boost circuit will use an update frequency given by the VBFDIV bits in CMU_LCDCTRL, see

Table 33.8 (p. 798) ). It is possible to adjust the frequency to optimize performance for all kinds of LCD

panels (large capacitors may require less frequent updates, while small capacitors may require more

frequent updates). A lower update frequency would in general lead to smaller current consumption.

Table 33.8. LCD VBOOST Frequency

VBFDIV VBOOST Update Frequency

000 LFACLK

001 LFACLK/2

010 LFACLK/4

011 LFACLK/8

100 LFACLK/16

101 LFACLK/32

110 LFACLK/64

111 LFACLK/128

33.3.7 Frame rate

It is important to choose the correct frame rate for the LCD display. Normally, the frame rate should be

between 30 and 100 Hz. A frame rate below 30 Hz may lead to flickering, while a frame rate above 100

Hz may lead to ghostering and unnecessarily high power consumption.

33.3.7.1 Clock Selection and Prescaler

The LFACLK is prescaled to LFACLKLCDprein the CMU. The available prescaler settings are:

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• LFCLK16: LFACLKLCDpre = LFACLK/16

• LFCLK32: LFACLKLCDpre = LFACLK/32

• LFCLK64: LFACLKLCDpre = LFACLK/64

• LFCLK128: LFACLKLCDpre = LFACLK/128

In addition to selecting the correct prescaling, the clock source can be selected in the CMU.

To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0, in addition to

the module clock.

33.3.7.2 Frame rate Division Register

The frame rate is set in the CMU by programming the frame rate division bits FDIV in CMU_LCDCTRL.

This setting should not be changed while the LCD driver is running. The equation for calculating the

resulting frame rate is given from Equation 33.1 (p. 799)

LCD Frame rate Calculation

LFACLKLCD = LFACLKLCDpre/(1 + FDIV) (33.1)

Table 33.9. LCD Frame rate Conversion Table

Resulting Frame rate, CLKFRAME(Hz)

LFACLKLCDpre = 2

kHz LFACLKLCDpre = 1

kHz LFACLKLCDpre =

0.5 kHz LFACLKLCDpre =

0.25 kHz

MUX Mode Frame- rate

formula

Min Max Min Max Min Max Min Max

Static LFACLKLCD/2 128 1024 64 512 32 256 16 128

Duplex LFACLKLCD/4 64 512 32 256 16 128 8 64

Triplex LFACLKLCD/6 43 341 21 171 11 85 5 43

Quadruplex LFACLKLCD/8 32 256 16 128 8 64 4 32

Sextaplex LFACLKLCD/12 21.33 170.67 10.67 85.33 5.33 42.67 2.67 21.33

Octaplex LFACLKLCD/16 16 128 8 64 4 32 2 16

Table settings: Min: FDIV = 7, Max: FDIV = 0

33.3.8 Data Update

The LCD Driver logic that controls the output waveforms is clocked on LFACLKLCDpre. The LCD data and

Control Registers are clocked on the HFCORECLK. To avoid metastability and unpredictable behavior,

the data in the Segment Data (SEGDn) registers must be synchronized to the LCD driver logic. Also,

it is important that data is updated at the beginning of an LCD frame since the segment waveform

depends on the segment data and a change in the middle of a frame may lead to a DC-component in that

frame. The LCD driver has dedicated functionality to synchronize data transfer to the LCD frames. The

synchronization logic is applied to all data that need to be updated at the beginning of the LCD frames:

• LCD_SEGDn

• LCD_AREGA

• LCD_AREGB

• LCD_BACTRL

The different methods to update data are controlled by the UDCTRL bits in LCD_CTRL.

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Table 33.10. LCD Update Data Control (UDCTRL) Bits

UDCTRL Mode Description

00 REGULAR The data transfer is controlled by SW and data synchronization is

initiated by writing data to the buffers. Data is transferred as soon as

possible, possibly creating a frame with a DC component on the LCD.

01 FCEVENT The data transfer is done at the next event triggered by the Frame

Counter (FC). See Section 33.3.10 (p. 800) for details on how to

configure the Frame Counter. Optionally, the Frame Counter can also

generate an interrupt at every event.

10 FRAMESTART The data transfer is done at frame-start.

33.3.9 Direct Segment Control (DSC)

It is possible to gain direct control over the bias levels for each SEG/COM line by setting DSC in

LCD_CTRL, overwriting the BIAS settings in LCD_DISPCTRL. The SEG lines bias levels can be set in

SEGD0-SEGD3, while the COM line bias levels can be set in SEGD4. To represent the different bias

levels, 2-bits per SEG lines are needed. For example, SEG0's bias levels can be set using SEGD0[1:0],

and SEG1 can be controlled through SEGD0[3:2] etc. Bias level encoding is shown in Table 33.11 (p.

800) .

Table 33.11. DSC BIAS Encoding

SEGD Mode Bias setting

00 Static Static (2 levels)

01 Half Bias 1/2 Bias (3 levels)

10 Third Bias 1/3 Bias (4 levels)

11 Fourth Bias 1/4 Bias (5 levels)

33.3.10 Frame Counter (FC)

The Frame Counter is synchronized to the LCD frame start and will generate an event after a

programmable number of frames. An FC event can trigger:

• LCD ready interrupt

• Blink (controlling the blink frequency)

• Next state in the Animation State Machine

• Data update if UDCTRL = 01

The Frame Counter is a down counter. It is enabled by writing FCEN in LCD_BACTRL. Optionally, the

Frame Counter can be prescaled so that the Frame Counter is decremented at:

• Every frame

• Every second frame

• Every fourth frame

• Every eight frame

This is controlled by the FCPRESC in LCD_BACTRL, see Table 33.12 (p. 801)

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Table 33.12. FCPRESC

FCPRESC Mode Description General equation

00 Div1 CLKFRAME/1

01 Div2 CLKFRAME/2

10 Div4 CLKFRAME/4

11 Div8 CLKFRAME/8

CLKFC = CLKFRAME/2FCPRESC

The top value for the Frame Counter is set by FCTOP in LCD_BACTRL. Every time the frame counter

reaches zero, it is reloaded with the top value, and at the same time an event, which can cause an

interrupt, data update, blink, or an animation state transition is triggered.

LCD Event Frequency Equation

CLKEVENT = CLKFC/(1 + FCTOP[5:0]) Hz (33.2)

The above equation shows how to set-up the LCD event frequency. In this example, the frame rate is

64Hz, and the LCD event frequency should be set-up to 2 seconds.

Example 33.1. LCD Event Frequency Example

• Write FCPRESC to 3 => CLKFC = 8Hz (0.125 seconds)

• Write FCTOP to 15 => CLKEVENT = 0.5Hz (2 seconds)

If higher resolution is required, configure a lower prescaler value and increase the FCPRESC in

LCD_BACTRL accordingly (e.g. FCPRESC = 2, FCTOP = 31).

Figure 33.43. LCD Clock System in LCD Driver

LFXO

LFRCO

Counter

FDIV[2:0]

LCD Frame

Counter

FCTOP[5:0]

LFACLKLCDpre

CLKFC CLKEVENT

div2

CLKFRAME

MUX in

LCD_DISPCTRL

LFACLKLCD

LCD in

CMU_LFAPRESC0

CMU

div16

div32

div64

div128

div1

div2

div4

div8 FCPRESC in

LCD_BACTRL

LFACLK

div4

div6

div8

div12

div16

static

duplex

triplex

quadruplex

sextaplex

octaplex

33.3.11 LCD Interrupt

The LCD interrupt can be used to synchronize data update. The FC interrupt flag is set at every LCD

Frame Counter Event, which must be set-up separately. The interrupt is enabled by setting FC bit in

LCD_IEN.

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33.3.12 Blink, Blank, and Animation Features

33.3.12.1 Blink

The LCD driver can be configured to blink, alternating all enabled segments between on and off. The blink

frequency is given by the CLKEVENT frequency, see Section 33.3.10 (p. 800) . See Section 33.3.8 (p.

799) for details regarding synchronization of the blink feature. The FC must be on for blink to work.

33.3.12.2 Blank

Setting BLANK in LCD_BACTRL will output the “OFF” waveform on all enabled segments, effectively

blanking the entire display. Writing the BLANK bit to zero disables the blanking and segment data will

be output as normal. See Section 33.3.8 (p. 799) for details regarding synchronization of blank.

33.3.12.3 Animation State Machine

The Animation State Machine makes it possible to enable different animations without updating the data

registers, allowing specialized patterns running on the LCD panel while the microcontroller remains in

Low Energy Mode and thus saving power consumption. The animation feature is available on 8 segments

multiplexed with LCD_COM0. The 8 segments can be either segments 0 to 7 or 8 to 15, depending on

ALOC in LCD_BACTRL. The animation is implemented as two programmable 8 bits registers that are

shifted left or right every other Animation state for a total of 16 states.

The shift operations applied to the shift registers are controlled by AREGASC and AREGBSC in

LCD_BACTRL as shown in the table below. Note also that the FC must be on for animation to work, as

it is the FC event that drives the animation state machine.

Table 33.13. LCD Animation Shift Register

AREGnSC, n = A

or B Mode Description

00 NOSHIFT No Shift operation

01 SHIFTLEFT Animation register is shifted left (LCD_AREGA is shifted every odd state,

LCD_AREGB is shifted every even state)

10 SHIFTRIGHT Animation register is shifted right (LCD_AREGA is shifted every odd state,

LCD_AREGB is shifted every even state)

11 Reserved Reserved

The two registers are either OR’ed or AND’ed to achieve the displayed animation pattern. This is

controlled by ALOGSEL in LCD_BACTRL as shown in Table 33.14 (p. 802) . In addition, the regular

segment data SEGD0[7:0] / SEGD0[15:8] is OR’ed with the animation pattern to generate the resulting

output.

Table 33.14. LCD Animation Pattern

ALOGSEL Mode Description

0 AND LCD_AREGA and LCD_AREGB are AND’ed together

1 OR LCD_AREGA and LCD_AREGB are OR’ed together

Each state is displayed one CLKEVENT period, see Section 33.3.10 (p. 800) . By reading ASTATE in

LCD_STATUS, software can identify which state that is currently active in the state sequence. Note that

the shifting operation is performed on internal registers that are not accessible in SW (when reading

LCD_AREGA and LCD_AREGB, the data that was original written will also be read back). The SW must

utilize the knowledge about the current state (ASTATE) to calculate what is currently output. ASTATE is

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cleared when LCD_AREGA or LCD_AREGB are updated with new values. See Table 33.15 (p. 803)

for an example.

Table 33.15. LCD Animation Example

ASTATE LCD_AREGA LCD_AREGB Resulting Data

0 11000000 11000000 11000000

1 01100000 11000000 11100000

2 01100000 01100000 01100000

3 00110000 01100000 01110000

4 00110000 00110000 00110000

5 00011000 00110000 00111000

6 00011000 00011000 00011000

7 00001100 00011000 00011100

8 00001100 00001100 00001100

9 00000110 00001100 00001110

10 00000110 00000110 00000110

11 00000011 00000110 00000111

12 00000011 00000011 00000011

13 10000001 00000011 10000011

14 10000001 10000001 10000001

15 11000000 10000001 11000001

In the table, AREGASC = 10, AREGBSC = 10, ALOGSEL = 1 and the resulting data is to be displayed

on segment lines 7-0 or 15-8 multiplexed with LCD_COM0.

Figure 33.44. LCD Block Diagram of the Animation Circuit

AREGA

AREGB

AREGASC = 1 => shift left

AREGASC = 2 => shift right

Odd animation states

AREGBSC = 1 => shift left

AREGBSC = 2 => shift right

Even animation states

ALOGSEL

Data Out[7:0] / [15:8]

CLKEVENT

SEGD0[7:0] / SEGD0[15:8]

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Example 33.2. LCD Animation Enable Example

• Write data into the animation registers LCD_AREGA, LCD_AREGB

• Enable the correct shift direction (if any)

• Decide which logical function to perform on the registers

• ALOGSEL = 0: Data_out = LCD_AREGA & LCD_AREGB

• ALOGSEL = 1:Data_out = LCD_AREGA | LCD_AREGB

• Configure the right animation period (CLKEVENT)

• Enable the animation pattern and frame counter (AEN = 1, FCEN = 1)

For updating data in the LCD while it is running an animation, and the new animation data depends on

the pattern visible on the LCD, see the following example.

Example 33.3. LCD Animation Dependence Example

• Enable the LCD interrupt (the interrupt will be triggered simultaneously as the Animation State machine

changes state)

• In the interrupt handler, read back the current state (ASTATE)

• Knowing the current state of the Animation State Machine makes it possible to calculate what data

that is currently output

• Modify data as required (Data will be updated at the next Frame Counter Event). It is important that

new data is written before the next Frame Counter Event.

33.3.13 LCD in Low Energy Modes

As long as the LFACLK is running (EM0-EM2), the LCD controller continues to output LCD waveforms

according to the data that is currently synchronized to the LCD Driver logic. In addition, the following

features are still active if enabled:

• Animation State Machine

• Blink

• LCD Event Interrupt

33.3.14 Register access

Since this module is a Low Energy Peripheral, and runs off a clock which is asynchronous to

the HFCORECLK, special considerations must be taken when accessing registers. Please refer to

Section 5.3 (p. 20) for a description on how to perform register accesses to Low Energy Peripherals.

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33.4 Register Map

The offset register address is relative to the registers base address.

Offset Name Type Description

0x000 LCD_CTRL RW Control Register

0x004 LCD_DISPCTRL RW Display Control Register

0x008 LCD_SEGEN RW Segment Enable Register

0x00C LCD_BACTRL RW Blink and Animation Control Register

0x010 LCD_STATUS R Status Register

0x014 LCD_AREGA RW Animation Register A

0x018 LCD_AREGB RW Animation Register B

0x01C LCD_IF R Interrupt Flag Register

0x020 LCD_IFS W1 Interrupt Flag Set Register

0x024 LCD_IFC W1 Interrupt Flag Clear Register

0x028 LCD_IEN RW Interrupt Enable Register

0x040 LCD_SEGD0L RW Segment Data Low Register 0

0x044 LCD_SEGD1L RW Segment Data Low Register 1

0x048 LCD_SEGD2L RW Segment Data Low Register 2

0x04C LCD_SEGD3L RW Segment Data Low Register 3

0x050 LCD_SEGD0H RW Segment Data High Register 0

0x054 LCD_SEGD1H RW Segment Data High Register 1

0x058 LCD_SEGD2H RW Segment Data High Register 2

0x05C LCD_SEGD3H RW Segment Data High Register 3

0x060 LCD_FREEZE RW Freeze Register

0x064 LCD_SYNCBUSY R Synchronization Busy Register

0x0B4 LCD_SEGD4H RW Segment Data High Register 4

0x0B8 LCD_SEGD5H RW Segment Data High Register 5

0x0BC LCD_SEGD6H RW Segment Data High Register 6

0x0C0 LCD_SEGD7H RW Segment Data High Register 7

0x0CC LCD_SEGD4L RW Segment Data Low Register 4

0x0D0 LCD_SEGD5L RW Segment Data Low Register 5

0x0D4 LCD_SEGD6L RW Segment Data Low Register 6

0x0D8 LCD_SEGD7L RW Segment Data Low Register 7

33.5 Register Description

33.5.1 LCD_CTRL - Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x000

Reset

0x0

Access

Name

DSC

UDCTRL

Bit Name Reset Access Description

31:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23 DSC 0 RW Direct Segment Control

This bit enables direct control over bias levels for each SEG/COM line.

Value Description

0 DSC disable

1 DSC enable

22:3 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

2:1 UDCTRL 0x0 RW Update Data Control

These bits control how data from the SEGDn registers are transferred to the LCD driver.

Value Mode Description

0 REGULAR The data transfer is controlled by SW. Transfer is performed as soon as possible

1 FCEVENT The data transfer is done at the next event triggered by the Frame Counter

2 FRAMESTART The data transfer is done continuously at every LCD frame start

0 EN 0 RW LCD Enable

When this bit is set, the LCD driver is enabled and the driver will start outputting waveforms on the com/segment lines.

33.5.2 LCD_DISPCTRL - Display Control Register

Offset Bit Position

0x004

Reset

0x3

0x1F

0x0

Access

Name

MUXE

VBLEV

VLCDSEL

CONCONF

CONLEV

WAVE

BIAS

MUX

Bit Name Reset Access Description

31:23 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

22 MUXE 0 RW Extended Mux Configuration

This bit redefines the meaning of the MUX field.

Value Mode Description

0 MUX Multiplex mode determined by MUX field.

1 MUXE Mux extended mode. Extends the meaning of the MUX field.

21 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

20:18 VBLEV 0x3 RW Voltage Boost Level

These bits control Voltage Boost level. Please refer to datasheet for further details of the boost levels.

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Bit Name Reset Access Description

Value Mode Description

0 LEVEL0 Minimum boost level

1 LEVEL1

2 LEVEL2

3 LEVEL3

4 LEVEL4

5 LEVEL5

6 LEVEL6

7 LEVEL7 Maximum boost level

17 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

16 VLCDSEL 0 RW VLCD Selection

This bit controls which Voltage source that is connected to VLCD.

Value Mode Description

0 VDD VDD

1 VEXTBOOST Voltage Booster/External VDD

15 CONCONF 0 RW Contrast Configuration

This bit selects whether the contrast adjustment is done relative to VLCD or Ground.

Value Mode Description

0 VLCD Contrast is adjusted relative to VLCD

1 GND Contrast is adjusted relative to Ground

14:13 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

12:8 CONLEV 0x1F RW Contrast Level

These bits control the contrast setting according to this formula: VLCD_OUT = VLCD × 0.5(1+CONLEV/31).

Value Mode Description

0 MIN Minimum contrast

31 MAX Maximum contrast

7:5 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

4 WAVE 0 RW Waveform Selection

This bit configures the output waveform.

Value Mode Description

0 LOWPOWER Low power waveform

1 NORMAL Normal waveform

3:2 BIAS 0x0 RW Bias Configuration

These bits set the bias mode for the LCD Driver.

Value Mode Description

0 STATIC Static

1 ONEHALF 1/2 Bias

2 ONETHIRD 1/3 Bias

3 ONEFOURTH 1/4 Bias

1:0 MUX 0x0 RW Mux Configuration

These bits set the multiplexing mode for the LCD Driver. The field is dependent on the value of MUXE field

MUX MUXE Mode Description

0 0 STATIC Static. Uses com line LCD_COM0.

1 0 DUPLEX Duplex. Uses com lines LCD_COM0-

LCD_COM1.

2 0 TRIPLEX Triplex. Uses com lines LCD_COM0-

LCD_COM2.

3 0 QUADRUPLEX Quadruplex. Uses com lines LCD_COM0-

LCD_COM3.

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Bit Name Reset Access Description

MUX MUXE Mode Description

1 1 SEXTAPLEX Sextaplex. Uses com lines LCD_COM0-

LCD_COM5.

3 1 OCTAPLEX Octaplex. Uses com lines LCD_COM0-

LCD_COM7.

33.5.3 LCD_SEGEN - Segment Enable Register

Offset Bit Position

0x008

Reset

0x000

Access

Name

SEGEN

Bit Name Reset Access Description

31:10 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

9:0 SEGEN 0x000 RW Segment Enable

Determines which segment lines are enabled. Each bit represents a group of 4 segment lines. To enable segment lines X to X+3,

set bit X/4, i.e. to enable output on segment lines 4,5,6 and 7, set bit 1. Each LCD segment pin can also be individually disabled by

setting the pin to any other state than DISABLED in the GPIO pin configuration.

33.5.4 LCD_BACTRL - Blink and Animation Control Register (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x00C

Reset

0x00

0x0

Access

Name

ALOC

FCTOP

FCPRESC

FCEN

ALOGSEL

AREGBSC

AREGASC

AEN

BLANK

BLINKEN

Bit Name Reset Access Description

31:29 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

28 ALOC 0 RW Animation Location

Set the LCD segments which animation applies to

Value Mode Description

0 SEG0TO7 Animation appears on segments 0 to 7

1 SEG8TO15 Animation appears on segments 8 to 15

27:24 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

23:18 FCTOP 0x00 RW Frame Counter Top Value

These bits contain the Top Value for the Frame Counter: CLKEVENT = CLKFC / (1 + FCTOP[5:0]).

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Bit Name Reset Access Description

17:16 FCPRESC 0x0 RW Frame Counter Prescaler

These bits controls the prescaling value for the Frame Counter input clock.

Value Mode Description

0 DIV1 CLKFC = CLKFRAME / 1

1 DIV2 CLKFC = CLKFRAME / 2

2 DIV4 CLKFC = CLKFRAME / 4

3 DIV8 CLKFC = CLKFRAME / 8

15:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 FCEN 0 RW Frame Counter Enable

When this bit is set, the frame counter is enabled.

7 ALOGSEL 0 RW Animate Logic Function Select

When this bit is set, the animation registers are AND'ed together. When this bit is cleared, the animation registers are OR'ed together.

Value Mode Description

0 AND AREGA and AREGB AND'ed

1 OR AREGA and AREGB OR'ed

6:5 AREGBSC 0x0 RW Animate Register B Shift Control

These bits controls the shift operation that is performed on Animation register B.

Value Mode Description

0 NOSHIFT No Shift operation on Animation Register B

1 SHIFTLEFT Animation Register B is shifted left

2 SHIFTRIGHT Animation Register B is shifted right

4:3 AREGASC 0x0 RW Animate Register A Shift Control

These bits controls the shift operation that is performed on Animation register A.

Value Mode Description

0 NOSHIFT No Shift operation on Animation Register A

1 SHIFTLEFT Animation Register A is shifted left

2 SHIFTRIGHT Animation Register A is shifted right

2 AEN 0 RW Animation Enable

When this bit is set, the animate function is enabled.

1 BLANK 0 RW Blank Display

When this bit is set, all segment output waveforms are configured to blank the LCD display. The Segment Data Registers are not

affected when writing this bit.

Value Description

0 Display is not "blanked"

1 Display is "blanked"

0 BLINKEN 0 RW Blink Enable

When this bit is set, the Blink function is enabled. Every "ON" segment will alternate between on and off at every Frame Counter Event.

33.5.5 LCD_STATUS - Status Register

Offset Bit Position

0x010

Reset

0x0

Access

Name

BLINK

ASTATE

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Bit Name Reset Access Description

31:9 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

8 BLINK 0 R Blink State

This bits indicates the blink status. If this bit is 1, all segments are off. If this bit is 0, the segments(LCD_SEGDxn) which are set

to 1 are on.

7:4 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

3:0 ASTATE 0x0 R Current Animation State

Contains the current animation state (0-15).

33.5.6 LCD_AREGA - Animation Register A (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x014

Reset

0x00

Access

Name

AREGA

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 AREGA 0x00 RW Animation Register A Data

This register contains the A data for generating animation pattern.

33.5.7 LCD_AREGB - Animation Register B (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x018

Reset

0x00

Access

Name

AREGB

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 AREGB 0x00 RW Animation Register B Data

This register contains the B data for generating animation pattern.

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33.5.8 LCD_IF - Interrupt Flag Register

Offset Bit Position

0x01C

Reset

Access

Name

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 FC 0 R Frame Counter Interrupt Flag

Set when Frame Counter is zero.

33.5.9 LCD_IFS - Interrupt Flag Set Register

Offset Bit Position

0x020

Reset

Access

Name

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 FC 0 W1 Frame Counter Interrupt Flag Set

Write to 1 to set FC interrupt flag.

33.5.10 LCD_IFC - Interrupt Flag Clear Register

Offset Bit Position

0x024

Reset

Access

Name

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 FC 0 W1 Frame Counter Interrupt Flag Clear

Write to 1 to clear FC interrupt flag.

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33.5.11 LCD_IEN - Interrupt Enable Register

Offset Bit Position

0x028

Reset

Access

Name

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 FC 0 RW Frame Counter Interrupt Enable

Set to enable interrupt on frame counter interrupt flag.

33.5.12 LCD_SEGD0L - Segment Data Low Register 0 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x040

Reset

0x00000000

Access

Name

SEGD0L

Bit Name Reset Access Description

31:0 SEGD0L 0x00000000 RW COM0 Segment Data Low

This register contains segment data for segment lines 0-31 for COM0.

33.5.13 LCD_SEGD1L - Segment Data Low Register 1 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x044

Reset

0x00000000

Access

Name

SEGD1L

Bit Name Reset Access Description

31:0 SEGD1L 0x00000000 RW COM1 Segment Data Low

This register contains segment data for segment lines 0-31 for COM1.

33.5.14 LCD_SEGD2L - Segment Data Low Register 2 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x048

Reset

0x00000000

Access

Name

SEGD2L

Bit Name Reset Access Description

31:0 SEGD2L 0x00000000 RW COM2 Segment Data Low

This register contains segment data for segment lines 0-31 for COM2.

33.5.15 LCD_SEGD3L - Segment Data Low Register 3 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x04C

Reset

0x00000000

Access

Name

SEGD3L

Bit Name Reset Access Description

31:0 SEGD3L 0x00000000 RW COM3 Segment Data Low

This register contains segment data for segment lines 0-31 for COM3.

33.5.16 LCD_SEGD0H - Segment Data High Register 0 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x050

Reset

0x00

Access

Name

SEGD0H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD0H 0x00 RW COM0 Segment Data High

This register contains segment data for segment lines 32-39 for COM0.

33.5.17 LCD_SEGD1H - Segment Data High Register 1 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x054

Reset

0x00

Access

Name

SEGD1H

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Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD1H 0x00 RW COM1 Segment Data High

This register contains segment data for segment lines 32-39 for COM1.

33.5.18 LCD_SEGD2H - Segment Data High Register 2 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x058

Reset

0x00

Access

Name

SEGD2H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD2H 0x00 RW COM2 Segment Data High

This register contains segment data for segment lines 32-39 for COM2.

33.5.19 LCD_SEGD3H - Segment Data High Register 3 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x05C

Reset

0x00

Access

Name

SEGD3H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD3H 0x00 RW COM3 Segment Data High

This register contains segment data for segment lines 32-39 for COM3.

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33.5.20 LCD_FREEZE - Freeze Register

Offset Bit Position

0x060

Reset

Access

Name

REGFREEZE

Bit Name Reset Access Description

31:1 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

0 REGFREEZE 0 RW Register Update Freeze

When set, the update of the LCD is postponed until this bit is cleared. Use this bit to update several registers simultaneously.

Value Mode Description

0 UPDATE Each write access to an LCD register is updated into the Low Frequency domain as

soon as possible.

1 FREEZE The LCD is not updated with the new written value.

33.5.21 LCD_SYNCBUSY - Synchronization Busy Register

Offset Bit Position

0x064

Reset

Access

Name

SEGD7L

SEGD6L

SEGD5L

SEGD4L

SEGD7H

SEGD6H

SEGD5H

SEGD4H

SEGD3H

SEGD2H

SEGD1H

SEGD0H

SEGD3L

SEGD2L

SEGD1L

SEGD0L

AREGB

AREGA

BACTRL

CTRL

Bit Name Reset Access Description

31:20 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

19 SEGD7L 0 R SEGD7L Register Busy

Set when the value written to SEGD7L is being synchronized.

18 SEGD6L 0 R SEGD6L Register Busy

Set when the value written to SEGD6L is being synchronized.

17 SEGD5L 0 R SEGD5L Register Busy

Set when the value written to SEGD5L is being synchronized.

16 SEGD4L 0 R SEGD4L Register Busy

Set when the value written to SEGD4L is being synchronized.

15 SEGD7H 0 R SEGD7H Register Busy

Set when the value written to SEGD7H is being synchronized.

14 SEGD6H 0 R SEGD6H Register Busy

Set when the value written to SEGD6H is being synchronized.

13 SEGD5H 0 R SEGD5H Register Busy

Set when the value written to SEGD5H is being synchronized.

12 SEGD4H 0 R SEGD4H Register Busy

Set when the value written to SEGD4H is being synchronized.

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Bit Name Reset Access Description

11 SEGD3H 0 R SEGD3H Register Busy

Set when the value written to SEGD3H is being synchronized.

10 SEGD2H 0 R SEGD2H Register Busy

Set when the value written to SEGD2H is being synchronized.

9 SEGD1H 0 R SEGD1H Register Busy

Set when the value written to SEGD1H is being synchronized.

8 SEGD0H 0 R SEGD0H Register Busy

Set when the value written to SEGD0H is being synchronized.

7 SEGD3L 0 R SEGD3L Register Busy

Set when the value written to SEGD3L is being synchronized.

6 SEGD2L 0 R SEGD2L Register Busy

Set when the value written to SEGD2L is being synchronized.

5 SEGD1L 0 R SEGD1L Register Busy

Set when the value written to SEGD1L is being synchronized.

4 SEGD0L 0 R SEGD0L Register Busy

Set when the value written to SEGD0L is being synchronized.

3 AREGB 0 R AREGB Register Busy

Set when the value written to AREGB is being synchronized.

2 AREGA 0 R AREGA Register Busy

Set when the value written to AREGA is being synchronized.

1 BACTRL 0 R BACTRL Register Busy

Set when the value written to BACTRL is being synchronized.

0 CTRL 0 R CTRL Register Busy

Set when the value written to CTRL is being synchronized.

33.5.22 LCD_SEGD4H - Segment Data High Register 4 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x0B4

Reset

0x00

Access

Name

SEGD4H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD4H 0x00 RW COM0 Segment Data High

This register contains segment data for segment lines 32-39 for COM0.

33.5.23 LCD_SEGD5H - Segment Data High Register 5 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x0B8

Reset

0x00

Access

Name

SEGD5H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD5H 0x00 RW COM1 Segment Data High

This register contains segment data for segment lines 32-39 for COM1.

33.5.24 LCD_SEGD6H - Segment Data High Register 6 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x0BC

Reset

0x00

Access

Name

SEGD6H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

7:0 SEGD6H 0x00 RW COM2 Segment Data High

This register contains segment data for segment lines 32-39 for COM2.

33.5.25 LCD_SEGD7H - Segment Data High Register 7 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x0C0

Reset

0x00

Access

Name

SEGD7H

Bit Name Reset Access Description

31:8 Reserved To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)

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Bit Name Reset Access Description

7:0 SEGD7H 0x00 RW COM3 Segment Data High

This register contains segment data for segment lines 32-39 for COM3.

33.5.26 LCD_SEGD4L - Segment Data Low Register 4 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x0CC

Reset

0x00000000

Access

Name

SEGD4L

Bit Name Reset Access Description

31:0 SEGD4L 0x00000000 RW COM4 Segment Data

This register contains segment data for segment lines 0-23 for COM4.

33.5.27 LCD_SEGD5L - Segment Data Low Register 5 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x0D0

Reset

0x00000000

Access

Name

SEGD5L

Bit Name Reset Access Description

31:0 SEGD5L 0x00000000 RW COM5 Segment Data

This register contains segment data for segment lines 0-23 for COM5.

33.5.28 LCD_SEGD6L - Segment Data Low Register 6 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

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Offset Bit Position

0x0D4

Reset

0x00000000

Access

Name

SEGD6L

Bit Name Reset Access Description

31:0 SEGD6L 0x00000000 RW COM6 Segment Data

This register contains segment data for segment lines 0-23 for COM6.

33.5.29 LCD_SEGD7L - Segment Data Low Register 7 (Async Reg)

For more information about Asynchronous Registers please see Section 5.3 (p. 20) .

Offset Bit Position

0x0D8

Reset

0x00000000

Access

Name

SEGD7L

Bit Name Reset Access Description

31:0 SEGD7L 0x00000000 RW COM7 Segment Data

This register contains segment data for segment lines 0-23 for COM7.

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34 Revision History

34.1 Revision 1.2

April 24, 2017

Updated memory system map

Replaced static bit write instruction with reference to the Cortex-M3 manual

Updated GPIO pin configuration schematic

Added new package options CSP81 and full wafer.

Corrected bit alignment in PID0 register in section 3.

Changes in the I2C section

- Updated the note in the Enable and Reset section.

- Updated Clock Generation section.

Corrected typos and added notes in the DMA Controller section.

Updated EMU Backup power domain section.

Updated the register description of LEUARTn_CTRL.

Corrected the DAC fsine equation.

Added and modified notes in the WDOG Clock Source and Register Access sections.

Modified a note in the PCNT Clock Sources section.

Updated the register description of MSC_WDATA.

Updated the register description of LESENSE_BIASCTRL.

Updated the register description of BURTC_CTRL.

Updated the register descriptions of USARTn_IF, USARTn_TXDATAX and USARTn_TXDOUBLEX.

Updated the register descriptions of CMU_CTRL and CMU_CMD.

Updated the Block Diagram in the System Overview chapter.

Updated the MSC Erase and Write Operations section.

34.2 Revision 1.10

June 13th, 2014

Moved chapter "Device Revision" from 7.3.4 to 3.6 and added information about revision specific

behaviour.

Updated information on Family, Major Rev and Minor Rev register.

Updated current numbers and voltage supply range.

Updated block diagram.

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Added EMU_BUCTRL_BUMODEBODEN configuration bit.

Added USART_CTRL_SMSDELAY/SSSEARLY configuration bits.

Changed reset value of CMU_CTRL_LFXOBOOST to 0x1.

Added comment on flushing the receive buffer of the I2C before a new transaction can start.

34.3 Revision 1.00

August 28th, 2013

Updated 1 MHz band bitfield description in CMU_HFRCOBAND and CMU_AUXBAND register.

Updated 7 MHz band bitfield description in CMU_HFRCOBAND and CMU_AUXBAND register.

Updated 1 MHz HFRCOBAND and AUXHFRCOBAND to 1.2 MHz in the DI table.

Updated 7 MHz HFRCOBAND and AUXHFRCOBAND to 6.6 MHz in the DI table.

Updated Opamp System Overview description and block diagram.

Updated LETIMER Async Support in Reflex Producers table.

Updated the I2C Clock Mode table and added the Maximum Data Hold Time formula.

Added the minimum HFPERCLK requirement for I2C Slave Operation.

Added a new register access type RW1H.

Updated RMU Reset Cause Register Interpretation table.

Updated the register description of CMU_CTRL.

Updated CMU_CALCNT description.

Updated DMA_CHENC register description.

Updated description of number of wait-states for Immediate Synchronization.

Updated description of the Excite Phase timing in LESENSE.

Updated the LETIMER PRS description.

Updated OPAMP description.

Updated the EM4 with RTC and Data Retention with BURTC description.

Added LPFMODE recommendation for the ADC Input Filtering.

Updated the LETIMER description for usage in EM3.

Updated the RTC description for usage in EM3.

Updated WRITEONCE bitfield description in MSC_WRITECMD register.

Updated the MSC_TIMEBASE register description.

Updated the DMA and USB DMA access description.

Updated trademark, disclaimer and contact information.

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Other minor corrections.

34.4 Revision 0.95

April 25th, 2012

Changed default value for LFXOBOOST in CMU_CTRL.

Updated register description for the DMA controller.

34.5 Revision 0.90

January 24th, 2012

Initial preliminary revision.

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A Abbreviations

A.1 Abbreviations

This section lists abbreviations used in this document.

Table A.1. Abbreviations

Abbreviation Description

ACMP Analog Comparator

ADC Analog to Digital Converter

AHB AMBA Advanced High-performance Bus. AMBA is short for "Advanced Microcontroller Bus

Architecture".

APB AMBA Advanced Peripheral Bus. AMBA is short for "Advanced Microcontroller Bus

Architecture".

ALE Address Latch Enable

AUXHFRCO Auxiliary High Frequency RC Oscillator.

CC Compare / Capture

CLK Clock

CMD Command

CMU Clock Management Unit

CTRL Control

DAC Digital to Analog Converter

DBG Debug

DMA Direct Memory Access

DRD Dual Role Device

DTI Dead Time Insertion

EBI External Bus Interface

EFM Energy Friendly Microcontroller

EM Energy Mode

EM0 Energy Mode 0 (also called active mode)

EM1 to EM4 Energy Mode 1 to Energy Mode 4 (also called low energy modes)

EMU Energy Management Unit

ENOB Effective Number of Bits

FS Full-speed

GPIO General Purpose Input / Output

HFRCO High Frequency RC Oscillator

HFXO High Frequency Crystal Oscillator

HW Hardware

I2C Inter-Integrated Circuit interface

LCD Liquid Crystal Display

LESENSE Low Energy Sensor Interface

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Abbreviation Description

LETIMER Low Energy Timer

LEUART Low Energy Universal Asynchronous Receiver Transmitter

LFRCO Low Frequency RC Oscillator

LFXO Low Frequency Crystal Oscillator

LS Low-speed

MAC Media Access Controller

NVIC Nested Vector Interrupt Controller

OPA/OPAMP Operational Amplifier

OSR Oversampling Ratio

OTG On-the-go

PCNT Pulse Counter

PGA Programmable Gain Array

PHY Physical Layer

PRS Peripheral Reflex System

PSRR Power Supply Rejection Ratio

PWM Pulse Width Modulation

RC Resistance and Capacitance

RMU Reset Management Unit

RTC Real Time Clock

SAR Successive Approximation Register

SOF Start of Frame

SPI Serial Peripheral Interface

SW Software

THD Total Harmonic Distortion

UART Universal Asynchronous Receiver Transmitter

USART Universal Synchronous Asynchronous Receiver Transmitter

USB Universal Serial Bus

VCMP Voltage supply Comparator

WDOG Watchdog timer

XTAL Crystal

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B Disclaimer and Trademarks

B.1 Disclaimer

Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation

of all peripherals and modules available for system and software implementers using or intending to use

the Silicon Laboratories products. Characterization data, available modules and peripherals, memory

sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and

do vary in different applications. Application examples described herein are for illustrative purposes

only. Silicon Laboratories reserves the right to make changes without further notice and limitation to

product information, specifications, and descriptions herein, and does not give warranties as to the

accuracy or completeness of the included information. Silicon Laboratories shall have no liability for

the consequences of use of the information supplied herein. This document does not imply or express

not be used within any Life Support System without the specific written consent of Silicon Laboratories.

A "Life Support System" is any product or system intended to support or sustain life and/or health, which,

if it fails, can be reasonably expected to result in significant personal injury or death. Silicon Laboratories

products are generally not intended for military applications. Silicon Laboratories products shall under no

circumstances be used in weapons of mass destruction including (but not limited to) nuclear, biological

or chemical weapons, or missiles capable of delivering such weapons.

B.2 Trademark Information

Silicon Laboratories Inc., Silicon Laboratories, Silicon Labs, SiLabs and the Silicon Labs logo, CMEMS®,

EFM, EFM32, EFR, Energy Micro, Energy Micro logo and combinations thereof, "the world’s most

energy friendly microcontrollers", Ember®, EZLink®, EZMac®, EZRadio®, EZRadioPRO®, DSPLL®,

ISOmodem®, Precision32®, ProSLIC®, SiPHY®, USBXpress® and others are trademarks or registered

trademarks of Silicon Laboratories Inc. ARM, CORTEX, Cortex-M3 and THUMB are trademarks or

registered trademarks of ARM Holdings. Keil is a registered trademark of ARM Limited. All other products

or brand names mentioned herein are trademarks of their respective holders.

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C Contact Information

Silicon Laboratories Inc.

400 West Cesar Chavez

Austin, TX 78701

Please visit the Silicon Labs Technical Support web page:

http://www.silabs.com/support/pages/contacttechnicalsupport.aspx

and register to submit a technical support request.

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Table of Contents

1. Energy Friendly Microcontrollers .................................................................................................................. 2

1.1. Typical Applications ......................................................................................................................... 2

1.2. EFM32LG Development ................................................................................................................... 2

2. About This Document ................................................................................................................................ 3

2.1. Conventions ................................................................................................................................... 3

2.2. Related Documentation .................................................................................................................... 4

3. System Overview ...................................................................................................................................... 5

3.1. Introduction .................................................................................................................................... 5

3.2. Block Diagram ............................................................................................................................... 5

3.3. Features ....................................................................................................................................... 6

3.4. Energy Modes ................................................................................................................................ 7

3.5. Product Overview ........................................................................................................................... 8

3.6. Device Revision ............................................................................................................................ 10

4. System Processor .................................................................................................................................... 12

4.1. Introduction .................................................................................................................................. 12

4.2. Features ...................................................................................................................................... 12

4.3. Functional Description .................................................................................................................... 13

5. Memory and Bus System .......................................................................................................................... 15

5.1. Introduction .................................................................................................................................. 15

5.2. Functional Description .................................................................................................................... 16

5.3. Access to Low Energy Peripherals (Asynchronous Registers) ................................................................ 20

5.4. Flash .......................................................................................................................................... 22

5.5. SRAM ......................................................................................................................................... 23

5.6. Device Information (DI) Page .......................................................................................................... 23

6. DBG - Debug Interface ............................................................................................................................. 25

6.1. Introduction .................................................................................................................................. 25

6.2. Features ...................................................................................................................................... 25

6.3. Functional Description .................................................................................................................... 25

6.4. Debug Lock and Device Erase ........................................................................................................ 26

6.5. Register Map ............................................................................................................................... 28

6.6. Register Description ...................................................................................................................... 28

7. MSC - Memory System Controller ............................................................................................................. 30

7.1. Introduction .................................................................................................................................. 30

7.2. Features ...................................................................................................................................... 31

7.3. Functional Description .................................................................................................................... 31

7.4. Register Map ............................................................................................................................... 38

7.5. Register Description ...................................................................................................................... 38

8. DMA - DMA Controller ............................................................................................................................. 48

8.1. Introduction .................................................................................................................................. 48

8.2. Features ...................................................................................................................................... 48

8.3. Block Diagram .............................................................................................................................. 49

8.4. Functional Description .................................................................................................................... 50

8.5. Examples .................................................................................................................................... 70

8.6. Register Map ............................................................................................................................... 71

8.7. Register Description ...................................................................................................................... 72

9. RMU - Reset Management Unit ................................................................................................................. 97

9.1. Introduction .................................................................................................................................. 97

9.2. Features ...................................................................................................................................... 97

9.3. Functional Description .................................................................................................................... 97

9.4. Register Map .............................................................................................................................. 102

9.5. Register Description ..................................................................................................................... 102

10. EMU - Energy Management Unit ............................................................................................................. 105

10.1. Introduction ............................................................................................................................... 105

10.2. Features .................................................................................................................................. 105

10.3. Functional Description ................................................................................................................ 106

10.4. Register Map ............................................................................................................................ 116

10.5. Register Description ................................................................................................................... 116

11. CMU - Clock Management Unit ............................................................................................................. 124

11.1. Introduction ............................................................................................................................... 124

11.2. Features .................................................................................................................................. 124

11.3. Functional Description ................................................................................................................ 125

11.4. Register Map ............................................................................................................................ 134

11.5. Register Description ................................................................................................................... 135

12. WDOG - Watchdog Timer ...................................................................................................................... 157

12.1. Introduction ............................................................................................................................... 157

12.2. Features .................................................................................................................................. 157

12.3. Functional Description ................................................................................................................ 157

12.4. Register Map ............................................................................................................................ 159

12.5. Register Description ................................................................................................................... 159

13. PRS - Peripheral Reflex System ............................................................................................................. 162

13.1. Introduction ............................................................................................................................... 162

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13.2. Features .................................................................................................................................. 162

13.3. Functional Description ................................................................................................................ 162

13.4. Register Map ............................................................................................................................ 167

13.5. Register Description ................................................................................................................... 167

14. EBI - External Bus Interface .................................................................................................................. 173

14.1. Introduction ............................................................................................................................... 173

14.2. Features .................................................................................................................................. 173

14.3. Functional Description ................................................................................................................ 174

14.4. Register Map ............................................................................................................................ 210

14.5. Register Description ................................................................................................................... 211

15. USB - Universal Serial Bus Controller ...................................................................................................... 240

15.1. Introduction ............................................................................................................................... 240

15.2. Features .................................................................................................................................. 240

15.3. USB System Description ............................................................................................................. 241

15.4. USB Core Description ................................................................................................................. 247

15.5. Register Map ............................................................................................................................ 347

15.6. Register Description ................................................................................................................... 351

16. I2C - Inter-Integrated Circuit Interface ....................................................................................................... 413

16.1. Introduction ............................................................................................................................... 413

16.2. Features .................................................................................................................................. 413

16.3. Functional Description ................................................................................................................ 414

16.4. Register Map ............................................................................................................................ 435

16.5. Register Description ................................................................................................................... 435

17. USART - Universal Synchronous Asynchronous Receiver/Transmitter ............................................................ 447

17.1. Introduction ............................................................................................................................... 447

17.2. Features .................................................................................................................................. 447

17.3. Functional Description ................................................................................................................ 448

17.4. Register Map ............................................................................................................................ 474

17.5. Register Description ................................................................................................................... 474

18. UART - Universal Asynchronous Receiver/Transmitter ................................................................................. 494

18.1. Introduction ............................................................................................................................... 494

18.2. Features .................................................................................................................................. 494

18.3. Functional Description ................................................................................................................ 495

18.4. Register Description ................................................................................................................... 495

18.5. Register Map ............................................................................................................................ 495

19. LEUART - Low Energy Universal Asynchronous Receiver/Transmitter ............................................................ 496

19.1. Introduction ............................................................................................................................... 496

19.2. Features .................................................................................................................................. 496

19.3. Functional Description ................................................................................................................ 497

19.4. Register Map ............................................................................................................................ 508

19.5. Register Description ................................................................................................................... 508

20. TIMER - Timer/Counter ......................................................................................................................... 522

20.1. Introduction ............................................................................................................................... 522

20.2. Features .................................................................................................................................. 522

20.3. Functional Description ................................................................................................................ 523

20.4. Register Map ............................................................................................................................ 541

20.5. Register Description ................................................................................................................... 542

21. RTC - Real Time Counter ...................................................................................................................... 560

21.1. Introduction ............................................................................................................................... 560

21.2. Features .................................................................................................................................. 560

21.3. Functional Description ................................................................................................................ 561

21.4. Register Map ............................................................................................................................ 564

21.5. Register Description ................................................................................................................... 564

22. BURTC - Backup Real Time Counter ....................................................................................................... 569

22.1. Introduction ............................................................................................................................... 569

22.2. Features .................................................................................................................................. 569

22.3. Functional Description ................................................................................................................ 570

22.4. Register Map ............................................................................................................................ 574

22.5. Register Description ................................................................................................................... 574

23. LETIMER - Low Energy Timer ................................................................................................................ 584

23.1. Introduction ............................................................................................................................... 584

23.2. Features .................................................................................................................................. 584

23.3. Functional Description ................................................................................................................ 585

23.4. Register Map ............................................................................................................................ 598

23.5. Register Description ................................................................................................................... 598

24. PCNT - Pulse Counter .......................................................................................................................... 607

24.1. Introduction ............................................................................................................................... 607

24.2. Features .................................................................................................................................. 607

24.3. Functional Description ................................................................................................................ 607

24.4. Register Map ............................................................................................................................ 613

24.5. Register Description ................................................................................................................... 613

25. LESENSE - Low Energy Sensor Interface ................................................................................................. 622

25.1. Introduction ............................................................................................................................... 622

25.2. Features .................................................................................................................................. 622

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25.3. Functional description ................................................................................................................. 623

25.4. Register Map ............................................................................................................................ 638

25.5. Register Description ................................................................................................................... 639

26. ACMP - Analog Comparator ................................................................................................................... 668

26.1. Introduction ............................................................................................................................... 668

26.2. Features .................................................................................................................................. 668

26.3. Functional Description ................................................................................................................ 669

26.4. Register Map ............................................................................................................................ 673

26.5. Register Description ................................................................................................................... 673

27. VCMP - Voltage Comparator .................................................................................................................. 679

27.1. Introduction ............................................................................................................................... 679

27.2. Features .................................................................................................................................. 679

27.3. Functional Description ................................................................................................................ 680

27.4. Register Map ............................................................................................................................ 683

27.5. Register Description ................................................................................................................... 683

28. ADC - Analog to Digital Converter ........................................................................................................... 687

28.1. Introduction ............................................................................................................................... 687

28.2. Features .................................................................................................................................. 687

28.3. Functional Description ................................................................................................................ 688

28.4. Register Map ............................................................................................................................ 698

28.5. Register Description ................................................................................................................... 698

29. DAC - Digital to Analog Converter ........................................................................................................... 711

29.1. Introduction ............................................................................................................................... 711

29.2. Features .................................................................................................................................. 711

29.3. Functional Description ................................................................................................................ 712

29.4. Register Map ............................................................................................................................ 717

29.5. Register Description ................................................................................................................... 717

30. OPAMP - Operational Amplifier ............................................................................................................... 732

30.1. Introduction ............................................................................................................................... 732

30.2. Features .................................................................................................................................. 732

30.3. Functional Description ................................................................................................................ 733

30.4. Register Description ................................................................................................................... 742

30.5. Register Map ............................................................................................................................ 742

31. AES - Advanced Encryption Standard Accelerator ...................................................................................... 743

31.1. Introduction ............................................................................................................................... 743

31.2. Features .................................................................................................................................. 743

31.3. Functional Description ................................................................................................................ 743

31.4. Register Map ............................................................................................................................ 747

31.5. Register Description ................................................................................................................... 747

32. GPIO - General Purpose Input/Output ...................................................................................................... 755

32.1. Introduction ............................................................................................................................... 755

32.2. Features .................................................................................................................................. 755

32.3. Functional Description ................................................................................................................ 756

32.4. Register Map ............................................................................................................................ 763

32.5. Register Description ................................................................................................................... 764

33. LCD - Liquid Crystal Display Driver ......................................................................................................... 781

33.1. Introduction ............................................................................................................................... 781

33.2. Features .................................................................................................................................. 781

33.3. Functional Description ................................................................................................................ 782

33.4. Register Map ............................................................................................................................ 805

33.5. Register Description ................................................................................................................... 805

34. Revision History ................................................................................................................................... 821

34.1. Revision 1.2 .............................................................................................................................. 821

34.2. Revision 1.10 ............................................................................................................................ 821

34.3. Revision 1.00 ............................................................................................................................ 822

34.4. Revision 0.95 ............................................................................................................................ 823

34.5. Revision 0.90 ............................................................................................................................ 823

A. Abbreviations ........................................................................................................................................ 824

A.1. Abbreviations .............................................................................................................................. 824

B. Disclaimer and Trademarks ..................................................................................................................... 826

B.1. Disclaimer .................................................................................................................................. 826

B.2. Trademark Information ................................................................................................................. 826

C. Contact Information ................................................................................................................................ 827

C.1. ............................................................................................................................................... 827

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List of Figures

3.1. Block Diagram of EFM32LG .................................................................................................................... 5

3.2. Energy Mode Indicator ............................................................................................................................. 5

3.3. Revision Number Extraction .................................................................................................................... 11

4.1. Interrupt Operation ................................................................................................................................ 13

5.1. EFM32LG Bus System ........................................................................................................................... 16

5.2. System Address Space .......................................................................................................................... 17

5.3. Write operation to Low Energy Peripherals ................................................................................................ 21

5.4. Read operation from Low Energy Peripherals ............................................................................................. 22

6.1. AAP - Authentication Access Port ............................................................................................................ 26

6.2. Device Unlock ...................................................................................................................................... 27

6.3. AAP Expansion .................................................................................................................................... 27

7.1. Instruction Cache .................................................................................................................................. 35

8.1. DMA Block Diagram .............................................................................................................................. 49

8.2. Polling flowchart .................................................................................................................................... 53

8.3. Ping-pong example ................................................................................................................................ 55

8.4. Memory scatter-gather example ............................................................................................................... 58

8.5. Peripheral scatter-gather example ............................................................................................................ 60

8.6. Memory map for 12 channels, including the alternate data structure ................................................................ 62

8.7. Detailed memory map for the 12 channels, including the alternate data structure ............................................... 63

8.8. channel_cfg bit assignments ................................................................................................................... 64

8.9. 2D copy .............................................................................................................................................. 69

9.1. RMU Reset Input Sources and Connections. .............................................................................................. 98

9.2. RMU Power-on Reset Operation .............................................................................................................. 99

9.3. RMU Brown-out Detector Operation ........................................................................................................ 100

10.1. EMU Overview .................................................................................................................................. 106

10.2. EMU Energy Mode Transitions ............................................................................................................. 107

10.3. Backup power domain overview ........................................................................................................... 112

10.4. Entering and leaving backup mode ....................................................................................................... 113

10.5. BOD calibration using DAC ................................................................................................................. 114

11.1. CMU Overview .................................................................................................................................. 126

11.2. CMU Switching from HFRCO to HFXO before HFXO is ready .................................................................... 129

11.3. CMU Switching from HFRCO to HFXO after HFXO is ready ....................................................................... 130

11.4. HFXO Pin Connection ........................................................................................................................ 130

11.5. LFXO Pin Connection ......................................................................................................................... 131

11.6. HW-support for RC Oscillator Calibration ................................................................................................ 132

11.7. Single Calibration (CONT=0) ................................................................................................................ 132

11.8. Continuous Calibration (CONT=1) ......................................................................................................... 132

13.1. PRS Overview ................................................................................................................................... 163

13.2. TIMER0 overflow starting ADC0 single conversions through PRS channel 5. ................................................. 166

14.1. EBI Overview .................................................................................................................................... 175

14.2. EBI Non-multiplexed 8-bit Data, 8-bit Address Read Operation ................................................................... 176

14.3. EBI Non-multiplexed 8-bit Data, 8-bit Address Write Operation ................................................................... 176

14.4. EBI Address Latch Setup .................................................................................................................... 177

14.5. EBI Multiplexed 16-bit Data, 16-bit Address Read Operation ...................................................................... 177

14.6. EBI Multiplexed 16-bit Data, 16-bit Address Write Operation ...................................................................... 177

14.7. EBI Multiplexed 8-bit Data, 24-bit Address Read Operation ........................................................................ 178

14.8. EBI Multiplexed 8-bit Data, 24-bit Address Write Operation ........................................................................ 178

14.9. EBI Non-multiplexed 16-bit Data Read Operation with Extended Address ...................................................... 179

14.10. EBI Non-multiplexed 16-bit Data Write Operation with Extended Address .................................................... 179

14.11. EBI Page Mode Read Operation for D8A8 addressing mode .................................................................... 180

14.12. EBI Page Mode Read Operation for D16A16ALE addressing mode ............................................................ 180

14.13. EBI Page Mode Read Operation for D8A24ALE addressing mode ............................................................. 181

14.14. EBI Page Mode Read Operation for D16 addressing mode ...................................................................... 181

14.15. EBI Page Closing ............................................................................................................................. 181

14.16. EBI Extended Address Latch Setup ..................................................................................................... 182

14.17. EBI 16-bit Data Multiplexed Read Operation using Extended Addressing ..................................................... 182

14.18. EBI 16-bit Data Multiplexed Write Operation using Extended Addressing ..................................................... 182

14.19. EBI Multiplexed Read Operation with Reduced Length Strobes ................................................................. 184

14.20. EBI Multiplexed Write Operation with Reduced Length Strobes ................................................................. 184

14.21. EBI Enforced IDLE cycles between Transactions ................................................................................... 185

14.22. EBI No Enforced IDLE cycles between Transactions ............................................................................... 185

14.23. EBI Default Memory Map (ALTMAP = 0) .............................................................................................. 188

14.24. EBI Alternative Memory Map (ALTMAP = 1) .......................................................................................... 189

14.25. EBI Connection with Standard NAND Flash .......................................................................................... 190

14.26. EBI Connection with Chip Enable Don't Care NAND Flash ....................................................................... 191

14.27. EBI NAND Flash Command Latch Timing ............................................................................................. 192

14.28. EBI NAND Flash Address Latch Timing ................................................................................................ 192

14.29. EBI NAND Flash Data Input Timing ..................................................................................................... 193

14.30. EBI NAND Flash Data Output Timing .................................................................................................. 194

14.31. EBI ECC Generation ........................................................................................................................ 196

14.32. EBI EBI_ECCPARITY Format ............................................................................................................. 197

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14.33. EBI TFT Size .................................................................................................................................. 199

14.34. EBI TFT Direct Drive from Internal Memory ........................................................................................... 200

14.35. EBI TFT Direct Drive from External Memory (non-multiplexed address/data) ................................................ 201

14.36. EBI TFT Direct Drive from External Memory (multiplexed address/data) ...................................................... 201

14.37. EBI Direct Drive Address ................................................................................................................... 202

14.38. EBI TFT Alpha Blending and Masking .................................................................................................. 203

14.39. EBI TFT Pixel Timing ........................................................................................................................ 206

14.40. EBI TFT Direct Drive Internal Timing ................................................................................................... 206

14.41. EBI TFT Direct Drive External Timing .................................................................................................. 206

14.42. EBI TFT Horizontal Porch Timing ........................................................................................................ 207

14.43. EBI TFT Vertical Porch Timing ........................................................................................................... 207

14.44. EBI TFT Pixel Timing: EBI_DCLK driven off Positive Edge Internal Clock .................................................... 207

14.45. EBI TFT Pixel Timing: EBI_DCLK driven off Negative Edge Internal Clock ................................................... 208

14.46. EBI TFT Interrupts ........................................................................................................................... 209

15.1. USB Block Diagram ........................................................................................................................... 241

15.2. Bus-powered Device .......................................................................................................................... 243

15.3. Self-powered Device .......................................................................................................................... 243

15.4. Self-powered Device (with bus-power switch) .......................................................................................... 244

15.5. OTG Dual Role Device (5V) ................................................................................................................ 245

15.6. OTG Dual Role Device (5V step-up regulator) ......................................................................................... 245

15.7. Host ................................................................................................................................................ 246

15.8. Transmit Transaction-Level Operation in Slave Mode ................................................................................ 253

15.9. Receive Transaction-Level Operation in Slave Mode ................................................................................ 253

15.10. Transmit FIFO Write Task in Slave Mode ............................................................................................. 258

15.11. Receive FIFO Read Task in Slave Mode .............................................................................................. 258

15.12. Normal Bulk/Control OUT/SETUP and Bulk/Control IN Transactions in Slave Mode ....................................... 260

15.13. Normal Bulk/Control OUT/SETUP and Bulk/Control IN Transactions in DMA Mode ........................................ 265

15.14. Interrupt Service Routine for Bulk/Control OUT Transaction in DMA Mode ................................................... 266

15.15. Normal Interrupt OUT/IN Transactions in Slave Mode ............................................................................. 270

15.16. Normal Interrupt OUT/IN Transactions in DMA Mode .............................................................................. 274

15.17. Normal Isochronous OUT/IN Transactions in Slave Mode ........................................................................ 278

15.18. Normal Isochronous OUT/IN Transactions in DMA Mode ......................................................................... 281

15.19. Processing a SETUP Packet .............................................................................................................. 289

15.20. Two-Stage Control Transfer ............................................................................................................... 292

15.21. Receive FIFO Packet Read in Slave Mode ........................................................................................... 293

15.22. Slave Mode Bulk OUT Transaction ...................................................................................................... 297

15.23. ISOC OUT Application Flow for Periodic Transfer Interrupt Feature ............................................................ 302

15.24. Isochronous OUT Core Internal Flow for Periodic Transfer Interrupt Feature ................................................ 303

15.25. Bulk IN Stall .................................................................................................................................... 307

15.26. USBTRDTIM Max Timing Case ERROR wrong image ............................................................................. 310

15.27. Slave Mode Bulk IN Transaction ......................................................................................................... 312

15.28. Slave Mode Bulk IN Transfer (Pipelined Transaction) .............................................................................. 314

15.29. Slave Mode Bulk IN Two-Endpoint Transfer .......................................................................................... 315

15.30. Periodic IN Application Flow for Periodic Transfer Interrupt Feature ............................................................ 319

15.31. Periodic IN Core Internal Flow for Periodic Transfer Interrupt Feature ......................................................... 321

15.32. SRP Detection by Core When Operating as A-device .............................................................................. 325

15.33. SRP Initiation by the Core When Acting as a B-Device ............................................................................ 326

15.34. HNP When the Core is an A-Device .................................................................................................... 327

15.35. HNP When the Core is a B-Device ..................................................................................................... 328

15.36. Core Interrupt Handler ...................................................................................................................... 336

16.1. I2C Overview .................................................................................................................................... 414

16.2. I2C-Bus Example ............................................................................................................................... 414

16.3. I2C START and STOP Conditions ......................................................................................................... 415

16.4. I2C Bit Transfer on I2C-Bus ................................................................................................................. 415

16.5. I2C Single Byte Write to Slave ............................................................................................................. 416

16.6. I2C Double Byte Read from Slave ......................................................................................................... 416

16.7. I2C Single Byte Write, then Repeated Start and Single Byte Read ............................................................... 416

16.8. I2C Master Transmitter/Slave Receiver with 10-bit Address ........................................................................ 417

16.9. I2C Master Receiver/Slave Transmitter with 10-bit Address ........................................................................ 417

16.10. I2C Master State Machine .................................................................................................................. 421

16.11. I2C Slave State Machine ................................................................................................................... 428

17.1. USART Overview ............................................................................................................................... 448

17.2. USART Asynchronous Frame Format .................................................................................................... 449

17.3. USART Transmit Buffer Operation ........................................................................................................ 453

17.4. USART Receive Buffer Operation ......................................................................................................... 455

17.5. USART Sampling of Start and Data Bits ................................................................................................ 456

17.6. USART Sampling of Stop Bits when Number of Stop Bits are 1 or More ....................................................... 457

17.7. USART Local Loopback ...................................................................................................................... 458

17.8. USART Half Duplex Communication with External Driver ........................................................................... 459

17.9. USART Transmission of Large Frames .................................................................................................. 460

17.10. USART Transmission of Large Frames, MSBF ...................................................................................... 460

17.11. USART Reception of Large Frames ..................................................................................................... 461

17.12. USART ISO 7816 Data Frame Without Error ......................................................................................... 462

17.13. USART ISO 7816 Data Frame With Error ............................................................................................. 463

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17.14. USART SmartCard Stop Bit Sampling .................................................................................................. 463

17.15. USART SPI Timing .......................................................................................................................... 465

17.16. USART SPI timing with SMSDELAY .................................................................................................... 466

17.17. USART SPI Slave Timing with SSSEARLY ........................................................................................... 467

17.18. USART Standard I2S waveform .......................................................................................................... 468

17.19. USART Standard I2S waveform (reduced accuracy) ............................................................................... 469

17.20. USART Left-justified I2S waveform ...................................................................................................... 469

17.21. USART Right-justified I2S waveform .................................................................................................... 469

17.22. USART Mono I2S waveform .............................................................................................................. 470

17.23. USART Example RZI Signal for a given Asynchronous USART Frame ....................................................... 472

19.1. LEUART Overview ............................................................................................................................. 497

19.2. LEUART Asynchronous Frame Format .................................................................................................. 498

19.3. LEUART Transmitter Overview ............................................................................................................. 500

19.4. LEUART Receiver Overview ................................................................................................................ 502

19.5. LEUART Local Loopback .................................................................................................................... 505

19.6. LEUART Half Duplex Communication with External Driver ......................................................................... 505

19.7. LEUART - NRZ vs. RZI ...................................................................................................................... 507

20.1. TIMER Block Overview ....................................................................................................................... 524

20.2. TIMER Hardware Timer/Counter Control ................................................................................................ 525

20.3. TIMER Clock Selection ....................................................................................................................... 525

20.4. TIMER Connections ........................................................................................................................... 526

20.5. TIMER TOP Value Update Functionality ................................................................................................. 526

20.6. TIMER Quadrature Encoded Inputs ....................................................................................................... 527

20.7. TIMER Quadrature Decoder Configuration .............................................................................................. 527

20.8. TIMER X2 Decoding Mode .................................................................................................................. 528

20.9. TIMER X4 Decoding Mode .................................................................................................................. 528

20.10. TIMER Input Pin Logic ...................................................................................................................... 529

20.11. TIMER Input Capture Buffer Functionality ............................................................................................. 530

20.12. TIMER Output Compare/PWM Buffer Functionality ................................................................................. 530

20.13. TIMER Input Capture ........................................................................................................................ 531

20.14. TIMER Period and/or Pulse width Capture ............................................................................................ 531

20.15. TIMER Block Diagram Showing Comparison Functionality ........................................................................ 532

20.16. TIMER Output Logic ......................................................................................................................... 532

20.17. TIMER Up-count Frequency Generation ............................................................................................... 533

20.18. TIMER Up-count PWM Generation ...................................................................................................... 533

20.19. TIMER CC out in 2x mode ................................................................................................................ 534

20.20. TIMER Up/Down-count PWM Generation .............................................................................................. 535

20.21. TIMER CC out in 2x mode ................................................................................................................ 535

20.22. TIMER Dead-Time Insertion Unit Overview ........................................................................................... 536

20.23. TIMER Triple Half-Bridge ................................................................................................................... 536

20.24. TIMER Overview of Dead-Time Insertion Block for a Single PWM channel .................................................. 537

20.25. TIMER Polarity of Both Signals are Set as Active-High ............................................................................ 537

20.26. TIMER Output Polarities .................................................................................................................... 538

21.1. RTC Overview ................................................................................................................................... 561

22.1. BURTC Overview .............................................................................................................................. 570

23.1. LETIMER Overview ............................................................................................................................ 585

23.2. LETIMER State Machine for Free-running Mode ...................................................................................... 587

23.3. LETIMER One-shot Repeat State Machine ............................................................................................. 588

23.4. LETIMER Buffered Repeat State Machine .............................................................................................. 589

23.5. LETIMER Double Repeat State Machine ................................................................................................ 590

23.6. LETIMER Simple Waveforms Output ..................................................................................................... 592

23.7. LETIMER Repeated Counting .............................................................................................................. 592

23.8. LETIMER Dual Output ........................................................................................................................ 593

23.9. LETIMER Triggered Operation ............................................................................................................. 594

23.10. LETIMER Continuous Operation ......................................................................................................... 595

23.11. LETIMER LETIMERn_CNT Not Initialized to 0 ....................................................................................... 596

24.1. PCNT Overview ................................................................................................................................. 608

24.2. PCNT Quadrature Coding ................................................................................................................... 609

24.3. PCNT Direction Change Interrupt (DIRCNG) Generation ........................................................................... 612

25.1. LESENSE block diagram ..................................................................................................................... 623

25.2. Scan sequence ................................................................................................................................. 625

25.3. Timing diagram, short excitation ........................................................................................................... 625

25.4. Pin sequencing .................................................................................................................................. 627

25.5. Scan result and interrupt generation ...................................................................................................... 628

25.6. Sensor scan and decode sequence ...................................................................................................... 628

25.7. Decoder state transition evaluation ........................................................................................................ 630

25.8. Decoder hysteresis ............................................................................................................................ 631

25.9. Circular result buffer ........................................................................................................................... 632

25.10. Capacitive sense setup ..................................................................................................................... 634

25.11. LC sensor setup .............................................................................................................................. 634

25.12. LC sensor oscillations ....................................................................................................................... 635

25.13. FSM example 1 ............................................................................................................................... 636

25.14. FSM example 2 ............................................................................................................................... 636

26.1. ACMP Overview ................................................................................................................................ 669

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26.2. 20 mV Hysteresis Selected .................................................................................................................. 671

26.3. Capacitive Sensing Set-up ................................................................................................................... 672

27.1. VCMP Overview ................................................................................................................................ 680

27.2. VCMP 20 mV Hysteresis Enabled ......................................................................................................... 681

28.1. ADC Overview .................................................................................................................................. 689

28.2. ADC Conversion Timing ...................................................................................................................... 690

28.3. ADC Analog Power Consumption With Different WARMUPMODE Settings .................................................... 691

28.4. ADC RC Input Filter Configuration ........................................................................................................ 692

28.5. ADC Bias Programming ...................................................................................................................... 693

28.6. ADC Conversion Tailgating .................................................................................................................. 694

29.1. DAC Overview .................................................................................................................................. 712

29.2. DAC Bias Programming ...................................................................................................................... 714

29.3. DAC Sine Mode ................................................................................................................................ 715

30.1. OPAMP System Overview ................................................................................................................... 733

30.2. OPAMP Overview .............................................................................................................................. 734

30.3. Opamp Output Stage Overview ............................................................................................................ 735

30.4. Voltage Follower Unity Gain Overview ................................................................................................... 736

30.5. Inverting input PGA Overview .............................................................................................................. 737

30.6. Non-inverting PGA Overview ................................................................................................................ 737

30.7. Cascaded Inverting PGA Overview ....................................................................................................... 738

30.8. Cascaded Non-inverting PGA Overview ................................................................................................. 739

30.9. Two Op-amp Differential Amplifier Overview ........................................................................................... 740

30.10. Three Op-amp Differential Amplifier Overview ........................................................................................ 741

30.11. Dual Buffer ADC Driver Overview ....................................................................................................... 742

31.1. AES Key and Data Definitions .............................................................................................................. 744

31.2. AES Data and Key Orientation as Defined in the Advanced Encryption Standard ............................................ 744

31.3. AES Data and Key Register Operation .................................................................................................. 745

32.1. Pin Configuration ............................................................................................................................... 757

32.2. Tristated Output with Optional Pull-up or Pull-down .................................................................................. 758

32.3. Push-Pull Configuration ....................................................................................................................... 759

32.4. Open-drain ....................................................................................................................................... 759

32.5. EM4 Wake-up Logic ........................................................................................................................... 760

32.6. Pin n Interrupt Generation ................................................................................................................... 761

33.1. LCD Block Diagram ........................................................................................................................... 782

33.2. LCD Low-power Waveform for LCD_COM0 in Quadruples Multiplex Mode, 1/3 Bias ........................................ 784

33.3. LCD Normal Waveform for LCD_COM0 in Quadruples Multiplex Mode, 1/3 Bias ............................................ 784

33.4. LCD Static Bias and Multiplexing - LCD_COM0 ....................................................................................... 784

33.5. LCD 1/2 Bias and Duplex Multiplexing - LCD_COM0 ................................................................................ 785

33.6. LCD 1/2 Bias and Duplex Multiplexing - LCD_COM1 ................................................................................ 785

33.7. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0 ................................................................................. 785

33.8. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0 Connection ................................................................. 785

33.9. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM0 ................................................................ 786

33.10. LCD 1/2 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM1 .............................................................. 786

33.11. LCD 1/3 Bias and Duplex Multiplexing - LCD_COM0 .............................................................................. 786

33.12. LCD 1/3 Bias and Duplex Multiplexing - LCD_COM1 .............................................................................. 787

33.13. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0 ............................................................................... 787

33.14. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0 Connection ............................................................... 787

33.15. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM0 .............................................................. 788

33.16. LCD 1/3 Bias and Duplex Multiplexing - LCD_SEG0-LCD_COM1 .............................................................. 788

33.17. LCD 1/2 Bias and Triplex Multiplexing - LCD_COM0 ............................................................................... 788

33.18. LCD 1/2 Bias and Triplex Multiplexing - LCD_COM1 ............................................................................... 788

33.19. LCD 1/2 Bias and Triplex Multiplexing - LCD_COM2 ............................................................................... 789

33.20. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0 ............................................................................... 789

33.21. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0 Connection ................................................................ 789

33.22. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM0 .............................................................. 789

33.23. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM1 .............................................................. 790

33.24. LCD 1/2 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM2 .............................................................. 790

33.25. LCD 1/3 Bias and Triplex Multiplexing - LCD_COM0 ............................................................................... 790

33.26. LCD 1/3 Bias and Triplex Multiplexing - LCD_COM1 ............................................................................... 791

33.27. LCD 1/3 Bias and Triplex Multiplexing - LCD_COM2 ............................................................................... 791

33.28. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0 ............................................................................... 791

33.29. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0 Connection ................................................................ 791

33.30. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM0 .............................................................. 792

33.31. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM1 .............................................................. 792

33.32. LCD 1/3 Bias and Triplex Multiplexing - LCD_SEG0-LCD_COM2 .............................................................. 792

33.33. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM0 ........................................................................ 793

33.34. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM1 ........................................................................ 793

33.35. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM2 ........................................................................ 793

33.36. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_COM3 ........................................................................ 793

33.37. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0 ......................................................................... 794

33.38. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0 Connection ......................................................... 794

33.39. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0-LCD_COM0 ........................................................ 794

33.40. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0-LCD_COM1 ........................................................ 795

33.41. LCD 1/3 Bias and Quadruplex Multiplexing - LCD_SEG0-LCD_COM2 ........................................................ 795

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33.42. LCD 1/3 Bias and Quadruplex Multiplexing- LCD_SEG0-LCD_COM3 ......................................................... 795

33.43. LCD Clock System in LCD Driver ........................................................................................................ 801

33.44. LCD Block Diagram of the Animation Circuit ......................................................................................... 803

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List of Tables

2.1. Register Access Types ............................................................................................................................ 3

3.1. Energy Mode Description ......................................................................................................................... 8

3.2. EFM32LG Microcontroller Series ............................................................................................................... 8

3.3. Minor Revision Number Interpretation ....................................................................................................... 11

4.1. Interrupt Request Lines (IRQ) .................................................................................................................. 13

5.1. Memory System Core Peripherals ............................................................................................................ 18

5.2. Memory System Low Energy Peripherals ................................................................................................... 18

5.3. Memory System Peripherals .................................................................................................................... 19

5.4. Device Information Page Contents ........................................................................................................... 23

7.1. MSC Flash Memory Mapping .................................................................................................................. 32

7.2. Lock Bits Page Structure ........................................................................................................................ 32

8.1. AHB bus transfer arbitration interval ......................................................................................................... 51

8.2. DMA channel priority ............................................................................................................................. 51

8.3. DMA cycle types ................................................................................................................................... 53

8.4. channel_cfg for a primary data structure, in memory scatter-gather mode ......................................................... 57

8.5. channel_cfg for a primary data structure, in peripheral scatter-gather mode ...................................................... 59

8.6. Address bit settings for the channel control data structure ............................................................................. 62

8.7. src_data_end_ptr bit assignments ............................................................................................................ 63

8.8. dst_data_end_ptr bit assignments ............................................................................................................ 64

8.9. channel_cfg bit assignments ................................................................................................................... 64

8.10. DMA cycle of six words using a word increment ........................................................................................ 67

8.11. DMA cycle of 12 bytes using a halfword increment .................................................................................... 68

8.12. User data assignments when DESCRECT is set ....................................................................................... 69

9.1. RMU Reset Cause Register Interpretation ................................................................................................. 99

10.1. EMU Energy Mode Overview ............................................................................................................... 108

10.2. EMU Entering a Low Energy Mode ....................................................................................................... 110

10.3. EMU Wakeup Triggers from Low Energy Modes ...................................................................................... 111

11.1. Configuration For Operating Frequencies ............................................................................................... 133

13.1. Reflex Producers ............................................................................................................................... 164

13.2. Reflex Consumers ............................................................................................................................. 165

14.1. EBI Intrapage hit condition for read on address Addr (non-mentioned Addr bits are unchanged) ......................... 180

14.2. EBI Enabling EBI_ADDR lines for transaction with address Addr and data Data ............................................. 183

14.3. EBI Mapping of AHB Transactions to External Device Transactions ............................................................. 186

14.4. EBI NAND Flash Register Select .......................................................................................................... 191

14.5. EBI NAND Flash Write Timing ............................................................................................................. 193

14.6. EBI NAND Flash Read Timing ............................................................................................................. 194

14.7. EBI NAND Flash Read/Write Timing Requirements .................................................................................. 194

14.8. EBI ECC Bit/Column Parity .................................................................................................................. 196

14.9. EBI ECC Byte/Row Parity ................................................................................................................... 196

14.10. EBI EBI_ECCPARITY valid bits .......................................................................................................... 197

14.11. EBI Error Detection Result ................................................................................................................. 197

15.1. Host Programming Operations ............................................................................................................. 257

15.2. ...................................................................................................................................................... 286

15.3. ...................................................................................................................................................... 330

15.4. ...................................................................................................................................................... 331

16.1. I2C Reserved I2C Addresses ................................................................................................................ 416

16.2. I2C High and Low Periods for Low CLKDIV ............................................................................................ 418

16.3. I2C Clock Mode ................................................................................................................................. 419

16.4. I2C Interactions in Prioritized Order ....................................................................................................... 422

16.5. I2C Master Transmitter ........................................................................................................................ 424

16.6. I2C Master Receiver ........................................................................................................................... 426

16.7. I2C STATE Values ............................................................................................................................. 427

16.8. I2C Transmission Status ...................................................................................................................... 427

16.9. I2C Slave Transmitter ......................................................................................................................... 430

16.10. I2C - Slave Receiver ......................................................................................................................... 431

16.11. I2C Bus Error Response .................................................................................................................... 432

17.1. USART Asynchronous vs. Synchronous Mode ........................................................................................ 449

17.2. USART Pin Usage ............................................................................................................................. 449

17.3. USART Data Bits ............................................................................................................................... 450

17.4. USART Stop Bits ............................................................................................................................... 450

17.5. USART Parity Bits ............................................................................................................................. 451

17.6. USART Oversampling ......................................................................................................................... 451

17.7. USART Baud Rates @ 4MHz Peripheral Clock ....................................................................................... 452

17.8. USART SPI Modes ............................................................................................................................ 464

17.9. USART I2S Modes ............................................................................................................................ 468

17.10. USART IrDA Pulse Widths ................................................................................................................. 473

18.1. UART Limitations ............................................................................................................................... 495

19.1. LEUART Parity Bit ............................................................................................................................. 498

19.2. LEUART Baud Rates ......................................................................................................................... 499

20.1. TIMER Counter Response in X2 Decoding Mode ..................................................................................... 528

20.2. TIMER Counter Response in X4 Decoding Mode ..................................................................................... 528

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20.3. TIMER Events ................................................................................................................................... 540

21.1. RTC Resolution Vs Overflow ............................................................................................................... 562

22.1. Resolution and overflow ...................................................................................................................... 571

23.1. LETIMER Repeat Modes ..................................................................................................................... 586

23.2. LETIMER Underflow Output Actions ...................................................................................................... 591

24.1. PCNT QUAD Mode Counter Control Function ......................................................................................... 610

25.1. LESENSE scan configuration selection .................................................................................................. 624

25.2. LESENSE excitation pin mapping ......................................................................................................... 626

25.3. LESENSE decoder configuration .......................................................................................................... 636

25.4. LESENSE decoder configuration .......................................................................................................... 637

26.1. Bias Configuration .............................................................................................................................. 670

27.1. Bias Configuration .............................................................................................................................. 680

28.1. ADC Single Ended Conversion ............................................................................................................. 694

28.2. ADC Differential Conversion ................................................................................................................ 695

28.3. Oversampling Result Shifting and Resolution .......................................................................................... 695

28.4. ADC Results Representation ................................................................................................................ 696

28.5. Calibration Register Effect ................................................................................................................... 697

30.1. General Opamp Mode Configuration ..................................................................................................... 736

30.2. Voltage Follower Unity Gain Configuration .............................................................................................. 736

30.3. Inverting input PGA Configuration ......................................................................................................... 737

30.4. Non-inverting PGA Configuration .......................................................................................................... 737

30.5. Cascaded Inverting PGA Configuration .................................................................................................. 738

30.6. Cascaded Non-inverting PGA Configuration ............................................................................................ 739

30.7. OPA0/OPA1 Differential Amplifier Configuration ....................................................................................... 740

30.8. OPA1/OPA2 Differential Amplifier Configuration ....................................................................................... 740

30.9. Three Opamp Differential Amplifier Gain Programming .............................................................................. 741

30.10. Three Opamp Differential Amplifier Configuration ................................................................................... 741

30.11. Dual Buffer ADC Driver Configuration .................................................................................................. 742

32.1. Pin Configuration ............................................................................................................................... 757

32.2. EM4 WU Register bits to pin mapping ................................................................................................... 760

33.1. LCD Mux Settings .............................................................................................................................. 783

33.2. LCD BIAS Settings ............................................................................................................................ 783

33.3. LCD Wave Settings ............................................................................................................................ 784

33.4. LCD Contrast .................................................................................................................................... 796

33.5. LCD Contrast Function ....................................................................................................................... 796

33.6. LCD Principle of Contrast Adjustment for Different Bias Settings. ................................................................ 797

33.7. LCD VLCD ......................................................................................................................................... 798

33.8. LCD VBOOST Frequency ...................................................................................................................... 798

33.9. LCD Frame rate Conversion Table ........................................................................................................ 799

33.10. LCD Update Data Control (UDCTRL) Bits ............................................................................................. 800

33.11. DSC BIAS Encoding ......................................................................................................................... 800

33.12. FCPRESC ...................................................................................................................................... 801

33.13. LCD Animation Shift Register ............................................................................................................. 802

33.14. LCD Animation Pattern ...................................................................................................................... 802

33.15. LCD Animation Example .................................................................................................................... 803

A.1. Abbreviations ...................................................................................................................................... 824

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List of Examples

8.1. DMA Transfer ....................................................................................................................................... 70

17.1. USART Multi-processor Mode Example .................................................................................................. 461

20.1. TIMER DTI Example 1 ........................................................................................................................ 538

20.2. TIMER DTI Example 2 ........................................................................................................................ 538

23.1. LETIMER Triggered Output Generation .................................................................................................. 594

23.2. LETIMER Continuous Output Generation ............................................................................................... 595

23.3. LETIMER PWM Output ....................................................................................................................... 596

23.4. LETIMER PWM Output ....................................................................................................................... 596

31.1. AES Cipher Block Chaining ................................................................................................................. 746

32.1. GPIO Interrupt Example ...................................................................................................................... 762

33.1. LCD Event Frequency Example ............................................................................................................ 801

33.2. LCD Animation Enable Example ........................................................................................................... 804

33.3. LCD Animation Dependence Example ................................................................................................... 804

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List of Equations

5.1. Memory SRAM Area Set/Clear Bit ............................................................................................................ 17

5.2. Memory Peripheral Area Bit Modification ................................................................................................... 18

5.3. Memory Wait Cycles with Clock Equal or Faster than HFCORECLK ............................................................... 20

5.4. Memory Wait Cycles with Clock Slower than CPU ....................................................................................... 20

12.1. WDOG Timeout Equation .................................................................................................................... 158

14.1. EBI TFT Total Width .......................................................................................................................... 198

14.2. EBI TFT Total Height ......................................................................................................................... 198

14.3. EBI Alpha Blending Equation ............................................................................................................... 203

14.4. EBI In-place Alpha Blending into External Memory ................................................................................... 204

14.5. EBI Alpha Blending into External Memory with Background Color1 from Register ........................................... 204

14.6. EBI Internal Alpha Blending from Registers into Register ........................................................................... 204

16.1. I2C Pull-up Resistor Equation ............................................................................................................... 414

16.2. I2C Maximum Transmission Rate .......................................................................................................... 418

16.3. I2C High and Low Cycles Equations ...................................................................................................... 418

16.4. Maximum Data Hold Time ................................................................................................................... 418

17.1. USART Baud Rate ............................................................................................................................. 451

17.2. USART Desired Baud Rate ................................................................................................................. 451

17.3. USART Synchronous Mode Bit Rate ..................................................................................................... 464

17.4. USART Synchronous Mode Clock Division Factor .................................................................................... 464

19.1. LEUART Baud Rate Equation .............................................................................................................. 499

19.2. LEUART CLKDIV Equation .................................................................................................................. 499

19.3. LEUART Optimal Sampling Point .......................................................................................................... 503

19.4. LEUART Actual Sampling Point ............................................................................................................ 503

20.1. TIMER Rotational Position Equation ...................................................................................................... 528

20.2. TIMER Up-count Frequency Generation Equation .................................................................................... 533

20.3. TIMER Up-count PWM Resolution Equation ............................................................................................ 533

20.4. TIMER Up-count PWM Frequency Equation ............................................................................................ 533

20.5. TIMER Up-count Duty Cycle Equation ................................................................................................... 534

20.6. TIMER 2x PWM Resolution Equation .................................................................................................... 534

20.7. TIMER 2x Mode PWM Frequency Equation( Up-count) ............................................................................. 534

20.8. TIMER 2x Mode Duty Cycle Equation .................................................................................................... 534

20.9. TIMER Up/Down-count PWM Resolution Equation ................................................................................... 535

20.10. TIMER Up/Down-count PWM Frequency Equation .................................................................................. 535

20.11. TIMER Up/Down-count Duty Cycle Equation ......................................................................................... 535

20.12. TIMER 2x PWM Resolution Equation ................................................................................................... 535

20.13. TIMER 2x Mode PWM Frequency Equation( Up/Down-count) ................................................................... 536

20.14. TIMER 2x Mode Duty Cycle Equation .................................................................................................. 536

21.1. RTC Frequency Equation .................................................................................................................... 561

22.1. BURTC Frequency Equation ................................................................................................................ 570

22.2. Low power mode compare match resolution ........................................................................................... 571

23.1. LETIMER Clock Frequency .................................................................................................................. 590

24.1. Absolute position with hysteresis and even TOP value .............................................................................. 610

24.2. Absolute position with hysteresis and odd TOP value ............................................................................... 610

25.1. Scan frequency ................................................................................................................................. 625

26.1. VDD Scaled ....................................................................................................................................... 671

27.1. VCMP VDD Trigger Level .................................................................................................................... 681

28.1. ADC Total Conversion Time (in ADC_CLK cycles) Per Output .................................................................... 689

28.2. ADC Temperature Measurement .......................................................................................................... 692

29.1. DAC Clock Prescaling ........................................................................................................................ 713

29.2. DAC Single Ended Output Voltage ........................................................................................................ 714

29.3. DAC Differential Output Voltage ........................................................................................................... 714

29.4. DAC Sine Generation ......................................................................................................................... 715

33.1. LCD Frame rate Calculation ................................................................................................................ 799

33.2. LCD Event Frequency Equation ............................................................................................................ 801

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