All rights reserved.
Reproduction in whole or in part is prohibited without the prior written permission of the copyright holder.
April 2010
nRF24LU1+
Single Chip 2.4 GHz Transceiver with USB
Microcontroller and Flash Memory
Product Specification v1.1
Key Features
• nRF24L01+ compatible RF transceiver
• Worldwide 2.4 GHz ISM band operation
• Up to 2 Mbps on air data rate
• Enhanced ShockBurst™ hardware link layer
• Air compatible with nRF24LU1, nRF24LE1,
nRF24L01+, nRF24L01, nRF2401A, nRF2402,
nRF24E1 and nRF24E2
• Low cost external ±60 ppm 16 MHz crystal
• Full speed USB 2.0 compliant device controller
• Up to 12 Mbps USB transfer rate
• 2 control, 10 bulk/interrupt and 2 ISO endpoints
• Dedicated 512 bytes endpoint buffer RAM
• Software controlled pull-up resistor for D+
• PLL for full-speed USB operation
• Voltage regulator, 4.0 to 5.25V supply range
• Enhanced 8-bit 8051 compatible
microcontroller
• Drop-in compatibility with nRF24LU1
• Reduced instruction cycle time
• 32-bit multiplication-division unit
• 16 or 32 kbytes of on-chip flash memory
• 2 kbytes of on-chip SRAM
• 6 general purpose digital input/output pins
• Hardware SPI slave and master, UART
• 3 16-bit timers/counters
• AES encryption/decryption co-processor
• Supports firmware upgrade over USB
• Supports FS2 hardware debugger
• Compact 32-pin 5x5mm QFN package
Applications
• Compact USB dongles for wireless
peripherals
• USB dongles for mouse, keyboards and
remotes
• USB dongle 3-in-1 desktop bundles
• USB dongle for advanced media center
remote controls
• USB dongle for game controllers
•Toys
Revision 1.1 Page 2 of 187
nRF24LU1+ Product Specification
Liability disclaimer
Nordic Semiconductor ASA reserves the right to make changes without further notice to the product to
improve reliability, function or design. Nordic Semiconductor ASA does not assume any liability arising out
of the application or use of any product or circuits described herein.
All application information is advisory and does not form part of the specification.
Limiting values
Stress above one or more of the limiting values may cause permanent damage to the device. These are
stress ratings only and operation of the device at these or at any other conditions above those given in the
specifications are not implied. Exposure to limiting values for extended periods may affect device reliability.
Life support applications
Nordic Semiconductor’s products are not designed for use in life support appliances, devices, or systems
where malfunction of these products can reasonably be expected to result in personal injury. Nordic Semi-
conductor ASA customers using or selling these products for use in such applications do so at their own
risk and agree to fully indemnify Nordic Semiconductor ASA for any damages resulting from such improper
use or sale.
Contact details
For your nearest dealer, please see www.nordicsemi.com
Main office:
Otto Nielsens veg 12
7004 Trondheim
Phone: +47 72 89 89 00
Fax: +47 72 89 89 89
www.nordicsemi.com
Data sheet status
Objective product specification This product specification contains target specifications for product
development.
Preliminary product specification This product specification contains preliminary data; supplementary
data may be published from Nordic Semiconductor ASA later.
Product specification This product specification contains final product specifications. Nordic
Semiconductor ASA reserves the right to make changes at any time
without notice in order to improve design and supply the best possible
product.
Revision 1.1 Page 3 of 187
nRF24LU1+ Product Specification
Revision History
RoHS statement
nRF24LU1+ where explicitly stated in this product specification meets the requirements of Directive 2002/
95/EC of the European Parliament and of the Council on the Restriction of Hazardous Substances (RoHS).
Complete hazardous substance reports as well as material composition reports for all active Nordic
products can be found on our web site www.nordicsemi.com.
Date Version Description
April 2010 1.1 Updated section 1.3 on page 11, caption name for Table
46. on page 87. Updated Figure 2. on page 13, Figure 16.
on page 46, Figure 18. on page 48, section 1.3 on page
11, section 2.2 on page 15, Table 24. on page 65, Table
53. on page 90,section 7.7.3 on page 80 and Attention
box.
Revision 1.1 Page 4 of 187
nRF24LU1+ Product Specification
Contents
1 Introduction ............................................................................................... 10
1.1 Prerequisites ........................................................................................ 10
1.2 Writing conventions.............................................................................. 10
1.3 Features ............................................................................................... 11
1.4 Block diagram ...................................................................................... 12
1.5 Typical system usage........................................................................... 13
2 Pin Information.......................................................................................... 14
2.1 Pin Assignments .................................................................................. 14
2.2 Pin Functions ....................................................................................... 15
2.2.1 Antenna pins.................................................................................... 15
2.2.2 USB pins.......................................................................................... 15
2.2.3 Power supply pins ........................................................................... 15
2.2.4 PROG pin ........................................................................................ 15
2.2.5 Reference current pins .................................................................... 16
2.2.6 Port pins .......................................................................................... 16
2.2.7 External RESET Pin ........................................................................ 16
2.2.8 Crystal oscillator pins....................................................................... 16
3 Absolute Maximum Ratings ..................................................................... 17
4 Operating Conditions ............................................................................... 18
5 Electrical Specifications........................................................................... 19
5.1 Power consumption and timing characteristics .................................... 19
5.2 RF transceiver characteristics............................................................. 20
5.3 USB interface ....................................................................................... 23
5.4 Flash memory ...................................................................................... 23
5.5 Crystal specifications ........................................................................... 24
5.6 DC Electrical Characteristics................................................................ 24
6 RF Transceiver .......................................................................................... 26
6.1 Features ............................................................................................... 26
6.2 Block diagram ...................................................................................... 27
6.3 Functional description .......................................................................... 27
6.3.1 Operational Modes .......................................................................... 27
6.3.2 Air data rate ..................................................................................... 31
6.3.3 RF channel frequency ..................................................................... 31
6.3.4 Received Power Detector measurements ....................................... 31
6.3.5 PA control ........................................................................................ 31
6.3.6 RX/TX control .................................................................................. 32
6.4 Enhanced ShockBurst™ ...................................................................... 32
6.4.1 Features .......................................................................................... 32
6.4.2 Enhanced ShockBurst™ overview .................................................. 32
6.4.3 Enhanced Shockburst™ packet format ........................................... 33
6.4.4 Automatic packet assembly............................................................. 36
6.4.5 Automatic packet disassembly ........................................................ 37
6.4.6 Automatic packet transaction handling............................................ 38
6.4.7 Enhanced ShockBurstTM flowcharts............................................... 40
Revision 1.1 Page 5 of 187
nRF24LU1+ Product Specification
6.4.8 MultiCeiver™ ................................................................................... 43
6.4.9 Enhanced ShockBurst™ timing....................................................... 45
6.4.10 Enhanced ShockBurst™ transaction diagram................................. 48
6.4.11 Compatibility with ShockBurst™...................................................... 52
6.5 Data and control interface .................................................................... 53
6.5.1 SFR registers................................................................................... 53
6.5.2 SPI operation................................................................................... 54
6.5.3 Data FIFO........................................................................................ 55
6.5.4 Interrupt ........................................................................................... 56
6.6 Register map........................................................................................ 57
6.6.1 Register map table .......................................................................... 57
7 USB Interface............................................................................................. 63
7.1 Features ............................................................................................... 63
7.2 Block diagram ...................................................................................... 64
7.3 Functional description .......................................................................... 65
7.4 Control endpoints ................................................................................. 69
7.4.1 Control endpoint 0 implementation.................................................. 69
7.4.2 Endpoint 0 registers ........................................................................ 69
7.4.3 Control transfer examples ............................................................... 70
7.5 Bulk/Interrupt endpoints ....................................................................... 72
7.5.1 Bulk/Interrupt endpoints implementation ......................................... 72
7.5.2 Bulk/Interrupt endpoints registers ................................................... 72
7.5.3 Bulk and interrupt endpoints initialization ........................................ 73
7.5.4 Data packet synchronization ........................................................... 74
7.5.5 Endpoint pairing............................................................................... 75
7.6 Isochronous endpoints ......................................................................... 75
7.6.1 Isochronous endpoints implementation ........................................... 75
7.6.2 Isochronous endpoints registers ..................................................... 76
7.6.3 ISO endpoints initialization .............................................................. 76
7.6.4 ISO transfers ................................................................................... 76
7.7 Memory configuration........................................................................... 77
7.7.1 On-chip memory map ...................................................................... 77
7.7.2 Setting ISO FIFO size..................................................................... 78
7.7.3 Setting Bulk OUT size ..................................................................... 79
7.7.4 Setting Bulk IN size ......................................................................... 79
7.8 The USB controller interrupts............................................................... 80
7.8.1 Wakeup interrupt request ................................................................ 80
7.8.2 USB interrupt request ...................................................................... 80
7.8.3 USB interrupt vectors ...................................................................... 83
7.9 The USB controller registers ................................................................ 83
7.9.1 Bulk IN data buffers (inxbuf) ............................................................ 83
7.9.2 Bulk OUT data buffers (outxbuf)...................................................... 84
7.9.3 Isochronous OUT endpoint data FIFO (out8dat) ............................. 84
7.9.4 Isochronous IN endpoint data FIFOs (in8dat) ................................ 84
7.9.5 Isochronous data bytes counter (out8bch/out8bcl) ......................... 84
7.9.6 Isochronous transfer error register (isoerr) ..................................... 84
Revision 1.1 Page 6 of 187
nRF24LU1+ Product Specification
7.9.7 The zero byte count for ISO OUT endpoints (zbcout) .................... 85
7.9.8 Endpoints 0 to 5 IN interrupt request register (in_irq) ..................... 85
7.9.9 Endpoints 0 to 5 OUT interrupt request register (out_irq) .............. 85
7.9.10 The USB interrupt request register (usbirq) .................................... 85
7.9.11 Endpoint 0 to 5 IN interrupt enables (in_ien) .................................. 86
7.9.12 Endpoint 0 to 5 OUT interrupt enables (out_ien) ............................ 86
7.9.13 USB interrupt enable (usbien) ........................................................ 86
7.9.14 Endpoint 0 control and status register (ep0cs) ............................... 87
7.9.15 Endpoint 0 to 5 IN byte count registers (inxbc) ............................... 88
7.9.16 Endpoint 1 to 5 IN control and status registers (inxcs) ................... 88
7.9.17 Endpoint 0 to 5 OUT byte count registers (outxbc) ........................ 89
7.9.18 Endpoint 1 to 5 OUT control and status registers (outxcs) ............. 89
7.9.19 USB control and status register (usbcs) ......................................... 90
7.9.20 Data toggle control register (togctl) ................................................ 90
7.9.21 USB frame count low (usbframel/usbframeh) ................................. 91
7.9.22 Function address register (fnaddr) ................................................. 91
7.9.23 USB endpoint pairing register (usbpair) ......................................... 91
7.9.24 Endpoints 0 to 5 IN valid bits (Inbulkval) ........................................ 91
7.9.25 Endpoints 0 to 5 OUT valid bits (outbulkval) .................................. 92
7.9.26 Isochronous IN endpoint valid bits (inisoval) .................................. 92
7.9.27 Isochronous OUT endpoint valid bits (outisoval) ............................ 92
7.9.28 SETUP data buffer (setupbuf) ........................................................ 92
7.9.29 ISO OUT endpoint start address (out8addr) ................................... 92
7.9.30 ISO IN endpoint start address (in8addr) ......................................... 92
8 Encryption/Decryption Unit...................................................................... 93
8.1 Features ............................................................................................... 93
8.1.1 ECB – Electronic Code Book........................................................... 93
8.1.2 CBC – Cipher Block Chaining ......................................................... 93
8.1.3 CFB – Cipher FeedBack.................................................................. 94
8.1.4 OFB – Output FeedBack mode ....................................................... 94
8.1.5 CTR – Counter mode ...................................................................... 94
8.2 Functional description .......................................................................... 95
9 SPI master.................................................................................................. 98
9.1 Block diagram ...................................................................................... 98
9.2 Functional description .......................................................................... 98
9.3 SPI operation ....................................................................................... 99
10 SPI slave ................................................................................................... 100
10.1 Block diagram ..................................................................................... 100
10.2 Functional description ......................................................................... 100
10.3 SPI timing ............................................................................................ 101
11 Timer/Counters ......................................................................................... 102
11.1 Features .............................................................................................. 102
11.2 Block diagram ..................................................................................... 102
11.3 Functional description ......................................................................... 102
11.3.1 Timer 0 and Timer 1 ....................................................................... 102
11.3.2 Timer 2 ........................................................................................... 105
Revision 1.1 Page 7 of 187
nRF24LU1+ Product Specification
11.4 SFR registers ...................................................................................... 107
11.4.1 Timer/Counter control register – TCON .......................................... 107
11.4.2 Timer mode register - TMOD .......................................................... 108
11.4.3 Timer0 – TH0, TL0 ......................................................................... 108
11.4.4 Timer1 – TH1, TL1 ......................................................................... 108
11.4.5 Timer 2 control register – T2CON .................................................. 109
11.4.6 Timer 2 – TH2, TL2 ........................................................................ 109
11.4.7 Compare/Capture enable register – CCEN .................................... 110
11.4.8 Capture registers – CC1, CC2, CC3 .............................................. 110
11.4.9 Compare/Reload/Capture register – CRCH, CRCL ....................... 111
12 Serial Port (UART) .................................................................................... 112
12.1 Features .............................................................................................. 112
12.2 Block diagram ..................................................................................... 112
12.3 Functional description ......................................................................... 112
12.4 SFR registers ...................................................................................... 113
12.4.1 Serial Port 0 control register – S0CON ........................................... 113
12.4.2 Serial port 0 data buffer – S0BUF .................................................. 114
12.4.3 Serial port 0 reload register – S0RELH, S0RELL ........................... 114
12.4.4 Serial Port 0 baud rate select register - WDCON ........................... 114
13 Input/Output port (GPIO) ......................................................................... 115
13.1 Normal IO ............................................................................................ 115
13.2 Expanded IO ....................................................................................... 117
14 MCU ........................................................................................................... 118
14.1 Features .............................................................................................. 118
14.2 Block diagram ..................................................................................... 119
14.3 Arithmetic Logic Unit (ALU) ................................................................. 120
14.4 Instruction set summary ...................................................................... 120
14.5 Opcode map ........................................................................................ 124
15 Memory and I/O organization .................................................................. 126
15.1 Special function registers .................................................................... 127
15.1.1 Special function registers locations ................................................ 127
15.1.2 Special function registers reset values ........................................... 128
15.1.3 Accumulator - ACC ......................................................................... 130
15.1.4 B register – B .................................................................................. 130
15.1.5 Program Status Word register - PSW ............................................. 131
15.1.6 Stack Pointer – SP ......................................................................... 131
15.1.7 Data Pointer – DPH, DPL ............................................................... 131
15.1.8 Data Pointer 1 – DPH1, DPL1 ........................................................ 132
15.1.9 Data Pointer Select register – DPS ................................................ 132
16 Random Access Memory (RAM) ............................................................. 133
16.1 Cycle control ....................................................................................... 133
17 Flash Memory ........................................................................................... 134
17.1 Features .............................................................................................. 134
17.2 Block diagram ..................................................................................... 134
17.3 Functional description ......................................................................... 134
17.3.1 Flash memory configuration ........................................................... 134
Revision 1.1 Page 8 of 187
nRF24LU1+ Product Specification
17.3.2 InfoPage content ............................................................................ 136
17.3.3 Protected pages and data pages .................................................... 136
17.3.4 16 kB Flash memory size option .................................................... 137
17.3.5 Software compatibility with nRF24LU1 ........................................... 137
17.3.6 SFR registers for flash memory operations .................................... 138
17.4 Brown-out ............................................................................................ 138
17.5 Flash programming from the MCU ...................................................... 139
17.5.1 MCU write and erase of the MainBlock .......................................... 139
17.5.2 Hardware support for firmware upgrade ......................................... 140
17.6 Flash programming through USB ........................................................ 140
17.6.1 Flash Layout ................................................................................... 140
17.6.2 USB Protocol .................................................................................. 141
17.7 Flash programming through SPI ......................................................... 144
17.7.1 SPI commands ............................................................................... 144
17.7.2 Standalone programming requirements ......................................... 149
17.7.3 In circuit programming over SPI ..................................................... 152
17.7.4 SPI programming sequences ......................................................... 152
18 MDU – Multiply Divide Unit ...................................................................... 155
18.1 Features .............................................................................................. 155
18.2 Block diagram ..................................................................................... 155
18.3 Functional description ......................................................................... 155
18.4 SFR registers ...................................................................................... 155
18.4.1 Loading the MDx registers .............................................................. 156
18.4.2 Executing calculation ...................................................................... 157
18.4.3 Reading the result from the MDx registers ..................................... 157
18.4.4 Normalizing ..................................................................................... 157
18.4.5 Shifting ............................................................................................ 157
18.4.6 The mdef flag .................................................................................. 157
18.4.7 The mdov flag ................................................................................. 158
19 Watchdog and wakeup functions ........................................................... 159
19.1 Features .............................................................................................. 159
19.2 Block diagram ..................................................................................... 159
19.3 Functional description ......................................................................... 160
19.3.1 The Low Frequency Clock (CKLF) ................................................. 160
19.3.2 Tick calibration ................................................................................ 160
19.3.3 RTC wakeup timer .......................................................................... 160
19.3.4 Programmable GPIO wakeup function ........................................... 161
19.3.5 Watchdog ....................................................................................... 161
19.3.6 Programming interface to watchdog and wakeup functions ........... 161
20 Power management ................................................................................. 164
20.1 Features .............................................................................................. 164
20.2 Block diagram ..................................................................................... 164
20.3 Modes of operation ............................................................................. 165
20.4 Functional description ......................................................................... 166
20.4.1 Clock control – CLKCTL ................................................................ 166
20.4.2 Power down control – PWRDWN ................................................... 167
Revision 1.1 Page 9 of 187
nRF24LU1+ Product Specification
20.4.3 Reset result – RSTRES .................................................................. 167
20.4.4 Wakeup configuration register – WUCONF .................................... 167
20.4.5 Power control register - PCON ....................................................... 168
21 Power supply supervisor ........................................................................ 169
21.1 Features ............................................................................................. 169
21.2 Functional description ......................................................................... 169
21.2.1 Power-on reset ............................................................................... 169
21.2.2 Brown-out detection ........................................................................ 169
22 Interrupts .................................................................................................. 170
22.1 Features .............................................................................................. 170
22.2 Block diagram ..................................................................................... 170
22.3 Functional description ......................................................................... 171
22.4 SFR registers ...................................................................................... 171
22.4.1 Interrupt enable 0 register – IEN0 .................................................. 171
22.4.2 Interrupt enable 1 register – IEN1 .................................................. 172
22.4.3 Interrupt priority registers – IP0, IP1 ............................................... 172
22.4.4 Interrupt request control registers – IRCON ................................... 173
23 HW debugger support ............................................................................. 174
23.1 Features .............................................................................................. 174
23.2 Functional description ......................................................................... 174
24 Peripheral information ............................................................................. 175
24.1 Antenna output .................................................................................... 175
24.2 Crystal oscillator .................................................................................. 175
24.3 PCB layout and decoupling guidelines ................................................ 175
25 Application example ................................................................................ 177
25.1 Schematics .......................................................................................... 177
25.2 Layout ................................................................................................. 177
25.3 Bill Of Materials (BOM) ....................................................................... 178
26 Mechanical specifications ....................................................................... 179
27 Ordering information ............................................................................... 180
27.1 Package marking ................................................................................ 180
27.1.1 Abbreviations .................................................................................. 180
27.2 Product options ................................................................................... 181
27.2.1 RF silicon ........................................................................................ 181
27.2.2 Development tools .......................................................................... 181
28 Glossary of terms ..................................................................................... 182
Appendix A - (USB memory configurations) ......................................... 183
Configuration 1 .................................................................................... 183
Configuration 2 .................................................................................... 183
Configuration 3 .................................................................................... 184
Configuration 4 .................................................................................... 185
Appendix B - Configuration for compatibility with nRF24XX ...............186
Revision 1.1 Page 10 of 187
nRF24LU1+ Product Specification
1 Introduction
The nRF24LU1+ is a unique single chip solution for compact USB dongles. The internal nRF24L01+ 2.4
GHz RF transceiver supports a wide range of applications including PC peripherals, sports accessories
and game peripherals.
With an air data rate of 2 Mbps combined with full speed USB, supporting up to 12 Mbps, the nRF24LU1+
meets the stringent performance requirements of applications such as wireless mouse, game controllers
and media center remote controls with displays.
The nRF24LU1+ integrates:
• A nRF24L01+ 2.4 GHz RF transceiver
• A full speed USB 2.0 compliant device controller
• An 8-bit microcontroller
• 16 or 32 kbytes of flash memory
All this is packaged on a compact 5x5mm package, low cost external BOM.
With an internal voltage regulator that enables the chip to be powered directly from the USB bus, it does
not require an external voltage regulator, saving cost and board space. With a fully integrated RF synthe-
sizer and PLL for the USB no external loop filters, resonators or VCO varactor diodes are required. All that
is needed is a low cost ±60ppm 16 MHz crystal, matching circuitry and the antenna.
The main benefits of nRF24LU1+ are:
• Very compact USB dongle
• Low cost external BOM
• No need for an external voltage regulator
• Single low cost ±60ppm 16 MHz crystal
• Flash memory for firmware upgrades
1.1 Prerequisites
In order to fully understand the product specification, a good knowledge of electronic and software engi-
neering is necessary.
1.2 Writing conventions
This product specification follows a set of typographic rules that makes the document consistent and easy
to read. The following writing conventions are used:
• Commands, bit state conditions, and register names are written in Courier.
• Pin names and pin signal conditions are written in Courier bold.
• Cross references are underlined and highlighted in blue.
Revision 1.1 Page 11 of 187
nRF24LU1+ Product Specification
1.3 Features
Features of the nRF24LU1+ include:
• Fast 8-bit MCU:
XIntel MCS 51 compliant instruction set
XReduced instruction cycle time, up to 12x compared to legacy 8051
X32 bit multiplication – division unit
•Memory:
X16 or 32 kbytes of on-chip flash memory with security features
X2 kbytes of on-chip RAM memory
XPre-programmed USB bootloader in the on-chip flash memory.
• 6 programmable digital input/output pins configurable as:
XGPIO
XSPI master
XSPI slave
XExternal interrupts
XTimer inputs
XFull duplex serial port
XDebug interface
• High performance 2.4 GHz RF-transceiver
XTrue single chip GFSK transceiver
XEnhanced ShockBurst™ link layer support in HW:
X Packet assembly/disassembly
X Address and CRC computation
X Auto ACK and retransmit
XOn the air data rate 250 kbps, 1 Mbps or 2 Mbps
XDigital interface (SPI) speed 0-8 Mbps
X125 RF channel option, with 79 (2.402 GHz-2.480 GHz) channels within 2.400 - 2.4835 GHz
XShort switching time enable frequency hopping
XFully RF compatible with nRF24LXX
XRF compatible with nRF2401A, nRF2402, nRF24E1, nRF24E2 in 250 kbps and 1 Mbps mode
• AES encryption/decryption HW-block with 128 bits key length
XECB – Electronic Code Book mode
XCBC – Cipher Block Chaining
XCFB – Cipher FeedBack mode
XOFB – Output FeedBack mode
XCTR – Counter mode
• Full speed USB 2.0 compliant device controller supporting:
XData transfer rates up to 12 Mbit/s
XControl, Interrupt, Bulk and ISO data transfer
XEndpoint 0 for control
X5 input and 5 output Bulk/Interrupt endpoints
X1 input and 1 output iso-synchronous endpoints
XTotal 512 bytes of USB buffer endpoint memory sharable between endpoints
XOn-chip USB transceiver PHY
XOn-chip pull-up resistor on D+ line with software controlled disconnect
• Power management function:
XLow power design supporting fully static stop/ standby/ suspend modes
XProgrammable MCU clock frequency from 64 kHz to 16 MHz
XOn-chip voltage regulators supporting low power mode (supplied from USB power)
XWatchdog and wakeup functionality running in low power mode
Revision 1.1 Page 12 of 187
nRF24LU1+ Product Specification
• On-chip oscillator and PLL to obtain full speed USB operation and to reduce the need for external
components
• On-chip power on reset generator and brown-out detector
• On-chip support for FS2 and nRFprobeTM HW debugger, supported by Keil development tools.
• Complete firmware platform available:
XHardware abstraction layer (HAL) Functions
XUSB library Functions
XStandard and HID specific USB Requests and Descriptors
XnRF24LU1+ Library functions
XAES HAL
XApplication examples
XDevice Firmware Upgrade
1.4 Block diagram
Figure 1. nRF24LU1+ block diagram
To find more information on the block diagram, see Table 1.
MEM-bus
SFR-bus
USB FLASH
16/32 kbytes
SRAM
2 kbytes
PLL 48MHz
XOSC
16MHz
RTC Watch
dog Wakeup
Slow clock bridge
2.4GHz
RF
Transceiver
Enhanced
ShockBurst
SPI Master
MCU
8051
AES co-
processor
Power
Management
Brown-out
Detector
IRAM
256 byte
Interrupt
Control
Voltage
regulator
Power on
reset
OCI SPI Master/Slave
Port Interface
Revision 1.1 Page 13 of 187
nRF24LU1+ Product Specification
Table 1. Block diagram cross references
1.5 Typical system usage
Figure 2. Typical system usage
Name Reference
USB chapter 7 on page 63
FLASH chapter 17 on page 135
SRAM chapter 15 on page 127
2.4 GHz RF transceiver chapter 6 on page 26
XOSC section 24.2 on page 176
Enhanced ShockBurstTM section 6.4 on page 32
IRAM chapter 16 on page 134
MCU chapter 14 on page 119
RTC, Watchdog and Wakeup chapter 19 on page 160
SPI Master chapter 9 on page 99
Interrupt control chapter 21 on page 170
SPI master/slave chapter 9 on page 99 and chapter 10 on page 101
AES co-processor chapter 8 on page 94
Power management chapter 20 on page 165
Brown-out detector section 17.4 on page 139
Antenna
Matching
Xtal
nRF24LU1+
ESD
USB Connector
Revision 1.1 Page 14 of 187
nRF24LU1+ Product Specification
2 Pin Information
2.1 Pin Assignments
Figure 3. nRF24LU1+ pin assignment (top view) for a QFN32 5x5 mm package.
VDD
VBUS
VDD
D+
D-
VSS
PROG
RESET
VDD
VSS
ANT2
ANT1
VDD_PA
VDD
VSS
VSS
VDD
P0.0
P0.1
VSS
P0.2
P0.3
P0.4
P0.5
VSS
XC1
XC2
DEC2
DEC1
VDD
VSS
IREF
1
2
3
4
5
6
7
8
24
23
22
21
20
19
18
17
910 11 12 13 14 15 16
2526272829303132
nRF24LU1+
QFN32 5X5
Exposed die pad
Revision 1.1 Page 15 of 187
nRF24LU1+ Product Specification
2.2 Pin Functions
Table 2. nRF24LU1+ pin functions
2.2.1 Antenna pins
ANT1 and ANT2 are connections for the external antenna (both receive and transmit).
2.2.2 USB pins
D- and D+ are the connections to the USB data lines. External ESD protection is recommended.
2.2.3 Power supply pins
VBUS and VSS are the power supply and ground pins. The nRF24LU1+ can operate from a single power
supply.
The nRF24LU1+ contains an on-chip regulator that produces +3.3V on the VDD pins, from the VBUS supply
line (4.0 – 5.25 V). Alternatively, the VBUS pin can be left open and the VDD pins may be fed from an
external 3.3V supply. In this case, the on-chip 3.3V regulator is switched off.
Additional on-chip regulators produce voltages for internal analog and digital functions blocks. External
decoupling capacitors are required on DEC1 and DEC2.
VDD_PA is a 1.8V output that is used to switch on an external RF Power Amplifier.
2.2.4 PROG pin
When set high this pin enables external SPI flash programming and Port 0 is configured as a slave SPI
port.
The PROG pin needs an external pull-down resistor.
Pin Name Type Description
21, 22 ANT1, ANT2 RF Antenna connection
5, 4 D-, D+ Digital I/O USB data
28, 29 DEC1, DEC2 Power Positive Digital Supply output for de-coupling pur-
poses
25 IREF Analog Input Reference current output.
10, 11, 13, 14,
15, 16
P0.0 – P0.5 Digital I/O General purpose data Port 0, bit 0 - 5. See Table 99.
on page 118 for alternative pin functions.
7PROG Digital Input Enables SPI flash programming
8RESET Digital Input Reset for microcontroller, active low
2VBUS Power USB power connection
1, 3, 9,
19, 24, 27
VDD Power Alternative power supply pins. The VDD pins must
always be connected and de-coupled externally.
20 VDD_PA Power Output Power supply (+1.8V) to Power Amplifier
6, 12, 17, 18,
23, 26, 30
VSS Power Ground (0V)
32, 31 XC1, XC2 Analog Input Crystal connection
Exposed die
pad
Power/heat
relief
Not connected
Revision 1.1 Page 16 of 187
nRF24LU1+ Product Specification
2.2.5 Reference current pins
The IREF pin must be connected to an external resistor.
2.2.6 Port pins
P0.0 – P0.5 are six general purpose I/O pins. Their functions are described in chapter 13 on page 116.
2.2.7 External RESET Pin
A logic 0 on the RESET pin forces the nRF24LU1+ to a known start-up state.
2.2.8 Crystal oscillator pins
XC1 and XC2 are connections to an external crystal.
Revision 1.1 Page 17 of 187
nRF24LU1+ Product Specification
3 Absolute Maximum Ratings
Maximum ratings are the extreme limits that you can expose the nRF24LU1+ to without permanently dam-
aging it. Exposure to absolute maximum ratings for prolonged periods of time may affect device reliability.
Table 3. Absolute maximum ratings
Operating conditions Minimum Maximum Units
Supply voltages
VBUS -0.3 +5.75 V
VSS 0V
VDD -0.3 +3.6 V
Input voltage
VI -0.3 +3.6 V
Temperatures
Operating Temperature -40 +85 °C
Storage Temperature -40 +125 °C
Attention!
Observe precaution for handling
Electrostatic Sensitive Device.
HBM (Human Body Model): Class 1C
Revision 1.1 Page 18 of 187
nRF24LU1+ Product Specification
4 Operating Conditions
Table 4. Operating conditions
Symbol Parameter (condition) Notes Min. Typ. Max. Units
VBUS Supply voltage 4.0 5 5.25 V
VDD Alternative supply voltage 3.05 3.27 3.5 V
TEMP Operating Temperature -40 +27 +85 ºC
Revision 1.1 Page 19 of 187
nRF24LU1+ Product Specification
5 Electrical Specifications
This section contains electrical and timing specifications.
5.1 Power consumption and timing characteristics
Table 5. Power consumption and timing characteristics
Symbol Parameter (condition) Notes Min. Typ. Max. Units
IOP Average supply current in operating
mode
a
a. MCU running radio receive at 2 Mbps and USB transmit
24 mA
ISTANDBY Supply current in standby mode b
b. When MCU is in standby, USB is suspended and the RF Transceiver is in standby
480 µA
MCU
IMCU16MPLL Running @ 16 MHz, generated from
PLL
6.3 mA
IMCU12MPLL Running @ 12 MHz, generated from
PLL
5mA
IMCU8MPLL Running @ 8 MHz, generated from PLL 4 mA
IMCU4MPLL Running @ 4 MHz, generated from PLL 3 mA
IMCU1.6MPLL Running @ 1.6 MHz, generated from
PLL
2mA
IMCU4MXO Running @ 4 MHz, generated from XO 2.4 mA
IMCU1.6MXO Running @ 1.6 MHz, generated from XO 1.75 mA
IMCU.32MXO Running @ 0.32 MHz, generated from
XO
1.1 mA
IMCU64KXO Running @ 0.064 MHz MHz, generated
from XO
1mA
Trst_act From RESET to MCU active 2 ms
Tint_act From INTERRUPT to MCU active 300 µs
Tact_stby MCU from active to standby c
c. Measured from start of the software instruction which executes the change of mode, see also Table 15.
32 µs
RF Transceiver
ITX RF Transceiver TX current @0dBm out-
put power
11.1 mA
RF Transceiver RX current @ 2 Mbps 13.3 mA
IRX RF Transceiver RX current @ 1 Mbps 12.9 mA
Tstby2a RF Transceiver from standby to active c130 µs
Trst_radio From RESET to RF Transceiver power
down
50 ms
USB
IUSB USB active current 4.4 mA
Tusb_wh USB wakeup from host 500 µs
Tusb_wmcu USB wakeup from MCU 300 µs
Tusbact_susp USB from active to suspend c32 µs
PLL
Tplloff_on PLL from off to on time c d
d. Only possible when USB is in suspend mode
250 µs
Tpllon_off PLL from on to off time c d32 µs
Revision 1.1 Page 20 of 187
nRF24LU1+ Product Specification
5.2 RF transceiver characteristics
Symbol Parameter (condition) Notes Min. Typ. Max. Units
General RF conditions
fOP Operating frequency a2400 2525 MHz
PLLres PLL Programming resolution 1 MHz
fXTAL Crystal frequency 16 MHz
Δf250 Frequency deviation @ 250 kbps ±160 kHz
Δf1M Frequency deviation @ 1 Mbps ±160 kHz
Δf2M Frequency deviation @ 2 Mbps ±320 kHz
RGFSK Air data rate b250 2000 kbps
FCHANNEL 1M Non-overlapping channel spacing @
250 kbps/1 Mbps)
c1MHz
FCHANNEL 2M Non-overlapping channel spacing @ 2
Mbps
2MHz
Transmitter operation
PRF Maximum output power d0+4dBm
PRFC RF power control range 16 18 20 dB
PRFCR RF power accuracy ±4 dB
PBW2 20dB bandwidth for modulated carrier
(2 Mbps)
1800 2000 kHz
PBW1 20dB bandwidth for modulated carrier
(1 Mbps)
950 1100 kHz
PBW250 20dB bandwidth for modulated carrier
(250 kbps)
700 800 kHz
PRF1.2 1st Adjacent Channel Transmit Power 2
MHz (2 Mbps)
-20 dBc
PRF2.2 2nd Adjacent Channel Transmit Power
4 MHz (2 Mbps)
-45 dBc
PRF1.1 1st Adjacent Channel Transmit Power 1
MHz (1 Mbps)
-20 dBc
PRF2.1 2nd Adjacent Channel Transmit Power
2 MHz (1 Mbps)
-40 dBc
PRF1.250 1st Adjacent Channel Transmit Power 1
MHz (250 kbps)
-25 dBc
PRF2.250 2nd Adjacent Channel Transmit Power
2 MHz (250 kbps)
-40 dBc
Receiver operation
RXMAX Maximum received signal at < 0.1%
BER
0dBm
RXSENS Sensitivity (0.1% BER) @ 2 Mbps -82 dBm
RXSENS Sensitivity (0.1% BER) @ 1 Mbps -85 dBm
RXSENS Sensitivity (0.1% BER) @ 250 kbps e-94 dBm
RX selectivity according to ETSI EN 300 440-1 V1.3.1 (2001-09) page 27
C/ICO C/I co-channel (2 Mbps) 7 dBc
C/I1ST 1st ACS (Adjacent Channel Selectivity),
C/I 2 MHz (2 Mbps)
3dBc
C/I2ND 2nd ACS, C/I 4 MHz (2 Mbps) -17 dBc
Revision 1.1 Page 21 of 187
nRF24LU1+ Product Specification
C/I3RD 3rd ACS, C/I 6 MHz (2 Mbps) -21 dBc
C/INth Nth ACS, C/I fi > 12 MHz (2 Mbps) f-40 dBc
C/INth Nth ACS, C/I fi > 36 MHz (2 Mbps) -48 dBc
C/ICO C/I co-channel (1 Mbps) 9 dBc
C/I1ST 1st ACS, C/I 1 MHz (1 Mbps) 8dBc
C/I2ND 2nd ACS, C/I 2 MHz (1 Mbps) -20 dBc
C/I3RD 3rd ACS, C/I 3 MHz (1 Mbps) -30 dBc
C/INth Nth ACS, C/I fi > 6 MHz (1 Mbps) -40 dBc
C/INth Nth ACS, C/I fi > 25 MHz (1 Mbps) f-47 dBc
C/ICO C/I co-channel (250 kbps) 12 dBc
C/I1ST 1st ACS, C/I 1 MHz (250 kbps) -12 dBc
C/I2ND 2nd ACS, C/I 2 MHz (250 kbps) -33 dBc
C/I3RD 3rd ACS, C/I 3 MHz (250 kbps) -38 dBc
C/INth Nth ACS, C/I fi > 6 MHz (250 kbps) -50 dBc
C/INth Nth ACS, C/I fi > 25 MHz (250 kbps) f-60 dBc
RX selectivity with nRF24L01 equal modulation on interfering signal (Pin = -67dBm for wanted
signal)
C/ICO C/I co-channel (2 Mbps) (modulated
carrier)
11 dBc
C/I1ST 1st ACS (Adjacent Channel Selectivity),
C/I 2 MHz (2 Mbps)
4dBc
C/I2ND 2nd ACS, C/I 4 MHz (2 Mbps) -18 dBc
C/I3RD 3rd ACS, C/I 6 MHz (2 Mbps) -24 dBc
C/INth Nth ACS, C/I fi > 12 MHz (2 Mbps) -40 dBc
C/INth Nth ACS, C/I fi > 36 MHz (2 Mbps) -48 dBc
C/ICO C/I co-channel (1 Mbps) 12 dBc
C/I1ST 1st ACS, C/I 1 MHz (1 Mbps) 8dBc
C/I2ND 2nd ACS, C/I 2 MHz (1 Mbps) -21 dBc
C/I3RD 3rd ACS, C/I 3 MHz (1 Mbps) -30 dBc
C/INth Nth ACS, C/I fi > 6 MHz (1 Mbps) -40 dBc
C/INth Nth ACS, C/I fi > 25 MHz (1 Mbps) -50 dBc
C/ICO C/I co-channel (250 kbps) 7 dBc
C/I1ST 1st ACS, C/I 1 MHz (250 kbps) -12 dBc
C/I2ND 2nd ACS, C/I 2 MHz (250 kbps) -34 dBc
C/I3RD 3rd ACS, C/I 3 MHz (250 kbps) -39 dBc
C/INth Nth ACS, C/I fi > 6 MHz (250 kbps) -50 dBc
C/INth Nth ACS, C/I fi > 25 MHz (250 kbps) -60 dBc
RX intermodulation performance according to Bluetooth specification version 2.0, 4th November
2004, page 42
P_IM(6)
@ 2 Mbps
Input power of IM interferers at 6 and
12 MHz distance from wanted signal
g-42 dBm
P_IM(8)
@ 2Mbps
Input power of IM interferers at 8 and
16 MHz distance from wanted signal
g-38 dBm
Symbol Parameter (condition) Notes Min. Typ. Max. Units
Revision 1.1 Page 22 of 187
nRF24LU1+ Product Specification
Table 6. RF Transceiver specifications
P_IM(10)
@ 2Mbps
Input power of IM interferers at 10 and
20 MHz distance from wanted signal
g-37 dBm
P_IM(3)
@ 1Mbps
Input power of IM interferers at 3 and
6 MHz distance from wanted signal
g-36 dBm
P_IM(4)
@ 1Mbps
Input power of IM interferers at 4 and
8 MHz distance from wanted signal
g-36 dBm
P_IM(5)
@ 1Mbps
Input power of IM interferers at 5 and
10 MHz distance from wanted signal
g-36 dBm
P_IM(3)
@ 250 kbps
Input power of IM interferers at 3 and
6 MHz distance from wanted signal
g-36 dBm
P_IM(4)
@ 250 kbps
Input power of IM interferers at 4 and
8 MHz distance from wanted signal
g-36 dBm
P_IM(5)
@ 250 kbps
Input power of IM interferers at 5 and
10 MHz distance from wanted signal
g-36 dBm
a. Usable band is determined by local regulations.
b. Data rate in each burst on-air.
c. The minimum channel spacing is 1 MHz.
d. Antenna load impedance = 15Ω + j88Ω.
e. For 250 kpbs sensitivity, frequencies which are integer multiples of 16 MHz (2400, 2416 and so on,)
sensitivity is reduced.
f. Narrow Band (In Band) Blocking measurements:
0 to ±40 MHz; 1 MHz step size
For Interferer frequency offsets n*2*fxtal, blocking performance is degraded by approximately 5dB com-
pared to adjacent figures.
g. Wanted signal level at Pin = -64dBm. Two interferers with equal input power are used. The interferer clos-
est in frequency is unmodulated, the other interferer is modulated equal with the wanted signal. The input
power of interferers where the sensitivity equals BER = 0.1% is presented.
Symbol Parameter (condition) Notes Min. Typ. Max. Units
Revision 1.1 Page 23 of 187
nRF24LU1+ Product Specification
5.3 USB interface
The USB interface electrical performance is compliant with the USB specification 2.0.
Table 7. USB interface characteristics
5.4 Flash memory
Table 8. Flash memory characteristics
Table 9. Flash memory and page size
Characteristic Symbol Conditions Min. Typ. Max Unit
Electrical characteristics
Input high voltage (driven) VIH 2.0 V
Input low voltage VIL 0.8 V
Differential input sensitivity VDI |(D+) – (D-)| 0.2 V
Differential common mode range VCM Includes VDI
range
0.8 2.5 V
Single ended receiver threshold VSE 0.8 2.0 V
Single ended receiver hysteresis VSEH 200 mV
Output low voltage VOL 0 0.3 V
Output high voltage VOH 2.8 3.6 V
Differential output signal cross-point
voltage
VCRS 1.3 2.0 V
Internal pull-up resistor (Standby
mode)
RPU1 900 1100 1575 Ω
Internal pull-up resistor (Active mode) RPU2 1425 2100 3090 Ω
Termination voltage connected to RPU VTRM 3.05 3.5 V
Output driver resistance (does not
include the series resistance)
ZDRV Steady state
drive
15 Ω
Timing characteristics
Driver rise time TFR CL=50pF 4 20 ns
Driver fall time TFF CL=50pF 4 20 ns
Rise/fall time matching TFRFF TRF / TFF 90 111 %
Transceiver pad capacitance CIN Pad to ground 20 pF
Characteristic Symbol Conditions Min. Typ. Max Unit
Endurance Nendur 1000 cycles
Data retention Tret 25°C 100 years
Name Size Unit
Flash memory MainBlock 32768 bytes
Flash InfoPage 512 bytes
Flash page size 512 bytes
Revision 1.1 Page 24 of 187
nRF24LU1+ Product Specification
5.5 Crystal specifications
Table 10. Crystal specifications
5.6 DC Electrical Characteristics
Table 11. DC characteristics
Table 12. Digital input pin
Symbol Parameter (condition) Notes Min. Typ. Max. Units
fNOM Nominal frequency (parallel resonant) 16.000 MHz
fTOL Frequency tolerance a b
a. Includes initial accuracy, stability over temperature, aging and frequency pulling due to incorrect load
capacitance.
b. Frequency regulations in certain regions set tighter requirements on frequency tolerance (for example
Japan and South Korea max ±50ppm).
±60 ppm
CLLoad capacitance 9 16 pF
C0Shunt capacitance 3 7 pF
ESR Equivalent series resistance 50 100 Ω
PDDrive level 100 µW
Symbol Parameter (condition) Notes Min. Typ. Max. Units
Operating conditions
VBUS Supply voltage 4.0 5.0 5.25 V
TEMP Operating Temperature -40 +27 +85 ºC
On-chip voltage regulators
VDD Output voltage a
a. Also valid for VDD input voltage.
3.05 3.27 3.5 V
IVDD External load current 2 mA
Symbol Parameter (condition) Notes Min. Typ. Max. Units
VIH HIGH level input voltage 0.7 VDD VDD V
VIL LOW level input voltage VSS 0.3 VDD V
Revision 1.1 Page 25 of 187
nRF24LU1+ Product Specification
Table 13. Digital output pin
Symbol Parameter (condition) Notes Min. Typ. Max. Units
VOH HIGH level output voltage
(IOH= -1.0mA)
aVDD-0.3 VDD V
VOL LOW level output voltage
(IOL= 1.0mA))
VSS 0.3 V
a. When the nRF24LU1+ is supplied from VBUS, there is a limit (IVDD) on the current that can be
drawn from VDD by external devices. Current sourced by high outputs are supplied to external
devices for this purpose.
Revision 1.1 Page 26 of 187
nRF24LU1+ Product Specification
6 RF Transceiver
The nRF24LU1+ uses the same 2.4 GHz GFSK RF transceiver with embedded protocol engine
(Enhanced ShockBurst™) that is found in the nRF24L01+ single chip RF Transceiver and in the
nRF24LE1 on-chip solution. The RF Transceiver is designed for operation in the world wide ISM frequency
band at 2.400 - 2.4835 GHz and is very well suited for ultra low power wireless applications.
The RF Transceiver module is configured and operated through the RF transceiver map. This register map
is accessed by the MCU through a dedicated on-chip Serial Peripheral interface (SPI) and is available in all
power modes of the RF Transceiver module.
The embedded protocol engine (Enhanced ShockBurst™) enables data packet communication and sup-
ports various modes from manual operation to advanced autonomous protocol operation. Data FIFOs in
the RF Transceiver module ensure a smooth data flow between the RF Transceiver module and the
nRF24LU1+ MCU.
The rest of this chapter is written in the context of the RF Transceiver module as the core and the rest of
the nRF24LU1+ as external circuitry to this module.
6.1 Features
Features of the RF Transceiver include:
• General
XWorldwide 2.4GHz ISM band operation
XCommon antenna interface in transmit and receive
XGFSK modulation
X250 kbps, 1 and 2Mbps on air data rate
• Transmitter
XProgrammable output power: 0, -6, -12 or -18dBm
X11.1mA at 0dBm output power
• Receiver
XIntegrated channel filters
X13.3mA at 2 Mbps
X-82dBm sensitivity at 2 Mbps
X-85dBm sensitivity at 1 Mbps
X-94dBm sensitivity at 250 kbps
• RF Synthesizer
XFully integrated synthesizer
X1 MHz frequency programming resolution
XAccepts low cost ±60ppm 16 MHz crystal
X1 MHz non-overlapping channel spacing at 1 Mbps
X2 MHz non-overlapping channel spacing at 2 Mbps
• Enhanced ShockBurst™
X1 to 32 bytes dynamic payload length
XAutomatic packet handling (assembly/disassembly)
XAutomatic packet transaction handling (auto ACK, auto retransmit)
• 6 data pipe MultiCeiver™ for 6:1 star networks
Revision 1.1 Page 27 of 187
nRF24LU1+ Product Specification
6.2 Block diagram
Figure 4. RF Transceiver block diagram
6.3 Functional description
This section describes the different operating modes of the RF Transceiver and the parameters used to
control it.
The RF Transceiver module has a built-in state machine that controls the transitions between the different
operating modes. The state machine is controlled by SFR register RFCON and RF transceiver register
CONFIG, see section 6.5 for details.
6.3.1 Operational Modes
You can configure the RF Transceiver to power down, standby, RX and TX mode. This section describes
these modes in detail.
6.3.1.1 State diagram
The state diagram (Figure 5.) shows the operating modes of the RF Transceiver and how they function. At
the end of the reset sequence the RF Transceiver enters Power Down mode. When the RF Transceiver
enters Power Down mode the MCU can still control the module through the SPI and the rfcsn bit in the
RFCON register.
There are three types of distinct states highlighted in the state diagram:
•Recommended operating mode: is a recommended state used during normal operation.
•Possible operating mode: is a possible operating state, but is not used during normal operation.
•Transition state: is a time limited state used during start up of the oscillator and settling of the PLL.
RF Receiver
ANT1
ANT2
Enhanced ShockBurst
Baseband Engine
TX FIFOs
RX FIFOs
Radio Control
GFSK
Modulator
SPI
(Slave)
PA
LNA
TX
Filter
RX
Filter
RF Synthesiser Power Management
RF Transmitter Baseband
RFIRQ
GFSK
Demodulator
Register map
RFCON.rfcken
XOSC16M
RFCON.rfce
RFCON.rfcsn
SPI
(Master)
Revision 1.1 Page 28 of 187
nRF24LU1+ Product Specification
.
Figure 5. Radio control state diagram
6.3.1.2 Power down mode
In power down mode the RF Transceiver is disabled with minimal current consumption. All the register val-
ues available from the SPI are maintained and the SPI can be activated. For start up times see Table 15.
Power down mode is entered by setting the PWR_UP bit in the CONFIG register low.
6.3.1.3 Standby modes
Standby-I mode
By setting the PWR_UP bit in the CONFIG register to 1, the RF Transceiver enters standby-I mode. Standby-
I mode is used to minimize average current consumption while maintaining short start up times. Change to
the active mode only happens if the rfce bit is enabled and when it is not enabled, the RF Transceiver
returns to standby-I mode from both the TX and RX modes.
Possible operating mode
Recommended path between operating modes
Possible path between operating modes
Recommended operating mode
Transition state
CE = 1 Pin signal condition
PWR_DN = 1 Bit state condition
Undefined
TX FIFO empty System information
Undefined
Legend:
Undefined
Power Down
Standby-I
RX Mode
TX Mode
Standby-II
RX Settling
130 us
PWR_UP = 0
TX Settling
130 us
TX FIFO not empty
PRIM_RX = 0
rfce = 1 for more than 10µs
PRIM_RX = 1
rfce = 1
rfce = 0
TX FIFO empty
rfce = 1
TX FIFO not empty
rfce = 1
PRIM_RX = 0
TX FIFO empty
rfce = 1
PWR_UP = 0
PWR_UP = 0
PWR_UP=0
rfce = 0
PWR_UP=0
PWR_UP=0
TX finished with one packet
rfce = 0
rfce = 1
TX FIFO not empty
PWR_UP = 1
Start up time is
150µs
Power on
reset
50ms
Revision 1.1 Page 29 of 187
nRF24LU1+ Product Specification
Standby-II mode
In standby-II mode extra clock buffers are active and more current is used compared to standby-I mode.
The RF Transceiver enters standby-II mode if the rfce bit is held high on a PTX operation with an empty
TX FIFO. If a new packet is downloaded to the TX FIFO, the PLL immediately starts and the packet is
transmitted after the normal PLL settling delay (130µs).
The register values are maintained and the SPI can be activated during both standby modes. For start up
times see Table 15.
6.3.1.4 RX mode
The RX mode is an active mode where the RF Transceiver is used as a receiver. To enter this mode, the
RF Transceiver must have the PWR_UP bit, PRIM_RX bit and the rfce bit is set high.
In RX mode the receiver demodulates the signals from the RF channel, constantly presenting the demodu-
lated data to the baseband protocol engine. The baseband protocol engine constantly searches for a valid
packet. If a valid packet is found (by a matching address and a valid CRC) the payload of the packet is pre-
sented in a vacant slot in the RX FIFOs. If the RX FIFOs are full, the received packet is discarded.
The RF Transceiver remains in RX mode until the MCU configures it to standby-I mode or power down
mode. However, if the automatic protocol features (Enhanced ShockBurst™) in the baseband protocol
engine are enabled, the RF Transceiver can enter other modes in order to execute the protocol.
In RX mode a Received Power Detector (RPD) signal is available. The RPD is a signal that is set high
when a RF signal higher than -64dBm is detected inside the receiving frequency channel. The internal RPD
signal is filtered before presented to the RPD register. The RF signal must be present for at least 40µs
before the RPD is set high. How to use the RPD is described in Section 6.3.4 on page 31.
6.3.1.5 TX mode
The TX mode is an active mode for transmitting packets. To enter this mode, the RF Transceiver must
have the PWR_UP bit set high, PRIM_RX bit set low, a payload in the TX FIFO and a high pulse on the
rfce bit for more than 10µs.
The RF Transceiver stays in TX mode until it finishes transmitting a packet. If rfce = 0, RF Transceiver
returns to standby-I mode. If rfce = 1, the status of the TX FIFO determines the next action. If the TX
FIFO is not empty the RF Transceiver remains in TX mode and transmits the next packet. If the TX FIFO is
empty the RF Transceiver goes into standby-II mode. The RF Transceiver transmitter PLL operates in
open loop when in TX mode. It is important never to keep the RF Transceiver in TX mode for more than
4ms at a time. If the Enhanced ShockBurst™ features are enabled, RF Transceiver is never in TX mode
longer than 4ms.
Revision 1.1 Page 30 of 187
nRF24LU1+ Product Specification
6.3.1.6 Operational modes configuration
The following table (Table 14.) describes how to configure the operational modes.
Table 14. RF Transceiver main modes
6.3.1.7 Timing information
The timing information in this section relates to the transitions between modes and the timing for the rfce
bit. The transition from TX mode to RX mode or vice versa is the same as the transition from the standby
modes to TX mode or RX mode (130µs), as described in Table 15.
Table 15. Operational timing of RF Transceiver
Note: If VDD is turned off, the register values are lost and you must reconfigure the RF Transceiver
before entering the TX or RX modes.
Mode PWR_UP
register
PRIM_RX
register rfce FIFO state
RX mode111-
TX mode 1 0 1 Data in TX FIFO. Will empty all lev-
els in TX FIFOa.
a. If the rfce bit is held high the TX FIFO is emptied and all necessary ACK and possible retransmits
are carried out. The transmission continues as long as the TX FIFO is refilled. If the TX FIFO is empty
when the rfce bit is still high, the RF Transceiver enters standby-II mode. In this mode the transmis-
sion of a packet is started as soon as the rfcsn is set high after an upload (UL) of a packet to TX
FIFO.
TX mode 1 0 Minimum 10µs
high pulse
Data in TX FIFO.Will empty one
level in TX FIFOb.
b. This operating mode pulses the rfce bit high for at least 10µs. This allows one packet to transmit.
This is the normal operating mode. After the packet is transmitted, the RF Transceiver enters
standby-I mode.
Standby-II 1 0 1 TX FIFO empty
Standby-I 1 - 0 No ongoing packet transmission
Power Down 0 - - -
Name RF Transceiver Max. Min. Comments
Tpd2stby Power Down Î Standby mode 150µs
Tstby2a Standby modes Î TX/RX mode 130µs
Thce Minimum rfce high 10µs
Tpece2csn Delay from rfce pos. edge to
rfcsn low
4µs
Revision 1.1 Page 31 of 187
nRF24LU1+ Product Specification
6.3.2 Air data rate
The air data rate is the modulated signaling rate the RF Transceiver uses when transmitting and receiving
data. It can be 250 kbps, 1 Mbps or 2 Mbps. Using lower air data rate gives better receiver sensitivity than
higher air data rate. But, high air data rate gives lower average current consumption and reduced probabil-
ity of on-air collisions.
The air data rate is set by the RF_DR bit in the RF_SETUP register. A transmitter and a receiver must be
programmed with the same air data rate to communicate with each other.
The RF Transceiver is fully compatible with nRF24L01. For compatibility with nRF2401A, nRF2402,
nRF24E1, and nRF24E2 the air data rate must be set to 250 kbps or 1 Mbps.
6.3.3 RF channel frequency
The RF channel frequency determines the center of the channel used by the RF Transceiver. The channel
occupies a bandwidth of less than 1 MHz at 250 kbps and 1 Mbps and a bandwidth of less than 2 MHz at 2
Mbps. The RF Transceiver can operate on frequencies from 2.400 GHz to 2.525 GHz. The programming
resolution of the RF channel frequency setting is 1 MHz.
At 2 Mbps the channel occupies a bandwidth wider than the resolution of the RF channel frequency set-
ting. To ensure non-overlapping channels in 2 Mbps mode, the channel spacing must be 2 MHz or more.
At 1 Mbps and 250 kbps the channel bandwidth is the same or lower than the resolution of the RF fre-
quency.
The RF channel frequency is set by the RF_CH register according to the following formula:
F0= 2400 + RF_CH MHz
You must program a transmitter and a receiver with the same RF channel frequency to communicate with
each other.
6.3.4 Received Power Detector measurements
Received Power Detector (RPD), located in register 09, bit 0, triggers at received power levels above
-64dBm that are present in the RF channel you receive on. If the received power is less than -64dBm,
RDP = 0.
The RPD can be read out at any time while the RF Transceiver is in receive mode. This offers a snapshot
of the current received power level in the channel. The RPD is latched whenever a packet is received or
when the MCU sets rfce low
The status of RPD is correct when RX mode is enabled and after a wait time of Tstby2a +Tdelay_AGC=
130 µs + 40 µs. The RX gain varies over temperature which means that the RPD threshold also varies
over temperature. The RPD threshold value is reduced by - 5dB at T = -40°C and increased by + 5dB at
85°C.
6.3.5 PA control
The PA (Power Amplifier) control is used to set the output power from the RF Transceiver power amplifier.
In TX mode PA control has four programmable steps, see Table 16.
Revision 1.1 Page 32 of 187
nRF24LU1+ Product Specification
The PA control is set by the RF_PWR bits in the RF_SETUP register.
Conditions: VDD = 3.0V, VSS = 0V, TA = 27ºC, Load impedance = 15Ω+j88Ω.
Table 16. RF output power setting for the RF Transceiver
6.3.6 RX/TX control
The RX/TX control is set by PRIM_RX bit in the CONFIG register and sets the RF Transceiver in transmit/
receive.
6.4 Enhanced ShockBurst™
Enhanced ShockBurst™ is a packet based data link layer that features automatic packet assembly and
timing, automatic acknowledgement and retransmissions of packets. Enhanced ShockBurst™ enables the
implementation of ultra low power and high performance communication. The Enhanced ShockBurst™
features enable significant improvements of power efficiency for bi-directional and uni-directional systems,
without adding complexity on the host controller side.
6.4.1 Features
The main features of Enhanced ShockBurst™ are:
• 1 to 32 bytes dynamic payload length
• Automatic packet handling
• Auto packet transaction handling
XAuto Acknowledgement
XAuto retransmit
• 6 data pipe MultiCeiver™ for 1:6 star networks
6.4.2 Enhanced ShockBurst™ overview
Enhanced ShockBurst™ uses ShockBurst™ for automatic packet handling and timing. During transmit,
ShockBurst™ assembles the packet and clocks the bits in the data packet for transmission. During
receive, ShockBurst™ constantly searches for a valid address in the demodulated signal. When Shock-
Burst™ finds a valid address, it processes the rest of the packet and validates it by CRC. If the packet is
valid the payload is moved into a vacant slot in the RX FIFOs. All high speed bit handling and timing is con-
trolled by ShockBurst™.
Enhanced ShockBurst™ features automatic packet transaction handling for the easy implementation of a
reliable bi-directional data link. An Enhanced ShockBurst™ packet transaction is a packet exchange
between two transceivers, with one transceiver acting as the Primary Receiver (PRX) and the other trans-
ceiver acting as the Primary Transmitter (PTX). An Enhanced ShockBurst™ packet transaction is always
initiated by a packet transmission from the PTX, the transaction is complete when the PTX has received an
SPI RF-SETUP
(RF_PWR) RF output power DC current
consumption
11 0dBm 11.1mA
10 -6dBm 8.8mA
01 -12dBm 7.3
00 -18dBm 6.8mA
Revision 1.1 Page 33 of 187
nRF24LU1+ Product Specification
acknowledgment packet (ACK packet) from the PRX. The PRX can attach user data to the ACK packet
enabling a bi-directional data link.
The automatic packet transaction handling works as follows:
1. You begin the transaction by transmitting a data packet from the PTX to the PRX. Enhanced
ShockBurst™ automatically sets the PTX in receive mode to wait for the ACK packet.
2. If the packet is received by the PRX, Enhanced ShockBurst™ automatically assembles and
transmits an acknowledgment packet (ACK packet) to the PTX before returning to receive mode.
3. If the PTX does not receive the ACK packet immediately, Enhanced ShockBurst™ automatically
retransmits the original data packet after a programmable delay and sets the PTX in receive
mode to wait for the ACK packet.
In Enhanced ShockBurst™ it is possible to configure parameters such as the maximum number of retrans-
mits and the delay from one transmission to the next retransmission. All automatic handling is done without
the involvement of the MCU.
6.4.3 Enhanced Shockburst™ packet format
The format of the Enhanced ShockBurst™ packet is described in this section. The Enhanced Shock-
Burst™ packet contains a preamble field, address field, packet control field, payload field and a CRC field.
Figure 6. shows the packet format with MSB to the left.
Figure 6. An Enhanced ShockBurst™ packet with payload (0-32 bytes)
6.4.3.1 Preamble
The preamble is a bit sequence used to synchronize the receivers demodulator to the incoming bit stream.
The preamble is one byte long and is either 01010101 or 10101010. If the first bit in the address is 1 the
preamble is automatically set to 10101010 and if the first bit is 0 the preamble is automatically set to
01010101. This is done to ensure there are enough transitions in the preamble to stabilize the receiver.
6.4.3.2 Address
This is the address for the receiver. An address ensures that the correct packet is detected by the receiver.
The address field can be configured to be 3, 4 or, 5 bytes long with the AW register.
Note: Addresses where the level shifts only one time (that is, 000FFFFFFF) can often be detected in
noise and can give a false detection, which may give a raised Packet-Error-Rate. Addresses
as a continuation of the preamble (hi-low toggling) raises the Packet-Error-Rate.
Preamble 1 byte Address 3-5 byte 9 bit Payload 0 - 32 byte CRC 1-2
byte
Packet Control Field
Revision 1.1 Page 34 of 187
nRF24LU1+ Product Specification
6.4.3.3 Packet Control Field
Figure 7. shows the format of the 9-bit packet control field, MSB to the left.
Figure 7. Packet control field
The packet control field contains a 6-bit payload length field, a 2-bit PID (Packet Identity) field and a 1-bit
NO_ACK flag.
Payload length
This 6-bit field specifies the length of the payload in bytes. The length of the payload can be from 0 to 32
bytes.
Coding: 000000 = 0 byte (only used in empty ACK packets.) 100000 = 32 byte, 100001 = Don’t care.
This field is only used if the Dynamic Payload Length function is enabled.
PID (Packet identification)
The 2-bit PID field is used to detect if the received packet is new or retransmitted. PID prevents the PRX
operation from presenting the same payload more than once to the MCU. The PID field is incremented at
the TX side for each new packet received through the SPI. The PID and CRC fields (see section 6.4.3.5 on
page 35) are used by the PRX operation to determine if a packet is retransmitted or new. When several
data packets are lost on the link, the PID fields may become equal to the last received PID. If a packet has
the same PID as the previous packet, the RF Transceiver compares the CRC sums from both packets. If
the CRC sums are also equal, the last received packet is considered a copy of the previously received
packet and discarded.
No Acknowledgment flag (NO_ACK)
The Selective Auto Acknowledgement feature controls the NO_ACK flag.
This flag is only used when the auto acknowledgement feature is used. Setting the flag high, tells the
receiver that the packet is not to be auto acknowledged.
6.4.3.4 Payload
The payload is the user defined content of the packet. It can be 0 to 32 bytes wide and is transmitted on-air
when it is uploaded (unmodified) to the device.
Enhanced ShockBurst™ provides two alternatives for handling payload lengths; static and dynamic.
The default is static payload length. With static payload length all packets between a transmitter and a
receiver have the same length. Static payload length is set by the RX_PW_Px registers on the receiver side.
The payload length on the transmitter side is set by the number of bytes clocked into the TX_FIFO and
must equal the value in the RX_PW_Px register on the receiver side.
NO_ACK 1bitPID 2bitPayload length 6bit
Revision 1.1 Page 35 of 187
nRF24LU1+ Product Specification
Dynamic Payload Length (DPL) is an alternative to static payload length. DPL enables the transmitter to
send packets with variable payload length to the receiver. This means that for a system with different pay-
load lengths it is not necessary to scale the packet length to the longest payload.
With the DPL feature the nRF24L01+ can decode the payload length of the received packet automatically
instead of using the RX_PW_Px registers. The MCU can read the length of the received payload by using
the R_RX_PL_WID command.
Note: Always check if the packet width reported is 32 bytes or shorter when using the
R_RX_PL_WID command. If its width is longer than 32 bytes then the packet contains errors
and must be discarded. Discard the packet by using the Flush_RX command.
In order to enable DPL the EN_DPL bit in the FEATURE register must be enabled. In RX mode the DYNPD
register must be set. A PTX that transmits to a PRX with DPL enabled must have the DPL_P0 bit in DYNPD
set.
6.4.3.5 CRC (Cyclic Redundancy Check)
The CRC is the error detection mechanism in the packet. It may either be 1 or 2 bytes and is calculated
over the address, Packet Control Field and Payload.
The polynomial for 1 byte CRC is X8 + X2 + X + 1. Initial value 0xFF.
The polynomial for 2 byte CRC is X16+ X12 + X5 + 1. Initial value 0xFFFF.
No packet is accepted by Enhanced ShockBurst™ if the CRC fails.
Revision 1.1 Page 36 of 187
nRF24LU1+ Product Specification
6.4.4 Automatic packet assembly
The automatic packet assembly assembles the preamble, address, packet control field, payload and CRC
to make a complete packet before it is transmitted.
Figure 8. Automatic packet assembly
Start:
Collect Address from
TX_ADDR register
TX_ADDR MSB =1
Add preamble 0x55 Add preamble 0xAA
EN_DPL=1
PCF[8:3]= #bytes in upper
level of TX_FIFO
Yes
No
Yes
No
SPI TX command
PCF[0]=0 PCF[0]=1
PCF[2:1]++
Collect Payload from
TX_FIFO
Calculate and add 1 Byte CRC
based on Address, PCF and
Payl oad
EN_CRC = 1
CRCO = 1
Calculate and add 2 Byte
CRC based on Address, PCF
and Payload
W_TX_PAYLOAD
W_TX_PAYLOAD_NOACK
Yes
Yes
No
STOP
No
New data in
TX_FIFO
REUSE_TX_PL
active
Yes
No
Yes
No
Revision 1.1 Page 37 of 187
nRF24LU1+ Product Specification
6.4.5 Automatic packet disassembly
After the packet is validated, Enhanced ShockBurst™ disassembles the packet and loads the payload into
the RX FIFO, and asserts the RX_DR IRQ.
Figure 9. Automatic packet disassembly
Start
Received window =
RX_ADDR_Px
Read Address width
from SETUP_AW
Monitor SETUP_AW wide
window of received bit
stream
PCF = 9 first bits
received after valid
address
EN_DPL=1
PCF[2:1]
Changed from last
packet
STOP
Payload = PCF[8:3] bytes
from received bit stream
Payload = RX_PW_Px
bytes from received bit
stream
CRCO = 1
RX_CRC = 2 Byte CRC
calculated from received
Address, PCF and Payload
TX_CRC = 2 Bytes from
received bit stream
TX_CRC = 1 Byte from
received bit stream
RX_CRC = 1 Byte CRC
calculated from received
Address, PCF and Payload
TX_CRC = RX_CRC
CRC
Changed from last
packet
New packet received
Yes
No
Yes
No
Yes
No
Yes
No
Yes No
Reject the duplicate received
packet
No
Revision 1.1 Page 38 of 187
nRF24LU1+ Product Specification
6.4.6 Automatic packet transaction handling
Enhanced ShockBurst™ features two functions for automatic packet transaction handling; auto acknowl-
edgement and auto re-transmit.
6.4.6.1 Auto Acknowledgement
Auto acknowledgment is a function that automatically transmits an ACK packet to the PTX after it has
received and validated a packet. The auto acknowledgement function reduces the load of the system MCU
and reduces average current consumption. The Auto Acknowledgement feature is enabled by setting the
EN_AA register.
Note: If the received packet has the NO_ACK flag set, auto acknowledgement is not executed.
An ACK packet can contain an optional payload from PRX to PTX. In order to use this feature, the
Dynamic Payload Length (DPL) feature must be enabled. The MCU on the PRX side has to upload the
payload by clocking it into the TX FIFO by using the W_ACK_PAYLOAD command. The payload is pending
in the TX FIFO (PRX) until a new packet is received from the PTX. The RF Transceiver can have three
ACK packet payloads pending in the TX FIFO (PRX) at the same time.
Figure 10. TX FIFO (PRX) with pending payloads
Figure 10. shows how the TX FIFO (PRX) is operated when handling pending ACK packet payloads. From
the MCU the payload is clocked in with the W_ACK_PAYLOAD command. The address decoder and buffer
controller ensure that the payload is stored in a vacant slot in the TX FIFO (PRX). When a packet is
received, the address decoder and buffer controller are notified with the PTX address. This ensures that
the right payload is presented to the ACK generator.
If the TX FIFO (PRX) contains more than one payload to a PTX, payloads are handled using the first in –
first out principle. The TX FIFO (PRX) is blocked if all pending payloads are addressed to a PTX where the
link is lost. In this case, the MCU can flush the TX FIFO (PRX) by using the FLUSH_TX command.
In order to enable Auto Acknowledgement with payload the EN_ACK_PAY bit in the FEATURE register
must be set.
6.4.6.2 Auto Retransmission (ART)
The auto retransmission is a function that retransmits a packet if an ACK packet is not received. It is used
in an auto acknowledgement system on the PTX. When a packet is not acknowledged, you can set the
number of times it is allowed to retransmit by setting the ARC bits in the SETUP_RETR register. PTX enters
RX mode and waits a time period for an ACK packet each time a packet is transmitted. The amount of time
the PTX is in RX mode is based on the following conditions:
TX FIFO
Payload 1
Payload 2
Payload 3
Address decoder and buffer controller
SPI
Module
ACK
generator
RX Pipe
address TX Pipe
address
From
MCU
Revision 1.1 Page 39 of 187
nRF24LU1+ Product Specification
• Auto Retransmit Delay (ARD) elapsed.
• No address match within 250µs.
• After received packet (CRC correct or not) if address match within 250µs.
The RF Transceiver asserts the TX_DS IRQ when the ACK packet is received.
The RF Transceiver enters standby-I mode if there is no more untransmitted data in the TX FIFO and the
rfce bit in the RFCON register is low. If the ACK packet is not received, the RF Transceiver goes back to
TX mode after a delay defined by ARD and retransmits the data. This continues until acknowledgment is
received, or the maximum number of retransmits is reached.
Two packet loss counters are incremented each time a packet is lost, ARC_CNT and PLOS_CNT in the
OBSERVE_TX register. The ARC_CNT counts the number of retransmissions for the current transaction.
You reset ARC_CNT by initiating a new transaction. The PLOS_CNT counts the total number of retrans-
missions since the last channel change. You reset PLOS_CNT by writing to the RF_CH register. It is possi-
ble to use the information in the OBSERVE_TX register to make an overall assessment of the channel
quality.
The ARD defines the time from the end of a transmitted packet to when a retransmit starts on the PTX.
ARD is set in SETUP_RETR register in steps of 250µs. A retransmit is made if no ACK packet is received by
the PTX.
There is a restriction on the length of ARD when using ACK packets with payload. The ARD time must
never be shorter than the sum of the startup time and the time on-air for the ACK packet.
• For 2 Mbps data rate and 5 byte address; 15 byte is maximum ACK packet payload length for
ARD=250 µs (reset value).
• For 1 Mbps data rate and 5 byte address; 5 byte is maximum ACK packet payload length for
ARD=250 µs (reset value).
ARD=500µs is long enough for any ACK payload length in 1 or 2 Mbps mode.
• For 250 kbps data rate and 5byte address the following values apply:
Table 17. Maximum ACK payload length for different retransmit delays at 250 kbps
As an alternative to Auto Retransmit it is possible to manually set the RF Transceiver to retransmit a
packet a number of times. This is done by the REUSE_TX_PL command. The MCU must initiate each
transmission of the packet with a pulse on the CE pin when this command is used.
ARD ACK packet size (in bytes)
1500 µs All ACK payload sizes
1250 µs < 24
1000 µs < 16
750 µs < 8
500 µs Empty ACK with no payload
Revision 1.1 Page 40 of 187
nRF24LU1+ Product Specification
6.4.7 Enhanced ShockBurstTM flowcharts
This section contains flowcharts outlining PTX and PRX operation in Enhanced ShockBurst™.
6.4.7.1 PTX operation
The flowchart in Figure 11. outlines how a RF Transceiver configured as a PTX behaves after entering
standby-I mode.
Note: ShockBurst™ operation is outlined with a dashed square.
Figure 11. PTX operations in Enhanced ShockBurst™
Start Primary TX
Standby-I mode
Standby-II mode
Is rfce=1?
Packet in TX
FIFO?
TX mode
Transmit Packet
Is Auto Re-
Transmit
enabled?
RX mode
Yes
Yes
Yes
No
Packet in TX
FIFO?
No
Is an ACK
received?
Timeout?
Has ARD
elapsed?
Yes
Standby-II mode
TX mode
Retransmit last
packet
Packet in TX
FIFO?
Yes
Is rfce =1?
No
Is rfce =1? No
Yes
No
YesNo
Yes
TX Settling Number of
retries = ARC?
No
RX Settling
Set MAX_RT IRQ
No
No
Yes
Set TX_DS IRQ
Yes
Has the ACK
payload?
Put payload in RX
FIFO.
Set TX_DS IRQ
and RX_DR IRQ
Set TX_DS IRQ
Yes
No
No_ACK?
No
Yes
NoYes
ShockBurstTM operation
Packet assembly
and TX Settling
Revision 1.1 Page 41 of 187
nRF24LU1+ Product Specification
Activate PTX mode by setting the rfce bit in the RFCON register high. If there is a packet present in the TX
FIFO the RF Transceiver enters TX mode and transmits the packet. If Auto Retransmit is enabled, the
state machine checks if the NO_ACK flag is set. If it is not set, the RF Transceiver enters RX mode to
receive an ACK packet. If the received ACK packet is empty, only the TX_DS IRQ is asserted. If the ACK
packet contains a payload, both TX_DS IRQ and RX_DR IRQ are asserted simultaneously before the RF
Transceiver returns to standby-I mode.
If the ACK packet is not received before timeout occurs, the RF Transceiver returns to standby-II mode. It
stays in standby-II mode until the ARD has elapsed. If the number of retransmits has not reached the ARC,
the RF Transceiver enters TX mode and transmits the last packet once more.
While executing the Auto Retransmit feature, the number of retransmits can reach the maximum number
defined in ARC. If this happens, the RF Transceiver asserts the MAX_RT IRQ and returns to standby-I
mode.
If the rfce bit in the RFCON register is high and the TX FIFO is empty, the RF Transceiver enters Standby-
II mode.
Revision 1.1 Page 42 of 187
nRF24LU1+ Product Specification
6.4.7.2 PRX operation
The flowchart in Figure 12. outlines how a RF Transceiver configured as a PRX behaves after entering
standby-I mode.
Note: ShockBurst™ operation is outlined with a dashed square.
Figure 12. PRX operations in Enhanced ShockBurst™
Activate PRX mode by setting the rfce bit in the RFCON register high. The RF Transceiver enters RX
mode and starts searching for packets. If a packet is received and Auto Acknowledgement is enabled, the
RF Transceiver decides if the packet is new or a copy of a previously received packet. If the packet is new
Start Primary RX
Standby-I mode
Is rfce =1?
TX mode
Transmit ACK
Is A uto
Acknowledgement
enabled?
RX mode
Yes
No
No_ACK set in
received packet?
Is the received
packet a new
packet?
TX Settling
Was there payload
attached with the last
ACK?
RX S ettling
Pending
payload in TX
FIFO?
Put payload in RX
FIFO and
set RX_DR IRQ
Valid packet
received?
Yes
No
No
Yes
Is rfce =1?
No
Yes
Put payload in RX
FIFO and
set RX_DR IRQ
Discard packet
No Yes
Yes
TX mode
Transmit ACK with
payload
TX Settling
No
Set TX_DS IRQ
Yes
No
YesNo
ShockBurstTM operation
RX FIFO
Full?
Received window =
RX_ADDR_Px
Packet disassembly
Monitor SETUP_AW wide
window of received bit
stream
Yes
No
Yes
Revision 1.1 Page 43 of 187
nRF24LU1+ Product Specification
the payload is made available in the RX FIFO and the RX_DR IRQ is asserted. If the last received packet
from the transmitter is acknowledged with an ACK packet with payload, the TX_DS IRQ indicates that the
PTX received the ACK packet with payload. If the No_ACK flag is not set in the received packet, the PRX
enters TX mode. If there is a pending payload in the TX FIFO it is attached to the ACK packet. After the
ACK packet is transmitted, the RF Transceiver returns to RX mode.
A copy of a previously received packet might be received if the ACK packet is lost. In this case, the PRX
discards the received packet and transmits an ACK packet before it returns to RX mode.
6.4.8 MultiCeiver™
MultiCeiver™ is a feature used in RX mode that contains a set of six parallel data pipes with unique
addresses. A data pipe is a logical channel in the physical RF channel. Each data pipe has its own physical
address (data pipe address) decoding in the RF Transceiver.
Figure 13. PRX using MultiCeiver™
The RF Transceiver configured as PRX (primary receiver) can receive data addressed to six different data
pipes in one frequency channel as shown in Figure 13. Each data pipe has its own unique address and can
be configured for individual behavior.
Up to six RF Transceivers configured as PTX can communicate with one RF Transceiver configured as
PRX. All data pipe addresses are searched for simultaneously. Only one data pipe can receive a packet at
a time. All data pipes can perform Enhanced ShockBurst™ functionality.
PRX
PTX1
PTX2
PTX3 PTX4
PTX5
PTX6
Data Pipe 1
Data Pipe 2
Data Pipe 3
Data Pipe 4
Data Pipe 5
Data Pipe 0
Frequency Channel N
Revision 1.1 Page 44 of 187
nRF24LU1+ Product Specification
The following settings are common to all data pipes:
• CRC enabled/disabled (CRC always enabled when Enhanced ShockBurst™ is enabled)
• CRC encoding scheme
• RX address width
• Frequency channel
• Air data rate
•LNA gain
The data pipes are enabled with the bits in the EN_RXADDR register. By default only data pipe 0 and 1 are
enabled. Each data pipe address is configured in the RX_ADDR_PX registers.
Note: Always ensure that none of the data pipes have the same address.
Each pipe can have up to a 5 byte configurable address. Data pipe 0 has a unique 5 byte address. Data
pipes 1-5 share the four most significant address bytes. The LSByte must be unique for all six pipes. Fig-
ure 14. is an example of how data pipes 0-5 are addressed.
Figure 14. Addressing data pipes 0-5
0xC2 0xC20xC20xC2
0xC2 0xC20xC20xC2
0xC2 0xC20xC20xC2
0xC2 0xC20xC20xC2
Byte 4 Byte 0Byte 1Byte 2Byte 3
0xC2
0xC2
0xC20xC20xC2
0xC3
0xC4
0xC5
0xC6
Data pipe 1
(RX_ADDR_P1)
Data pipe 2
(RX_ADDR_P2)
Data pipe 3
(RX_ADDR_P3)
Data pipe 4
(RX_ADDR_P4)
Data pipe 5
(RX_ADDR_P5)
0xE7 0x770x350xF00xD3Data pipe 0
(RX_ADDR_P0)
Revision 1.1 Page 45 of 187
nRF24LU1+ Product Specification
The PRX, using MultiCeiver™ and Enhanced ShockBurst™, receives packets from more than one PTX. To
ensure that the ACK packet from the PRX is transmitted to the correct PTX, the PRX takes the data pipe
address where it received the packet and uses it as the TX address when transmitting the ACK packet.
Figure 15. is an example of an address configuration for the PRX and PTX. On the PRX the RX_ADDR_Pn,
defined as the pipe address, must be unique. On the PTX the TX_ADDR must be the same as the
RX_ADDR_P0 and as the pipe address for the designated pipe.
Figure 15. Example of data pipe addressing in MultiCeiver™
Only when a data pipe receives a complete packet can other data pipes begin to receive data. When mul-
tiple PTXs are transmitting to a PRX, the ARD can be used to skew the auto retransmission so that they
only block each other once.
6.4.9 Enhanced ShockBurst™ timing
This section describes the timing sequence of Enhanced ShockBurst™ and how all modes are initiated
and operated. The Enhanced ShockBurst™ timing is controlled through the Data and Control interface.
The RF Transceiver can be set to static modes or autonomous modes where the internal state machine
PRX
PTX1
PTX2
PTX3 PTX4
PTX5
PTX6
Data Pipe 1
Data Pipe 2
Data Pipe 3
Data Pipe 4
Data Pipe 5
Data Pipe 0
Frequency Channel N
TX_ADDR: 0xB3B4B5B605
RX_ADDR_P0:0xB3B4B5B605
TX_ADDR: 0xB3B4B5B60F
RX_ADDR_P0:0xB3B4B5B60F
TX_ADDR: 0xB3B4B5B6A3
RX_ADDR_P0:0xB3B4B5B6A3
TX_ADDR: 0xB3B4B5B6CD
RX_ADDR_P0:0xB3B4B5B6CD
TX_ADDR: 0xB3B4B5B6F1
RX_ADDR_P0:0xB3B4B5B6F1
TX_ADDR: 0x7878787878
RX_ADDR_P0:0x7878787878
Addr Data Pipe 0 (RX_ADDR_P0): 0x7878787878
Addr Data Pipe 1 (RX_ADDR_P1): 0xB3B4B5B6F1
Addr Data Pipe 2 (RX_ADDR_P2): 0xB3B4B5B6CD
Addr Data Pipe 3 (RX_ADDR_P3): 0xB3B4B5B6A3
Addr Data Pipe 4 (RX_ADDR_P4): 0xB3B4B5B60F
Addr Data Pipe 5 (RX_ADDR_P5): 0xB3B4B5B605
Revision 1.1 Page 46 of 187
nRF24LU1+ Product Specification
controls the events. Each autonomous mode/sequence ends with a RFIRQ interrupt. All the interrupts are
indicated as IRQ events in the timing diagrams.
Figure 16. Transmitting one packet with NO_ACK on
The following equations calculate various timing measurements:
Table 18. Timing equations
Symbol Description Equation
TOA Time on-air
TACK Time on-air Ack
TUL Time Upload
TESB Time Enhanced Shock-
Burst™ cycle
TESB = TUL + 2 . Tstby2a + TOA + TACK + TIRQ
1 IRQ if No Ack is on.
TIRQ = 8.2 µs @ 1 Mbps, TIRQ = 6.0 µs @ 2 Mbps
Standby 1 PLL Lock TX
PTX IRQ
PTX MODE
UL
PTX rfce
PTX SPI
TOA
130 µsTUL
IRQ:
TX DS1
Standby-I
TIRQ
>10 µs
[] [][ ] [] []
[]
s
bit
ratedataair
bitbytesorbytesNbytesorbyte
byte
bit
ratedataair
lengthpacket
TfieldcontrolpacketCRCpayloadaddresspreamble
OA
92154,318 +
⎟
⎠
⎞
⎜
⎝
⎛+++⋅
⎥
⎦
⎤
⎢
⎣
⎡
==
[] [ ][ ] [ ] []
[]
s
bit
ratedataair
bitbytesorbytesNbytesorbyte
byte
bit
ratedataair
lengthpacket
TfieldcontrolpacketCRCpayloadaddresspreamble
ACK
92154,318 +
⎟
⎠
⎞
⎜
⎝
⎛+++⋅
⎥
⎦
⎤
⎢
⎣
⎡
==
[]
[]
s
bit
ratedataSPI
bytesN
byte
bit
ratedataSPI
lengthpayload
Tpayload
UL
⋅
⎥
⎦
⎤
⎢
⎣
⎡
==
8
Revision 1.1 Page 47 of 187
nRF24LU1+ Product Specification
Figure 17. Timing of Enhanced ShockBurst™ for one packet upload (2 Mbps)
In Figure 17. the transmission and acknowledgement of a packet is shown. The PRX operation activates
RX mode (rfce=1), and the PTX operation is activated in TX mode (rfce=1 for minimum 10 µs). After
130 µs the transmission starts and finishes after the elapse of TOA.
When the transmission ends the PTX operation automatically switches to RX mode to wait for the ACK
packet from the PRX operation. When the PRX operation receives the packet it sets the interrupt for the
host MCU and switches to TX mode to send an ACK. After the PTX operation receives the ACK packet it
sets the interrupt to the MCU and clears the packet from the TX FIFO.
Standby 1 PLL Lock TX Standby 1
PTX IRQ
PTX MODE
UL
PTX rfce
PTX SPI
TOA
130 µsTUL
PLL Lock
TX
RX
PLL Lock PLL Lock PLL LockPRX MODE
PRX IRQ
PRX rfce
RX
PRX SPI
TESB Cycle
RX
IRQ:
TX DS
TIRQ
Standby 1
>10 µs
130 µs 130 µs 130 µsTACK
IRQ:RX DR/DL
TIRQ
Revision 1.1 Page 48 of 187
nRF24LU1+ Product Specification
In Figure 18. the PTX timing of a packet transmission is shown when the first ACK packet is lost. To see
the complete transmission when the ACK packet fails see Figure 21.
Figure 18. Timing of Enhanced ShockBurst™ when the first ACK packet is lost (2 Mbps)
6.4.10 Enhanced ShockBurst™ transaction diagram
This section describes several scenarios for the Enhanced ShockBurst™ automatic transaction handling.
The call outs in this section’s figures indicate the IRQs and other events. For MCU activity the event may
be placed at a different timeframe.
Note: The figures in this section indicate the earliest possible download (DL) of the packet to the
MCU and the latest possible upload (UL) of payload to the transmitter.
Standby I PLL Lock TX TX
PTX IRQ
PTX MODE
UL
PTX RFCE
PTX SPI
TOA
130 µsTUL
PLL Lock
>10 µs ARD
Standby IIRX
250 µs
max
PLL Lock
130 µs
130 µs
Revision 1.1 Page 49 of 187
nRF24LU1+ Product Specification
6.4.10.1 Single transaction with ACK packet and interrupts
In Figure 19. the basic auto acknowledgement is shown. After the packet is transmitted by the PTX and
received by the PRX the ACK packet is transmitted from the PRX to the PTX. The RX_DR IRQ is asserted
after the packet is received by the PRX, whereas the TX_DS IRQ is asserted when the packet is acknowl-
edged and the ACK packet is received by the PTX.
Figure 19. TX/RX cycles with ACK and the according interrupts
6.4.10.2 Single transaction with a lost packet
Figure 20. is a scenario where a retransmission is needed due to loss of the first packet transmit. After the
packet is transmitted, the PTX enters RX mode to receive the ACK packet. After the first transmission, the
PTX waits a specified time for the ACK packet, if it is not in the specific time slot the PTX retransmits the
packet as shown in Figure 20.
Figure 20. TX/RX cycles with ACK and the according interrupts when the first packet transmit fails
1 Radio Turn Around Delay
TX:PID=1 RX
PTX
PRX RX ACK:PID=1
UL
MCU PTX
130us1
IRQ
DL
MCU PRX
Packet received
IRQ: RX DR (PID=1)
Ack received
IRQ:TX DS (PID=1)
TX:PID=1 RX
PTX
PRX RX ACK:PID=1
DL
MCU PRX
UL
MCU PTX
130us1
TX:PID=1 RX
IRQ
ARD
Auto retransmit delay
elapsed
No address detected.
RX off to save current
Retransmit of packet
PID=1
Packet PID=1 lost
during transmission
Packet received.
IRQ: RX DR (PID=1)
ACK received
IRQ: TX DS (PID=1)
130us1130us1
1 Radio Turn Around Delay
Revision 1.1 Page 50 of 187
nRF24LU1+ Product Specification
When an address is detected the PTX stays in RX mode until the packet is received. When the retransmit-
ted packet is received by the PRX (see Figure 20. ) , the RX_DR IRQ is asserted and an ACK is transmit-
ted back to the PTX. When the ACK is received by the PTX, the TX_DS IRQ is asserted.
6.4.10.3 Single transaction with a lost ACK packet
Figure 21. is a scenario where a retransmission is needed after a loss of the ACK packet. The correspond-
ing interrupts are also indicated.
Figure 21. TX/RX cycles with ACK and the according interrupts when the ACK packet fails
6.4.10.4 Single transaction with ACK payload packet
Figure 22. is a scenario of the basic auto acknowledgement with payload. After the packet is transmitted by
the PTX and received by the PRX the ACK packet with payload is transmitted from the PRX to the PTX.
The RX_DR IRQ is asserted after the packet is received by the PRX, whereas on the PTX side the TX_DS
IRQ is asserted when the ACK packet is received by the PTX. On the PRX side, the TX_DS IRQ for the
ACK packet payload is asserted after a new packet from PTX is received. The position of the IRQ in Figure
22. shows where the MCU can respond to the interrupt.
Figure 22. TX/RX cycles with ACK Payload and the according interrupts
TX:PID=1 RX
PTX
PRX RX ACK:PID=1
DL
MCU PRX
UL
MCU PTX
130us1
TX:PID=1 RX
IRQ
ARD
Auto retransmit delay
elapsed
No address detected.
RX off to save current
Retransmit of packet
PID=1
ACK PID=1 lost
during transmission
Packet received.
IRQ: RX DR (PID=1)
ACK received
IRQ: TX DS (PID=1)
ACK:PID=1 RX
Packet detected as
copy of previous,
discarded
130us1130us1
1 Radio Turn Around Delay
1 Radio Turn Around Delay
2 Uploading Payload for Ack Packet
3 Delay defined by MCU on PTX side, ≥ 130 µs
TX:PID=1 RX
PTX
PRX RX
MCU PRX
UL1
MCU PTX
TX:PID=2
DL
IRQ
ACK received
IRQ: TX DS (PID=1)
RX DR (ACK1PAY)
Transmit of packet
PID=2
Packet received.
IRQ: RX DR (PID=1)
RX
Packet received.
IRQ: RX DR (PID=2)
TX DS (ACK1PAY)
DL DL
IRQ
UL2
UL2
130 µs1≥130 µs3
ACK1 PAY
Revision 1.1 Page 51 of 187
nRF24LU1+ Product Specification
6.4.10.5 Single transaction with ACK payload packet and lost packet
Figure 23. is a scenario where the first packet is lost and a retransmission is needed before the RX_DR IRQ
on the PRX side is asserted. For the PTX both the TX_DS and RX_DR IRQ are asserted after the ACK
packet is received. After the second packet (PID=2) is received on the PRX side both the RX_DR (PID=2)
and TX_DS (ACK packet payload) IRQ are asserted.
Figure 23. TX/RX cycles and the according interrupts when the packet transmission fails
6.4.10.6 Two transactions with ACK payload packet and the first ACK packet lost
Figure 24. TX/RX cycles with ACK Payload and the according interrupts when the ACK packet fails
In Figure 24. the ACK packet is lost and a retransmission is needed before the TX_DS IRQ is asserted, but
the RX_DR IRQ is asserted immediately. The retransmission of the packet (PID=1) results in a discarded
packet. For the PTX both the TX_DS and RX_DR IRQ are asserted after the second transmission of ACK,
which is received. After the second packet (PID=2) is received on the PRX both the RX_DR (PID=2) and
TX_DS (ACK1PAY) IRQ is asserted. The callouts explains the different events and interrupts.
TX:PID=1 RX
PTX
PRX RX
DL
MCU PRX
UL1
MCU PTX
130us1
TX:PID=1 RX
ARD
No address detected .
RX off to save current
Retransmit of packet
PID=1
ACK received
IRQ: TX DS (PID=1)
RX DR (ACK1PAY)
TX:PID=2
RXACK1 PAY
Packet received.
IRQ: RX DR (PID=2)
TX DS (ACK1PAY)
Auto retransmit delay
elapsed
130us1130us1
Packet PID=1 lost
during transmission
Packet received.
IRQ: RX DR (PID=1)
DLUL2
UL2 DL
IRQ
≥130us3
1 Radio Turn Around Delay
2 Uploading Paylod for Ack Packet
3 Delay defined by MCU on PTX side, ≥ 130us
TX:PID=1 RX
PTX
PRX RX
MCU PRX
UL1
MCU PTX
130us1
TX:PID=1 RX
ARD
No address detected.
RX off to save current
Retransmit of packet
PID=1
ACK PID=1 lost
during transmission
Packet received.
IRQ: RX DR (PID=1)
ACK received
IRQ: TX DS (PID=1)
RX DR (ACK1PAY)
RXACK1 PAY
TX:PID=2
RX
UL2
ACK1 PAY
Packet received.
IRQ: RX DR (PID=2)
TX DS (ACK1PAY)
Auto retransmit delay
elapsed
130us1130us1
DLUL12
DL
IRQ
DL
IRQ
UL22
RX
ACK received
IRQ: TX DS (PID=2)
RX DR (ACK2PAY)
ACK2 PAY
130us1
TX:PID=3
RX
Packet received.
IRQ: RX DR (PID=3)
TX DS (ACK2PAY)
UL3
≥130us3≥130us3
Packet detected as
copy of previous,
discarded
1 Radio Turn Around Delay
2 Uploading Payload for Ack Packet
3 Delay defined by MCU on PTX side, ≥ 130us
Revision 1.1 Page 52 of 187
nRF24LU1+ Product Specification
6.4.10.7 Two transactions where max retransmissions is reached
Figure 25. TX/RX cycles with ACK Payload and the according interrupts when the transmission fails. ARC
is set to 2.
MAX_RT IRQ is asserted if the auto retransmit counter (ARC_CNT) exceeds the programmed maximum limit
(ARC). In Figure 25. the packet transmission ends with a MAX_RT IRQ. The payload in TX FIFO is NOT
removed and the MCU decides the next step in the protocol. A toggle of the rfce bit in the RFCON register
starts a new transmitting sequence of the same packet. The payload can be removed from the TX FIFO
using the FLUSH_TX command.
6.4.11 Compatibility with ShockBurst™
You must disable Enhanced ShockBurst™ for backward compatibility with the nRF2401A, nRF2402,
nRF24E1 and, nRF24E2. Set the register EN_AA = 0x00 and ARC = 0 to disable Enhanced ShockBurst™.
In addition, the RF Transceiver air data rate must be set to 1 Mbps or 250 kbps.
6.4.11.1 ShockBurst™ packet format
The ShockBurst™ packet format is described in this chapter. Figure 26. shows the packet format with MSB
to the left.
Figure 26. A ShockBurst™ packet compatible with nRF2401/nRF2402/nRF24E1/nRF24E2 devices.
The ShockBurst™ packet format has a preamble, address, payload and CRC field that are the same as
the Enhanced ShockBurst™ packet format described in section 6.4.3 on page 33.
TX:PID=1 RX
PTX
PRX RX
MCU PRX
UL
MCU PTX
130us1
ARD
No address detected.
RX off to save current
Retransmit of packet
PID=1
ACK PID=1 lost
during transmission
Packet received.
IRQ: RX DR (PID=1)
RXACK1 PAY
Auto retransmit delay
elapsed
130us1130us1
DLUL2
IRQ
≥130us3
RX
No address detected.
RX off to save current
TX:PID=1 TX:PID=1 RX
130us1
ARD
ACK PID=1 lost
during transmission
ACK1 PAY
No address detected.
RX off to save current.
IRQ:MAX_RT reached
130us1
RX
ACK PID=1 lost
during transmission
Packet detected as
copy of previous,
discarded
1 Radio Turn Around Delay
2 Uploading Paylod for Ack Packet
3 Delay defined by MCU on PTX side, ≥ 130us
Preamble 1 byte Address 3-5 byte Payload 1 - 32 byte CRC 1-2
byte
Revision 1.1 Page 53 of 187
nRF24LU1+ Product Specification
The differences between the ShockBurst™ packet and the Enhanced ShockBurst™ packet are:
• The 9-bit Packet Control Field is not present in the ShockBurst™ packet format.
• The CRC is optional in the ShockBurst™ packet format and is controlled by the EN_CRC bit in the
CONFIG register.
6.5 Data and control interface
The data and control interface gives you access to all the features in the RF Transceiver. Compared to the
standalone nRF24L01+ chip, SFR registers are used instead of port pins, so that the SFR RCON bits
rfcsn, rfce and rfcken control the CSN, CE and CKEN pins of the standalone component.
6.5.1 SFR registers
The MCU uses an internal SPI to communicate with the RF Transceiver. This SPI is controlled by the SFR
registers shown in the tables below.
Table 19. RFDAT register
Table 20. RFCTL register
Table 21. RFCON register
Address Reset value Bit Name R/W Function
0xE5 0x00 data RW SPI data input/output
Address Reset value Bit Name R/W Function
0xE6 0x00 7:5 - Must be zero
4 ss RW SPI enable:
0: disable, 1: enable
3:0 rfctl RW Divider factor from MCU clock (Cclk) to
SPI clock frequency
000X: 1/2 of Cclk frequency
0010: 1/4 of Cclk frequency
0011: 1/8 of Cclk frequency
0100: 1/16 of Cclk frequency
0101: 1/32 of Cclk frequency
other: 1/64 of Cclk frequency
Address Reset
value Bit Name R/W Function
0x90 0x02 7:3 - Reserved
2 rfcken RW RF Clock Enable (16 MHz)
1 rfcsn RW RF SPI CSN 0: enabled 1: disabled
0 rfce RW RF CE 1: enabled 0: disabled
Revision 1.1 Page 54 of 187
nRF24LU1+ Product Specification
6.5.2 SPI operation
This section describes the SPI commands and timing.
6.5.2.1 SPI commands
The SPI commands are shown in Table 22. Every new command must be started by writing 0 to rfcsn in
the RFCON register.
The SPI command is transferred to RF Transceiver by writing the command to the RFDAT register. After
the first transfer the RF Transceiver's STATUS register can be read from RFDAT when the transfer is com-
pleted.
The serial shifting SPI commands is in the following format:
<Command word: MSBit to LSBit (one byte)>
<Data bytes: LSByte to MSByte, MSBit in each byte first>
Command name Command
word (binary) # Data bytes Operation
R_REGISTER 000A AAAA 1 to 5
LSByte first
Read command and status registers. AAAAA =
5 bit Register Map Address
W_REGISTER 001A AAAA 1 to 5
LSByte first
Write command and status registers. AAAAA = 5
bit Register Map Address
Executable in power down or standby modes
only.
R_RX_PAYLOAD 0110 0001 1 to 32
LSByte first
Read RX-payload: 1 – 32 bytes. A read operation
always starts at byte 0. Payload is deleted from
FIFO after it is read. Used in RX mode.
W_TX_PAYLOAD 1010 0000 1 to 32
LSByte first
Write TX-payload: 1 – 32 bytes. A write operation
always starts at byte 0 used in TX payload.
FLUSH_TX 1110 0001 0 Flush TX FIFO, used in TX mode
FLUSH_RX 1110 0010 0 Flush RX FIFO, used in RX mode
Should not be executed during transmission of
acknowledge, that is, acknowledge package will
not be completed.
REUSE_TX_PL 1110 0011 0 Used for a PTX operation
Reuse last transmitted payload.
TX payload reuse is active until
W_TX_PAYLOAD or FLUSH TX is executed. TX
payload reuse must not be activated or deacti-
vated during package transmission.
R_RX_PL_WIDa0110 0000 1 Read RX payload width for the top
R_RX_PAYLOAD in the RX FIFO.
Note: Flush RX FIFO if the read value is larger
than 32 bytes.
Revision 1.1 Page 55 of 187
nRF24LU1+ Product Specification
Table 22. Command set for the RF Transceiver SPI
The W_REGISTER and R_REGISTER commands operate on single or multi-byte registers. When accessing
multi-byte registers read or write to the MSBit of LSByte first. You can terminate the writing before all bytes
in a multi-byte register are written, leaving the unwritten MSByte(s) unchanged. For example, the LSByte
of RX_ADDR_P0 can be modified by writing only one byte to the RX_ADDR_P0 register. The content of the
status register is always read to MISO after a high to low transition on CSN.
Note: The 3-bit pipe information in the STATUS register is updated during the RFIRQ high to low
transition. The pipe information is unreliable if the STATUS register is read during an RFIRQ
high to low transition.
6.5.3 Data FIFO
The data FIFOs store transmitted payloads (TX FIFO) or received payloads that are ready to be clocked
out (RX FIFO). The FIFOs are accessible in both PTX mode and PRX mode.
The following FIFOs are present in the RF Transceiver:
• TX three level, 32 byte FIFO
• RX three level, 32 byte FIFO
Both FIFOs have a controller and are accessible through the SPI by using dedicated SPI commands. A TX
FIFO in PRX can store payloads for ACK packets to three different PTX operations. If the TX FIFO con-
tains more than one payload to a pipe, payloads are handled using the first in - first out principle. The TX
FIFO in a PRX is blocked if all pending payloads are addressed to pipes where the link to the PTX is lost.
In this case, the MCU can flush the TX FIFO using the FLUSH_TX command.
The RX FIFO in PRX can contain payloads from up to three different PTX operations and a TX FIFO in
PTX can have up to three payloads stored.
You can write to the TX FIFO using these three commands; W_TX_PAYLOAD and
W_TX_PAYLOAD_NO_ACK in PTX mode and W_ACK_PAYLOAD in PRX mode. All three commands provide
access to the TX_PLD register.
The RX FIFO can be read by the command R_RX_PAYLOAD in PTX and PRX mode. This command pro-
vides access to the RX_PLD register.
W_ACK_PAYLOADa1010 1PPP 1 to 32
LSByte first
Used in RX mode.
Write Payload to be transmitted together with
ACK packet on PIPE PPP. (PPP valid in the
range from 000 to 101). Maximum three ACK
packet payloads can be pending. Payloads with
same PPP are handled using first in - first out
principle. Write payload: 1– 32 bytes. A write
operation always starts at byte 0.
W_TX_PAYLOAD_NO
ACK
1011 0000 1 to 32
LSByte first
Used in TX mode. Disables AUTOACK on this
specific packet.
NOP 1111 1111 0 No Operation. Might be used to read the STATUS
register
a. The bits in the FEATURE register shown in Table 23. have to be set.
Command name Command
word (binary) # Data bytes Operation
Revision 1.1 Page 56 of 187
nRF24LU1+ Product Specification
The payload in TX FIFO in a PTX is not removed if the MAX_RT IRQ is asserted.
Figure 27. FIFO (RX and TX) block diagram
You can read if the TX and RX FIFO are full or empty in the FIFO_STATUS register. TX_REUSE (also avail-
able in the FIFO_STATUS register) is set by the SPI command REUSE_TX_PL, and is reset by the SPI
commands W_TX_PAYLOAD or FLUSH TX.
6.5.4 Interrupt
The RF Transceiver can send interrupts to the MCU. The interrupt (RFIRQ) is activated when TX_DS,
RX_DR or MAX_RT are set high by the state machine in the STATUS register. RFIRQ is deactivated when
the MCU writes '1' to the interrupt source bit in the STATUS register. The interrupt mask in the CONFIG reg-
ister is used to select the IRQ sources that are allowed to activate RFIRQ. By setting one of the mask bits
high, the corresponding interrupt source is disabled. By default all interrupt sources are enabled.
Note: The 3-bit pipe information in the STATUS register is updated during the RFIRQ high to low
transition. The pipe information is unreliable if the STATUS register is read during a RFIRQ
high to low transition.
Data
TX FIFO
32 byte
32 byte
32 byte
TX FIFO Controller
Data
Control
SPI
command
decoder
RX FIFO
32 byte
32 byte
32 byte
RX FIFO Controller
Data Data
Control
SPI
Revision 1.1 Page 57 of 187
nRF24LU1+ Product Specification
6.6 Register map
You can configure and control the radio (using read and write commands) by accessing the register map
through the SPI.
6.6.1 Register map table
All undefined bits in the table below are redundant. They are read out as '0'.
Note: Addresses 18 to 1B are reserved for test purposes, altering them makes the chip malfunction.
Address
(Hex) Mnemonic Bit Reset
Value Type Description
00 CONFIG Configuration Register
Reserved 7 0 R/W Only '0' allowed
MASK_RX_DR 6 0 R/W Mask interrupt caused by RX_DR
1: Interrupt not reflected on the RFIRQ
0: Reflect RX_DR as active low on RFIRQ
MASK_TX_DS 5 0 R/W Mask interrupt caused by TX_DS
1: Interrupt not reflected on the RFIRQ
0: Reflect TX_DS as active low interrupt on RFIRQ
MASK_MAX_RT 4 0 R/W Mask interrupt caused by MAX_RT
1: Interrupt not reflected on RFIRQ
0: Reflect MAX_RT as active low on RFIRQ
EN_CRC 3 1 R/W Enable CRC. Forced high if one of the bits in the
EN_AA is high
CRCO 2 0 R/W CRC encoding scheme
'0' - 1 byte
'1' – 2 bytes
PWR_UP 1 0 R/W 1: POWER UP, 0:POWER DOWN
PRIM_RX 0 0 R/W RX/TX control
1: PRX, 0: PTX
01 EN_AA
Enhanced
ShockBurst™
Enable ‘Auto Acknowledgment’ Function Disable
this functionality to be compatible with nRF2401.
Reserved 7:6 00 R/W Only '00' allowed
ENAA_P5 5 1 R/W Enable auto acknowledgement data pipe 5
ENAA_P4 4 1 R/W Enable auto acknowledgement data pipe 4
ENAA_P3 3 1 R/W Enable auto acknowledgement data pipe 3
ENAA_P2 2 1 R/W Enable auto acknowledgement data pipe 2
ENAA_P1 1 1 R/W Enable auto acknowledgement data pipe 1
ENAA_P0 0 1 R/W Enable auto acknowledgement data pipe 0
02 EN_RXADDR Enabled RX Addresses
Reserved 7:6 00 R/W Only '00' allowed
ERX_P5 5 0 R/W Enable data pipe 5.
ERX_P4 4 0 R/W Enable data pipe 4.
ERX_P3 3 0 R/W Enable data pipe 3.
ERX_P2 2 0 R/W Enable data pipe 2.
ERX_P1 1 1 R/W Enable data pipe 1.
ERX_P0 0 1 R/W Enable data pipe 0.
Revision 1.1 Page 58 of 187
nRF24LU1+ Product Specification
03 SETUP_AW Setup of Address Widths
(common for all data pipes)
Reserved 7:2 000000 R/W Only '000000' allowed
AW 1:0 11 R/W RX/TX Address field width
'00' - Illegal
'01' - 3 bytes
'10' - 4 bytes
'11' – 5 bytes
LSByte is used if address width is below 5 bytes
04 SETUP_RETR Setup of Automatic Retransmission
ARDa7:4 0000 R/W Auto Retransmit Delay
‘0000’ – Wait 250 µs
‘0001’ – Wait 500 µs
‘0010’ – Wait 750 µs
……..
‘1111’ – Wait 4000 µs
(Delay defined from end of transmission to start of
next transmission)b
ARC 3:0 0011 R/W Auto Retransmit Count
‘0000’ –Re-Transmit disabled
‘0001’ – Up to 1 Re-Transmit on fail of AA
……
‘1111’ – Up to 15 Re-Transmit on fail of AA
05 RF_CH RF Channel
Reserved 7 0 R/W Only '0' allowed
RF_CH 6:0 0000010 R/W Sets the frequency channel the RF Transceiver
operates on
06 RF_SETUP RF Setup Register
CONT_WAVE 7 0 R/W Enables continuous carrier transmit when high.
Reserved 6 0 R/W Only '0' allowed
RF_DR_LOW 5 0 R/W Set RF Data Rate to 250 kbps. See RF_DR_HIGH
for encoding.
PLL_LOCK 4 0 R/W Force PLL lock signal. Only used in test
RF_DR_HIGH 3 1 R/W Select between the high speed data rates. This bit
is don’t care if RF_DR_LOW is set.
Encoding:
RF_DR_LOW, RF_DR_HIGH:
‘00’ – 1 Mbps
‘01’ – 2 Mbps
‘10’ – 250 kbps
‘11’ – Reserved
RF_PWR 2:1 11 R/W Set RF output power in TX mode
'00' – -18dBm
'01' – -12dBm
'10' – -6dBm
'11' – 0dBm
Address
(Hex) Mnemonic Bit Reset
Value Type Description
Revision 1.1 Page 59 of 187
nRF24LU1+ Product Specification
Obsolete 0 Don’t care
07 STATUS Status Register (In parallel to the SPI command
word applied on the MOSI pin, the STATUS register
is shifted serially out on the MISO pin)
Reserved 7 0 R/W Only '0' allowed
RX_DR 6 0 R/W Data Ready RX FIFO interrupt. Asserted when
new data arrives RX FIFOc.
Write 1 to clear bit.
TX_DS 5 0 R/W Data Sent TX FIFO interrupt. Asserted when
packet transmitted on TX. If AUTO_ACK is acti-
vated, this bit is set high only when ACK is
received.
Write 1 to clear bit.
MAX_RT 4 0 R/W Maximum number of TX retransmits interrupt
Write 1 to clear bit. If MAX_RT is asserted it must
be cleared to enable further communication.
RX_P_NO 3:1 111 R Data pipe number for the payload available for
reading from RX_FIFO
000-101: Data Pipe Number
110: Not Used
111: RX FIFO Empty
TX_FULL 0 0 R TX FIFO full flag.
1: TX FIFO full.
0: Available locations in TX FIFO.
08 OBSERVE_TX Transmit observe register
PLOS_CNT 7:4 0 R Count lost packets. The counter is overflow pro-
tected to 15, and discontinues at max until reset.
The counter is reset by writing to RF_CH.
ARC_CNT 3:0 0 R Count retransmitted packets. The counter is reset
when transmission of a new packet starts.
09 RPD
Reserved 7:1 000000 R
RPD 0 0 R Received Power Detector. This register is called
CD (Carrier Detect) in the nRF24L01. The name is
different in the RF Transceiver due to the different
input power level threshold for this bit. See section
6.3.4 on page 31.
0A RX_ADDR_P0 39:0 0xE7E7E
7E7E7
R/W Receive address data pipe 0. 5 Bytes maximum
length. (LSByte is written first. Write the number of
bytes defined by SETUP_AW)
0B RX_ADDR_P1 39:0 0xC2C2C
2C2C2
R/W Receive address data pipe 1. 5 Bytes maximum
length. (LSByte is written first. Write the number of
bytes defined by SETUP_AW)
0C RX_ADDR_P2 7:0 0xC3 R/W Receive address data pipe 2. Only LSB. MSBytes
are equal to RX_ADDR_P1 39:8
0D RX_ADDR_P3 7:0 0xC4 R/W Receive address data pipe 3. Only LSB. MSBytes
are equal to RX_ADDR_P139:8
Address
(Hex) Mnemonic Bit Reset
Value Type Description
Revision 1.1 Page 60 of 187
nRF24LU1+ Product Specification
0E RX_ADDR_P4 7:0 0xC5 R/W Receive address data pipe 4. Only LSB. MSBytes
are equal to RX_ADDR_P139:8
0F RX_ADDR_P5 7:0 0xC6 R/W Receive address data pipe 5. Only LSB. MSBytes
are equal to RX_ADDR_P139:8
10 TX_ADDR 39:0 0xE7E7E
7E7E7
R/W Transmit address. Used for a PTX operation only.
(LSByte is written first)
Set RX_ADDR_P0 equal to this address to handle
automatic acknowledge if this is a PTX operation
with Enhanced ShockBurst™ enabled.
11 RX_PW_P0
Reserved 7:6 00 R/W Only '00' allowed
RX_PW_P0 5:0 0 R/W Number of bytes in RX payload in data pipe 0 (1 to
32 bytes).
0 Pipe not used
1 = 1 byte
…
32 = 32 bytes
12 RX_PW_P1
Reserved 7:6 00 R/W Only '00' allowed
RX_PW_P1 5:0 0 R/W Number of bytes in RX payload in data pipe 1 (1 to
32 bytes).
0 Pipe not used
1 = 1 byte
…
32 = 32 bytes
13 RX_PW_P2
Reserved 7:6 00 R/W Only '00' allowed
RX_PW_P2 5:0 0 R/W Number of bytes in RX payload in data pipe 2 (1 to
32 bytes).
0 Pipe not used
1 = 1 byte
…
32 = 32 bytes
14 RX_PW_P3
Reserved 7:6 00 R/W Only '00' allowed
RX_PW_P3 5:0 0 R/W Number of bytes in RX payload in data pipe 3 (1 to
32 bytes).
0 Pipe not used
1 = 1 byte
…
32 = 32 bytes
15 RX_PW_P4
Reserved 7:6 00 R/W Only '00' allowed
Address
(Hex) Mnemonic Bit Reset
Value Type Description
Revision 1.1 Page 61 of 187
nRF24LU1+ Product Specification
RX_PW_P4 5:0 0 R/W Number of bytes in RX payload in data pipe 4 (1 to
32 bytes).
0 Pipe not used
1 = 1 byte
…
32 = 32 bytes
16 RX_PW_P5
Reserved 7:6 00 R/W Only '00' allowed
RX_PW_P5 5:0 0 R/W Number of bytes in RX payload in data pipe 5 (1 to
32 bytes).
0 Pipe not used
1 = 1 byte
…
32 = 32 bytes
17 FIFO_STATUS FIFO Status Register
Reserved 7 0 R/W Only '0' allowed
TX_REUSE 6 0 R Used for a PTX operation
Pulse the rfce high for at least 10µs to Reuse last
transmitted payload. TX payload reuse is active
until W_TX_PAYLOAD or FLUSH TX is executed.
TX_REUSE is set by the SPI command
REUSE_TX_PL, and is reset by the SPI commands
W_TX_PAYLOAD or FLUSH TX
TX_FULL 5 0 R TX FIFO full flag. 1: TX FIFO full. 0: Available loca-
tions in TX FIFO.
TX_EMPTY 4 1 R TX FIFO empty flag.
1: TX FIFO empty.
0: Data in TX FIFO.
Reserved 3:2 00 R/W Only '00' allowed
RX_FULL 1 0 R RX FIFO full flag.
1: RX FIFO full.
0: Available locations in RX FIFO.
RX_EMPTY 0 1 R RX FIFO empty flag.
1: RX FIFO empty.
0: Data in RX FIFO.
N/A ACK_PLD 255:0 X W Written by separate SPI command
ACK packet payload to data pipe number PPP
given in SPI command.
Used in RX mode only.
Maximum three ACK packet payloads can be
pending. Payloads with same PPP are handled
first in first out.
N/A TX_PLD 255:0 X W Written by separate SPI command TX data pay-
load register 1 - 32 bytes.
This register is implemented as a FIFO with three
levels.
Used in TX mode only.
Address
(Hex) Mnemonic Bit Reset
Value Type Description
Revision 1.1 Page 62 of 187
nRF24LU1+ Product Specification
Table 23. Register map of the RF Transceiver
N/A RX_PLD 255:0 X R Read by separate SPI command.
RX data payload register. 1 - 32 bytes.
This register is implemented as a FIFO with three
levels.
All RX channels share the same FIFO.
1C DYNPD Enable dynamic payload length
Reserved 7:6 0 R/W Only ‘00’ allowed
DPL_P5 5 0 R/W Enable dynamic payload length data pipe 5.
(Requires EN_DPL and ENAA_P5)
DPL_P4 4 0 R/W Enable dynamic payload length data pipe 4.
(Requires EN_DPL and ENAA_P4)
DPL_P3 3 0 R/W Enable dynamic payload length data pipe 3.
(Requires EN_DPL and ENAA_P3)
DPL_P2 2 0 R/W Enable dynamic payload length data pipe 2.
(Requires EN_DPL and ENAA_P2)
DPL_P1 1 0 R/W Enable dynamic payload length data pipe 1.
(Requires EN_DPL and ENAA_P1)
DPL_P0 0 0 R/W Enable dynamic payload length data pipe 0.
(Requires EN_DPL and ENAA_P0)
1D FEATURE R/W Feature Register
Reserved 7:3 0 R/W Only ‘00000’ allowed
EN_DPL 2 0 R/W Enables Dynamic Payload Length
EN_ACK_PAYd1 0 R/W Enables Payload with ACK
EN_DYN_ACK 0 0 R/W Enables the W_TX_PAYLOAD_NOACK command
a. Please take care when setting this parameter. If the ACK payload is more than 15 byte in 2 Mbps mode
the ARD must be 500 µs or more, if the ACK payload is more than 5 byte in 1 Mbps mode the ARD must
be 500 µs or more. In 250 kbps mode (even when the payload is not in ACK) the ARD must be 500 µs or
more.
b. This is the time the PTX is waiting for an ACK packet before a retransmit is made. The PTX is in RX mode
for a minimum of 250 µs, but it stays in RX mode to the end of the packet if that is longer than 250 µs.
Then it goes to standby-I mode for the rest of the specified ARD. After the ARD it goes to TX mode and
then retransmits the packet.
c. The RX_DR IRQ is asserted by a new packet arrival event. The procedure for handling this interrupt
should be: 1) read payload through SPI, 2) clear RX_DR IRQ, 3) read FIFO_STATUS to check if there
are more payloads available in RX FIFO, 4) if there are more data in RX FIFO, repeat from step 1).
d. If ACK packet payload is activated, ACK packets have dynamic payload lengths and the Dynamic Payload
Length feature should be enabled for pipe 0 on the PTX and PRX. This is to ensure that they receive the
ACK packets with payloads. If the ACK payload is more than 15 byte in 2 Mbps mode the ARD must be
500 µs or more, and if the ACK payload is more than 5 byte in 1 Mbps mode the ARD must be 500 µs or
more. In 250 kbps mode (even when the payload is not in ACK) the ARD must be 500 µs or more.
Address
(Hex) Mnemonic Bit Reset
Value Type Description
Revision 1.1 Page 63 of 187
nRF24LU1+ Product Specification
7 USB Interface
The USB device controller provides a full speed USB function interface that meets the 1.1 and 2.0 revision
of the USB specification. It handles byte transfers autonomously and bridges the USB interface to a simple
read/write parallel interface.
7.1 Features
• Serial Interface Engine
XSupports full speed devices
XExtraction of clock and data signals in internal DPLL
XNRZI decoding/encoding
XBit stuffing/stripping
XCRC checking/generation
XOn-chip transceiver
XOn-chip pull-up resistor on D+ with software controlled disconnect
• 2 control, 10 bulk/interrupt and 2 ISO endpoints
XSupports control transfers by endpoint #0
XSupports bulk, interrupt on endpoint #1 - #5 (in/out)
XSupport double buffering for isochronous endpoint #8 (in/out)
XProgrammable double buffering for bulk and interrupt endpoints
• Automatic data retry mechanism
• Data toggle synchronization mechanism
• Suspend and resume power management functions
• Remote Wakeup function
• Flexible endpoint buffers RAM
X512 bytes buffer total
XUp to 64 bytes buffer size for endpoint 0-5
XUp to 128bytes buffer size for endpoint 8
The endpoint set up allows for five different applications (for example, Mouse, Keyboard, Remote Control,
Gamepad and Joystick) to use both input and output data transfer on separate endpoints.
The nRF24LU1+ supports a total of 14 endpoints. EP0 IN/OUT supports input and output control data
transfer, EP1-5 IN/OUT supports input and output bulk and interrupt data transfer. In addition, EP8 IN/OUT
can be configured for input and output isynchronous data transfer. These two endpoints share memory
buffer area with EP0-5. This sharing is controlled by nRF24LU1+ firmware.
Revision 1.1 Page 64 of 187
nRF24LU1+ Product Specification
7.2 Block diagram
Figure 28. USB block diagram
address
usbcs.discon
data
we
rst
wakeup
A
D
WE
USBIRQ
USBWU
rst
wakeup
Endpoint buffer
RAM
USB controller
D-
D+
USB transceiver
PHY
usbramaddr
usbramdata
RPU
VDD
MCU
Revision 1.1 Page 65 of 187
nRF24LU1+ Product Specification
7.3 Functional description
The USB module is designed to serve as a Full Speed (FS) USB device as defined in the Universal Serial
Bus Specification Rev 2.0. It is controlled both with SFR registers and XDATA mapped registers. There are
two SFR registers, USBCON and USBSLP, and the rest of the registers are XDATA mapped registers.
Table 24. USBCON register
Set wu=1 in USBCON to enable USB clock
Table 25. USBSLP register
The other USB registers and buffer RAM are accessible through a 2k “window” in XDATA space using the
MOVX instruction.
Note: Undefined addresses should not be written or read.
Note: Key to abbreviations used in Table 27. on page 70:
Xu - unchanged value after reset
Xx - unknown
Address Reset
value Bit Name R/W Description
0xA0 0x00 7 swrst RW 1: reset USB
6 wu RW 1: wakeup USB, must be cleared before set-
ting USBSLP.
5 suspend R 1: USB is suspended. This bit acknowledges
USBSLP=1, after a delay of up to 32 µs.
4:0 ivec[6:2] R Interrupt vector ivec, see Table 34. on page 84
Address Reset
value Bit Name R/W Description
0xD9 0x00 7:1 - - Not used
0 Sleep WO 1: Disable USB clock, bit automatically cleared.
Hex
address Name
Hex
hard
reset
USB
reset bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
C440-
C47Fa
out5buf x x d7 d6 d5 d4 d3 d2 d1 d0
C480-
C4BF
in5buf x x d7 d6 d5 d4 d3 d2 d1 d0
C4C0-
C4FF
out4buf x x d7 d6 d5 d4 d3 d2 d1 d0
C500-
C53F
in4buf x x d7 d6 d5 d4 d3 d2 d1 d0
C540-
C57F
out3buf x x d7 d6 d5 d4 d3 d2 d1 d0
C580-
C5BF
in3buf x x d7 d6 d5 d4 d3 d2 d1 d0
C5C0-
C5FF
out2buf x x d7 d6 d5 d4 d3 d2 d1 d0
Revision 1.1 Page 66 of 187
nRF24LU1+ Product Specification
C600-
C63F
in2buf x x d7 d6 d5 d4 d3 d2 d1 d0
C640-
C67F
out1buf x x d7 d6 d5 d4 d3 d2 d1 d0
C680-
C6BF
in1buf x x d7 d6 d5 d4 d3 d2 d1 d0
C6C0-
C6FF
out0buf x x d7 d6 d5 d4 d3 d2 d1 d0
C700-
C73F
in0buf x x d7 d6 d5 d4 d3 d2 d1 d0
C760 out8data x uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C768 in8data x uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C770 out8bch 00 uuuuu
uuu
000000bc9bc8
C771 out8bcl 00 uuuuu
uuu
bc7 bc6 bc5 bc4 bc3 bc2 bc1 bc0
C781 bout1addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C782 bout2addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C783 bout3addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C784 bout4addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C785 bout5addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C788 binstaddr 00 uuuuu
uuu
addr9 addr8 addr7 addr6 addr5 addr4 addr3 addr2
C789 bin1addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C78A bin2addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C78B bin3addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C78C bin4addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C78D bin5addr 00 uuuuu
uuu
addr8 addr7 addr6 addr5 addr4 addr3 addr2 addr1
C7A0 isoerr 00 uuuuu
uuu
0000000iso8err
C7A2 zbcout 00 uuuuu
uuu
0000000ep8
C7A8 ivec 00 uuuuu
uuu
0 iv4 iv3 iv2 iv1 iv0 0 0
C7A9 in_irq 00 uuuuu
uuu
0 0 in5ir in4ir in3ir in2ir in1ir in0ir
C7AA out_irq 00 uuuuu
uuu
0 0 out5ir out4ir out3ir out2ir out1ir out0ir
Hex
address Name
Hex
hard
reset
USB
reset bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Revision 1.1 Page 67 of 187
nRF24LU1+ Product Specification
C7AB usbirq 00 uuuuu
uuu
0 0 ibnir uresir suspir sutokir sofir sudavir
C7AC in_ien 00 uuuuu
uuu
0 0 in5ien in4ien in3ien in2ien in1ien in0ien
C7AD out_ien 00 uuuuu
uuu
00out5ie
n
out4ien out3ien out2ien out1ie
n
out0ien
C7AE usbien 00 uuuuu
uuu
0 0 ibnie uresie suspie sutokie sofie sudavie
C7AF usbbav 00 uuuuu
uuu
0000000aven
C7B4 ep0cs 08 uuuu
u0uu
0 0 chgset dstall outbsy inbsy hsnak ep0stall
C7B5 in0bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7B6 in1cs 00 uuuu
uu00
000000in1bsyin1stl
C7B7 in1bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7B8 in2cs 00 uuuu
uu00
000000in2bsyin2stl
C7B9 in2bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7BA in3cs 00 uuuu
uu00
000000in3bsyin3stl
C7BB in3bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7BC in4cs 00 uuuu
uu00
000000in4bsyin4stl
C7BD in4bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7BE in5cs 00 uuuu
uu00
000000in5bsyin5stl
C7BF in5bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7C5 out0bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7C6 out1cs 02 uuuuu
uuu
0 0 0 0 0 0 out1bs
y
out1stl
C7C7 out1bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7C8 out2cs 02 uuuuu
uuu
0 0 0 0 0 0 out2bs
y
out2stl
C7C9 out2bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7CA out3cs 02 uuuuu
uuu
0 0 0 0 0 0 out3bs
y
out3stl
C7CB out3bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7CC out4cs 02 uuuuu
uuu
0 0 0 0 0 0 out4bs
y
out4stl
Hex
address Name
Hex
hard
reset
USB
reset bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Revision 1.1 Page 68 of 187
nRF24LU1+ Product Specification
C7CD out4bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7CE out5cs 02 uuuuu
uuu
0 0 0 0 0 0 out5bs
y
out5stl
C7CF out5bc 00 uuuuu
uuu
0 bc6bc5bc4bc3bc2bc1bc0
C7D6 usbcs 00 uuuuu
uuu
wakesr
c
0 sofgen 0 discon 0 forcej sigr-
sume
C7D7 togctlb00 uuuuu
uuu
q s r io 0 ep2 ep1 ep0
C7D8 usbfrml 00 uuuuu
uuu
fc7 fc6 fc5 fc4 fc3 fc2 fc1 fc0
C7D9 usbfrmh 00 uuuuu
uuu
0 0 0 0 0 fc10 fc9 fc8
C7DB fnaddr 00 0000
0000
0 fa6fa5fa4fa3fa2fa1fa0
C7DD usbpair 00 uuuuu
uuu
isosend
0
0 0 pr4out pr2out 0 pr4in pr2in
C7DE inbulkval 57 uuuuu
uuu
0 0 in5val in4val in3val in2val in1val 1
C7DF outbulkval 55 uuuuu
uuu
00out5va
l
out4val out3val out2val out1va
l
1
C7E0 inisoval 07 uuuuu
uuu
0000000in8val
C7E1 outisoval 07 uuuuu
uuu
0 0 0 0 0 0 0 out8val
C7E2 isostaddr 00 uuuuu
uuu
0 addr10 addr9 addr8 addr7 addr6 addr5 addr4
C7E3 isosize 00 uuuuu
uuu
0 size10 size9 size8 size7 size6 size5 size4
C7E8 setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7E9 setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7EA setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7EB setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7EC setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7ED setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
Hex
address Name
Hex
hard
reset
USB
reset bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Revision 1.1 Page 69 of 187
nRF24LU1+ Product Specification
Table 26. USB buffer and register map
7.4 Control endpoints
Each USB device is allocated by endpoint numbers. The endpoint 0 (EP0) is reserved for control transfers.
Using USB requests, the host uses EP0 for device configuration.
The device processes the SET_ADDRESS request and sets the address in the fnaddr register. Firmware
interrupts this request as configured in the usbien register.
All other USB device requests must be processed by firmware.
7.4.1 Control endpoint 0 implementation
Every USB device must have the endpoint 0, it is the special control endpoint.
C7EE setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7EF setupbuf 00 uuuuu
uuu
d7 d6 d5 d4 d3 d2 d1 d0
C7F0 out8addr 00 uuuuu
uuu
a9 a8 a7 a6 a5 a4 0 0
C7F8 in8addr 00 uuuuu
uuu
a9 a8 a7 a6 a5 a4 0 0
a. The addresses for outxbuf and inxbuf are indirect addresses which are mapped according to the end-
point definitions given in register boutxaddr and binxaddr.
b. See also section 7.5.4
Note: Key to abbreviations used in the table:
XU - unchanged value after reset
XUn - unknown
Hex
address Name
Hex
hard
reset
USB
reset bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Revision 1.1 Page 70 of 187
nRF24LU1+ Product Specification
7.4.2 Endpoint 0 registers
Table 27. Endpoint 0 Register
Register name Bit name Bit description
usbien(0) sudavie Setup data valid interrupt enable
usbien(2) sutokie Setup token interrupt enable
usbirq(0) sudavir Setup data valid interrupt request
usbirq(2) sutokir Setup token interrupt request
setupdat0
setupdat7
Setup Data
Buffer
8 bytes setup data packet
in_irq(0) in0ir IN 0 endpoint interrupt request
out_irq(0) out0ir OUT 0 endpoint interrupt request
in_ien(0) in0ien IN 0 endpoint interrupt enable
out_ien(0) out0ien OUT 0 endpoint interrupt enable
ep0cs(0) ep0stall Endpoint 0 STALL bit
ep0cs(1) hsnak Handshake NAK
ep0cs(2) inbsy IN 0 buffer busy flag
ep0cs(3) outbsy OUT 0 buffer busy flag
ep0cs(4) dstall Send STALL in the data stage
ep0cs(5) chgset Setup Buffer content was changed
in0bc Register IN 0 byte counter
out0bc Register OUT 0 byte counter
Revision 1.1 Page 71 of 187
nRF24LU1+ Product Specification
7.4.3 Control transfer examples
A control transfer consists of two or three stages:
• Setup stage
• Data stage (optional)
• Status stage
7.4.3.1 Control write transfer example
Figure 29. Control Write Transfer
After receiving the SETUP token, the USB controller sets the hsnak and sutokir bits. If an 8-byte data
packet is received correctly, the USB controller sets the sudavir bit. Setting sutokir and (or) sudavir bits
generates the appropriate interrupts. The data stage consists of one or more OUT bulk-like transactions.
The USB controller generates the OUT 0 interrupt request by setting the out0ir bit after each correct OUT
transaction during the data stage. Out0bc register contains the number of data bytes received in the last
OUT transaction. The MCU services the interrupt request and then prepares the endpoint for the next
transaction by reloading the out0bc register with any value (setting outbsy bit). The status stage of a con-
trol transfer is the last operation in the sequence.
The MCU clears the hsnak bit (by writing 1 to it) to instruct the USB controller to ACK the status stage. The
USB controller sends a STALL handshake when both hsnak and stall bits are set.
SETUP(0)
SETUP
Token
8 Bytes Data0
Packet
ACK
Packet
OUT(1)
OUT
Token
Payload Data1
Packet
ACK
Packet
OUT(0)
OUT
Token
Payload Data0
Packet
ACK
Packet
IN
Token
Setup Stage:
Data Stage:
Status Stage:
set sudavir
set sutokir,
set hsnak
set out0ir
set out0ir
setupdat buffer now
contains data that
arrived in data0
packet
MCU services out0
interrupt request and
reloads out0bc
register
MCU clears
hsnak or dstall (or sets
stal bit)
IN(1)
IN
Token
0 Bytes Data1
Packet
ACK
Packet
Host to Device
Device to Host
NAK
Packet
Revision 1.1 Page 72 of 187
nRF24LU1+ Product Specification
7.4.3.2 Control read transfer example
Figure 30. Control Read Transfer
Control read transfer is similar to control write transfer with the only difference in the data stage. During the
data stage of control read transfers, the USB controller generates the IN 0 interrupt request by setting in0ir
bit. This is done after each acknowledge by the host data packet. The MCU loads new data into the IN 0
buffer and then reloads the in0bc register with a valid number of loaded data. Reloading the in0bc register
causes the inbsy bit to set and arms the endpoint for the next IN transaction.
The status stage of a control transfer is the last operation in the sequence. The MCU clears the hsnak bit
(by writing 1 to it) to instruct the USB controller to ACK the status stage. The USB controller sends the
STALL handshake when both hsnak and stall bits are set.
7.4.3.3 No-data control transfer example
Figure 31. No-data Control Transfer
OUT (1) OUT(1)
SETUP(0)
SETUP
Token
8 Bytes Data0
Packet
ACK
Packet
IN (1)
IN
Token
Payload Data1
Packet
ACK
Packet
IN(0)
IN
Token
Payload Data0
Packet
ACK
Packet
Setup Stage:
Data Stage:
Status Stage:
set sudavir
set sutokir,
set hsnak
set in0ir
set in0ir
setupdat buffer now
contains data that
arrived in data0
packet
Microcontroller
services in0 interrupt
request and reloads
in0bc register
Microcontroller clears
hsnak or dstall (or sets
stall bit)
Host to Device
Device to Host
ACK
Packet
0 Bytes Data1
Packet
OUT
Token
0 Bytes Data1
Packet
OUT
Token
NAK
Packet
SETUP(0)
SETUP
Token
8 Bytes Data0
Packet
ACK
Packet
Setup Stage:
set sudavir
set sutokir,
set hsnak
setupdat buffer now
contains data that
arrived in data0
packet
Host to Device
Device to Host
Status Stage:
IN(1)
ACK
Packet
0 Bytes Data1
Packet
IN
Token
Microcontroller clears
hsnak (or sets stall bit)
NAK
Packet
IN
Token
Revision 1.1 Page 73 of 187
nRF24LU1+ Product Specification
Some control transfers do not have a data stage. In this case the status stage consists of the IN data
packet. The MCU clears the hsnak bit (by writing 1 to it) to instruct the USB controller to ACK (acknowl-
edge) the status stage.
7.5 Bulk/Interrupt endpoints
Each USB transaction is formed as a token packet, optional data packet and, optional handshake packet.
Data transfers consist of two or three phases:
• Token packet
• Data packet
• Handshake packet (optional)
Only control, bulk and, interrupt transfers have their own handshake phase.
Isochronous transfers do not contain a handshake phase. Data is transferred during the data packet
phase. Two PID types are available for this: DATA0 and DATA1.
7.5.1 Bulk/Interrupt endpoints implementation
The USB controller has 1 to 5 bulk IN endpoints and 1 to 5 bulk OUT endpoints.
7.5.2 Bulk/Interrupt endpoints registers
Table 28. Bulk/Interrupt IN endpoints registers
Table 29. Bulk OUT endpoints registers
Register name Bit name Bit description
inbulkval(x) Inxval IN x endpoint valid (x = endpoint number)
usbpair Register Endpoint pairing register
in_ien(x) Inxien IN x endpoint interrupt enable (x = endpoint number)
inxbuf Buffer Endpoint x buffer (x = endpoint number)
inxbc Register IN x byte count register (x = endpoint number)
inxcs(0) inxstl IN x endpoint stall bit (x = endpoint number)
inxcs(1) inxbsy IN x endpoint busy bit (x = endpoint number)
in_irq(x) inxir IN x endpoint interrupt request
Register name Bit name Bit description
out-
bulkval(x)
Outxval OUT x endpoint valid (x = endpoint number)
usbpair Register Endpoint pairing register
out_ien(x) Outxien OUT x endpoint interrupt enable (x = endpoint number)
outxbuf Buffer Endpoint x buffer (x = endpoint number)
outxbc Register OUT x byte count register (x = endpoint number)
outxcs(0) Outxstl OUT x endpoint stall bit (x = endpoint number)
outxcs(1) Outxbsy OUT x endpoint busy bit (x = endpoint number)
out_irq(x) Outxir OUT x endpoint interrupt request
Revision 1.1 Page 74 of 187
nRF24LU1+ Product Specification
7.5.3 Bulk and interrupt endpoints initialization
The MCU sets the appropriate valid bits in the in(out)bulkval register to enable bulk IN (OUT) endpoints for
normal operation.
7.5.3.1 Bulk and interrupt transfers
a) IN transfers
Figure 32. Bulk IN transfer
The host issues an IN token to receive bulk data. If the inxbsy bit is set, the USB controller responds by
returning a data packet. If the host receives a valid data packet, it responds with an ACK handshake.
After receiving a valid ACK handshake from the host, the USB controller sets the inxir bit and clears the
inxbsy bit. Setting the inxir bit generates an interrupt request for IN x endpoint (x = appropriate number of
endpoint).
The MCU services the interrupt request. During a service interrupt request the MCU loads new data into
the inxbuf buffer and then reloads the inxbc register with a valid number of data bytes to set the inxbsy bit.
IN x endpoint is armed for the next transfer when the inxbsy bit is set.
When the inxbsy bit is not set, the USB controller returns NAK handshake for each IN token from the host.
When the inxstl bit is set, the USB controller returns the STALL handshake.
Table 30. The USB controller response for IN Token
Errors in IN token Inxbsy Inxstl USB controller to host response
NO 1 0 Inxbc bytes data packet
NO 0 1 STALL
NO 0 0 NAK
NO 1 1 STALL
YES - - No response
IN
Token
Payload Data
Packet
ACK
Packet
set inxir
clear inxbsy
IN(0/1)
Host to Device
Device to Host
Revision 1.1 Page 75 of 187
nRF24LU1+ Product Specification
b) OUT transfers
Figure 33. Bulk OUT transfer
When the host wants to transmit bulk data, it issues an OUT Token packet followed by a data packet. An
ACK handshake is returned to the host and the outxir bit is set when the USB controller receives an error
free OUT, data packets and, the outxbsy bit is set. Setting the outxir bit generates an interrupt request for
the OUT x endpoint (x = appropriate number of endpoints).
The MCU services the OUT x interrupt request. The received data packet is available in the outxbuf buffer.
After servicing an interrupt request, the MCU reloads the outxbc register with any value to set the outxbsy
bit. When the outxbsy bit is set the OUT x endpoint is armed for the next OUT transfer.
A NAK handshake is returned to the host when the USB controller receives data packets and an error free
OUT but the outxbsy bit is not set.
A STALL handshake is returned to the host when the USB controller receives an error free OUT and data
packets and the outxstl bit is set. The USB controller does not return a handshake if any transmission error
occurs during an OUT token or data phase.
Table 31. The USB controller response for OUT transfers
7.5.4 Data packet synchronization
Data packet synchronization is achieved through the use of the data sequence toggle bits and the DATA0/
DATA1 PIDs. The USB controller automatically toggles DATA0/DATA1 PIDs every bulk transfer.
The MCU can directly set or clear data toggle bits using the togctl register. The MCU clears the toggle bits
when the host issues Clear Feature, Set Interface or, selects alternate settings.
To write a toggle bit the MCU performs the following sequence:
• Write to togctl register “000d0eee” value to select endpoint “eee” (“eee” – binary value). Endpoint
direction bit “d”: “d”=’0’ – OUT endpoint; “d”=’1’ – IN endpoint.
• Clear or set toggle bit by writing to togctl register “0srd0eee” value. “sr”=’10’ – setting toggle bit;
“sr”=’01’ – clearing toggle bit.
Errors in OUT token or
in data packet outxbsy outxstl USB controller to host response
NO 0 0 NAK
NO 0 1 STALL
NO 1 0 ACK
NO 1 1 STALL
YES - - No response
OUT
Token
Payload Data
Packet
ACK
Packet
set outxir
clear outxbsy
OUT (0/1)
Host to Device
Device to Host
Revision 1.1 Page 76 of 187
nRF24LU1+ Product Specification
7.5.5 Endpoint pairing
To enable double buffering the MCU sets the appropriate bits in the usbpair register to ‘1’ (see section 15.1
on page 128).
When double buffering is enabled, the MCU may access one buffer of the pair while the USB host
accesses the other. When an endpoint is paired, the MCU uses only an even numbered endpoint of the
pair.
For example, if the usbpair(0) bit is set, that means that the IN 2 and the IN 3 endpoints are paired. The
MCU should not access in3buf data buffer, in3val bit, in3bc register, in3ir bit, in3ien bit, or in3cs registers.
7.5.5.1 Paired IN endpoint status
When both endpoint buffers of the pair are filled and armed, the inxbsy bit is set to ‘1’ by the USB controller
and the MCU does not load new data into the inxbuf buffer.
When one or both buffers of the pair are empty (unarmed), the inxbsy bit is set to ‘0’ by the USB controller
and the MCU may fill inxbuf with new data and reload the inxbc register to arm the endpoint for transmis-
sion. Clearing the inxbsy bit (write a ‘1’) causes both of the paired endpoints to unarm. An interrupt request
is generated after each data packet is correctly sent, independent of the inxbsy bit.
7.5.5.2 Paired OUT endpoint status
When the MCU pairs OUT endpoints by setting bit in the usbpair register, it also reloads twice the outxbc
register to arm paired OUT endpoints.
When both endpoint buffers of the pair are empty and no data is available for the MCU, the outxbsy bit is
set to ‘1’ by the USB controller.
When one or both of the buffers contain valid data, the outxbsy bit is reset to ‘0’ by the USB controller.
Clearing the outxbsy bit (write a ‘1’) causes both of the paired endpoints to unarm. An interrupt request is
generated after each data packet is correctly received, independent of outxbsy bit or dstall. To receive an
interrupt you must arm the endpoint by setting outxbc to a non-zero value.
7.6 Isochronous endpoints
Isochronous (ISO) transactions have a token and a data phase, but no handshake phase. ISO transactions
do not support a handshake phase or retry capability and they do not support a data toggle synchroniza-
tion mechanism.
Isochronous transmission is double buffered. An ISO FIFO swap occurs for every start of frame packet.
7.6.1 Isochronous endpoints implementation
The USB controller contains one IN endpoint and one isochronous OUT endpoint (Endpoint 8 IN/OUT).
Revision 1.1 Page 77 of 187
nRF24LU1+ Product Specification
7.6.2 Isochronous endpoints registers
Table 32. ISO IN endpoint registers
Table 33. ISO OUT endpoint registers
7.6.3 ISO endpoints initialization
The MCU performs the following steps to enable isochronous IN (OUT) endpoints for normal operation:
• Sets the appropriate valid bits into the in(out)isoval register.
• Sets the endpoint’s FIFO size by loading the start address into the in(out)8addr register.
• Sets the isosend0 bit into the usbpair register - for IN endpoints only.
• Enables the start of frame interrupt by setting the sofie bit in the usbien register.
7.6.4 ISO transfers
The MCU serves all the ISO endpoints in response to a start of frame interrupt request.
7.6.4.1 ISO IN transfers
Figure 34. ISO IN transfer
The MCU loads new data into the ISO IN endpoint buffer(s) at every start of frame interrupt request. The
ISO IN endpoint is accessed through the in8data register. The USB controller keeps track of the number of
bytes that the MCU loads and sends loaded data during the next frame.
Register name Bit name Bit description
inisoval in8val IN 8 endpoint valid
in8addr register IN 8 endpoint address register
usbpair(7) isosend0 ISO endpoints send a zero length data packet if it is empty
usbien(1) sofie Start of Frame interrupt enable
in8data register IN 8 endpoint data register
usbirq(1) sofir Start of Frame interrupt request
Register name Bit name Bit description
outisoval out8val OUT 8 endpoint valid
out8addr register OUT 8 endpoint address register
usbien(1) sofie Start of Frame interrupt enable
out8data register OUT 8 endpoint data register
usbirq(1) sofir Start of Frame interrupt request
out8bch register Received byte count register high
out8bcl register Received byte count register low
isoerr iso8err OUT 8 endpoint CRC error
IN
Token
Payload Data
Packet
IN (0)
Host to Device
Device to Host
Revision 1.1 Page 78 of 187
nRF24LU1+ Product Specification
When the host wants to receive ISO data, it issues an IN token for a specific endpoint. If the IN buffer the
host selected contains data, the USB controller responds by returning a data packet.
If the buffer is empty the USB controller behavior depends on the isosend0 bit:
• If the isosend0 bit is set, the USB controller responds with a zero byte length data packet.
• If the isosend0 bit is not set, USB controller does not respond.
7.6.4.2 ISO OUT transfers
Figure 35. ISO OUT transfer
With every start of frame interrupt request the MCU reads data that was sent by the host in the previous
frame. Out8bch and out8bcl registers contain the number of transferred bytes. Data is accessible through
the out8data register. The USB controller sets the iso8err bit when the ISO data packet is corrupted.
7.7 Memory configuration
7.7.1 On-chip memory map
All endpoint buffers are located in a single 512 byte memory block. Bulk OUT buffers block start at address
0. You can program localization of the Bulk IN buffers using binstaddr register. If the host sends a packet
which is larger than the configured buffer size, the USB controller will not NAK or STALL.
You can program start of ISO buffers using isostaddr register. Additionally, program size of the ISO buffers
using isosize register.
Note: All ISO endpoints are double buffered.
Figure 36. shows on-chip memory organization. See Appendix A on page 184 for various USB memory
configurations.
IN
Token
Payload Data
Packet
OUT (0)
Host to Device
Device to Host
Revision 1.1 Page 79 of 187
nRF24LU1+ Product Specification
Figure 36. On-chip memory map
7.7.2 Setting ISO FIFO size
128 byte ISO buffers memory may be distributed over the two endpoint addresses: EP8 IN and EP8 OUT.
The MCU initializes the endpoint FIFO sizes by setting the starting address for each FIFO. The first FIFO
starting address is 0x000. The size of an isochronous endpoint FIFO is determined by subtracting consec-
utive values of FIFO 8 starting addresses.
Note: Only the six most significant bits can be written by the MCU (see Figure 37. on page 79).
Figure 37. FIFO 8 starting address
Bulk OUT buffers
up to 192 Bytes
0x000
0x180 (max)
sum of sizes of all Bulk OUT endpoints
binstaddr =
4
(Bulk starts at 0x000)
0x0C0 (max)
On-Chip Memory
usbramaddr
comments
0x1C0 (max)
Bulk IN buffers
up to 192 Bytes
sum of sizes of all Bulk endpoints
isostaddr =
16
ISO buffers
up to 64 Bytes
( toggle 0 )
ISO buffers
up to 64 Bytes
( toggle 1 )
(*4)
(*16)
(*16)
sum of sizes of all ISO endpoints
isosize =
16
+
+
addr9
addr8 addr7
addr6 addr5 addr4 0 0 0 0
8-bit in(out)8addr register
FIFO 8 starting address
Revision 1.1 Page 80 of 187
nRF24LU1+ Product Specification
The LSB values of the in(out)8addr register are always zero, that is, the smallest size of FIFO buffer for
each ISO endpoints is 16 bytes.
7.7.3 Setting Bulk OUT size
Figure 38. Bulk OUT x starting address
Bulk OUT buffers memory can be distributed over the 6 bulk OUT endpoints. Size of each Bulk OUT end-
point should be programmed using boutxaddr registers. When OUT x endpoint is not used the boutxaddr
for this endpoint should be set to 0x000.
The first starting address (EP0 OUT) is 0x000. The size of a bulk OUT endpoint is determined by subtract-
ing consecutive values of bulk OUT x starting addresses. The size of Bulk OUT buffer is a multiple of two
bytes.
Here is an example initialization of the boutxaddr registers:
const uint8_t EP0OUTSTARTADDR = 0; // start address for EP0 OUT
bout1addr = EP0OUTSTARTADDR + (EP0OUT_SIZE/2);
bout2addr = bout1addr + (EP1OUT_SIZE/2);
bout3addr = bout2addr + (EP2OUT_SIZE/2);
bout4addr = bout3addr + (EP3OUT_SIZE/2);
bout5addr = bout4addr + (EP4OUT_SIZE/2);
binstaddr = (bout5addr + (EP5OUT_SIZE/2))/2; // beginning of
Bulk IN buffers
7.7.4 Setting Bulk IN size
Figure 39. Bulk IN x starting address
Bulk IN buffers memory can be distributed over the 6 bulk IN endpoints. Size of each bulk IN endpoint is
programmed using binxaddr registers.
addr9
addr8 addr7
addr6 addr5 addr4 0
8-bit boutxaddr register
Bulk OUT x starting address
addr3 addr2
addr9 addr8 addr7
addr6 addr5 addr4 0
8-bit binxaddr register
Bulk IN x starting address
addr3 addr2
Revision 1.1 Page 81 of 187
nRF24LU1+ Product Specification
When IN x endpoint does not exist (or is not used) the binxaddr for it should be set to 0x000. The first start-
ing address (EP0 IN) is 0x000. The size of a Bulk IN endpoint is determined by subtracting consecutive
values of Bulk IN x starting addresses. The size of Bulk IN buffer is a multiple of two bytes.
Here is an example initialization of the binxaddr registers:
const unsigned char EP0INSTARTADDR = 0; // start address for EP0 IN
bin1addr = EP0INSTARTADDR + (EP0IN_SIZE/2);
bin2addr = bin1addr + (EP1IN_SIZE/2);
bin3addr = bin2addr + (EP2IN_SIZE/2);
bin4addr = bin3addr + (EP3IN_SIZE/2);
bin5addr = bin4addr + (EP4IN_SIZE/2);
isostaddr = (bin5addr + (EP5IN_SIZE/2))/8 + binstaddr/4; // beginning of the ISO buffers
7.8 The USB controller interrupts
The USB controller provides the two following interrupt signals for MCUs:
• USBWU
• USBIRQ
The USB controller generates interrupts by setting the USBWU or USBIRQ signal high and then setting it
low. This interrupt request pulse is detected by the MCU as an edge triggered interrupt.
7.8.1 Wakeup interrupt request
When the USB controller is suspended by the host, it can be resumed in two ways:
• By the MCU setting the wakeup bit 6 of USBCON SFR register.
• By receiving a resume request from the host.
After resuming, the USB controller generates a wakeup interrupt request by setting the USBWU signal
high.
7.8.2 USB interrupt request
The USB interrupt request is provided through the USBIRQ signal and includes:
• 12 bulk endpoint interrupts
• Start of frame interrupt (sofir)
• Suspend interrupt (suspir)
• USB reset interrupt (uresir)
• Setup token interrupt (sutokir)
• Setup data valid interrupt (sudavir)
Figure 40. on page 83 shows all the interrupt sources and their natural priority.
After servicing the USB controller interrupt, the MCU clears the individual interrupt request flag in the USB
registers. If any other USB interrupts are pending, the act of clearing the interrupt request flag causes the
USB controller to generate another pulse for the highest priority pending interrupt. If more than one inter-
rupt is pending, each is serviced in the priority order.
The sequence of clearing the interrupt requests is important. The MCU first clears the main interrupt
request flag (USBIRQ) and then each individual interrupt request in the USB controller register (usbirq).
Revision 1.1 Page 82 of 187
nRF24LU1+ Product Specification
Clearing the interrupt source immediately generates an interrupt pulse for the next pending interrupt. The
interrupt may be lost when the MCU clears the main interrupt request flag after clearing the individual inter-
rupt source.
Note: There is a difference between the interrupt USBIRQ, which is defined in Table 138., and the
register usbirq described in Table 44.
Revision 1.1 Page 83 of 187
nRF24LU1+ Product Specification
Figure 40. The USB controller interrupt sources
usbirq(0) usbien(0)
1
0
sudav
sof usbirq(1) usbien(1)
1
0
usbirq(2) usbien(2)
1
0
usbirq(3) usbien(3)
1
0
usbirq(4) usbien(4)
1
0
in_irq(0) in_ien(0)
1
0
out_irq(0) out_ien(0)
1
0
in_irq(1) in_ien(1)
1
0
out_irq(1) out_ien(1)
1
0
in_irq(2) in_ien(2)
1
0
out_irq(2) out_ien(2)
1
0
in_irq(3) in_ien(3)
1
0
out_ien(3)
1
0
in_irq(4) in_ien(4)
1
0
out_irq(4)
out_ien(4)
1
0
in_irq(5) in_ien(5)
1
0
out_irq(5)
out_ien(5)
1
0
sutok
susp
ures
in0
out0
in1
out1
in2
out2
in3
out3
in4
out4
in5
out5
USBIRQ
interrupt
request bits
interrupt
enable bits
natural
priority
highest
lowest
out_irq(3)
interrupt
request
generator
Revision 1.1 Page 84 of 187
nRF24LU1+ Product Specification
7.8.3 USB interrupt vectors
The USB controller prioritizes the USB interrupts if two or more occur simultaneously. The vector of the
active interrupt is available in the ivec register. Table 34. shows the contents of the ivec register for the
USB interrupts.
Table 34. Interrupt vectors
7.9 The USB controller registers
The microprocessor interfaces with the USB controller logic through the following registers and RAM buf-
fers.
7.9.1 Bulk IN data buffers (inxbuf)
Six 32 byte bulk IN buffers are in RAM memory.
Note: The sum of all endpoints (IN+OUT+ISO) must be less or equal to 512.
Table 35.Bulk IN endpoints memory locations
Source of
interrupt Register bit Contents of ivec
register
sudav usbirq(0) 0x00
sof usbirq(1) 0x04
sutok usbirq(2) 0x08
suspend usbirq(3) 0x0C
usbreset usbirq(4) 0x10
ep0in In_irq(0) 0x18
ep0out out07irq(0) 0x1C
ep1in In_irq(1) 0x20
ep1out out07irq(1) 0x24
ep2in In_irq(2) 0x28
ep2out out07irq(2) 0x2C
ep3in In_irq(3) 0x30
ep3out out07irq(3) 0x34
ep4in In_irq(4) 0x38
ep4out out07irq(4) 0x3C
ep5in In_irq(5) 0x40
ep5out out07irq(5) 0x44
Address Name Function
0xC700-0xC73F in0buf Max 64 bytes bulk 0 IN buffer
0xC680-0xC6BF in1buf Max 64 bytes bulk 1 IN buffer
0xC600-0xC63F in2buf Max 64 bytes bulk 2 IN buffer
0xC580-0xC5BF in3buf Max 64 bytes bulk 3 IN buffer
0xC500-0xC53F in4buf Max 64 bytes bulk 4 IN buffer
0xC480-0xC4BF in5buf Max 64 bytes bulk 5 IN buffer
Revision 1.1 Page 85 of 187
nRF24LU1+ Product Specification
7.9.2 Bulk OUT data buffers (outxbuf)
Six 32 byte bulk OUT buffers are in RAM memory.
Note: The sum of all endpoints (IN+OUT+ISO) must be less or equal to 512.
Table 36.Bulk OUT endpoints memory locations
7.9.3 Isochronous OUT endpoint data FIFO (out8dat)
Table 37. The out8dat register
7.9.4 Isochronous IN endpoint data FIFOs (in8dat)
Table 38. The in8dat register
7.9.5 Isochronous data bytes counter (out8bch/out8bcl)
Table 39. The outxbch/bcl register
7.9.6 Isochronous transfer error register (isoerr)
Table 40. The isoerr register
The isoerr register is updated at every Start Of Frame. The iso8err bits indicate that an error occurred dur-
ing the receiving of ISO OUT 8 endpoint data packet.
Iso8err bit = 1 means that a CRC error occurred, but received data is available in the out8data register.
Address Name Function
0xC6C0-0xC6FF out0buf Max 64 bytes bulk 0 OUT buffer
0xC640-0xC67F out1buf Max 64 bytes bulk 1 OUT buffer
0xC5C0-0xC5FF out2buf Max 64 bytes bulk 2 OUT buffer
0xC540-0xC57F out3buf Max 64 bytes bulk 3 OUT buffer
0xC4C0-0xC4FF out4buf Max 64 bytes bulk 4 OUT buffer
0xC440-0xC47F out5buf Max 64 bytes bulk 5 OUT buffer
Address Name Function
0xC760 out8data ISO OUT endpoint 8 data FIFO register
Address Name Function
0xC768 in8data ISO IN endpoint 8 FIFO data register
Address Name Function
0xC770 out8bch ISO OUT endpoint 8 data counter high
0xC771 out8bcl ISO OUT endpoint 8 data counter low
Address MSB LSB
0xC7A0 - - - - - - - iso8err
Revision 1.1 Page 86 of 187
nRF24LU1+ Product Specification
7.9.7 The zero byte count for ISO OUT endpoints (zbcout)
Table 41. The zbcout register
The ep8 bit is set to ‘1’ when zero-byte ISO OUT data packet is received for OUT 8 endpoint in the previ-
ous frame.
7.9.8 Endpoints 0 to 5 IN interrupt request register (in_irq)
Table 42. The in_irq register
inxir is set to ‘1’ when IN packet transmits and ACK receives from the host. Firmware sets inxir to ‘1’ to
clear interrupt.
7.9.9 Endpoints 0 to 5 OUT interrupt request register (out_irq)
Table 43. The out_irq register
outxir is set to ‘1’ when OUT packet is received error free. Firmware sets outxir to ‘1’ to clear interrupt.
7.9.10 The USB interrupt request register (usbirq)
Table 44. The usbirq bit functions
Firmware clears an interrupt request by writing ‘1’ to the corresponding request bit.
Address MSB LSB
0xC7A2 - ------ep8
Address MSB LSB
0xC7A9 - - in5ir in4ir in3ir in2ir in1ir in0ir
Address MSB LSB
0xC7AA - - out5ir out4ir out3ir out2ir out1ir out0ir
Address Bit Name Function
0xC7AB 7:5 Must be zero
4uresir USB reset interrupt request
1: a USB bus reset is detected
3suspir USB suspend interrupt request
1: USB SUSPEND signaling detected
2sutokir SETUP token interrupt request
1: SETUP token detected
1sofir Start of frame interrupt request
1: SOF packet received
0sudavir SETUP data valid interrupt request
1: error free SETUP data packet received
Revision 1.1 Page 87 of 187
nRF24LU1+ Product Specification
7.9.11 Endpoint 0 to 5 IN interrupt enables (in_ien)
Table 45. The in_ien register
Firmware sets inxien to ‘1’ to enable interrupt.
7.9.12 Endpoint 0 to 5 OUT interrupt enables (out_ien)
Table 46. The out_ien register
Firmware sets outxien to ‘1’ to enable interrupt.
7.9.13 USB interrupt enable (usbien)
Table 47. The usbien register
Address MSB LSB
0xC7AC - - in5ien in4ien in3ien in2ien in1ien in0ien
Address MSB LSB
0xC7AD - - out5ien out4ien out3ien out2ien out1ien out0ien
Address Bit Name Function
0xC7AE 7:5 -Must be zero
4uresie USB reset interrupt enable
3suspie USB suspend interrupt enable
2sutokie SETUP token interrupt enable
1sofie Start of frame interrupt enable
0sudavie SETUP data valid interrupt enable
Revision 1.1 Page 88 of 187
nRF24LU1+ Product Specification
7.9.14 Endpoint 0 control and status register (ep0cs)
Table 48. ep0cs register
Address Bit Name Function
0xC7B4 7:6 - Must be zero
5chgset Setup Buffer content was changed.
Chgset=1 - setup buffer was changed.
Chgset=0 - setup buffer was not changed.
The MCU clears the chgset bit by writing a ‘1’ to it.
The chgset bit is automatically set when USB controller
receives setup data packet.
4dstall Send STALL in the data stage.
If dstall bit is set to ‘1’, the USB controller sends a
STALL handshake for any IN or OUT token in the data
stage. When dstall is set and USB controller sends
STALL in the data stage, the ep0stall is automatically
set to ‘1’ and USB controller sends STALL handshake
also in the status stage. dstall is automatically cleared
when a SETUP token arrives. The MCU sets this bit by
writing ‘1’ to it.
The MCU should set dstall bit after last successful trans-
action in the data stage. When there were not excessive
transactions in the data stage and the next transaction
is in the correct status stage the USB controller will
answer based on hsnak and ep0stall settings.
3outbsy OUT0 endpoint busy bit. Outbsy is a read only bit that is
automatically cleared when a SETUP token arrives. The
MCU sets this bit by writing a dummy value to the
out0bc register.
1: USB controller controls the OUT 0 endpoint buffer.
0: the MCU controls of the OUT 0 endpoint buffer.
2inbsy IN0 endpoint busy bit. inbsy is a read only bit that is
automatically cleared when a SETUP token arrives. The
MCU sets this bit by reloading the in0bc register.
1: USB controller controls the IN 0 endpoint buffer.
0: the MCU controls the IN 0 endpoint buffer.
1hsnak If hsnak bit is set to ‘1’, the USB controller responds with
a NAK handshake for every packet in the status stage.
hsnak bit is automatically set when a SETUP token
arrives. The MCU clears the hsnak bit by writing a ‘1’ to
it.
0ep0stall Endpoint 0 stall.
1: the USB controller sends a STALL handshake for any
IN or OUT token. This is done in the data or handshake
phases of the CONTROL transfer. Ep0stall is automati-
cally cleared when a SETUP token arrives. The MCU
sets this bit by writing ‘1’ to it.
Revision 1.1 Page 89 of 187
nRF24LU1+ Product Specification
7.9.15 Endpoint 0 to 5 IN byte count registers (inxbc)
Table 49. Endpoint 0 to 5 IN byte count register locations
After loading the IN x endpoint buffer, the MCU writes to the inxbc register with the number of loaded bytes.
Writing to the inxbc register causes the arming of IN x endpoint by setting the inxbsy bit to ‘1’.
When the host sends IN token for IN x endpoint and inxbsy bit is set, the USB controller responds with an
inxbc size data packet.
7.9.16 Endpoint 1 to 5 IN control and status registers (inxcs)
Table 50. Endpoint 1 to 5 IN control and status register locations
Table 51. The inxcs register description
Address Name Function
0xC7B5 in0bc IN 0 endpoint byte count register
0xC7B7 in1bc IN 1 endpoint byte count register
0xC7B9 in2bc IN 2 endpoint byte count register
0xC7BB in3bc IN 3 endpoint byte count register
0xC7BD in4bc IN 4 endpoint byte count register
0xC7BF in5bc IN 5 endpoint byte count register
Address Name Function
0xC7B6 in1cs IN 1 endpoint control and status register
0xC7B8 in2cs IN 2 endpoint control and status register
0xC7BA in3cs IN 3 endpoint control and status register
0xC7BC in4cs IN 4 endpoint control and status register
0xC7BE in5cs IN 5 endpoint control and status register
Bit Symbol Function
7:2 - Not used.
1inxbsy IN x endpoint busy bit.
1: the USB controller takes control of the IN x endpoint buffer.
0: the MCU takes control of the IN x endpoint buffer.
When the host sends an IN token for IN x endpoint and the inxbsy
bit is set, the USB controller responds with inxbc size data packet
and clears the inxbsy bit.
0: the IN x endpoint is empty and ready for loading by the MCU.
1: the MCU does not access the IN x endpoint buffer.
A ‘1’ to ‘0’ transition of the inxbsy bit generates an interrupt request
for the IN x endpoint. The MCU sets the inxbsy bit by reloading the
inxbc register.
0inxstl IN x endpoint stall bit.
1: the USB controller returns a STALL handshake for all requests
to the endpoint x.
Revision 1.1 Page 90 of 187
nRF24LU1+ Product Specification
7.9.17 Endpoint 0 to 5 OUT byte count registers (outxbc)
Table 52. Endpoint 0 to 5 OUT byte count register locations
The outxbc register contains the number of bytes sent during the last OUT transfer from the host to an
OUT x endpoint. The outxbc is a read only register that is updated by the USB controller.
7.9.18 Endpoint 1 to 5 OUT control and status registers (outxcs)
Table 53. Endpoint 1 to 5 OUT control and status register locations
Table 54. The outxcs register description
Address Name Function
0xC7C5 out0bc OUT 0 endpoint byte count register
0xC7C7 out1bc OUT 1 endpoint byte count register
0xC7C9 out2bc OUT 2 endpoint byte count register
0xC7CB out3bc OUT 3 endpoint byte count register
0xC7CD out4bc OUT 4 endpoint byte count register
0xC7CF out5bc OUT 5 endpoint byte count register
Address Name Function
0xC7C6 out1cs OUT 1 endpoint control and status register
0xC7C8 out2cs OUT 2 endpoint control and status register
0xC7CA out3cs OUT 3 endpoint control and status register
0xC7CC out4cs OUT 4 endpoint control and status register
0xC7CE out5cs OUT 5 endpoint control and status register
Bit Symbol Function
- Not used
1outxbsy OUT x endpoint busy bit.
1: the USB controller takes control of the OUT x endpoint buffer.
0: the MCU takes control of the OUT x endpoint buffer.
When the host sends an OUT token for an OUT x endpoint and the
outxbsy bit is set, the USB controller receives an OUT data
packet and clears the outxbsy bit. If outxbsy=’1’, the OUT x end-
point is empty and ready to receive the next data packet from the
host. When outxbsy=’1’, the MCU does not read the OUT x end-
point buffer. A ‘1’ to ‘0’ transition of the outxbsy bit generates an
interrupt request for the OUT x endpoint. The MCU sets the outx-
bsy bit by reloading the outxbc register with a dummy value.
0outxstl OUT x endpoint stall bit.
If outxstl=’1’, the USB controller returns a STALL handshake for all
requests to the endpoint x.
Revision 1.1 Page 91 of 187
nRF24LU1+ Product Specification
7.9.19 USB control and status register (usbcs)
Table 55. The usbcs bit functions
7.9.20 Data toggle control register (togctl)
Table 56. The togctl bit functions
Address Bit Name Function
0xC7D6 7 wakesrc Wakeup source. This bit indicates that a wakeup pin
resumed the USB controller. The MCU resets this bit
by writing a ‘1’ to it.
6-Not used.
5sofgen Sofgen= 1 - internal SOF timer is used to generate
SOF interrupt in case when SOF issued by USB host
was missed.
Sofgen= 0 - internal SOF timer is disabled.
Default value (after reset) is ‘0’.
4-Not used.
3discon 1: Disconnect the 1.5 kohm internal pull-up resistor
on D+ line, 0: Normal
2-Not used.
1forcej Forcej should be used only in the suspend state. The
MCU should set forcej bit to drive J state on the USB
lines and then clear forcej and set sigrsume to drive
resume-K state on the USB lines. Forcing J state
between idle and K state can be done to raise the
crossover voltage and eliminate any false SE0.
0sigrsume Signal remote device resume. If the MCU sets this bit
to ‘1’, the USB controller sets K state on the USB.
Address Bit Name Function
0xC7D7 7 q Data toggle value q=’1’ means that data toggle for endpoint
selected by ep2,ep1,ep0 and io bits is set to DATA1. q=’0’
means that data toggle for endpoint selected by ep2,ep1,ep0
and io bits is set to DATA0. Before reading this bit, the MCU
writes the ep2, ep1, ep0 and io bits.
6s Set data toggle to DATA1. Writing ‘1’ to this bit when endpoint is
selected (ep2, ep1, ep0, io bits) causes setting the data toggle
to DATA1.
5r Reset data toggle to DATA0. Write ‘1’ to this bit when endpoint
is selected (ep2, ep1, ep0, io bits) causes setting data toggle to
DATA0.
4io Select IN or OUT endpoint io=’1’ selects IN endpoint, i0=’0’
selects OUT endpoint.
3-Not used.
2ep2 Select number of endpoint. Valid values are 0 to 5 (000 – 101).
1ep1
0ep0
Revision 1.1 Page 92 of 187
nRF24LU1+ Product Specification
7.9.21 USB frame count low (usbframel/usbframeh)
Table 57. USB frame count low (usbframel/usbframeh)
The USB controller copies the frame count into the usbframel and usbframeh registers at every SOF
(Start Of Frame). These registers are read only.
Note: Frame count wraps from 3ffh to 0x000.
7.9.22 Function address register (fnaddr)
Table 58. Function address register (fnaddr)
The USB controller copies the “function address” which was sent by the host into the fnaddr register. The
USB controller responds only with its assigned address. The fnaddr is a read only register.
7.9.23 USB endpoint pairing register (usbpair)
Table 59. The usbpair bit functions
7.9.24 Endpoints 0 to 5 IN valid bits (Inbulkval)
Table 60. The inbulkval register
If inxval=’1’, the IN x endpoint is active. When inxval=’0’, the IN x endpoint is inactive and the USB control-
ler does not respond if IN x endpoint is addressed.
Address Name Function
0xC7D8 usbframel USB frame count low
0xC7D9 usbframeh USB frame count high
Address Name Function
0xC7DB fnaddr USB function address (1-127)
Address Bit Name Function
0xC7DD 7 isosend0 ISO endpoints send zero length data packet.
If the USB controller receives IN token for the isochro-
nous endpoint and IN endpoint FIFO is empty, the
USB controller response depends on the isosend0
bit.
If isosend0=’1’, the USB controller sends a zero
length data packet.
If isosend0=’0’, the USB controller does not respond.
6:5 Not used.
4pr4out 1: Pair bulk OUT 4 and bulk OUT 5 endpoints.
3pr2out 1: Pair bulk OUT 2 and bulk OUT 3 endpoints.
2pr6in 1: Pair bulk IN 6 and bulk IN 7 endpoints.
1pr4in 1: Pair bulk IN 4 and bulk IN 5 endpoints.
0pr2in 1: Pair bulk IN 2 and bulk IN 3 endpoints.
Address MSB LSB
0xC7DE 0 0 in5val in4val in3val in2val in1val 1
Revision 1.1 Page 93 of 187
nRF24LU1+ Product Specification
7.9.25 Endpoints 0 to 5 OUT valid bits (outbulkval)
Table 61. The outbulkval register
If outxval=’1’, the OUT x endpoint is active. When outxval=’0’, the OUT x endpoint is inactive and the USB
controller does not respond if OUT x endpoint is addressed.
7.9.26 Isochronous IN endpoint valid bits (inisoval)
Table 62. The inisoval register
If in8val=’1’, the IN 8 endpoint is active. When in8val=’0’, the IN 8 endpoint is inactive and the USB control-
ler does not respond if IN 8 endpoint is addressed.
7.9.27 Isochronous OUT endpoint valid bits (outisoval)
Table 63. The outisoval register
If out8val=’1’, the OUT 8 endpoint is active. When out8val=’0’, the OUT 8 endpoint is inactive and the USB
controller does not respond if OUT 8 endpoint is addressed.
7.9.28 SETUP data buffer (setupbuf)
Table 64. The setupbuf buffer
The setupbuf contains the 8 bytes of the SETUP data packet from the latest CONTROL transfer.
7.9.29 ISO OUT endpoint start address (out8addr)
Table 65. The out8addr start address
7.9.30 ISO IN endpoint start address (in8addr)
Table 66. The in8addr start address
Address MSB LSB
0xC7DF 0 0 out5val out4val out3val out2val out1val 1
Address MSB LSB
0xC7E0 0 0 0 0 0 0 0 in8val
Address MSB LSB
0xC7E1 0 0 0 0 0 0 0 out8val
Address MSB LSB
0xC7E8-0xC7EF D7 D6D5D4D3D2D1D0
Address MSB LSB
0xC7F0 A9 A8 A7 A6 A5 A4 0 0
Address MSB LSB
0xC7F8 A9 A8 A7 A6 A5 A4 0 0
Revision 1.1 Page 94 of 187
nRF24LU1+ Product Specification
8 Encryption/Decryption Unit
The nRF24LU1+ has dedicated HW for data encryption or decryption according to the AES (Advanced
Encryption Standard) algorithm. An AES encryption/decryption consists of the transformation of a 128-bit
block into an encrypted 128-bit block.
8.1 Features
The AES block supports both encryption and decryption in ECB, CBC, CFB, OFB and CTR modes using a
128-bit key and optionally a 128-bit initialization vector.
8.1.1 ECB – Electronic Code Book
ECB is the most basic AES encryption/decryption mode. In encryption E the plaintext on DI is converted to
a ciphertext on DO. In decryption D the ciphertext on DI is converted to plaintext on DO. ECB must use the
last expanded key to decrypt. Decryption reverses encryption operations and is identical to the encryption
function.
Figure 41. ECB – Electronic Code Book
8.1.2 CBC – Cipher Block Chaining
CBC adds a feedback mechanism to a block cipher. The result of the previous encryption operation is
XOR’ed with incoming data. An initialization vector IV is used for the first iteration. CBC must use the last
expanded key to decrypt. Decryption reverses encryption operations and is identical to the encryption
function.
Figure 42. CBC – Cipher Block Chaining mode
E D
Plaintext
DI
KEY KEY
Ciphertext
DI
DO
Ciphertext
DO
Plaintext
E
IV
E E
IV
D D D
Revision 1.1 Page 95 of 187
nRF24LU1+ Product Specification
8.1.3 CFB – Cipher FeedBack
In CFB the output of an encryption operation is fed back to the input of the AES block. An initialization vec-
tor IV is used for the first iteration. Input data is encrypted by XORing it with the output of the encryption
module. Decryption reverses encryption operations and is identical to the encryption function.
Figure 43. CFB – Cipher FeedBack mode
8.1.4 OFB – Output FeedBack mode
In OFB the output of an encryption operation is fed back to the input of the AES core. An initialization vec-
tor IV is used for the first iteration. Input data is encrypted by XORing it with the output of the encryption
module. Decryption reverses encryption operations and is identical to the encryption function.
Figure 44. OFB – Output FeedBack mode
8.1.5 CTR – Counter mode
In CTR the output of a counter is the input of the AES core. When entering CTR mode, an initialization vec-
tor IV is used to initialize the counter. Input data is encrypted by XORing it with the output of the encryption
module. Decryption reverses encryption operations and is identical to the encryption function.
AES
IV
INIT
KEY
DIN DOUT
E/D
AES
IV
INIT
KEY
DIN DOUT
Revision 1.1 Page 96 of 187
nRF24LU1+ Product Specification
Note: The counter cannot be reinitialized without changing mode.
Figure 45. CTR – Counter mode
8.2 Functional description
The MCU initializes the AES block with key (AESKIN) and optionally the initialization vector (AESIV). Then
the MCU loads a 128-bit block into AESD, selects mode and starts the operation with AESCS.
When the result is ready, the AESIRQ is asserted and the MCU reads out the AESD register. Alternatively,
the AESCS[0] can be polled instead of using interrupts.
Table 67. AESCS register
The AESKIN, AESIV and AESD are 128-bit registers. In order to update or read one of these registers, 16
consecutive write (or read) operations to a single register are required.
The order of writing (or reading) to update a register in nRF24LU1+ begins with the last (16th) operation
and works back to the first.
Address Reset
value Bit Name Description
0xE8 0x00 7:5 - Not used
4:2 mode Type of AES encryption/decryption
000: CBC, 001: CFB, 010: OFB, 011: CTR, 100: ECB
1 decr 0: Encrypt, 1: Decrypt
0 go Set by SW to ‘1’ to start operation. SW can poll this signal to
check if AES block is busy. Automatically reset by HW when
operation is completed. An encrypt or decrypt operation takes
about 45 Cclk cycles.
AES
INIT
KEY
DIN DOUT
Counter
IV
Revision 1.1 Page 97 of 187
nRF24LU1+ Product Specification
AES data sets are normally organized in two dimensional arrays (ai,j):
Table 68. A two dimensional array
The array position to write to is decided by AESIA1 which contains two 4 bit pointers for the AESKIN regis-
ter and the AESIV register. These pointers are incremented by each read/write to AESKIN or AESIV. After
16 reads/writes, the pointers wrap around to the starting value.
The relation of the byte pointer address n and the position in the AES array (ai,j) is given by the following
definition:
i = n mod 4; j = [n / 4]; n = 15 - i - 4 * j
The relationship between the byte pointer address and the AES array position in nRF24LU1+ is shown in
Table 69. below:
Table 69. Relation between the byte pointer address and AES data array
Table 70. AESKIN, AESIV and AESD registers
A partial update can be done by using the AESIA1 or AESIA2 registers (see Table 71. and Table 72.).
By setting AESIA1 a single byte or a smaller block can be updated.
Table 71. AESIA1 register
a0,0 a0,1 a0,2 a0,3
a1,0 a1,1 a1,2 a1,3
a2,0 a2,1 a2,2 a2,3
a3,0 a3,1 a3,2 a3,3
n = 15 n = 11 n = 7 n = 3
n = 14 n = 10 n = 6 n = 2
n = 13 n = 9 n = 5 n = 1
n = 12 n = 8 n = 4 n = 0
Address Reset
value Bit R/W Description
0xF1 0x00 7:0 RW AESKIN
0xF2 0x00 7:0 RW AESIV
0xF3 0x00 7:0 RW AESD
Address Reset value Bit Name Description
0xF5 0x00 7:4 ia_kin AESKIN byte pointer address
3:0 ia_iv AESIV byte pointer address
Revision 1.1 Page 98 of 187
nRF24LU1+ Product Specification
The AESIA2 works like AESIA1, but only contains a 4-bit pointer for AESD.
Table 72. AESIA2 register
Address Reset value Bit Name Description
0xF6 0x00 7:4 - not used
3:0 ia_data AESD byte pointer address
Revision 1.1 Page 99 of 187
nRF24LU1+ Product Specification
9 SPI master
The system features a simple single buffered SPI (Serial Peripheral Interface) master working in mode 0,
that is, capture MISO in rising SCK, and changing MOSI on falling SCK.
The SPI bus (MMISO, MSCK and MMOSI) are available at the programmable digital I/O. The SPI hard-
ware does not generate any chip select signal. Another programmable digital I/O must be used to act as
chip selects for one or more external SPI devices, see Table 98. on page 117 for details.
9.1 Block diagram
Figure 46. Master SPI block diagram
9.2 Functional description
The SPI hardware is controlled by SFR registers SMDAT and SMCTRL.
Table 73. SMDAT register
Table 74. SMCTRL register.
Address Reset value Bit R/W Function
0xB2 0x00 R/W SPI data input/output
Address Reset value Bit R/W Function
0xB3 0x00 7:5 - Not used
4 RW 00: disable, 01: enable
3:0 RW Divider factor from MCU clock (Cclk) to SPI clock fre-
quency
0000: 1/2 of Cclk frequency
0001: 1/2 of Cclk frequency
0010: 1/4 of Cclk frequency
0011: 1/8 of Cclk frequency
0100: 1/16 of Cclk frequency
0101: 1/32 of Cclk frequency
0110: 1/64 of Cclk frequency
other: 1/64 of Cclk frequency
MMISO SMDAT MMOSI
MSCK
MC
U
Revision 1.1 Page 100 of 187
nRF24LU1+ Product Specification
9.3 SPI operation
A sequence of 8 pulses is started on MSCK every time you write to the SMDAT register. Also, the 8 bits of
SMDAT register are clocked out on MMOSI with MSB clocking out first. Simultaneously, 8 bits from MMISO
are clocked into SMDAT register. Output data is shifted on the negative edge of MSCK, and input data is
read on the positive edge of MSCK. This is illustrated in Figure 47.
When the 8 bits from MMISO are finished, MSDONE interrupt goes active, and the 8 bits from MMISO can
be read from SMDAT register. The interrupt bit must be cleared, by writing to SMDAT register again, before
starting another SPI transaction.
Figure 47. Master SPI timing
Conditions: Output load= 10pF, MMISO rise/fall time=5ns.
Table 75. Master SPI timing values
Minimum time between two consecutive SPI transactions is: 8.5 TMsck + Tdready + Tsw where Tsw is the
time taken by the software to process MSDONE interrupt and write to SMDAT register.
Value Description
TMsck = TMch +
TMcl
SCK cycle time, as defined by SMCTRL register.
TMcc Time from writing to SMDAT register to first MSCK pulse, TMsck / 2.
TMcd Delay from negative edge of MSCK to new MMOSI output data, may vary
from -10ns to 10ns.
TMdc MMISO setup time to positive edge of MSCK, TMdc > 45ns.
TMdh MMISO hold time to positive edge of MSCK, TMdh > 0ns.
Tdready Time from last MSCK pulse to MSDONE interrupt goes active. 7 MCU clock
cycles.
S7 S6 S0
C7 C0
TMcd TMcsd
T
Mdh
T
Mdc
TMcl
TMch TMcc
MSCK
MMISO
MMOSI
End of
write to
SMDAT
register
SPI_READY
interrupt
Tdready
Revision 1.1 Page 101 of 187
nRF24LU1+ Product Specification
10 SPI slave
The system features a simple single buffered SPI (Serial Programmable Interface) slave working in mode
0, that is, capturing SMOSI on rising SSCK, and changing SMISO in falling SSCK.
The slave SPI monitors the SCSN, SMOSI and SSCK pins, and controls the SMISO pin. They are available
on P0.3 to P0.0, see chapter 13 on page 116 for details.The SPI slave may also be used for flash pro-
gramming when PROG=1, see section 17.7.
10.1 Block diagram
Figure 48. Slave SPI block diagram
10.2 Functional description
The following registers control the slave SPI.
Table 76. SSCONF register
Table 77. SSSTAT register
Table 78. SSDAT register
Address Reset value Bit R/W Function
0xBC 0x00 7:6 - Not used
5 RW 1: Disable interrupt when SCSN goes high
4 RW 1: Disable interrupt when SCSN goes low
3 RW 1: Disable slave SPI interrupts
2:1 - Not used
0 RW 1: Enable slave SPI
Address Reset value Bit R/W Function
0xBE 0x00 7:3 - Not used
2 R 1: Interrupt caused by positive edge of SCSN
1 R 1: Interrupt caused by negative edge of SCSN
0R
1: Interrupt caused by data-byte sent or receiveda
a. If SPI is polled (no interrupts), then IRCON.2 (see chapter 22.4.4 on page 174) should be
polled, since reading SSSTAT clears the status-flags.
Address Reset value Bit R/W Function
0xBD 0x00 RW Data register
SMOSI SSDAT SMISO
SSCK
MCU
Revision 1.1 Page 102 of 187
nRF24LU1+ Product Specification
10.3 SPI timing
Figure 49. SPI NOP timing diagram)
Conditions: SMISO load= 10pF, SSCK rise/fall time=2ns, other inputs rise/fall time=5ns.
Table 79. SPI timing parameters
Parameter Symbol Min. Max Units
SMOSI to SSCK Setup TSdc 5ns
SSCK to SMOSI Hold TSdh 2 ns
SCSN to SMISO Active TScsd 35 ns
SSCK to SMISO Valid TScd 42 ns
SSCK Low Time TScl 50 ns
SSCK High Time TSch 50 ns
SSCK Frequency FSSCK 08MHz
SCSN to SSCK Setup TScc 8ns
SSCK to SCSN Hold TScch 2ns
SCSN inactive time TScwh 130 ns
SCSN to SMISO High Z TScdz 25 ns
C7 C6 C0
S7 S0
TScdz TScd TScsd
TSdh
TSdc
TS cch TScl
TSch TScc
TScwh
SCSN
SSCK
SMOSI
SMISO
Revision 1.1 Page 103 of 187
nRF24LU1+ Product Specification
11 Timer/Counters
The nRF24LU1+ contains a set of counters used for timing up important system events.
11.1 Features
nRF24LU1+ includes the following set of timers/counters:
• Three 16-bit timers/counters (Timer 0, Timer 1 and Timer 2) which can operate as either a timer with
a clock rate based on the MCU clock, or as an event counter clocked by signals from the program-
mable digital I/O.
• In addition there is a RTC2 wakeup timer which is described in section 19.3.3 on page 161.
11.2 Block diagram
Figure 50. Block diagram of timers/counters
11.3 Functional description
11.3.1 Timer 0 and Timer 1
In timer mode, Timer 0/1 is incremented every 12 clock cycles.
In the counter mode, the Timers 1 and 0 are incremented when the falling edge is detected at the corre-
sponding input pin T0 for Timer 0, or T1 for Timer 1.
Note: Timer input pins TO, T1, and T2 must be configured as described in section 13.2 on page 118.
tf1 (irq)
tf0 (irq)
Timer 1/Timer 0
TH1
TCON
TL1
TH0 TL0
TMOD
TIMER1
(from pin)
TIMER0
(from pin)
Timer 2
TH2
T2CON
TL2
CRCH
TIMER2
(from pin)
CRCL
CCH3 CCL3
CCH2 CCL2
CCH1 CCL1
CCEN
tf2 (irq)
exf2 (irq)
Cclk
t2ex
CKLF/2
Revision 1.1 Page 104 of 187
nRF24LU1+ Product Specification
Since it takes two clock cycles to recognize a 1-to-0 event, the maximum input count rate is ½ of the oscil-
lator frequency. There are no restrictions on the duty cycle, however to ensure proper recognition of 0 or 1
state, an input should be stable for at least 1 clock cycle.
Timer 0 and Timer 1 status and control are in TCON and TMOD register. The actual 16-bit Timer 0 value is in
TH0 (8 msb) and TL0 (8 lsb), while Timer 1 use TH1 and TL1.
Four operating modes can be selected for Timer 0 and Timer 1. Two Special Function Registers, TMOD and
TCON, are used to select the appropriate mode.
11.3.1.1 Mode 0 and Mode 1
In mode 0, Timer 0 and Timer 1 are configured as 13-bit registers (TL0/TL1 = 5 bits, TH0/TH1 = 8 bits).
The upper three bits of TL0/TL1 are unchanged and should be ignored. In mode 1 Timer 0 and Timer 1 are
configured as 16-bit registers.
Figure 51.
Timer 0 in mode 0 and 1
Figure 52. Timer 1 in mode 0 and 1
/12
TL0 TCON.tf0
TMOD.ct0=0
Cclk
T0 (from pin)
P0.3
TCON.tr0
TMOD.gate0
TMOD.ct0=1
TH0
/12
TL1 TCON.tf1
TMOD.ct1=0
Cclk
T1 (from pin)
TCON.tr1
TMOD.ct1=1
TH1
Revision 1.1 Page 105 of 187
nRF24LU1+ Product Specification
11.3.1.2 Mode 2
In this mode, Timer 0 and Timer 1 are configured as 8-bit registers with auto reload.
Figure 53. Timer 0 in mode 2
Figure 54. Timer 1 in mode 2
/12
TL0 TCON.tf0
TMOD.ct0=0
TMOD.ct0=1
Cclk
T0 (from pin)
P0.3 TH0
TCON.tr0
TMOD.gate0
/12
TL1 TCON.tf1
Cclk
T1 (from pin)
THi
TCON.tr1
TMOD.ct1=0
TMOD.ct1=1
Revision 1.1 Page 106 of 187
nRF24LU1+ Product Specification
11.3.1.3 Mode 3
In mode 3 Timer 0 and Timer 1 are configured as one 8-bit timer/counter and one 8-bit timer, but timer 1 in
this mode holds its count. When Timer 0 works in mode 3 Timer 1 can still be used in other modes by the
serial port as a baud rate generator, or as an application not requiring an interrupt from Timer 1.
Figure 55. Timer 0 in mode 3
11.3.2 Timer 2
Timer 2 is controlled by T2CON while the value is in TH2 and TL2. Timer 2 also has four capture and one
compare/reload registers which can read a value without pausing or reload a new 16-bit value when Timer
2 reaches zero, see chapter 11.4.7 on page 111 and chapter 11.4.8 on page 111.
Figure 56. Timer 2 block diagram
/12
TL0
TCON.tf0
TMOD.ct0=0
TMOD.ct0=1
Cclk
T0 (from pin)
P0.3
TH0 TCON.tf1
TCON.tr0
TMOD.gate0
TCON.tr1
TCON.tf0
CCL3 + CCH3
Prescaler
Cclk TIMER2
CRCL + CRCH
CCL3 + CCH3
CCL2 + CCH2
CCL1 + CCH1
Revision 1.1 Page 107 of 187
nRF24LU1+ Product Specification
11.3.2.1 Timer 2 description
Timer 2 can operate as a timer, event counter, or gated timer.
Figure 57. Timer 2 in Reload Mode
11.3.2.2 Timer mode
Timer mode is invoked by setting the t2i0=1 and t2i1=0 in the T2CON register. In this mode, the count rate
is derived from the clk input.
Timer 2 is incremented every 12 or 24 clock cycles depending on the 2:1 prescaler. The prescaler mode is
selected by bit t2ps of T2CON register. When t2ps=0, the timer counts up every 12 clock cycles, otherwise
every 24 cycles.
11.3.2.3 Event counter mode
This mode is invoked by setting the t2i0=0 and t2i1=1 in the T2CON register.
In this mode, Timer 2 is incremented when external signal T2 (P0.5) (see section 13.2 on page 118 for
more information on T2) changes its value from 1 to 0. The T2 input is sampled at every rising edge of the
clock. Timer 2 is incremented in the cycle following the one in which the transition was detected. The max-
imum count rate is ½ of the clock frequency.
11.3.2.4 Gated timer mode
This mode is invoked by setting the t2i0=1 and t2i1=1 in the T2CON register.
In this mode, Timer 2 is incremented every 12 or 24 clock cycles (depending on T2CON t2ps flag). Addi-
tionally, it is gated by the external signal T2 (P0.5). When T2=0, Timer 2 is stopped.
crch + crcl
th2 + tl2
Interrupt (exf2)
Reload Mode 0
Reload Mode 1
t2ex
exen2 Interrupt
(tf2)
count enable
Revision 1.1 Page 108 of 187
nRF24LU1+ Product Specification
11.3.2.5 Timer 2 reload
A 16-bit reload from the CRC register can be done in two modes:
• Reload Mode 0: Reload signal is generated by Timer 2 overflow (auto reload).
• Reload Mode 1: Reload signal is generated by negative transition at t2ex.
Note: t2ex is connected to an internal clock signal which is half frequency of CKLF (see section
19.3.1 on page 161.
11.4 SFR registers
11.4.1 Timer/Counter control register – TCON
TCON register reflects the current status of MCU Timer 0 and Timer 1 and it is used to control the operation
of these modules.
Table 80. TCON register
The tf0, tf1 (timer 0 and timer 1 overflow flags), ie0 and ie1 (external interrupt 0 and 1 flags) are automati-
cally cleared by hardware when the corresponding service routine is called.
Address Reset
value Bit Name Auto
clear Description
0x88 0x00 7 tf1 Yes Timer 1 overflow flag. Set by hardware when Timer1 over-
flows.
6 tr1 No Timer 1 Run control. If cleared, Timer 1 stops.
5 tf0 Yes Timer 0 overflow flag. Set by hardware when Timer 0 over-
flows.
4 tr0 No Timer 0 Run control. If cleared, Timer 0 stops.
3 ie1 Yes External interrupt 1 flag. Set by hardware.
2 it1 No External interrupt 1 type control. 1: falling edge, 0: low level
1 ie0 Yes External interrupt 0 flag. Set by hardware.
0 it0 No External interrupt 0 type control. 1: falling edge, 0: low level
Revision 1.1 Page 109 of 187
nRF24LU1+ Product Specification
11.4.2 Timer mode register - TMOD
TMOD register is used for configuration of Timer 0 and Timer1.
Table 81. TMOD register
11.4.3 Timer0 – TH0, TL0
Table 82. Timer 0 register (TH0:TL0)
These registers reflect the state of Timer 0. TH0 holds higher byte and TL0 holds lower byte. Timer 0 can
be configured to operate as either a timer or a counter.
11.4.4 Timer1 – TH1, TL1
Table 83. Timer 1 register (TH1:TL1)
These registers reflect the state of Timer 1. TH1 holds higher byte and TL1 holds lower byte. Timer 1 can
be configured to operate as either timer or counter.
Address Reset
value Bit Name Description
0x89 0x00 7 reserved Must be 0
6 ct1 Timer 1 counter/timer select. 1: Counter, 0: Timer
5-4 mode1 Timer 1 mode
00 – Mode 0: 13-bit counter/timer
01 – Mode 1: 16-bit counter/timer
10 – Mode 2: 8-bit auto-reload timer
11 – Mode 3: Timer 1 stopped
3 gate0 Timer 0 gate control
2 ct0 Timer 0 counter/timer select. 1: Counter, 0: Timer
1-0 mode0 Timer 0 mode
00 – Mode 0: 13-bit counter/timer
01 – Mode 1: 16-bit counter/timer
10 – Mode 2: 8-bit auto-reload timer
11 – Mode 3: two 8-bit timers/counters
Address Register name
0x8A TL0
0x8C TH0
Address Register name
0x8B TL1
0x8D TH1
Revision 1.1 Page 110 of 187
nRF24LU1+ Product Specification
11.4.5 Timer 2 control register – T2CON
T2CON register reflects the current status of Timer 2 and is used to control the Timer 2 operation.
Table 84. T2CON register
11.4.6 Timer 2 – TH2, TL2
Table 85. Timer 2 (TH2:TL2)
The TL2 and TH2 registers reflect the state of Timer 2. TH2 holds higher byte and TL2 holds lower byte.
Timer 2 can be configured to operate in compare, capture or, reload modes.
Address Reset
value Bit Name Description
0xC8 0x00 7 t2ps Prescaler select. 0: timer 2 is clocked with 1/12 of the Cclk frequency.
1: timer 2 is clocked with 1/24 of the Cclk frequency.
6 i3fr INT3 edge select. 0: falling edge, 1: rising edge
5 i2fr INT2 edge select: 0: falling edge, 1: rising edge
4:3 t2r Timer 2 reload mode. 0X – reload disabled, 10 – Mode 0, 11 – Mode 1
2 t2cm Timer 2 compare mode. 0: Mode 0, 1: Mode 1
1-0 t2i Timer 2 input select. 00: stopped, 01: f/12 or f/24, 10: falling edge of t2,
11: f/12 or f/24 gated by t2.
Address Register name
0xCC TL2
0xCD TH2
Revision 1.1 Page 111 of 187
nRF24LU1+ Product Specification
11.4.7 Compare/Capture enable register – CCEN
The CCEN register serves as a configuration register for the Compare/Capture Unit associated with the
Timer 2.
Table 86. CCEN register
11.4.8 Capture registers – CC1, CC2, CC3
The Compare/Capture registers (CC1, CC2, CC3) are 16-bit registers used by the Compare/Capture Unit
associated with the Timer 2. CCHn holds higher byte and CCLn holds lower byte of the CCn register.
Table 87. Capture Registers - CC1, CC2 and CC3
Address Reset
value Bit Name Description
0xC1 0x00 7:6 coca3 compare/capture mode for CC3 register
00: compare/capture disabled
01: reserved
10: reserved
11: capture on write operation into register CCL3
5:4 coca2 compare/capture mode for CC2 register
00: compare/capture disabled
01: reserved
10: reserved
11: capture on write operation into register CCL2ah3
3:2 coca1 compare/capture mode for CC1 register
00: compare/capture disabled
01: reserved
10: reserved
11: capture on write operation into register CCL1
1:0 coca0 compare/capture mode for CRC register
00: compare/capture disabled
01: reserved
10: compare enabled
11: capture on write operation into register CRCL
Address Register name
0xC2 CCL1
0xC3 CCH1
0xC4 CCL2
0xC5 CCH2
0xC6 CCL3
0xC7 CCH3
Revision 1.1 Page 112 of 187
nRF24LU1+ Product Specification
11.4.9 Compare/Reload/Capture register – CRCH, CRCL
Table 88. Compare/Reload/Capture register - CRCH, CRCL
CRC (Compare/Reload/Capture) register is a 16-bit wide register used by the Compare/Capture Unit asso-
ciated with Timer 2. CRCH holds higher byte and CRCL holds lower byte.
Address Reset value Register name
0xCA 0x00 CRCL
0xCB 0x00 CRCH
Revision 1.1 Page 113 of 187
nRF24LU1+ Product Specification
12 Serial Port (UART)
The MCU system is configured with one serial port that is identical in operation to the standard 8051 serial
port (Serial interface 0). The two serial port signals RXD and TXD are available at the programmable digital
I/O. See Chapter 13 on page 116.
The serial port (UART) derives its clock from the MCU clock; Cclk. See chapter 20.4.1 on page 167 for
more information.
12.1 Features
• Synchronous mode, fixed baud rate
• 8-bit UART mode, variable baud rate
• 9-bit UART mode, variable baud rate
• 9-bit UART mode, fixed baud rate
• Additional baud rate generator
12.2 Block diagram
Figure 58. Block diagram of serial port
12.3 Functional description
The serial port is controlled by S0CON, while the actual data transferred is read or written in the S0BUF
register. Transmission speed (baud rate) is selected using the S0RELL, S0RELH and WDCON registers.
UART/TXD
(to pin)
Transmit & Receive
S0CON
S0BUF
UART/RXD
(from pin)
Baud rate generator
S0RELH S0RELL
WDCON.7
From
Timer 1
Revision 1.1 Page 114 of 187
nRF24LU1+ Product Specification
12.4 SFR registers
12.4.1 Serial Port 0 control register – S0CON
The S0CON register controls the function of Serial Port 0.
Table 89. S0CON register
The baud rate for Mode 1 or Mode 3 is:
Figure 59. Equation of baud rate settings for Serial Port 0
Address Reset
value Bit Name Description
0x98 0x00 7:6 sm0:
sm1
Serial Port 0 mode select
0 0: Mode 0 – Shift register at baud rate Cclk / 12
0 1: Mode 1 – 8-bit UART. Baud rate see Figure 59. on page 114
1 0: Mode 2 – 9-bit UART at baud rate Cclk /32 or Cclk/64a
1 1: Mode 3 – 9 bit UART. Baud rate see Figure 59. on page 114
a. If smod = 0 baud rate is Cclk/64, if smod = 1 then baud rate is Cclk/32.
5 sm20 Multiprocessor communication enable
4 ren0 Serial reception enable: 1: Enable Serial Port 0.
3 tb80 Transmitter bit 8. This bit is used while transmitting data through
Serial Port 0 in Modes 2 and 3. The state of this bit corresponds with
the state of the 9th transmitted bit (for example, parity check or multi-
processor communication). It is controlled by software.
2 rb80 Received bit 8. This bit is used while receiving data through Serial
Port 0 in Modes 2 and 3. It reflects the state of the 9th received bit.
1 ti0 Transmit interrupt flag. It indicates completion of a serial transmission
at Serial Port 0. It is set by hardware at the end of bit 8 in mode 0 or
at the beginning of a stop bit in other modes. It must be cleared by
software.
0 ri0 Receive interrupt flag. It is set by hardware after completion of a
serial reception at Serial Port 0. It is set by hardware at the end of bit
8 in mode 0 or in the middle of a stop bit in other modes. It must be
cleared by software.
()
rels
Cclk
ratebaud
wdconbdfor
rateoverflowTimer
Cclk
ratebaud
wdconbdfor
mods
dosm
02*64
*2
:1)7.(
)1(*
32
*2
:0)7.(
10 −
=
=
=
=
Revision 1.1 Page 115 of 187
nRF24LU1+ Product Specification
Below is an explanation of some of the values used in Figure 59. :
Table 90. Values of S0CON equation
12.4.2 Serial port 0 data buffer – S0BUF
Table 91. S0BUF register
Writing data to the SOBUF register sets data in serial output buffer and starts the transmission through
Serial Port 0. Reading from the S0BUF reads data from the serial receive buffer.
12.4.3 Serial port 0 reload register – S0RELH, S0RELL
Serial Port 0 Reload register is used for Serial Port 0 baud rate generation. Only 10 bits are used, 8 bits
from the S0RELL, and 2 bits from the S0RELH.
Table 92. S0RELL/S0RELH register
12.4.4 Serial Port 0 baud rate select register - WDCON
The MSB of this register is used by Serial Port 0 for baud rate generation
Table 93. WDCON register
a. It is not recommended to use Timer1 overflow as baud generator.
Value Definition
smod (PCON.7) Serial Port 0 baud rate select flag
s0rel The contents of S0REL registers (s0relh, s0rell) see chapter 12.4.3 on
page 115.
bd (wdcon.7) The MSB of WDCON register see chapter 12.4.4 on page 115
Address Reset value Register name
0x99 0x00 S0BUF
Address Reset value Register name
0xAA 0xD9 S0RELL
0xBA 0x03 S0RELH
Address Reset
value Bit Name Description
0xD8 0x00 7 bd Serial Port 0 baud rate select (in modes 1 and 3)
When 1, additional internal baud rate generator is used, otherwise
Timer 1 overflow is used.a
6-0 Not used
Revision 1.1 Page 116 of 187
nRF24LU1+ Product Specification
13 Input/Output port (GPIO)
Six general purpose I/O lines are available on the nRF24LU1+. These can be used for general I/O with
selectable direction for each bit, or these lines can be used for specialized functions.
13.1 Normal IO
When PROG=0, the GPIO pins are controlled by the registers P0ALT, P0DIR and P0EXP, when PROG=1 the
GPIO pins are configured as a slave SPI port, see pins SCSN, SMISO,SMOSI, SSCK below. The P0ALT
register selects between the default and the alternate functions for each of the six port pins when
P0EXP=0. If P0ALT=0 then the default function is selected, port data is set with the P0 register, and pin
direction is set with P0DIR register.
Table 94. P0 register
Table 95. P0DIR register
The P0ALT and P0EXP registers are used to select alternate or expanded functions, see Table 98. on page
117 for details.
Table 96. P0ALT register
Table 97. P0EXP register
The relationship between the P0EXP and P0ALT registers is shown in Table 98. on page 117.
Address Reset
value bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bbit 0
0x80 0xFF - - D5 D4 D3 D2 D1 D0
Address Reset value Bit Description
0x94 0xFF 7:6 Not used
5:0 0: P0.x is output, 1: P0.x is input
Address Reset value Bit Description
0x95 0x00 7:6 Not used
5:0 1: Alternate function, 0: General I/O, see Table 99. on page 118
Address Reset value Bit Description
0xC9 0x00 7:6
5:4
3:2
1:0
Controls P0.5
Controls P0.4
Not used
Controls P0.3-P0.0, see Table 99. on page 118 for details
Revision 1.1 Page 117 of 187
nRF24LU1+ Product Specification
Table 98. Port functions
Pin
Normal
Expanded 1 Expanded 2 Expanded 3
Default
function Alternate
P0EXP[7:6]
00 01 10 11
P0ALT[5] P0ALT[5]
0 1 x
P0.5 D5 T0 (timer0
input)
T2 (timer2 input)
P0EXP[5:4]
00 01 10 11
P0ALT[4] P0ALT[4]
0 1 x
P0.4 D4 T1 (timer1 input)
P0EXP[1:0]
00 01 10 11
P0ALT[3-0] P0ALT[3-0]
0 1 x
P0.3 D3 INT0 (inter-
rupt) P0.3a
a. Configured as output, typically used for Master SPI, see chapter 9 on page 99.
SCSN
P0.2 D2 TXD (UART) MMISO SMISO
P0.1 D1 RXD (UART) MMOSI SMOSI
P0.0 D0 GTIMERb
b. GTIMER is an RTC output controlled by WGTIMER, see chapter 19.3.6 on page 162.
MSCK SSCK
Revision 1.1 Page 118 of 187
nRF24LU1+ Product Specification
13.2 Expanded IO
The combined effect of the P0ALT and P0EXP register is shown in Table 99. on page 118. The content of
both P0ALT and P0EXP is shown in binary. An ‘X’ in Table 104 means that the bit can both be ‘0’ or ‘1’.
Table 99. Alternative functions of Port 0
P0ALT P0EXP P0.5 P0.4 P0.3 P0.2 P0.1 P0.0
00000000 00000000 D5 D4 D3 D2 D1 D0
001XXXXX 00XXXXXX T0a
a. Timer0 input
001XXXXX 01XXXXXX T2b
b. Timer2 input
00X1XXXX XX00XXXX
00X1XXXX XX01XXXX T1c
c. Timer1 input
00X1XXXX XX11XXXX
00XX1XXX XXXXXX00 INT0d
d. Interrupt input INT0
00XX1XXX XXXXXX01 MCSN
00XX1XXX XXXXXX10 SCSN
00XX1XXX XXXXXX11 OCITDO
00XXX1XX XXXXXX00 TXD
00XXX1XX XXXXXX01 MMISO
00XXX1XX XXXXXX10 SMISO
00XXX1XX XXXXXX11 OCITDI
00XXXX1X XXXXXX00 RXD
00XXXX1X XXXXXX01 MMOSI
00XXXX1X XXXXXX10 SMOSI
00XXXX1X XXXXXX11 OCITMS
00XXXXX1 XXXXXX00 GTIMERe
e. GTIMER is an RTC output controlled by WGTIMER, see chapter 19.3.6 on page 162.
00XXXXX1 XXXXXX01 MSCK
00XXXXX1 XXXXXX10 SSCK
00XXXXX1 XXXXXX11 OCITCK
Revision 1.1 Page 119 of 187
nRF24LU1+ Product Specification
14 MCU
The nRF24LU1+ contains a fast 8-bit MCU, which executes the normal 8051 instruction set.
The architecture eliminates redundant bus states and implements parallel execution of fetch and execution
phases. Most of the one-byte instructions are performed in one single cycle. The MCU uses 1 clock per
cycle. This leads to a performance improvement rate of 8.0 (in terms of MIPS) with respect to legacy 8051
devices.
The original 8051 had a 12-clock architecture. A machine cycle needed 12 clocks and most instructions
were either one or two machine cycles. Except for MUL and DIV instructions, the 8051 used either 12 or 24
clocks for each instruction. Each cycle in the 8051 also used two memory fetches. In many cases, the sec-
ond fetch was a dummy, and extra clocks were wasted.
Table 100. shows the speed advantage compared to a legacy 8051. A speed advantage of 12 implies that
the instruction is executed twelve times faster. The average speed advantage is 8.0. However, the real
speed improvement seen in any system depends on the instruction mix.
Table 100. Speed advantage summary
14.1 Features
• Control Unit
X8-bit Instruction decoder
XReduced instruction cycle time (up to 12 times in respect to standard 80C51)
• Arithmetic-Logic Unit
X8-bit arithmetic and logical operations
XBoolean manipulations
X8 x 8 bit multiplication and 8 / 8 bit division
• Multiplication-Division Unit
X16 x 16 bit multiplication
X32 / 16 bit and 16 / 16 bit division
X32-bit normalization
X32-bit L/R shifting
• Three 16-bit Timers/Counters
X80C51-like Timer 0 & 1
X80515-like Timer 2
• Compare/Capture Unit, dedicated to Timer 2
XFour 16-bit Compare registers used for Pulse Width Modulation
XFour external Capture inputs used for Pulse Width Measuring
X16-bit Reload register used for Pulse Generation
Speed
advantage
Number of
instructions
Number of
opcodes
24 1 1
12 27 83
9.6 2 2
81638
64489
4.8 1 2
41831
329
Average: 8.0 Sum: 111 Sum: 255
Revision 1.1 Page 120 of 187
nRF24LU1+ Product Specification
• Full Duplex Serial Interfaces
XSerial 0 (80C51-like)
XSynchronous mode, fixed baud rate
X8-bit UART mode, variable baud rate
X9-bit UART mode, fixed baud rate
X9-bit UART mode, variable baud rate
XBaud Rate Generator
• Interrupt Controller
XFour Priority Levels with 13 interrupt sources
• Memory interface
Xaddresses up to 64 kB of External Program/Data Memory
XDual Data Pointer for fast data block transfer
• Hardware support for software debug
14.2 Block diagram
Figure 60. MCU block diagram
GPIO
SERIAL 0
S0CON S0BUF
ALU
RAM/SFR control
SP
Timer0 and 1
TL0
TL1
TH0
TH1
TCON
TMOD
Memory control
ACC B PSW
Internal
Flash and
RAM
Timers
inputs
Memory/SFR
Interface
Port 0.0-0.5
P0
Serial 0
Interface
Timer 2
4 x
CCU_PORT
T2CON
TL2 TH2
CRCH
CRCL
CCL1
CCL2
CCH3
CCH1
CCL3
CCH2
Timer 2
inputs
MDU
MD0
MD1
MD2 MD4
MD5
MD3
ARCON
ISR IP0
IEN0
Interrupt
inputs
IP1
IEN1
DPTR
PC
DPTR1
DPS
Revision 1.1 Page 121 of 187
nRF24LU1+ Product Specification
14.3 Arithmetic Logic Unit (ALU)
The Arithmetic Logic Unit (ALU) provides 8-bit division, 8-bit multiplication, and 8-bit addition with or with-
out carry. The ALU also provides 8-bit subtraction with borrow and some bitwise logic operations, that is,
logical AND, OR, Exclusive OR or NOT.
All operations are unsigned integer operations. Additionally, the ALU can increment or decrement 8-bit reg-
isters. For accumulator only, it can rotate left or right through carry or not, swap nibbles, clear or comple-
ment bits and perform a decimal adjustment.
The ALU is handled by three registers, which are memory mapped as special function registers. Operands
for operations may come from accumulator ACC, register B or from outside of the unit. The result may be
stored in accumulator ACC or may be driven outside of the unit. The control register, that contains flags
such as carry, overflow or parity, is the PSW (Program Status Word) register.
The nRF24LU1+ also contains an on-chip co-processor MDU (Multiplication Division Unit). This unit
enables 32-bit division, 16-bit multiplication, shift and normalize operations, see chapter 18 on page 156
for details.
14.4 Instruction set summary
All instructions are binary code compatible and perform the same functions as they do within the legacy
8051 processor. The following tables give a summary of instruction cycles of the MCU core.
Table 101. Arithmetic operations
Mnemonic Description Code Bytes Cycles
ADD A,Rn Add register to accumulator 0x28-0x2F 1 1
ADD A,direct Add directly addressed data to accumulator 0x25 2 2
ADD A,@Ri Add indirectly addressed data to accumulator 0x26-0x27 1 2
ADD A,#data Add immediate data to accumulator 0x24 2 2
ADDC A,Rn Add register to accumulator with carry 0x38-0x3F 1 1
ADDC A, direct Add directly addressed data to accumulator with carry 0x35 2 2
ADDC A,@Ri Add indirectly addressed data to accumulator with carry 0x36-0x37 1 2
ADDC A,#data Add immediate data to accumulator with carry 0x34 2 2
SUBB A,Rn Subtract register from accumulator with borrow 0x98-0x9F 1 1
SUBB A, direct Subtract directly addressed data from accumulator with bor-
row
0x95 2 2
SUBB A, @Ri Subtract indirectly addressed data from accumulator with bor-
row
0x96-0x97 1 2
SUBB A, #data Subtract immediate data from accumulator with borrow 0x94 2 2
INC A Increment accumulator 0x04 1 1
INC Rn Increment register 0x08-0x0F 1 2
INC direct Increment directly addressed location 0x05 2 3
INC @Ri Increment indirectly addressed location 0x06-0x07 1 3
INC DPTR Increment data pointer 0xA3 1 1
DEC A Decrement accumulator 0x14 1 1
DEC Rn Decrement register 0x18-0x1F 1 2
DEC direct Decrement directly addressed location 0x15 2 3
DEC @Ri Decrement indirectly addressed location 0x16-0x17 1 3
MUL AB Multiply A and B 0xA4 1 5
DIV Divide A by B 0x84 1 5
DA A Decimal adjust accumulator 0xD4 1 1
Revision 1.1 Page 122 of 187
nRF24LU1+ Product Specification
Table 102. Logic operations
Mnemonic Description Code Bytes Cycles
ANL A, Rn AND register to accumulator 0x58-0x5F 1 1
ANL A,direct AND directly addressed data to accumulator 0x55 2 2
ANL A,@Ri AND indirectly addressed data to accumulator 0x56-0x57 1 2
ANL A,#data AND immediate data to accumulator 0x54 2 2
ANL direct,A AND accumulator to directly addressed location 0x52 2 3
ANL
direct,#data
AND immediate data to directly addressed loca-
tion
0x53 3 4
ORL A,Rn OR register to accumulator 0x48-0x4F 1 1
ORL A,direct OR directly addressed data to accumulator 0x45 2 2
ORL A,@Ri OR indirectly addressed data to accumulator 0x46-0x47 1 2
ORL A,#data OR immediate data to accumulator 0x44 2 2
ORL direct,A OR accumulator to directly addressed location 0x42 2 3
ORL
direct,#data
OR immediate data to directly addressed loca-
tion
0x43 3 4
XRL A,Rn Exclusive OR register to accumulator 0x68-0x6F 1 1
XRL A, direct Exclusive OR indirectly addressed data to accu-
mulator
0x66-0x67 2 2
XRL A,@Ri Exclusive OR indirectly addressed data to accu-
mulator
0x66-0x67 2 2
XRL A,#data Exclusive OR immediate data to accumulator 0x64 2 2
XRL direct,A Exclusive OR accumulator to directly addressed
location
0x62 2 3
XRL
direct,#data
Exclusive OR immediate data to directly
addressed location
0x63 3 4
CLR A Clear accumulator 0xE4 1 1
CPL A Complement accumulator 0xF4 1 1
RL A Rotate accumulator left 0x23 1 1
RLC A Rotate accumulator left through carry 0x33 1 1
RR A Rotate accumulator right 0x03 1 1
RRC A Rotate accumulator right through carry 0x13 1 1
SWAP A Swap nibbles within the accumulator 0xC4 1 1
Mnemonic Description Code Bytes Cycles
MOV A,Rn Move register to accumulator 0xE8-0xEF 1 1
MOV A,direct Move directly addressed data to accumulator 0xE5 2 2
MOV A,@Ri Move indirectly addressed data to accumula-
tor
0xE6-0xE7 1 2
MOV A,#data Move immediate data to accumulator 0x74 2 2
MOV Rn,A Move accumulator to register 0xF8-0xFF 1 2
MOV Rn,direct Move directly addressed data to register 0xA8-0xAF 2 4
MOV Rn,#data Move immediate data to register 0x78-0x7F 2 2
MOV direct,A Move accumulator to direct 0xF5 2 3
MOV direct,Rn Move register to direct 0x88-0x8F 2 3
MOV
directl,direct2
Move directly addressed data to directly
addressed location
0x85 3 4
MOV
direct,@Ri
Move indirectly addressed data to directly
addressed location
0x86-0x87 2 4
Revision 1.1 Page 123 of 187
nRF24LU1+ Product Specification
Table 103. Data transfer operations
MOV
direct,#data
Move immediate data to directly addressed
location
0x75 3 3
MOV @Ri,A Move accumulator to indirectly addressed
location
0xF6-0xF7 1 3
MOV
@Ri,direct
Move directly addressed data to indirectly
addressed location
0xA6-0xA7 2 5
MOV
@Ri,#data
Move immediate data to indirectly addressed
location
0x76-0x77 2 3
MOV
DPTR,#datal6
Load data pointer with a 16-bit immediate 0x90 3 3
MOVC
A,@A+DPTR
Load accumulator with a code byte relative
to DPTR
0x93 1 3
MOVC
A,@A+PC
Load accumulator with a code byte relative
to PC
0x83 1 3
MOVX A,@Ri Movea external RAM (8-bit addr) to accumu-
lator
0xE2-0xE3 1 4
MOVX
A,@DPTR Movea external RAM (16-bit addr) to accu-
mulator
0xE0 1 4
MOVX @Ri,A Movea accumulator to external RAM (8-bit
addr)
0xF2-0xF3 1 5
MOVX
@DPTR,A Movea accumulator to external RAM (16-bit
addr)
0xF0 1 5
PUSH direct Push directly addressed data onto stack 0xC0 2 4
POP direct Pop directly addressed location from stack 0xD0 2 3
XCH A,Rn Exchange register with accumulator 0xC8-0xCF 1 2
XCH A,direct Exchange directly addressed location with
accumulator
0xC5 2 3
XCH A,@Ri Exchange indirect RAM with accumulator 0xC6-0xC7 1 3
XCHD A,@Ri Exchange low-order nibbles of indirect and
accumulator
0xD6-0xD7 1 3
a. The MOVX instructions perform one of two actions depending on the state of pmw bit (pcon.4).
Mnemonic Description Code Bytes Cycles
ACALL addr11 Absolute subroutine call xxx10001b 2 6
LCALL
addr16
Long subroutine call 0x12 3 6
RET Return from subroutine 0x22 1 4
RETI Return from interrupt 0x32 1 4
AJMP addr11 Absolute jump xxx00001b 2 3
LJMP addrl6 Long jump 0x02 3 4
SJMP rel Short jump (relative address) 0x80 2 3
JMP
@A+DPTR
Jump indirect relative to the DPTR 0x73 1 2
JZ rel Jump if accumulator is zero 0x60 2 3
JNZ rel Jump if accumulator is not zero 0x70 2 3
JC rel Jump if carry flag is set 0x40 2 3
JNC rel Jump if carry flag is not set 0x50 2 3
JB bit, rel Jump if directly addressed bit is set 0x20 3 4
JNB bit, rel Jump if directly addressed bit is not set 0x30 3 4
Mnemonic Description Code Bytes Cycles
Revision 1.1 Page 124 of 187
nRF24LU1+ Product Specification
Table 104. Program branches
Table 105. Boolean manipulation
JBC bit, rel Jump if directly addressed bit is set and clear bit 0x10 3 4
CJNE A, direct,
rel
Compare directly addressed data to accumulator
and jump if not equal
0xB5 3 4
CJNE
A,#data,rel
Compare immediate data to accumulator and
jump if not equal
0xB4 3 4
CJNE Rn,
#data, rel
Compare immediate data to register and jump if
not equal
0xB8-0xBF 3 4
CJNE @Ri,
#data, rel
Compare immediate data to indirect addressed
value and jump if not equal
0xB6-B7 3 4
DJNZ Rn, rel Decrement register and jump if not zero 0xD8-DF 2 3
DJNZ direct, rel Decrement directly addressed location and jump
if not zero
0xD5 3 4
NOP No operation 0x00 1 1
Mnemonic Description Code Bytes Cycles
CLR C Clear carry flag 0xC3 1 1
CLR bit Clear directly addressed bit 0xC2 2 3
SETB C Set carry flag 0xD3 1 1
SETB bit Set directly addressed bit 0xD2 2 3
CPL C Complement carry flag 0xB3 1 1
CPL bit Complement directly addressed bit 0xB2 2 3
ANL C,bit AND directly addressed bit to carry flag 0x82 2 2
ANL C,/bit AND complement of directly addressed bit to carry 0xB0 2 2
ORL C,bit OR directly addressed bit to carry flag 0x72 2 2
ORL C,/bit OR complement of directly addressed bit to carry 0xA0 2 2
MOV C,bit Move directly addressed bit to carry flag 0xA2 2 2
MOV bit,C Move carry flag to directly addressed bit 0x92 2 3
Mnemonic Description Code Bytes Cycles
Revision 1.1 Page 125 of 187
nRF24LU1+ Product Specification
14.5 Opcode map
Opcode Mnemonic Opcode Mnemonic Opcode Mnemonic
00H NOP 56H ANL A,@R0 ACH MOV R4,direct
01H AJMP addr11 57H ANL A,@R1 ADH MOV R5,direct
02H JUMP addrl6 58H ANL A,R0 AFH MOV R6,direct
03H RRA 59H ANL A,R1 AFH MOV R7,direct
04H INCA 5AH ANL A,R2 B0H ANL C,/bit
05H INC direct 5BH ANL A,R3 B1H ACALL addr11
06H INC @R0 5CH ANL A,R4 B2H CPL bit
07H INC @R1 5DH ANL A,R5 B3H CPLC
08H INC R0 5EH ANL A,R6 B4H CJNE A,#data,rel
09H INC R1 5FH ANL A,R7 B5H CJNE A, direct, rel
0AH INC R2 60H JZ rel B6H CJNE @R0,#data,rel
0BH INC R3 61H AJMP addr11 B7H CJNE @R1, #data,rel
0CH INC R4 62H XRL direct, A B8H CJNE R0, #data,rel
0DH INC R5 63H XRL direct, #data B9H CJNE R1,#data,rel
0EH INC R6 64H XRL A, #data BAH CJNE R2,#data,rel
0FH INC R7 65H XRL A,direct BBH CJNE R3,#data,rel
10H JBC bit, rel 66H XRLA,@R0 BCH CJNE R4,#data,rel
11H ACALL addr11 67H XRL A,@R1 BDH CJNE R5,#data,rel
12H LCALL add r16 68H XRL A,R0 BEH CJNE R6,#data,rel
13H RRC A 69H XRL A,R1 BFH CJNE R7,#data,rel
14H DEC A 6AH XRL A,R2 C0H PUSH direct
15H DEC direct 6BH XRL A,R3 C1H AJMP addr11
16H DEC @R0 6CH XRL A,R4 C2H CLR bit
17H DEC @R1 6DH XRL A,R5 C3H CLR C
18H DEC R0 6EH XRL A,R6 C4H SWAP A
19H DEC R1 6FH XRL A,R7 C5H XCH A, direct
1AH DEC R2 70H JNZ rel C6H XCH A,@R0
1BH DECR3 71H ACALL addr11 C7H XCH A,@R1
1CH DECR4 72H ORL C, bit C8H XCH A,R0
1DH DECR5 73H JMP @A+DPTR C9H XCH A,R1
1EH DECR6 74H MOV A, #data CAH XCH A,R2
1FH DECR7 75H MOV direct, #data CBH XCHA,R3
20H JB bit, rel 76H MOV @R0,#data CCH XCH A,R4
21H AJMP addr11 77H MOV @R1, #data CDH XCH A,R5
22H RET 78H MOV R0, #data CEH XCH A,R6
23H RL A 79H MOV R1, #data CFH XCHA,R7
24H ADD A, #data 7AH MOV R2, #data D0H POP direct
25H ADD A, direct 7BH MOV R3, #data D1H ACALL addr11
26H ADD A,@R0 7CH MOV R4, #data D2H SETB bit
27H ADD A,@R1 7DH MOV R5, #data D3H SETB C
28H ADD A,R0 7EH MOV R6, #data D4H DAA
29H ADD A,R1 7FH MOV R7, #data D5H DJNZ direct, rel
2AH ADD A,R2 80H SJMP rel D6H XCHDA,@R0
2BH ADD A,R3 81H AJMP addr11 D7H XCHD A,@R1
2CH ADD A,R4 82H ANL C, bit D8H DJNZ R0,rel
2DH ADD A,R5 83H MOVC A,@A+PC D9H DJNZ R1,rel
2EH ADD A,R6 84H DIV AB DAH DJNZ R2,rel
2FH ADD A,R7 85H MOV direct, direct DBH DJNZ R3,rel
30H JNB bit, rel 86H MOV direct,@R0 DCH DJNZ R4,rel
31H ACALL addr11 87H MOV direct,@R1 DDH DJNZ R5,rel
Revision 1.1 Page 126 of 187
nRF24LU1+ Product Specification
Table 106. Opcode map
32H RETI 88H MOV direct,R0 DFH DJNZ R6,rel
33H RLC A 89H MOV direct,R1 DFH DJNZ R7,rel
34H ADDC A,#data 8AH MOV direct,R2 F0H MOVX A,@DPTR
35H ADDC A, direct 8BH MOV direct,R3 F1H AJMP addr11
36H ADDC A,@R0 8CH MOV direct,R4 E2H MOVX A,@R0
37H ADDC A,@R1 8DH MOV direct, R5 F3H MOVX A,@R1
38H ADDC A,R0 8EH MOV direct,R6 E4H CLR A
39H ADDC A,R1 8FH MOV direct,R7 F5H MOVA, direct
3AH ADDC A,R2 90H MOV DPTR, #datal6 E6H MOVA,@R0
3BH ADDC A,R3 91H ACALL addr11 F7H MOV A,@R1
3CH ADDC A,R4 92H MOV bit, C E8H MOV A,R0
3DH ADDC A,R5 93H MOVCA,@A+DPTR F9H MOV A,R1
3EH ADDC A,R6 94H SUBB A, #data EAH MOV A,R2
3FH ADDC A,R7 95H SUBB A, direct FRH MOV A,R3
40H JC rel 96H SUBB A,@R0 ECH MOV A,R4
41H AJMP addr11 97H SUBB A,@R1 FDH MOV A,R5
42H ORL direct, A 98H SUBB A, R0 EEH MOV A,R6
43H ORL direct, #data 99H SUBB A,R1 EFH MOV A,R7
44H ORL A, #data 9AH SUBB A,R2 F0H MOVX @DPTR,A
45H ORL A, direct 9BH SUBB A,R3 F1H ACALL addr11
46H ORL A,@R0 9CH SUBB A,R4 F2H MOVX @R0,A
47H ORL A,@R1 9DH SUBB A,R5 F3H MOVX @R1,A
48H ORL A,R0 9EH SUBB A,R6 F4H CPL A
49H ORL A,R1 9FH SUBB A,R7 F5H MOV direct, A
4AH ORL A,R2 A0H ORL C,/bit F6H MOV @R0,A
4BH ORLA,R3 A1H AJMP addr11 F7H MOV @R1,A
4CH ORL A,R4 A2H MOV C, bit F8H MOV R0,A
4DH ORL A,R5 A3H INC DPTR F9H MOV R1,A
4EH ORL A,R6 A4H MUL AB FAH MOV R2,A
4FH ORLA,R7 A5H Debug FBH MOV R3,A
50H JNC rel A6H MOV @R0,direct FCH MOV R4,A
51H ACALL addr11 A7H MOV @R1,direct FDH MOV R5,A
52H ANL direct, A A8H MOV R0,direct FEH MOV R6,A
53H ANL direct, #data A9H MOV R1,direct FFH MOV R7,A
54H ANL A, #data AAH MOV R2,direct
55H ANL A, direct ABH MOV R3,direct
Opcode Mnemonic Opcode Mnemonic Opcode Mnemonic
Revision 1.1 Page 127 of 187
nRF24LU1+ Product Specification
15 Memory and I/O organization
The MCU has a 64 kbytes address space for code and data, an area of 256 byte for internal data (IRAM),
and an area of 128 byte for Special Function Registers (SFR).
The nRF24LU1+ has 16 or 32 kbytes of flash program memory, 2 kbytes of SRAM data memory and a
dedicated internal RAM of 256 byte for MCU internal data, see Figure 61. To allow erase and write flash
operations, the MCU must run the sequence described in section 17.5.1.
In addition, an area of 2 kbytes is reserved for the USB buffer RAM and the USB configuration registers.
Note: In a program running in a protected flash area, movc may not be used to access addresses
0x00 to 0x03.
Figure 61. nRF24LU1+ memory map
0x0000
0x7FFF
0x8000
0x87FF
0xFFFF
Accessible by
direct and indirect
addressing
0x00
0x7F
Accessible by
indirect
addressing only
0x80
0xFF
IRAM
Accessible by
direct addressing
only
SFR
0x80
0xFF
Special Funtion
Registers
0xC000
0xC7FF
Data (RAM)
(2 kB)
Program/Data
(Flash 32 kB)
Accessible with
movc and movx
USB (RAM)
(2 kB)
For Flash 16 kB,
address space is
0x0000 to 0x3FFF
Revision 1.1 Page 128 of 187
nRF24LU1+ Product Specification
15.1 Special function registers
15.1.1 Special function registers locations
The map of Special Function Registers is shown in Table 107.
Table 107. Special Function Registers locations
Note: Undefined locations are reserved and must not be read or written.
The registers in the X000 column in Table 107. above are both byte and bit addressable. The other regis-
ters are only byte addressable.
Address X000 X001 X010 X011 X100 X101 X110 X111
0xF8-0xFF FSR FPCR FCR
0xF0-0xF7 BAESKIN AESIV AESD AESIA1 AESIA2
0xE8-0xEF AESCS MD0 MD1 MD2 MD3 MD4 MD5 ARCON
0xE0-0xE7 ACC RFDAT RFCTL
0xD8-0xDF WDCON USBSLP
0xD0-0xD7 PSW
0xC8-0xCF T2CON P0EXP CRCL CRCH TL2 TH2
0xC0-0xC7 IRCON CCEN CCL1 4CCH1 CCL2 CCH2 CCL3 CCH3
0xB8-0xBF IEN1 IP1 S0RELH SSCONF SSDAT SSSTAT
0xB0-0xB7 RSTRES SMDAT SMCTRL TICKDV
0xA8-0xAF IEN0 IP0 S0RELL REGXH REGXL REGXC
0xA0-0xA7 USBCON CLKCTL PWRDWN WUCONF INTEXP
0x98-0x9F S0CON S0BUF
0x90-0x97 RFCON DPS P0DIR P0ALT
0x88-0x8F TCON TMOD TL0 TL1 TH0 TH1 CKCON
0x80-0x87 P0 SP DPL DPH DPL1 DPH1 PCON
Revision 1.1 Page 129 of 187
nRF24LU1+ Product Specification
15.1.2 Special function registers reset values
Register name Address Reset value More information Description
ACC 0xE0 0x00 Section 15.1.3 on page
131
Accumulator
AESCS 0xE8 0x00 Section 8.2 on page 96 AES Command/Status
AESD 0xF3 0x00 Section 8.2 on page 96 AES Data In/Out
AESIA1 0xF5 0x00 Section 8.2 on page 96 AES Indirect Address register 1
AESIA2 0xF6 0x00 Section 8.2 on page 96 AES Indirect Address register 2
AESIV 0xF2 0x00 Section 8.2 on page 96 AES Initialization Vector
AESKIN 0xF1 0x00 Section 8.2 on page 96 AES Key In
ARCON 0xEF 0x00 Section 18.3 on page 156 Arithmetic Control register
B0xF0 0x00 Section 15.1.4 on page
131
B register
CCEN 0xC1 0x00 Section 11.4.7 on page 111 Compare/Capture Enable register
CCH1 0xC3 0x00 Section 11.4.8 on page 111 Compare/Capture register 1, high
byte
CCH2 0xC5 0x00 Section 11.4.8 on page 111 Compare/Capture register 2, high
byte
CCH3 0xC7 0x00 Section 11.4.8 on page 111 Compare/Capture register 3, high
byte
CCL1 0xC2 0x00 Section 11.4.8 on page 111 Compare/Capture register 1, low
byte
CCL2 0xC4 0x00 Section 11.4.8 on page 111 Compare/Capture register 2, low
byte
CCL3 0xC6 0x00 Section 11.4.8 on page 111 Compare/Capture register 3, low
byte
CKCON 0x8E 0x01 Section 16.1 on page 134 Memory cycle control
CLKCTL 0xA3 0x80 Section 20.4.1 on page
167
CRCH 0xCB 0x00 Section 11.4.9 on page 112 Compare/Reload/Capture register,
high byte
CRCL 0xCA 0x00 Section 11.4.9 on page 112 Compare/Reload/Capture register,
low byte
DPH 0x83 0x00 Section 15.1.7 on page
132
Data Pointer High
DPL 0x82 0x00 Section 15.1.7 on page
132
Data Pointer Low
DPS 0x92 0x00 Section 15.1.9 on page
133
Data Pointer Select register
FCR 0xFA 0x00 Section 17.3.6 on page
139
Flash Command register
FPCR 0xF9 NA Section 17.3.6 on page
139
Flash Protect Configuration regis-
ter
FSR 0xF8 NA Section 17.3.6 on page
139
Flash Status register
IEN0 0xA8 0x00 Section 22.4.1 on page
172
Interrupt Enable register 0
IEN1 0xB8 0x00 Section 22.4.2 on page
173
Interrupt Priority register / Enable
register 1
INTEXP 0xA6 0x01 Section 22.4.2 on page
173
Revision 1.1 Page 130 of 187
nRF24LU1+ Product Specification
IP0 0xA9 0x00 Section 22.4.3 on page
173
Interrupt Priority register 0
IP1 0xB9 0x00 Section 22.4.3 on page
173
Interrupt Priority register 1
IRCON 0xC0 0x00 Section 22.4.4 on page
174
Interrupt Request Control register
MD0 0xE9 0x00 Section 18.3 on page 156 Multiplication/Division register 0
MD1 0xEA 0x00 Section 18.3 on page 156 Multiplication/Division register 1
MD2 0xEB 0x00 Section 18.3 on page 156 Multiplication/Division register 2
MD3 0xEC 0x00 Section 18.3 on page 156 Multiplication/Division register 3
MD4 0xED 0x00 Section 18.3 on page 156 Multiplication/Division register 4
MD5 0xEE 0x00 Section 18.3 on page 156 Multiplication/Division register 5
P0 0x80 0xFF Section 13.1 on page 116 Port 0 (only P0.0 – P0.5 available
externally)
P0ALT 0x95 0x00 Section 13.1 on page 116 GPIO port functions
P0DIR 0x94 0xFF Section 13.1 on page 116 GPIO pin direction control
P0EXP 0xC9 0x00 Section 13.1 on page 116
PCON 0x87 0x00 Section 20.4.5 on page
169
Power Control
PSW 0xD0 0x00 Section 15.1.5 on page
132
Program Status Word
PWRDWN 0xA4 0x00 Section 20.4.2 on page
168
REGXC 0xAD 0x00 Section 19.3.6 on page
162
Control register for watchdog and
wakeup functions
REGXH 0xAB 0x00 Section 19.3.6 on page
162
High byte of 16-bit watchdog/
wakeup register
REGXL 0xAC 0x00 Section 19.3.6 on page
162
Low byte of 16-bit watchdog/
wakeup register
RFCON 0x90 0x02 Section 6.5.1 on page 53 RF Transceiver configuration regis-
ter
RFCTL 0xE6 0x00 Section 6.5.1 on page 53 RF Transceiver control register
RFDAT 0xE5 0x00 Section 6.5.1 on page 53 RF data register
RSTRES 0xB1 0x00 Section 20.4.3 on page
168
S0BUF 0x99 0x00 Section 12.4.2 on page
115
Serial Port 0, Data Buffer
S0CON 0x98 0x00 Section 12.4.1 on page
114
Serial Port 0, Control register
S0RELH 0xBA 0x03 Section 12.4.3 on page
115
Serial Port 0, Reload register, high
byte
S0RELL 0xAA 0xD9 Section 12.4.3 on page
115
Serial Port 0, Reload register, low
byte
SMCTRL 0xB3 0x00 Section 9.2 on page 99 SPI Master Control register
SMDAT 0xB2 0x00 Section 9.2 on page 99 SPI Master data register
SP 0x81 0x07 Section 15.1.6 on page
132
Stack Pointer
SSCONF 0xBC 0x00 Section 10.2 on page 101 SPI Slave configuration
SSDAT 0xBD 0x00 Section 10.2 on page 101 SPI Slave Data register
SSSTAT 0xBE 0x00 Section 10.2 on page 101 SPI Slave Status register
T2CON 0xC8 0x00 Section 11.4.5 on page 110 Timer 2 Control register
Register name Address Reset value More information Description
Revision 1.1 Page 131 of 187
nRF24LU1+ Product Specification
Table 108. Special Function Registers reset values
15.1.3 Accumulator - ACC
Accumulator is used by most of the MCU instructions to hold the operand and to store the result of an
operation.
Note: The mnemonics for accumulator specific instructions refer to accumulator as A, not ACC.
Table 109. ACC register
15.1.4 B register – B
The B register is used during multiplying and division instructions. It can also be used as a scratch-pad reg-
ister to hold temporary data.
Table 110. B register
TCON 0x88 0x00 Section 11.4.1 on page
108
Timer/Counter Control register
TH0 0x8C 0x00 Section 11.4.3 on page
109
Timer 0, high byte
TH1 0x8D 0x00 Section 11.4.4 on page
109
Timer 1, high byte
TH2 0xCD 0x00 Section 11.4.6 on page 110 Timer 2, high byte
TICKDV 0xB5 0x03 Section 19.3.2 on page
161
Divider for watchdog and wakeup
functions
TL0 0x8A 0x00 Section 11.4.3 on page
109
Timer 0, low byte
TL1 0x8B 0x00 Section 11.4.4 on page
109
Timer 1, low byte
TL2 0xCC 0x00 Section 11.4.6 on page 110 Timer 2, low byte
TMOD 0x89 0x00 Section 11.4.2 on page
109
Timer Mode register
USBCON 0xA0 0xFF Section 7.3 on page 65 USB configuration/status register
USBSLP 0xD9 0x00 Section 7.3 on page 65 USB sleep
WDCON 0xD8 0x00 Section 12.4.4 on page
115
Serial Port 0 Baud Rate Select reg-
ister (only wdcon.7 bit used)
WUCONF 0xA5 0x00 Section 20.4.4 on page
168
Wakeup configuration register
Address Reset value bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
0xE0 0x00 acc.7 acc.6 acc.5 acc.4 acc.3 acc.2 acc.1 acc.0
Address Reset value bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
0xF0 0x00 b.7 b.6 b.5 b.4 b.3 b.2 b.1 b.0
Register name Address Reset value More information Description
Revision 1.1 Page 132 of 187
nRF24LU1+ Product Specification
15.1.5 Program Status Word register - PSW
The PSW register contains status bits that reflect the current state of the MCU.
Table 111. PSW register
Note: The Parity bit can only be modified by hardware in the ACC register state.
15.1.6 Stack Pointer – SP
This register points to the top of the stack in internal data memory space. It is used to store the return
address of a program before executing an interrupt routine or subprograms. The SP register is incre-
mented before executing PUSH or CALL instruction and it is decremented after executing POP or RET(I)
instruction (it always points to the top of the stack).
Table 112. SP register
15.1.7 Data Pointer – DPH, DPL
Table 113. Data Pointer register (DPH:DPL)
The Data Pointer registers can be accessed through DPL and DPH. The actual data pointer is selected by
DPS register.
The Data Pointer registers are intended to hold a 16-bit address in the indirect addressing mode used by
MOVX (move external memory), MOVC (move program memory) or JMP (computed branch) instructions.
They may be manipulated as 16-bit register or as two separate 8-bit registers. DPH holds a higher byte and
DPL holds a lower byte of an indirect address.
These registers are used to access external code or data space (for example, MOVC A, @A+DPTR or
MOV A, @DPTR).
Address Reset
value Bit Name Description
0xD0 0x00 7 cy Carry flag: Carry bit in arithmetic operations and accumulator
for Boolean operations.
6 ac Auxiliary Carry flag: Set if there is a carry-out from 3rd bit of
Accumulator in BCD operations
5 f0 General purpose flag 0
4-3 rs Register bank select, bank 0..3 (0x00-0x07, 0x08-0x0f, 0x10-
0x17, 0x18-0x1f)
2 ov Overflow flag: Set if overflow in Accumulator during arithme-
tic operations
1 f1 General purpose flag 1
0 p Parity flag: Set if odd number of ‘1’ in ACC.
Address Reset value Register name
0x81 0x07 SP
Address Reset value Register name
0x82 0x00 DPL
0X83 0x00 DPH
Revision 1.1 Page 133 of 187
nRF24LU1+ Product Specification
15.1.8 Data Pointer 1 – DPH1, DPL1
Table 114. Data Pointer 1 register (DPH1:DPL1)
The Data Pointer register 1 can be accessed through DPL1 and DPH1. The actual data pointer is selected
by DPS register.
These registers are intended to hold a 16-bit address in the indirect addressing mode used by MOVX
(move external memory), MOVC (move program memory) or JMP (computed branch) instructions. They
can be manipulated as a 16-bit register or as two separate 8-bit registers. DPH1 holds a higher byte and
DPL1 holds a lower byte of an indirect address.
These registers are used to access external code or data space (for example, MOVC A,@A+DPTR or
MOV A,@DPTR respectively).
The Data Pointer 1 is an extension to the standard 8051 architecture to speed up block data transfers.
15.1.9 Data Pointer Select register – DPS
The MCU contains two Data Pointer registers. Both Data Pointer registers can be used as 16-bits address
source for indirect addressing. The DPS register serves for selecting the active data pointer register.
Table 115. DPS register
Address Register name
0x84 DPL1
0X85 DPH1
Address Reset value Bit Name Description
0x92 0x00 7:1 - Not used
0 dps Data Pointer Select. 0: select DPH:DPL, 1: select
DPH1:DPL1
Revision 1.1 Page 134 of 187
nRF24LU1+ Product Specification
16 Random Access Memory (RAM)
The nRF24LU1+ contains two separate RAM blocks. These blocks are used to save temporary data or
programs.
The RAM blocks are 256x8 IRAM bits and 2048x8 bits.
Note: The information in these blocks is lost when power to the device is removed.
As described in chapter 15 on page 127, the RAM resides in different maps, that is, different instructions
are used to access them.
The smallest RAM-block (256 bytes) resides in the “internal” RAM-area, called IRAM, and contains
scratch-pad data, subroutine stacks, register files, and so on.
Note: The lower 128 bytes can be addressed direct or indirectly, while the upper 128 bytes can only
be accessed using indirect addressing.
The largest RAM (2048 bytes) resides in the XDATA space and is a fixed block located from address
0x8000 to 0x87FF. This block is used for data or program code.
16.1 Cycle control
The MCU has a programmable SFR register that controls timing to on-chip memory. Since this memory is
fast, the default values are recommended.
Table 116. CKCON register
Address Reset
value Bit Description
0x8E 0x01 7 Not used
6-4 Program memory wait state control
000: No wait-states (default at power-up)
Other values are reserved and should not be used
3 Not used
2-0 External data memory stretch control.
001: One stretch cycle (default)
Other values are reserved and should not be used
Revision 1.1 Page 135 of 187
nRF24LU1+ Product Specification
17 Flash Memory
This section describes the operation of the embedded flash memory. The MCU can read and write the
memory and perform erase page operations. You can configure and program the flash memory through an
external SPI slave interface and you can also configure it to inhibit readback or modification of the memory
content. You can also program the flash memory through the USB by using the USB bootloader.
17.1 Features
• 16 or 32 kB Flash memory
• Page size 512 bytes
• 32 or 64 pages of MainBlock + 1 InfoPage
• Endurance minimum 1000 write/erase cycles
• Direct SPI programmable
• Read and write accessible from MCU
• Configurable MCU write and erase protection
• Configurable SPI readback protection
• HW support for FW upgrade
17.2 Block diagram
Figure 62. Flash memory block diagram
17.3 Functional description
17.3.1 Flash memory configuration
The flash memory is divided into two blocks, the MainBlock and the information block (one InfoPage).
At the chip interface the flash behaves as an SPI programmable flash memory. All configuration and setup
of the behavior during normal mode (that is, when MCU is active and running) is defined through the SPI
InfoPage
PROG=1
PROG=0
0x1FF
0x00
MainBlock
0x7FFF
Page 63
Page 0
SPI
MCU
INFEN=0
INFEN=1
Revision 1.1 Page 136 of 187
nRF24LU1+ Product Specification
and the configuration data is stored in the InfoPage. During the chip reset/start-up sequence the configura-
tion data is read and stored in a set of registers that control flash memory behavior.
Figure 63. Flash memory organization
The MainBlock of flash memory can be configured through the SPI (Figure 63.) in the following ways:
• Unprotected program memory; can be read, written and erased through the SPI and by the MCU.
With no configuration the whole MainBlock is unprotected memory.
• Protected program memory; can be read, written and erased through the SPI but only read by the
MCU. Any number of pages can be configured as protected memory.
• Data memory; can be read, written and erased through the SPI and by the MCU. Two data pages 62
and 63 may be enabled. If enabled, the number of protected pages is reduced by two.
You can program the InfoPage through the SPI only, because the MCU has only read access to the
InfoPage, except for byte 0x23, which is writable from the MCU, see Table 117.
Note: You can write to a flash byte twice between each erase. A page (or full) erase sets the value
of all erased bytes to 0xFF. A write to a flash byte only programs the 0-bits of the byte, leav-
ing the 1-bits as they are (after the erase). Thus for the second write, only the remaining 1-
bits can be programmed. This results in an "and" function of the first and second write.
Example: Writing 0x46 and 0x27 to the same byte (without erase in between) will result in a
stored value 0x06.
Data
Protected
Program
Memory
Unprotected
Program
Memory
0
NUPP
FlashProtectConfigReg
DAEN
BootstartSelector
InfoPage
0
Page
size
MainBlock
Enable 2 pages
of data memory if
DAEN = 1
Even number of 1's,
set start program
execution at address
”0"
Odd number of 1's, set
start program execution
at the bottom of
protected area.
The content of the 16 highest
addresses is read during startup
and saved as BootStartSelector
Page address
NUPP
62
Revision 1.1 Page 137 of 187
nRF24LU1+ Product Specification
17.3.2 InfoPage content
The content of the InfoPage is given in Table 117. below. The InfoPage is erased at factory so that all
bytes, except CHIPID, initially have the value 0xFF.
Note: The InfoPage can only be erased if FSR.RDISMB= 0. See also section 17.7.4.1 on page 154.
Table 117. InfoPage content
17.3.3 Protected pages and data pages
The flash memory can be split into unprotected, protected and data areas. When you protect an area of
flash memory it becomes read only for the MCU, but it can still be read, written and erased through the SPI
interface. The protected area of the flash memory is safe from illegal erase/write operations from the MCU
and can typically be used for firmware upgrade functions, see section 17.5.2 on page 141.
The flash MainBlock consists of 32 or 64 pages each 512 bytes long. The factory configuration
FPCR.NUPP (Number of Unprotected Pages)=0xFF leaves all pages unprotected, that is, the MCU can
erase and write to any page. FPCR.DAEN=1 reserves the two highest pages (62-63) as data pages. The
FPCR.NUPP value is the page number of the first protected page, see Figure 62. on page 135. For exam-
InfoPage data Size Address Comment
Reserved 11 bytes 0x00 Reserved.
CHIPID 5 bytes 0x0B ID number for each individual device. The ID is gener-
ated by a pseudo random process. No ID will violate
the rules specificed in section 6.4.3.2
Reserved 16 bytes 0x10 Reserved.
Page address for
start of protected
area (that is, num-
ber of unprotected
pages)
1 byte 0x20 Read out during reset/start-up sequence of the chip to
register FPCR.NUPP
Byte value:
0xFF: all pages are unprotected
Other value: page address
Enable flash data
memory
1 byte 0x21 Read out during reset/start-up sequence of the chip.
Byte value:
0xFF: no data memory, FPCR.DAEN=0
Other value: data memory exists, FPCR.DAEN=1
Readback blocking
byte for InfoPage
1 byte 0x22 Read out during reset/start-up sequence of chip.
Byte value:
0xFF: FSR.RDISIP=0
Other value: FSR.RDISIP=1
Readback blocking
byte for MainBlock
1 byte 0x23 Read out during reset/start-up sequence of chip.
Byte value:
0xFF: FSR.RDISMB=0
Other value: FSR.RDISMB=1
Note: This byte may be written (to 0x00) by the MCU,
but the InfoPage cannot be erased by the MCU.
Enable debug 1 byte 0x24 Read out during reset/start-up sequence of chip.
Byte value:
0xFF: FSR.DBG=0
Other value: FSR.DBG=1 if FSR.RDISMB=0, enables
HW debug. See chapter 23 on page 175
Reserved 219 bytes 0x25 Reserved.
For user data 256 bytes 0x100 Free to use.
Revision 1.1 Page 138 of 187
nRF24LU1+ Product Specification
ple, FPCR.NUPP=12 and FPCR.DAEN=1 gives 12 unprotected pages (0-11) and 50 protected pages (12-
61) and two data pages (62-63), see Figure 63. on page 136.
If you have a protected and unprotected area, the value of the 16 topmost flash memory addresses decide
from which area the MCU will start code execution. During the reset/start up sequence these 16 bytes are
read automatically. If there is an even number of logic 1 databits in the 16 topmost addresses of the flash
memory, FSR.STP = 0, otherwise FSR.STP = 1. The factory configuration of FSR.STP=0 starts the code
execution at address 0x0000 which is the beginning of the unprotected area. If FSR.STP=1, the code exe-
cution starts from the beginning of the protected area.
To use this "start from protected" feature, data pages must be enabled (FPCR.DAEN=1), which will allow
MCU programming access to the highest page (63).
17.3.4 16 kB Flash memory size option
nRF24LU1+ has two flash memory size options, 32 k bytes and 16 k bytes, see also chapter 27.1.1 on
page 181.
For the 16 kB Flash version the data pages, if configured, always reside in pages 62-63.
Any MCU program, with a size less than 16 kB, running on a 32 kB Flash version, will run unmodified in a
16 kB Flash version. Likewise any MCU program running on a 16 kB Flash version will run unmodified on
a 32 kB Flash version.
Example configurations
Table 118. Example of Flash configurations for 32 kB and 16 kB size
17.3.5 Software compatibility with nRF24LU1
nRF24LU1 programs with no protected flash memory configured (FPCR.NUPP=0xFF) can be ported
unchanged to nRF24LU1+.
FPCR.
NUPP
FPCR.
DAEN
Flash
memory
size
Description
255 0 32 kB All memory unprotected (pages 0-63)
20 0 32 kB NA because FSR.STP cannot be set
0 0 32 kB All memory protected (pages 0-63)
255 1 32 kB Pages 0-61 unprotected, data pages 62-63
40 1 32 kB Pages 0-39 unprotected, pages 40-61 protected, data pages 62-63
20 1 32 kB Pages 0-19 unprotected, pages 20-61 protected, data pages 62-63
0 1 32 kB Pages 0-61 protected, data pages 62-63
255 0 16 kB All memory unprotected (pages 0-31)
20 0 16 kB NA because FSR.STP cannot be set
0 0 16 kB All memory protected (pages 0-31)
255 1 16 kB Pages 0-29 unprotected, data pages 62-63
40 1 16 kB Illegal (values >29 and < 64 are illegal)
20 1 16 kB Pages 0-19 unprotected, pages 20-29 protected, data pages 62-63
0 1 16 kB Pages 0-29 protected, data pages 62-63
Revision 1.1 Page 139 of 187
nRF24LU1+ Product Specification
For nRF24LU1 programs with protected flash memory configured (FPCR.NUPP < 30), the addresses of
the data pages must be changed. This is because the data pages in nRF24LU1 reside in pages 30-31
while the data pages in nRF24LU1+ reside in pages 62-63. This means that all addresses for write or
erase of the data pages in nRF24LU1 must be translated from pages 30-31 to pages 62-63 to run on
nRF24LU1+. However, this address translation is not required if no protected memory is configured.
17.3.6 SFR registers for flash memory operations
Table 119. FSR, FPCR and FCR registers
17.4 Brown-out
There is an on-chip power-fail detector, see chapter 21 on page 170, which ensures that any flash memory
program or erase access will be ignored when the ‘Power Fail’ signal (see Figure 83.) is active. Both the
micro controller and the flash memory still function according to specification, and any write operation that
was started will be completed. Flash erase operations will be aborted. If the supply voltage drops further,
that is when the signal “Reset” (see Figure 83.) is active, the chip will be reset. If the power supply rises
again before reaching the reset threshold, there will be no reset, and there is no status indication to show
Addr Reset
value Bit Name RW Function
0xF8 Read
from
Flash,
see
Tab le
117.
7DBG RW
FSR – Flash Status Register
1: Enable HW debugger, 0: Disable HW debugger, if
RDISMB = 0, DBG may be set (to one) by the MCU/SFR
write, but it will return back to reset value after a subse-
quent reset.
Read
from
Flash
6STP R 1: Start from protected program memory, 0: start from
address 0
05WEN RW Flash write (or erase) enable. 1: enable
04
RDYN R Flash interface ready. 0: ready
03
INFEN RW InfoPage enable. 1: enable
Read
from
Flash,
see
Tab le
117.
2RDISMB R SPI read-back disable of MainBlock. 1: read back disable
and also inhibits page erase and MainBlock write. Writ-
able by SPI command RDISMB and is cleared automati-
cally by the ERASE_ALL command. Can also be written
indirectly by MCU as described in Table 117. on page
137.
Read
from
Flash
1RDISIP R SPI read-back disable of InfoPage. 1: read back disable.
Only writable by SPI command RDISIP and is cleared
automatically if InfoPage is erased.
0 0 - Reserved, read as 0.
0xF9 N/A
7
6:0
DAEN
NUPP
R
R
FPCR – Flash Protect Configuration Register
1: The two upper flash pages reserved as data memory,
0: no data memory enabled.
Number of unprotected pages.
Note: NUPP < 0xFF reserves the 16 highest bytes of the
flash MainBlock.
0xFA 0x00
7:0 EPA RW
FCR – Flash Command Register
Byte value < 64:
Erase page address, otherwise used for secure MCU
flash write, see section 17.5.1 on page 140.
Revision 1.1 Page 140 of 187
nRF24LU1+ Product Specification
that this has happened.
To ensure proper programming of the flash in the cases where power supply may be unreliable, the user
should take the following precautions:
• Make sure there is no partial erase.
XIf the device is reset during an erase cycle, always assume that the erase was unsuccessful.
XIf there is no reset, make sure that the erase duration is longer than 20 ms. A sample firmware
code for such a check may be found in nRFGo SDK.
• Make sure the data read back from the flash is identical to what is written to flash. The mechanism
above will guarantee that the data is safely stored to flash if the value does compare. If the compare
fails, the write has been ignored due to a power supply event.
• Using the VBUS supply, the time from “Power Fail” to “Reset” is longer than one flash byte write
operation (around 46 µs), as this is assured by the 10µF capacitor on the VBUS pin. If using the
VDD supply, make sure that this requirement is met by sufficient reservoir on the supply.
17.5 Flash programming from the MCU
This section describes how you can write and erase the flash memory using the MCU. Note that all flash
write and erase operations require that Cclk ≥12 MHz, see Table 133. on page 167.
17.5.1 MCU write and erase of the MainBlock
When a flash write is initiated, the MCU is halted for 740 clock cycles (46µs @16 MHz) for each byte writ-
ten. When a page erase is initiated, the MCU can be halted for up to 360,000 clock cycles (22.5 ms @16
MHz). During this time the MCU does not respond to any interrupts. Firmware must assure that page erase
does not interfere with normal operation of the nRF24LU1+.
The MCU can perform erase page and write operations to the unprotected part and the data part of the
flash MainBlock. To prevent unwanted/harmful erase and write operations a security mechanism is imple-
mented.
To allow erase and write flash operations the MCU must run the following sequence:
1. Write 0xAA to the FCR register. This starts an internal 7 bit down counter. The counter counts
down from 127 to 0.
2. Before the count down period has expired (8 µs @16 MHz), write 0x55 to the FCR. This restarts
the internal 7 bit down counter. Then the counter again counts down from 127 to 0. In the count
down period (8 µs) the FSR.WEN bit is writeable from the MCU.
3. Set FSR.WEN high before count down period has expired.
4. The flash is now open for erase and write from the MCU until FSR.WEN is set low again.
FSR.WEN can be set low directly (no security mechanism applies).
5. To erase a page, write page address (range 0-63) to the FCR register. Bytes are written individu-
ally (there is no auto increment) to the flash using the specific memory address. When the pro-
gramming code executes from the flash, any erase or write operation is self timed and the MCU
stops until the operation is finished. If the programming code executes from the XDATA RAM the
code must wait until the operation has finished. This can be done either by polling the FSR.RDYN
bit to go low or by a wait loop. Do not set FSR.WEN low before the write or erase operation is fin-
ished. Memory address is identical to the flash address, see Chapter 15 on page 127 for memory
mapping.
Revision 1.1 Page 141 of 187
nRF24LU1+ Product Specification
17.5.2 Hardware support for firmware upgrade
If the FSR.STP bit is high the MCU starts a program execution from the lowest address in the protected
part of the flash memory (FPCR.NUPP<<9). If the FSR.STP bit is low (as it is in a normal case) the MCU
starts an execution from address “0” of the flash memory.
The FSR.STP bit can only be set indirectly by programming one of the 16 last bytes of flash MainBlock.
Upon the next Reset these 16 bytes will be read, and if the data area is enabled (FPCR.DAEN = 1) and the
content of the 16 highest addresses of the flash memory (MainBlock) have an odd number of 1’s then
FSR.STP is set high. Otherwise, FSR.STP is set low. If the data area is not enabled (FPCR.DAEN = 0)
FSR.STP is always low. This mechanism may be used to obtain a safe upgrade for the unprotected area
of the flash.
There is only one set of interrupt vectors (see Table 138.) and they always point to the first page of flash
memory, regardless of whether the page is defined as protected or unprotected memory. So, if a program
is placed in the protected part of flash memory starting at a higher page, the corresponding interrupt vec-
tors still point to the unprotected part of the memory. Unless the implications of this are clearly understood,
it is recommended not to use interrupt in programs intended to run from the protected area.
Here is an example of this mechanism in use:
• The application is running in an unprotected area and the program doing the upgrade resides in a
protected area.
• You must configure flash with FPCR.DAEN=1 to allow firmware control over the FSR.STP bit.
• The host initiates a firmware upgrade over the USB interface.
•Set
FSR.WEN as described in section 17.5.1 on page 140.
• A bit in one of the 16 highest addressed bytes is programmed to 0.
• You can now restart the system. The system restarts from the protected area.
• You can now perform erase and write operations safely in the unprotected area, that is, you can
update the unprotected area through the USB interface.
In case of a power failure or a restart, the MCU starts an execution in the protected area.
• When the upgrade is finished a new bit in one of the 16 highest addressed bytes is programmed to
0 which gives an even number of 1s in these bytes, implying FSR.STP=0, after next reset.
• You can now restart the system, and it restarts from the unprotected area.
Note: For program in protected area, see the restriction for movc in Figure 61. on page 127
17.6 Flash programming through USB
The nRF24LU1+ bootloader allows you to program the nRF24LU1+ through the USB interface. The boot-
loader is pre-programmed into the nRF24LU1+ flash memory and automatically starts when power is
applied. After start-up the bootloader copies the flash programming code to the internal SRAM from where
the complete flash memory can be programmed. The bootloader occupies the topmost 2K bytes (KB) of
the flash and is not deleted unless the user program extends into this area. If the program is larger than
30KB the bootloader is overwritten and lost. In addition to the topmost 2KB of the flash, the bootloader also
uses the 3 byte reset vector at address 0. If your application needs to re-execute the bootloader; you must
restore the reset vector so that the bootloader executes after power on reset.
17.6.1 Flash Layout
The 32 kB flash is divided into 64 pages of 512 bytes each. Since the maximum USB packet size in
nRF24LU1+ is 64 bytes the bootloader divides each flash page into 8 blocks of 64 bytes each as shown in
the following figure:
Revision 1.1 Page 142 of 187
nRF24LU1+ Product Specification
Figure 64. Relation between address, pages and blocks
17.6.2 USB Protocol
nRF24LU1+ begins enumerating when connected to a USB host and is available to the operating system.
A driver, or application, communicating with the bootloader must use the following parameters:
Table 120. Driver/application USB parameters for communication with bootloader
The USB host communicates with the bootloader by writing commands to the IN endpoint. All USB com-
mands to the bootloader start with a 1 byte identifier (cmd id) and return a packet. If the command takes
parameters, the parameters are written as one or two bytes after the one byte identifier, for example, com-
mand 0x02 takes the parameter pn. Each command returns a value that must be read from the OUT end-
point.
USB parameters Value
VID (Vendor Identification) 0x1915
PID (Product Identification) 0x0101
IN endpoint address 0x81
OUT endpoint address 0x01
block 0
block 7
block 15
block 511
page 0
page 1
page 63
0x0000
0x7FFF
Revision 1.1 Page 143 of 187
nRF24LU1+ Product Specification
17.6.2.1 Firmware Version (cmd id 0x01)
Figure 65. Command 0x01
This command returns firmware information of the bootloader. hb is the major version number and lb is the
minor version number.
17.6.2.2 Flash Write Init (cmd 0x02)
This command is sent to the bootloader to start writing a flash page to the page indicated by the parameter
pn. After this command is completed the host must send the 8 blocks that constitutes the page. This is
done by sending 64 byte packets to the USB IN endpoint with the contents of the block. The bootloader
responds with a one-byte packet (containing 0x00) after each packet has been sent.
Figure 66. Command 0x02
17.6.2.3 Read Flash (cmd 0x03)
This command is sent by the host to read one of the 64 byte flash blocks. The block is indicated by the
parameter bn (bits 0-7 only. Bit 8 is set by cmd 6 below). If the flash MainBlock readback disable is effec-
tive this command returns 0x00 in all bytes in the flash page containing the block is used (programmed)
and 0xff if it is empty.
Figure 67. Command 0x03
0x01 hb lb
Returns:
0x02 0x00
Returns:
b0 b1 b63 0x00
Returns:
...
b448 b449 b511 0x00
Returns:
...
...
pn
0x03 b0 b63
Returns:
bn ...
Revision 1.1 Page 144 of 187
nRF24LU1+ Product Specification
17.6.2.4 Flash Page Erase (cmd 0x04)
This command is used mainly for debugging purposes since the Flash Page Write command above auto-
matically erases the page if needed prior to programming. Using this command erases page pn.
Figure 68. Command 0x04
17.6.2.5 Turn on flash MainBlock readback disable (cmd 0x05)
Figure 69. Command 0x05
This command returns 0x00 if successful or 0x01 if the bootloader failed to turn on flash MainBlock read-
back disable. The device must be reset for the readback disable to be effective.
17.6.2.6 Select flash half (cmd 0x06)
Figure 70. Command 0x06
This command is used to select which flash half command 0x03 works against (bit 8 of the block number).
When n = 0 the lower 16 kB flash is selected and when n = 1 the upper 16 kB is selected. The reason for
having this command is to make sure the interface and commands for the nRF24LU1 bootloader are the
same on the nRF24LU1+.
0x04 0
Returns:
pn
0x05 0x00
Returns:
0x06 0
Returns:
n
Revision 1.1 Page 145 of 187
nRF24LU1+ Product Specification
17.7 Flash programming through SPI
The on-chip flash is designed to interface a standard SPI device for programming. The interface uses an 8
bit instruction register and a set of instructions/commands to program and configure the flash memory.
Note that all flash write and erase operations require that Cclk ≥12 MHz, see Table 133. on page 167.
17.7.1 SPI commands
To allow access through the SPI the external PROG pin must be set high during all flash operation com-
mands. After activation of the PROG pin you must wait at least 1.5 ms before you input the first flash com-
mand. When the PROG pin is set, the GPIO pins are automatically configured as slave SPI (see chapter 13
on page 116. Further description of SPI slave is found in chapter 10 on page 101). Before each flash write
or erase command, FSR.WEN must be set, because this bit is automatically cleared after any write or erase
command. The value of FSR.INFEN always decides if access goes to the flash MainBlock or the InfoPage.
Table 121. Flash SPI operation commands
Command Command
format Address Number of
databytes Command operation
WREN 0x06 NA 0 Set flash write enable,FSR.WEN
WRDIS 0x04 NA 0 Reset flash write enable, FSR.WEN
RDSR 0x05 NA 1 (or more) Read Flash Status Register (FSR)
WRSR 0x01 NA 1 Write Flash Status Register (FSR). Only bits 5
and 3 (WEN and INFEN) are writable by this
command.
READ 0x03 Start
address,
2 bytes
1-32768 Read data from flash
PROGRAM 0x02 Start
address,
2 bytes
1-256 Write data to flash
ERASE PAGE 0x52 page
number,
1 byte
0 Erase addressed flash page
ERASE ALL 0x62 NA 0 Erase all pages of flash MainBlock
RDFPCR 0x89 NA 1 Read Flash Protect Configuration Register
(FPCR)
RDISIP 0x84 NA 0 Set flash InfoPage read-back disable,
FSR.RDISIP, and write 0x00 to InfoPage byte
0x22.
RDISMB 0x85 NA 0 Set flash MainBlock read-back disable,
FSR.RDISMB and write 0x00 to InfoPage byte
0x23.
ENDEBUG 0x86 NA 0 Write 0x00 to InfoPage byte 0x24, and after
next reset, the HW debugger will be enabled,
see chapter 23 on page 175 for details, and
FSR.DBG will be set.
Revision 1.1 Page 146 of 187
nRF24LU1+ Product Specification
Figure 71. SPI read command without address
Figure 72. SPI flash read operation, shown with 1 databyte
Figure 73. SPI write command without address
Figure 74. SPI flash write operation, shown with 1 databyte
C7
C6 C5 C4 C3 C2 C1 C0
D7
D6
D5
D4
D3
D2
D1
D0
CSN (P0.3)
SCK (P0.0)
MOSI (P0.1)
MISO (P0.2)
D7 D6 D5 D4 D3 D2 D1 D0
C7
C6 C5 C4 C3 C2 C1 C0 A15 A14 A13 A12
A11 A10 A9 A7 A6 A5 A4 A3 A2 A1 A0
CSN (P0.3)
SCK (P0.0)
MOSI (P0.1)
MISO (P0.2)
A8
C7
C6 C5 C4 C3 C2 C1 C0 D7 D6 D5 D4 D3 D2 D1
D0
Optional
MISO (P0.2)
MOSI (P0.1)
SCK (P0.0)
CSN (P0.3)
D7 D6 D5 D4 D3 D2 D1 D0
C7
C6 C5 C4 C3 C2 C1 C0 A15 A14 A13 A12
A11 A10 A9 A7 A6 A5 A4 A3 A2 A1 A0
CSN (P0.3)
SCK (P0.0)
MOSI (P0.1)
MISO (P0.2)
A8
Revision 1.1 Page 147 of 187
nRF24LU1+ Product Specification
An SPI command always starts with the external master sending a command byte to the flash slave, fol-
lowed by a variable number of address and data bytes. The number of address and data bytes are specific
to each command, as shown in Table 121. on page 145. In Figure 71. to Figure 74. Cn is the SPI command
bit, An is the address bit and Dn is the data bit (note: MSBit in each byte first). After CSN is deactivated, a
flash write or erase command requires the chip to do the flash programming or erase, and this will take
some time to complete therefore, it is advised not to issue a new command until the specified amount of
time has elapsed. Alternatively, you can repeatedly issue RDSR commands until the FSR.RDYN bit reads
back as 0.
17.7.1.1 WREN/WRDIS
SPI command WREN sets the flash write enable bit FSR.WEN, and SPI command WRDIS resets FSR.WEN.
This bit enables all SPI write and erase operations to the flash memory. The device powers up in write dis-
able state and will automatically return to write disable state after any SPI flash write or erase command.
Each SPI flash write and erase instruction must therefore be preceded by a WREN command. Both WREN
and WRDIS are 1-byte commands with no data.
17.7.1.2 RDSR
The SPI command RDSR reads out the content of the flash status register FSR, and consists of 1-com-
mand byte and 1-data byte as shown in Figure 71. on page 146. By keeping the CSN line active after the
first data byte, FSR will be repeatedly re-read until CSN is set inactive.
17.7.1.3 WRSR
The SPI command WRSR writes to the flash status register FSR, and consists of a 1-command byte and
1-data byte as shown in Figure 73. on page 146.
17.7.1.4 READ
The SPI command READ reads out the content of the flash memory, starting from the given address. If
FSR.INFEN=0, flash MainBlock will be read. If FSR.INFEN=1, flash InfoPage will be read. The following
sequence is required:
1. The CSN line is activated (that is, pulled low) to enable/ activate the SPI slave.
2. The READ command is transmitted through the MOSI line followed by the two byte address to the
byte to be read as shown in Figure 72. on page 146.
3. The addressed data byte is shifted out on the MISO line.
If the CSN line is kept active after the first byte is read out the read command can be extended, the
address is auto incremented and data continues to be shifted out. The internal address counter rolls over
when the highest address is reached, allowing the complete memory to be read in one continuous read
command.
A readback of the flash content is only possible if the respective read disable bit FSR.RDISMB or
FSR.RDISIP is not set.
17.7.1.5 PROGRAM
The SPI command PROGRAM writes to (or programs) the flash memory, starting from the given address. If
FSR.INFEN=0, flash MainBlock will be written to. If FSR.INFEN=1, flash InfoPage will be written to. The
following sequence is required:
Revision 1.1 Page 148 of 187
nRF24LU1+ Product Specification
1. Enable the device for writing (set FSR.WEN) using the WREN or WRSR command.
2. The CSN line is pulled low to enable the SPI slave.
3. The PROGRAM command is sent on the MOSI line followed by the two-byte address (address of
the first byte) and the data to be programmed/ written, as shown in Figure 74. on page 146.
4. The on-chip driven program sequence is started when you set the CSN pin high/ deactivated.
5. Programming n bytes takes (n + 1)*365 clock cycles (XC1) after CSN is deactivated. During the
program sequence all SPI commands are ignored except the RDSR command.
The CSN line can be kept active to write up to 256 bytes (with address auto increment) in one PROGRAM
command. The first byte can be anywhere in a page. Normally, a byte can not be reprogrammed without
erasing the whole page, see also the Note: on page 136.
Note: FSR.RDISMB = 1 inhibits the write to flash MainBlock.
The device returns to write disable after completion of a PROGRAM command.
17.7.1.6 ERASE PAGE
The SPI command ERASE PAGE erases 1 addressed page in the flash memory, so that the content of the
page will be 0xFF. If FSR.INFEN=0, a page in flash MainBlock will be erased. If FSR.INFEN=1, flash
InfoPage will be erased. The following sequence is required:
1. Enable the device for writing (set FSR.WEN) using the WREN or WRSR command.
2. The CSN line is pulled low to enable the SPI slave.
3. The ERASE PAGE command is sent on the MOSI line followed by the page number (0-63) to be
erased.
4. The on-chip driven erase sequence is started when the CSN pin is set high.
5. Erasing a page takes about 360000 clock cycles (XC1) after CSN is deactivated. During the
erase sequence all SPI commands are ignored except the RDSR command.
Note: FSR.RDISMB = 1 inhibits page erase of both flash MainBlock and the InfoPage. The device
returns to write disable after completion of an ERASE PAGE command.
17.7.1.7 ERASE ALL
The SPI command ERASE ALL erases all content of the flash MainBlock memory to value 0xFF. The fol-
lowing sequence is required:
1. Enable the device for writing (set FSR.WEN) using the WREN or WRSR command.
2. The CSN line is pulled low to enable the SPI slave.
3. The ERASE ALL command is sent on the MOSI line.
4. The on-chip driven erase sequence is started when the CSN pin is set high.
5. ERASE_ALL takes about 360000 clock cycles (XC1) after CSN is deactivated. During the erase
sequence all SPI commands are ignored except the RDSR command.
The ERASE_ALL command cannot be used to erase the flash InfoPage, but is always allowed to erase
flash MainBlock. The device returns to write disable after completion of an ERASE ALL command.
17.7.1.8 RDFPCR
The SPI command RDFPCR reads out the content of the flash project configuration register FPCR, and
consists of 1 command byte and 1 data byte as shown in Figure 71. on page 146.
Revision 1.1 Page 149 of 187
nRF24LU1+ Product Specification
17.7.1.9 RDISIP
Flash InfoPage readback disables and writes 0x00 to byte 0x22 in flash InfoPage. The command disables
all read access to the flash InfoPage from the external SPI interface. This is a single byte command with
no data.The following sequence is required:
1. Enable the device for writing (set FSR.WEN) using the WREN or WRSR command.
2. The CSN line is pulled low to enable the SPI slave.
3. The RDISIP command is sent on the MOSI line.
4. The on-chip driven program sequence is started when the CSN pin is high/deactivated.
5. The program sequence takes 730 clock cycles (XC1) after CSN is deactivated. During this
sequence all SPI commands are ignored except the RDSR command.
The device returns to write disable after completion of an RDISIP command. FSR.RDISIP can only be
cleared by erasing flash InfoPage with an ERASE PAGE command, which is only allowed if
FSR.RDISMB=0.
17.7.1.10 RDISMB
Flash MainBlock readback disables and writes 0x00 to byte 0x23 in flash InfoPage. The command disables
all read, write and page erase access to the flash MainBlock from any external interface (SPI or HW debug-
ger). It also prevents erase of flash InfoPage and enabling of HW debugger. This will protect the content
of the flash MainBlock from being read out over the external SPI or HW debugger interface. This is a single
byte command with no data. The following sequence is required:
1. Enable the device for writing (set FSR.WEN) using the WREN or WRSR command.
2. The CSN line is pulled low to enable the SPI slave.
3. The RDISMB command is sent on the MOSI line.
4. The on-chip driven program sequence is started when the CSN pin is high/deactivated.
5. The program sequence takes 730 clock cycles (XC1) after CSN is deactivated. During this
sequence all SPI commands are ignored except the RDSR command.
The device returns to write disable after completion of an RDISMB command. The only way to clear
FSR.RDISMB is to erase the whole flash MainBlock with an ERASE ALL command, and thereafter do an
ERASE PAGE of the flash InfoPage to set the value of byte 0x23 to 0xFF.
17.7.1.11 ENDEBUG
The SPI command ENDEBUG writes 0x00 to the flash InfoPage byte 0x24, and after the next reset
FSR.DBG is set and the HW Debugger is enabled. To clear FSR[7] first erase the flash InfoPage, and then
perform a reset. This is a single byte command with no data. This command is only allowed if FSR.DBG=0,
and is ignored otherwise.
The following sequence is required:
1. Enable the device for writing (set FSR.WEN) using the WREN or WRSR command.
2. The CSN line is pulled low to enable the SPI slave.
3. The ENDEBUG command is sent on the MOSI line.
4. The on-chip driven program sequence is started when the CSN pin is high/deactivated.
5. The program sequence takes 730 clock cycles (XC1) after CSN is deactivated. During this
sequence all SPI commands are ignored except the RDSR command.
Revision 1.1 Page 150 of 187
nRF24LU1+ Product Specification
FSR.DBG may be set (only when FSR.RDISMB=0) without involving the flash InfoPage, by the following
sequence:
MCU writes a "1" to FSR.DBG. The HW debugger is then temporarily enabled until next reset, when the
flash InfoPage value takes control.
Note: There is no SPI command for directly setting or clearing FSR.DBG.
The device returns to write disable after completion of an ENDEBUG command.
17.7.1.12 SPI Readback disable
A mechanism to prevent readback over the external SPI interface is implemented. Two bytes of the
InfoPage are reserved for this. The InfoPage and MainBlock each have their own readback disable signal,
FSR.RDISIP and FSR.RDISMB. The InfoPage content is checked whenever the chip is started or
restarted. If byte 0x22 of InfoPage=0xFF, FSR.RDISIP=0, otherwise FSR.RDISIP=1. If byte 0x23 of
InfoPage=0xFF, FSR.RDISMB=0, otherwise FSR.RDISMB=1.
The InfoPage bytes may be written once, (by using command SPI commands RDISIP or RDISMB) which
enables the readback disable function. The InfoPage byte 0x23 (RDISMB) is also writable by MCU. Until
the flash memory is erased again, the readback function cannot be enabled. FSR.RDISMB=1 inhibits page
erase and write to flash (both MainBlock and InfoPage), but erase all is always allowed, as it is the only
way to clear FSR.RDISMB.
17.7.2 Standalone programming requirements
When programming the nRF24LU1+ in a standalone flash/EEPROM/MCU programmer, an adapter board
(or socket assembly) with capacitors and resistors and possibly an oscillator are required. The following
table describes how the device pins are used:
Signal Pins Disposition Further information
VDD 1, 3, 9, 19, 24,
27
Connect together to supply and decouple See 17.7.2.2
VBUS 3 Open See 17.7.2.2
D+ 4 Leave open
D- 5 Leave open
VSS 6, 12, 17, 18,
23, 26, 30
Connect to ground net (plane) See 17.7.2.2
PROG 7 Connect to pin electronics or strap to
VDD
See 2.2.2
RESET 8 Connect to pin electronics or strap to
VDD
See 2.2.7
SCK 10 Connect to pin electronics (nRF24LU1+
in)
See 17.7.1
MOSI 11 Connect to pin electronics (nRF24LU1+
in)
See 17.7.1
MISO 13 Connect to pin electronics (nRF24LU1+
out)
See 17.7.1
CSN 14 Connect to pin electronics (nRF24LU1+
in)
See 17.7.1
P0.4 15 Leave open
P0.5 16 Leave open
VDD_PA 20 Leave open
Revision 1.1 Page 151 of 187
nRF24LU1+ Product Specification
Table 122. Device pins
17.7.2.1 Clock requirements
The XC1 requires a clock between 9 MHz and 16 MHz during the entire programming sequence. The pro-
gramming speed is directly proportional to the speed of the clock so, we recommend a clock speed of 16
MHz +/- 60ppm. The clock source can be a crystal between XC1 and XC2 or an external clock source con-
nected to the XC1 pin:
• From an oscillator module on the adapter board or a pin driver in the programmer.
XRequired amplitude is at least 0.5V p-p, maximum 3.3V p-p.
XWaveform is sine or square.
XRequired duty cycle is 40% to 60% (V/2 in the sine case).
Figure 75. External clock source
• From a crystal between XC1 (pin 32) and XC2 (pin 31)
ANT1 21 Leave open
ANT2 22 Leave open
IREF 25 Leave open
DEC1 28 Leave open
DEC2 29 Decouple to VSS See 17.7.2.2
XC2 31 leave open (optionally connect to XTAL) See 17.7.2.1
XC1 32 Connect to clock source See 17.7.2.1
Signal Pins Disposition Further information
nRF24LU1+
MISO
MOSI
SCK
CSN
RESET
PROG
XC1
XC2
OSC
Revision 1.1 Page 152 of 187
nRF24LU1+ Product Specification
XSee chapter 24 on page 176 for oscillator circuitry details.
XMake sure the socket solution does not add significant parasitic to the circuit.
Figure 76. Clock source from a crystal between XC1 and XC2 pins
17.7.2.2 Power supply requirements
All VSS pins should be well connected to the adapter board, preferably using a ground plan. All VDD pins
should be connected together and decoupled with at least three capacitors (two 10nF capacitors and one
100nF capacitor), to VSS. The DEC2 pin should be decoupled with 33nF to VSS.
Using 3.3V supply (preferred)
Leave the VBUS pin open and connect a 3.3V +/- 5% power supply to the VDD pins.
17.7.2.3 Signal pin requirements
SPI Port
The pins CSN, SCK and MOSI must be driven by programmer pin electronics. All write operations to the
FLASH are controlled by these three signals. The pin MISO is an output of the nRF24LU1+ that must be
read to validate flash contents, and can be read to check status during write or erase operations.
nRF24LU1+
MISO
MOSI
SCK
CSN
RESET
PROG
XC1
XC2
Revision 1.1 Page 153 of 187
nRF24LU1+ Product Specification
The clock frequency of the SPI port is not correlated to the XC1 clock (it does not need to be synchronous).
The SPI data signals have no defined relation to the XC1 clock (can be any phase). For more information
see chapter 5 on page 19.
Control pins PROG and RESET
If power on sequence is clean (that is, nRF24LU1+ is well seated when power is ramped and power ramp
is monotonous), the program and reset signals may be strapped to VDD. However, if possible, these sig-
nals should be controlled by pin drivers so that they are independent of power ramp quality.
17.7.3 In circuit programming over SPI
You can program a finished PCB with nRF24LU1+ that has all parts mounted. There are similar require-
ments to a standalone programmer with the following exceptions:
• All pins must be connected according to application requirements.
•PROG pin needs a pull-down on the PCB.
•PROG pin should be under control of the programmer over the edge of the PCB or through a pogo
pin.
•RESET pin needs a pull-up on the PCB.
•RESET pin should be under control of the programmer over the edge of the PCB or through a pogo
pin (to restart device after programming if required).
• The SPI input pins (CSN, SCK, MOSI) should be under control of the programmer over the edge of
the PCB or through a pogo pin.
• The SPI output pin (MISO) should be readable by programmer over the edge of the PCB or through
a pogo pin.
• The applications use of the SPI port pins should not conflict with the use of these pins as a SPI port.
• nRF24LU1+ can be powered effectively by a 5V connected to VBUS (over USB plug or pogo pin) or
by a 3.3V +/- 5% connected to VDD over the edge of the PCB or through a pogo pin.
17.7.4 SPI programming sequences
The details of SPI timing are described in section 10.3 on page 102. With limit track length (and other load-
ing on MISO) it is possible to operate the SPI up to 8 MHz. Reducing that to 4 MHz (or even 2 MHz) does
not significantly impact the overall programming time.
The sequences of command and data in an SPI command are found in Figure 72. on page 146 and Figure
74. on page 146. In these figures only 1 byte of data is shown. Typically for read and write data transfers
the block should be as long as possible (64 to 256 data bytes gives the best performance).
The typical production line sequence of commands is:
1. Pulse RESET pin low and return to high.
2. Pull PROG pin high and wait for 2ms.
3. Issue WREN command
4. Issue ERASE_ALL command
5. Wait for the ERASE_ALL command to finish (this takes 360,000 clock cycles (XC1) after the posi-
tive edge of CSN).
6. Repeat the following 128 times for 32 kB flash memory, (64 times for 16 kB):
XIssue WREN command
XIssue PROGRAM command followed by the next address and then the next 256 data bytes.
XWait until the PROGRAM command is finished (this is 256 + 1 times 365 clock cycles (XC1) after
the positive edge of CSN).
Revision 1.1 Page 154 of 187
nRF24LU1+ Product Specification
7. Repeat the following 128 times for 32 kB flash memory:
XIssue READ command followed by next address then read out 256 bytes on MISO
XCompare read bytes against expected
The following are optional steps that update the InfoPage fields:
8. Issue WFSR to set FSR.INFEN bit to 1.
IF "Page address for start of protected area” is specified (not equal to 0xFF):
9. Issue SPI command WREN
10. Issue SPI command PROGRAM with address 0x0020 followed by the offset byte
11. Wait until PROGRAM command is finished
IF "Enable flash data memory" is specified:
12. Issue SPI command WREN
13. Issue SPI command PROGRAM with address 0x0021 followed by a byte that is not 0xFF
14. Wait until PROGRAM command has completed (this is 365 clock cycles (XC1) after the positive
edge of CSN).
IF "Readback blocking for MainBlock" is specified:
15. Issue SPI command RDISMB
16. Wait until PROGRAM command has completed (this is 365 clock cycles (XC1) after the positive
edge of CSN).
IF "Readback blocking for InfoPage" is specified:
17. Issue SPI command RDISIP
18. Wait until PROGRAM command has completed (This is 365 clock cycles (XC1) after the positive
edge of CSN).
Note: The completion of the ERASE_ALL and/or the PROGRAM command may be ensured by wait-
ing the specified amount of time, or alternatively repeatedly issuing RDSR commands until the
FSR.RDYN bit reads back as 0.
17.7.4.1 Erasing and programming the InfoPage
Our devices have all user defined fields of the InfoPage pre-erased. The above programming sequence
does not erase the InfoPage. If InfoPage needs to be erased due to re-programming of a part, the following
steps must be added:
1. Issue WFSR to set FSR.INFEN bit to 1 and FSR.WEN bit to 1
2. Issue ERASE_PAGE 0
Note: To avoid losing the CHIP_ID (at address 0x0B to 0x0F), these bytes should be saved before
erasing, and programmed back afterwards.
3. Wait until ERASE_PAGE command is finished (this will be 360,000 clock cycles (XC1) after the
positive edge of CSN).
The InfoPage is now erased and ready for programming. If the flash MainBlock is read protected
(FSR.RDISMB=1), the InfoPage can only be erased if the MainBlock has been erased. This means that
Revision 1.1 Page 155 of 187
nRF24LU1+ Product Specification
step 1 of this sequence must come after step 5 (ERASE_ALL) in the programming sequence in section
17.7.4 on page 153.
Note: The completion of the ERASE_PAGE and/or the PROGRAM command may be ensured by wait-
ing the specified amount of time, or alternatively repeatedly issuing RDSR commands until the
FSR.RDYN bit reads back as 0.
Revision 1.1 Page 156 of 187
nRF24LU1+ Product Specification
18 MDU – Multiply Divide Unit
The MDU – Multiplication Division Unit, is an on-chip arithmetic co-processor which enables the MCU to
perform additional extended arithmetic operations like 32-bit division, 16-bit multiplication, shift and, nor-
malize operations.
18.1 Features
The MDU is controlled by the SFR registers MD0 .. MD5 and ARCON.
18.2 Block diagram
Figure 77. Block diagram of MDU
18.3 Functional description
All operations are unsigned integer operations. The MDU is handled by seven registers, which are memory
mapped as Special Function Registers. The arithmetic unit allows concurrent operations to be performed
independent of the MCU’s activity.
Operands and results are stored in MD0..MD5 registers. The module is controlled by the ARCON register.
Any calculation of the MDU overwrites its operands.
The MDU does not allow reentrant code and cannot be used in multiple threads of the main and interrupt
routines at the same time. Use the NOMDU_R515 directive to disable MDU operation in possible conflict-
ing functions.
18.4 SFR registers
The MD0 .. MD5 are registers used in the MDU operation.
Table 123. Multiplication/Division registers MD0..MD5
Address Register name
0xE9 MD0
0xEA MD1
0xEB MD2
0xEC MD3
0xED MD4
0xEE MD5
MDU
MD0
ARCON
MD2
MD1 MD3
MD4
MD5
Revision 1.1 Page 157 of 187
nRF24LU1+ Product Specification
The ARCON register controls the operation of MDU and informs you about its current state.
Table 124. ARCON register
The operation of the MDU consists of the following phases:
18.4.1 Loading the MDx registers
The type of calculation the MDU has to perform is selected in accordance with the order in which the MDx
registers are written.
Table 125. MDU registers write sequence
1. Write MD0 to start any operation.
2. Write operations, as shown in Table 125. to determine appropriate MDU operation.
3. Write (to MD5 or ARCON) starts selected operation.
The SFR Control detects some of the above sequences and passes control to the MDU. When a write
access occurs to MD2 or MD3 between write accesses to MD0 and finally to MD5, then a 32/16 bit division
is selected.
When a write access to MD4 or MD1 occurs before writing to MD5, then a 16/16 bit division or 16x16 bit
multiplication is selected. Writing to MD4 selects 16/16 bit division and writing to MD1 selects 16x16 bit
multiplication, that is, Num1 x Num2.
Address Reset value Bit Name Description
0xEF 0x00 7 mdef MDU Error flag MDEF. Indicates an improperly performed opera-
tion (when one of the arithmetic operations has been restarted or
interrupted by a new operation).
6 mdov MDU Overflow flag MDOV. Overflow occurrence in the MDU oper-
ation.
5 slr Shift direction, 0: shift left, 1: shift right.
4-0 sc Shift counter. When set to ‘0’s, normalize operation is selected.
After normalization, the “sc.0” … “sc.4” contains the number of
normalizing shifts performed.
Shift operation is selected when at least one of these bits is set
high. The number of shifts performed is determined by the num-
ber written to “sc.4”.., “sc.0”, where “sc.4” is the MSB.
Operation 32 bit/16 bit 16 bit / 16 bit 16 bit x 16 bit Shift/normalize
first write
last write
MD0 (lsb)
MD1
MD2
MD3 (msb)
Dividend
MD0 (lsb)
MD1 (msb)
Dividend
MD0 (lsb) Num1 MD0 (lsb)
MD1
MD2
MD3 (msb)
Number
MD4 (lsb) Num2
MD4 (lsb)
MD5 (msb)
Ddivisor
MD4 (lsb)
MD5 (msb)
Ddivisor
MD1 (msb) Num1
ARCON
MD5 (msb) Num2
Revision 1.1 Page 158 of 187
nRF24LU1+ Product Specification
18.4.2 Executing calculation
During executing operation, the MDU works on its own in parallel with the MCU.
Table 126. MDU operations execution times
18.4.3 Reading the result from the MDx registers
Table 127. MDU registers read sequence
The Read out sequence of the first MDx registers is not critical but the last read (from MD5 - division and
MD3 - multiplication, shift or normalize) determines the end of a whole calculation (end of phase three).
18.4.4 Normalizing
All leading zeroes of 32-bit integer variable stored in the MD0 .. MD3 registers are removed by shift left oper-
ations. The whole operation is completed when the MSB (Most Significant Bit) of MD3 register contains a
’1’. After normalizing, bits ARCON.4 (msb) .. ARCON.0 (lsb) contain the number of shift left operations that
were done.
18.4.5 Shifting
In shift operation, 32-bit integer variable stored in the MD0 ... MD3 registers (the latter contains the most sig-
nificant byte) is shifted left or right by a specified number of bits. The slr bit (ARCON.5) defines the shift
direction and bits ARCON.4 ... ARCON.0 specify the shift count (which must not be 0). During shift opera-
tion, zeroes come into the left end of MD3 for shifting right or they come in the right end of the MD0 for
shifting left.
18.4.6 The mdef flag
The mdef error flag (see Table 124. on page 157) indicates an improperly performed operation (when one
of the arithmetic operations is restarted or interrupted by a new operation). The error flag mechanism is
automatically enabled with the first write operation to MD0 and disabled with the final read instruction from
MD3 (multiplication or shift/norm) or MD5 (division) in phase three.
Operation Number of clock cycles
Division 32bit/16bit 17 clock cycles
Division 16bit/16bit 9 clock cycles
Multiplication 11 clock cycles
Shift min. 3 clock cycles (sc = 01h) max 18 clock cycles (sc = 1Fh)
Normalize min. 4 clock cycles (sc <- 01h) max 19 clock cycles (sc <- 1Fh)
Operation 32 bit/16 bit 16 bit / 16 bit 16 bit x 16 bit Shift/normalize
first read
last read
MD0 (lsb)
MD1
MD2
MD3 (msb)
Quotient
MD0 (lsb)
MD1 (msb)
Quotient
MD0 (lsb)
MD1
MD2
Product
MD0 (lsb)
MD1
MD2
Number
MD4 (lsb)
MD5 (msb)
Remainder
MD4 (lsb)
MD5 (msb)
Remainder
MD3 (msb) MD3 (msb)
Revision 1.1 Page 159 of 187
nRF24LU1+ Product Specification
The error flag is set when:
• If you write to MD0 .. MD5 and/or ARCON during phase two of MDU operation (restart or calcula-
tions interrupting).
• If any of the MDx registers are read during phase two of MDU operation when the error flag mecha-
nism is enabled. In this case, the error flag is set but the calculation is not interrupted.
The error flag is reset only after read access to the ARCON register. The error flag is read only.
18.4.7 The mdov flag
The mdov overflow flag (see Table 124. on page 157) is set when one of the following conditions occurs:
• division by zero.
• multiplication with a result greater than 0000 FFFFh.
• start of normalizing if the most significant bit of MD3 is set (“md3.7” = ‘1’).
Any operation of the MDU that does not match the above conditions clears the overflow flag.
Note: The overflow flag is exclusively controlled by hardware, it cannot be written.
Revision 1.1 Page 160 of 187
nRF24LU1+ Product Specification
19 Watchdog and wakeup functions
In order to achieve the lowest possible average current consumption, the processor clock can be stopped
under firmware control. Operation can be resumed (wakeup) on external events like toggling of GPIO pins
or from the internal RTC wakeup timer, USB or, the RF-module, see chapter 20 on page 165 for details.
In addition, a programmable watchdog timer can be enabled to reset the system if the software hangs.
19.1 Features
• 32 kHz operation
• Programmable 8-bit resoulution
• 16-bit range Watchdog
• Watchdog disabled (reset) only by a system reset
• 24-bit range wakeup timer
• Timer is a possible interrupt source
• Timer reload can be signalled on GPIO
19.2 Block diagram
Figure 78. Watchdog and wakeup functions block diagram
Divider
TICKDV
Enable
CKLF
RTC
24-bit
Down-Counter GTIMER
Data & Control Interface
REGXH
REGXC
REGXL
Latch logic
4-bit
Counter
To Wakeup & Interrupt
logic
24-bit
(8+16) 4-bit
Watchdog
16-bit
Down-Counter
Watchdog reset
Revision 1.1 Page 161 of 187
nRF24LU1+ Product Specification
19.3 Functional description
19.3.1 The Low Frequency Clock (CKLF)
CKLF frequency fCKLF is 32000 Hz (derived from the crystal oscillator1 and is used for wakeup functions
and the Watchdog. This clock is always running.
19.3.2 Tick calibration
The tick is an interval (in CKLF periods) that determines the resolution of the watchdog and the RTC
wakeup timer. By default the tick is set to 125 µs (4 CKLF cycles). The programmable range is from 31.25
µs to 8 ms. The tick is as accurate as the 32 kHz source.
The tick is controlled by the TICKDV register.
Table 128. TICKDV register
19.3.3 RTC wakeup timer
The RTC is a simple 24 bit down counter that produces an optional interrupt and reloads automatically
when the count reaches zero. This process is initially disabled, and is enabled with the first write to the
lower 16 bit of the timer latch (WRTCLAT). Writing the lower 16 bits of the timer latch is always followed by
a reload of the counter. Only write the upper 8 bit of the timer latch when the timer is disabled, see Tab le
130. on page 164.
The RTC counter may be disabled again by writing a disable opcode to the control register (WRTCDIS).
Both the latch and the counter value may be read by giving the respective codes in the control register, see
the description in Table 129. on page 163 and Table 130. on page 164.
The RTC counter is used for a wakeup sometime in the future (a relative time wakeup call). If ‘N’ is written
to the counter, the first wakeup happens between ‘N+1’ and ‘N+2’ “tick” from the completion of the write.
From then on a new wakeup is issued every “N+1” "tick" until the unit is disabled or another value is written
to the latch.
The wakeup timer is one of the sources that can generate a WU interrupt (see Table 140. on page 173) to
the MCU. You may poll the flag or enable the interrupt. If the MCU is in a power down or standby state, the
wakeup forces the device to exit power down or standby regardless of the state of the interrupt enable.
The MCU system does not provide any “absolute time functions”. Absolute time functions can be handled
in software since the RAM is continuously powered even when in sleep mode.
1. fCKLF is 1/500 of oscillator frequency.
Addr Reset value bit R/W Function
0xB5 0x03 7:0 RW Divider that is used in generating tick from CKLF frequency.
Ttick = (1 + TICKDV) / fCKLF
.
Revision 1.1 Page 162 of 187
nRF24LU1+ Product Specification
19.3.4 Programmable GPIO wakeup function
All pins in port 0 can be used as wakeup signals for the MCU system. The device can be programmed to
react on rising, falling or, both edges of each pin individually. Additionally, each pin is equipped with a pro-
grammable filter that is used for glitch suppression.
Figure 79. Wakeup filter, each pin for GPIO wakeup function
The debounce logic acts as a low pass filter. The input has to be stable for the number of clock pulses that
are given (in WGTIMER) to appear on the output. Edge triggers on positive, negative, or both edges. The
edge delay is 2 clock cycles. Please see Table 130. on page 164 and Table 131. on page 164 for filter con-
figuration.
19.3.5 Watchdog
The watchdog is activated on the first write to its control register REGXC. It cannot be disabled by any
other means than a reset.
The watchdog register is loaded by writing a 16-bit value (number of ticks) to the two 8-bit data registers
(REGXH and REGXL) and then writing the correct opcode to the control register. The watchdog counts
down towards 0 and when 0 is reached the complete MCU is reset.
To avoid the reset, the software must regularly load new values into the watchdog register.
19.3.6 Programming interface to watchdog and wakeup functions
Figure 80. on page 163 shows how the blocks that are always active are connected to the MCU.
RTC timer GPIO wakeup and Watchdog are controlled through three SFRs. The three registers, REGXH,
REGXL and, REGXC, are used to interface the blocks running on the slow CKLF clock. The 16-bit register
REGXH:REGXL can be written or read as two bytes from the MCU.
Typical sequences are:
Write:Write REGXH, Write REGXL, Write REGXC
Read: Write REGXC, Read REGXH, Read REGXL
Edge
[3:2]
Debounce
[1:0] Wakeup P0xP0x
WWCON
CKLF
Revision 1.1 Page 163 of 187
nRF24LU1+ Product Specification
Figure 80. Block diagram of wakeup and watchdog functions
Table 129. on page 163 describes the functions of the SFR registers that control those blocks, and Table
130. on page 164 explains the contents of the individual control registers for watchdog and wakeup func-
tions.
Table 129. REGXH, REGXL and REGXC registers
Addr Reset
value bit R/W Init Name Function
0xAB 0x00 7:0 RW 0x00 REGXH Most significant byte of 16-bit data register
0xAC 0x00 7:0 RW 0x00 REGXL Least significant byte of 16-bit data register
0xAD 0x00
7:5
4
3
2:0
-
R
RW
RW
0x00 REGXC Control register for 16 bit data register
Not used
Status of last REGXC write access 0: finished, 1: not finished
0: read, 1: write; see R/W column in Table 130. on page 164.
Indirect address, see the far left column in Table 130. on page
164.
Indirect
Address
Data register
Bit R/WaName Function
000 15:0 R RWD Watchdog register (count)
15:0 W WWD Watchdog register (count)
001 15:8
7:0
R
R
RGTIMER MSB part of RTC counter
MSB part of RTC latch
15:12
11:8
7:0
-
W
W
WGTIMER Not used
GTIMER latch
MSB part of RTC latch
010 15:0 R RRTCLAT Least significant part of RTC latch
15:0 W WRTCLAT Least significant part of RTC latch
011 15:0 R RRTC RTC counter value
- W WRTCDIS Disable RTC (data not used)
REGXC REGXH REGXL
8+16+4 bit Timer_latch
24-bit
down-counter
4-bit
cntr
Watchdog
16-bit down-
counter
load
load
GPIO
wakeup
Wakeup and Int
P0 GPIO
P0.0 GPIO
Watchdog
reset
tick
=0
P0ALT.0
Clocked on MCU clock
Clocked on
CKLF
=0
load
RTC
GTIMER
load
Revision 1.1 Page 164 of 187
nRF24LU1+ Product Specification
Table 130. Indirect addresses and functions
Table 131. GPIO wakeup filter configuration, WWCON
100
100
15:9
8
5:0
-
R
R
RWSTA0 Not used
Wakeup status for RTC timer
Wakeup status for pins P05-P00. RWSTA0 is
automatically cleared after read.
15:14
13:12
11:10
9:8
7:6
5:4
3:2
1:0
W
W
W
W
W
W
W
W
WWCON0 Edge selection of P03
Debounce filter for P03
Edge selection of P02
Debounce filter for P02
Edge selection of P01
Debounce filter for P01
Edge selection of P00
Debounce filter for P00, see Table 131. on page
164.
101 15:9
8
7:0
-
R
R
RWSTA1 Identical to RWSTA0 above
15:8
7:6
5:4
3:2
1:0
-
W
W
W
W
WWCON1 Not used
Edge selection of P05
Debounce filter for P05
Edge selection of P04
Debounce filter for P04, see Table 131. on page
164.
110 15:0 - - Reserved, do not use
111 15:0 - - Reserved, do not use
a. REGXC bit-3 selects between R(ead) and W(rite) operation
Debounce filter selection Edge selection
Code Number of clock pulses Code positive/negative trigger
00 0 00 Off
01 2 01 Positive
10 8 10 Negative
11 64 11 Both
Indirect
Address
Data register
Bit R/WaName Function
Revision 1.1 Page 165 of 187
nRF24LU1+ Product Specification
20 Power management
The nRF24LU1+ Power Management function controls the power dissipation through the administration of
modes of operation and by controlling clock frequencies.
20.1 Features
• Supports low power modes for MCU, RF Tranceiver, USB and 48 MHz PLL
• Programmable MCU clock frequency from 64 kHz to 16 MHz
• Multi-source MCU wakeup
• Watchdog and wakeup functionality running in low power mode
20.2 Block diagram
Figure 81. Power management block diagram
Clock Control
CLKCTL
Operational mode
control
PWRDWN
Wakeup logic
WUCONF
Oscillators/
Regulators/
Reset
sources
Wakeup
sources
Interrupts
Cclk
CKLF
Reset Control
RSTRES
Local reset
signals
Revision 1.1 Page 166 of 187
nRF24LU1+ Product Specification
20.3 Modes of operation
There are four main power consuming functions on the chip. These can be controlled on and off in different
ways depending on the required functionality after the start-up/reset sequence is ended.
These functions are:
•MCU
Xstates of operation: active and standby
Xactive at the end of the reset sequence
XSet to standby by software (write PWRDWN register = 0x01)
XSet to active by wakeup sources:
Interrupt from USB
Interrupt from RF Transceiver
Interrupt from external pin
Interrupt from on-chip RTC
• RF Transceiver
Xstates of operation: power down, standby and active (TX or RX)
Xpwrdwn at the end of the reset sequence
XSet to standby, active or power down by software, see section 6.3.1 on page 27
•USB
Xstates of operation: active and suspend
Xactive at the end of the reset sequence
XSet to suspend by software (write USBSLP register = 0x01)
XSet to active by software or by wakeup from USB host (through the USB bus)
•PLL
Xstates of operation: on and off
Xon at the end of the reset sequence
XSet to on or off by hardware with one exception:
if the USB is in suspend the PLL may be controlled by software
(Enable PLL, bit 7 in the CLKCTL register)
Table 132. on page 166 summarizes the available modes of operation after the reset sequence is ended:
•PROG is an external pin on the nRF24LU1+.
• RF Transceiver, USB, MCU and PLL represent the functions defined above.
Table 132. nRF24LU1+ modes of operation
PROG RF
Transceiver USB MCU PLL Comment
1 - - - - Flash programming mode via SPI
0 standby suspend standby OFF
0 standby suspend active software
0 standby active standby ON
0 standby active active ON
0 active suspend standby OFF
0 active suspend active software
0 active active standby ON
0 active active active ON
Revision 1.1 Page 167 of 187
nRF24LU1+ Product Specification
In nRF24LU1+ the 16 MHz oscillator is always running. An internal PLL can be enabled that multiplies the
16 MHz by three to get an internal 48 MHz clock. This clock is required for USB operation.
The internal 32.000 kHz clock (CKLF) is generated from the 16 MHz oscillator.
To save power when the USB is suspended, the PLL can be turned off, and the clock frequency to the
MCU can be reduced. This reduces power consumption, but also reduces performance.
To further reduce power, the MCU clock can be stopped using the PWRDWN register. In the PCON register
stop and idle modes can be selected, but since their effect on power consumption is minor use PWRDWN.
The following various internal and external events can resume the MCU clock:
• Interrupt from RF Transceiver, rfirq
• Interrupt from USB
• Interrupt from RTC timer or GPIO-pins (see chapter 19 on page 160)
The WUCONF register controls how these events are handled.
20.4 Functional description
20.4.1 Clock control – CLKCTL
Table 133. CLKCTL register
Addr Reset
value Bit R/W Function
0xA3 0x80 7 RW Enable PLL, 1: PLL on, 0: PLL off
6:4 RW Set Cclk (MCU clock) frequency when PLL is ON
000: 16 MHz
001: 12 MHz
010: 8 MHz
011: 4 MHz
100: 1.6 MHz
Other combinations: reserved.
3:2 - Not used
1:0 RW Set Cclk (MCU clock) frequency when PLL is OFF
00: 4 MHz
01: 1.6 MHz
10: 320 kHz
11: 64 kHz
Revision 1.1 Page 168 of 187
nRF24LU1+ Product Specification
20.4.2 Power down control – PWRDWN
Note: Any pending interrupt flags in IRCON must be cleared before setting MCU to standby.
Table 134.PWRDWN register
20.4.3 Reset result – RSTRES
The following three reset sources initiate the same reset/start-up sequence:
• Reset from the on-chip reset generator.
• Reset from pin.
• Reset generated from the on-chip watchdog function.
The RSTRES register stores the reset cause:
Table 135. RSTRES register
20.4.4 Wakeup configuration register – WUCONF
Note: IRCON flag will be set upon wakeup, even if interrupt is not enabled in IEN1.
Table 136.WUCONF register
Addr Reset value Bit R/W Function
0xA4 0x00 7:4 - Not used
3 R Read CKLF clock (32 kHz clock, always running)
2:0 W Set MCU to standby if different from 000
Addr Reset value Bit R/W Function
0xB1 0x00 7:1 - Not used
0 R Reset cause, 1: Watchdog, 0: other
Addr Reset
value Bit R/W Function
0xA5 0x00 7:6 RW 00: Enable wakeup on RFIRQ, if IEN1.1=1
01: Reserved, not used
10: Enable wakeup on RFIRQ, regardless of IEN1.1
11: Ignore RFIRQ
5:4 RW 00: Enable wakeup on WU, if IEN1.5=1a
01: Reserved, not used
10: Enable wakeup on WU, regardless of IEN1.5
11: Ignore WU
a. WU is generated as described in sections 19.3.3 and 19.3.4
3:2 RW 00: Enable wakeup on USBIRQ, if IEN1.4=1
01: Reserved, not used
10: Enable wakeup on USBIRQ, regardless of IEN1.4
11: Ignore USBIRQ
1:0 RW 00: Enable wakeup on USBWU, if IEN1.3=1
01: Reserved, not used
10: Enable wakeup on USBWU, regardless of IEN1.3
11: Ignore USBWU
Revision 1.1 Page 169 of 187
nRF24LU1+ Product Specification
20.4.5 Power control register - PCON
The PCON register is used to control the Power Down Modes (IDLE, STOP), the Program Memory Write
Mode and Serial Port 0 baud rate doubler.
Table 137. PCON register
Address Reset
value Bit Name Description
0x87 0x00 7 smod Serial Port 0 baud rate select, see Table 89. on page 114 (baud rate
doubler).
6 gf3 General purpose flag 3
5 gf2 General purpose flag 2
4 pmw Program memory write mode. Setting this bit enables the program
memory write mode.
3 gf1 General purpose flag 1
2 gf0 General purpose flag 0
1 stop Stop mode control. Setting this bit activates the Stop Mode. Always
read as 0.
0 idle Idle mode control. Setting this bit activates the Idle Mode. Always
read as 0.
Revision 1.1 Page 170 of 187
nRF24LU1+ Product Specification
21 Power supply supervisor
The power supply supervisor initializes the system at power-on, provides an early warning of impending
power failure, and puts the system in reset state if the supply voltage is too low for safe operation.
21.1 Features
• Power-on reset
• Brown-out reset
• Early power-fail warning with some hardware protection of data in flash memory
21.2 Functional description
21.2.1 Power-on reset
A Power-on reset generator initializes the system at power-on. The system is held in reset state until VDD
has reached around 2.7V or higher.
Figure 82. Power-on reset
21.2.2 Brown-out detection
If supply VBUS or VDD drops below around 2.7V (which is outside the operational specification), a power-
fail detection signal goes active. If the supply goes below around 1.8V, a brown-out reset signal goes on
and the chip is reset. The supply must rise above approximately 2.7V again before the reset signal is
released. The power-fail signal is used to prevent flash memory write or erase at low voltage, see section
17.4 on page 139.
Figure 83. Brown-out detection
X
VDD
Time
Voltage
>2.7V
Reset
0V
VDD
Time
Voltage
Power Fail
1.8V
Reset
2.7V
Revision 1.1 Page 171 of 187
nRF24LU1+ Product Specification
22 Interrupts
nRF24LU1+ has an advanced interrupt controller with 15 sources, as shown in Figure 84.. The unit
manages dynamic program sequencing based upon important real-time events as signalled from timers,
the RF Transceiver, the USB interface or pin activity.
22.1 Features
• Interrupt controller with 15 sources and 4 priority levels
• Interrupt request flags available
• Interrupt from pin with selectable polarity
22.2 Block diagram
Figure 84. nRF24LU1+ interrupt structure
P0[3]
tf0
AESIRQ
tf1
ri0
tf2
RFRDY
RFIRQ
MSDONE
USBWU
USBIRQ
WU
ti0
IEN0[7]
IEN0[0]
IEN1[0]
IEN0[1]
IEN1[1]
edge sel:
T2CON[5]
source:
INTEXP
edge sel:
T2CON[6]
IEN0[2]
IEN1[2]
IEN0[3]
IEN1[3]
IEN1 [4]
IEN0[5]
IEN1[5]
SSDONE
TCON[1]
edge/level
TCON[0]
edge/level
TCON[2]
IRCON[0]
IRCON[1]
TCON[3]
IRCON[2]
IRCON[3]
IRCON[4]
IRCON[6]
IRCON[5]
TCON[5]
TCON[7]
Auto clear
request flags
exf2
IEN1[7]
IRCON[7]
Request
flags
IP1[0]
IP0[0]
IP1[1]
IP0[1]
IP1[2]
IP0[2]
IP1[3]
IP0[3]
IP1[4]
IP0[4]
IP1[5]
IP0[5]
MCU
Processing sequence
IEN0[4]
S0CON[0]
S0CON[1]
(INT0)
(INT2)
(INT3)
interrupt
Revision 1.1 Page 172 of 187
nRF24LU1+ Product Specification
22.3 Functional description
When an enabled interrupt occurs, the MCU vectors to the address of the interrupt service routine (ISR)
associated with that interrupt, as listed in Table 138. on page 172. The MCU executes the ISR to comple-
tion unless another interrupt of higher priority occurs.
Table 138. nRF24LU1+ interrupt sources
22.4 SFR registers
Various SFR registers are used to control and prioritize between different interrupts.
The IRCON, SCON, IP0, IP1, IEN0, IEN1 and INTEXP are described in this section. In addition, a descrip-
tion of the TCON and T2CON registers is found in chapter 11 on page 103.
22.4.1 Interrupt enable 0 register – IEN0
The IEN0 register is responsible for global interrupt system enabling/disabling as well as Timer0, 1 and 2,
Port 0 and Serial Port individual interrupts enabling/disabling.
Table 139. IEN0 register
Source Vector Polarity Description
P0.3 0x0003 low/fall External pin P0.3
tf0 0x000B high Timer 0 interrupt
AESIRQ 0x0013 low/fall AES ready interrupt
tf1 0x001B high Timer 1 interrupt
ri0 0x0023 high Serial channel receive interrupt
ti0 0x0023 high Serial channel transmit interrupt
tf2 0x002B high Timer 2 interrupt
exf2 0x002B High Timer 2 external event (pin P0.5)
RFRDY 0x0043 high RF SPI ready
RFIRQ 0x004B fall/rise RF IRQ
MSDONE 0x0053 fall/rise Master SPI transaction completed
SSDONE 0x0053 fall/rise Slave SPI transaction completed
USBWU 0x005B rise USB wakeup interrupt
USBIRQ 0x0063 rise USB interrupt
WU 0x006B rise Internal Wakeup interrupt
Address Reset value Bit Description
0xA8 0x00 7 1: Enable interrupts. 0: all interrupts are disabled.
6 Not used.
5 1: Enable Timer2 interrupt.
4 1: Enable Serial Port interrupt.
3 1: Enable Timer1 overflow interrupt
2 1: Enable pin P0.4 interrupt.
1 1: Enable Timer0 overflow interrupt.
0 1: Enable pin P0.3 interrupt.
Revision 1.1 Page 173 of 187
nRF24LU1+ Product Specification
22.4.2 Interrupt enable 1 register – IEN1
The IEN1 register is responsible for RF, SPI, USB and Timer 2 interrupts.
Table 140. IEN1 register
Master SPI and Slave SPI share the same interrupt line.
Table 141. INTEXP register.
22.4.3 Interrupt priority registers – IP0, IP1
The 14 interrupt sources are grouped into six priority groups. For each of the groups, one of four priority
levels can be selected. It is achieved by setting appropriate values in IP0 and IP1 registers.
The contents of the Interrupt Priority Registers define the priority levels for each interrupt source according
to the tables below.
Table 142. IP0 register
Table 143. IP1 register
Address Reset value Bit Description
0xB8 0x00 7 1: Enable Timer2 external reload interrupt
6 Not used
5 1: Wakeup interrupt enable
4 1: USB interrupt enable
3 1: USB wakeup interrupt enable
2 1: Master or Slave SPI ready interrupt enable
1 1: RF interrupt enable
0 1: RF SPI ready enable
Address Reset
value Bit Function
0xA6 0x01 7:2 Not used
1 1: Enable Master SPI interrupt
0 1: Enable Slave SPI interrupt
Address Reset
value Bit Description
0xA9 0x00 7:6 Not used.
5:0 Interrupt priority. Each bit together with corresponding bit from IP1
register specifies the priority level of the respective interrupt priority
group.
Address Reset
value Bit Description
0xB9 0x00 7:6 Not used.
5:0 Interrupt priority. Each bit together with corresponding bit from IP0
register specifies the priority level of the respective interrupt priority
group.
Revision 1.1 Page 174 of 187
nRF24LU1+ Product Specification
Table 144. Priority groups
Table 145. Priority levels (x is the number of priority group)
22.4.4 Interrupt request control registers – IRCON
The IRCON register contains Timer 2, SPI, RF, USB and wakeup interrupt request flags.
Table 146. IRCON register
Group Interrupt bits Priority groups
0 ip1.0, ip0.0 P0.3 interrupt RF interrupt
1 ip1.1, ip0.1 Timer 0 interrupt RF SPI interrupt
2 ip1.2, ip0.2 P0.4 interrupt Master SPI Slave SPI
3 ip1.3, ip0.3 Timer 1 interrupt USB wakeup
4 ip1.4, ip0.4 Serial port receive Serial port transmit USB interrupt
5 ip1.5, ip0.5 Timer 2 interrupt Wakeup interrupt
ip1.x ip0.x Priority level
0 0 Level 0 (lowest)
01Level 1
10Level 2
1 1 Level 3 (highest)
Address Reset
value Flag Bit Auto cleara
a. Auto clear means that the flag is cleared by hardware automatically when the corresponding service
routine is vectored.
Description
0xC0 0x00 exf2 7 - Timer 2 external reload flag
tf2 6 - Timer 2 overflow flag
WU 5 Yes Wakeup interrupt flag
USBIRQ 4 Yes USB interrupt flag
USBWU 3 Yes USB wakeup interrupt flag
M- or S-DONE 2 Yes Master or Slave SPI interrupt flag
RFIRQ 1 Yes RF interrupt flag
RFRDY 0 - RF SPI interrupt flag
Revision 1.1 Page 175 of 187
nRF24LU1+ Product Specification
23 HW debugger support
The nRF24LU1+ has the following on-chip hardware debug support for a JTAG debugger:
• nRFProbe hardware debugger from Nordic Semiconductor.
• System Navigator from First Silicon Solutions (www.fs2.com).
These debug modules are available on device pins OCITO, OCTMS, OCITDO,OCITDI, OCITCK when
enabled in the flash InfoPage. The HW debug features can be interfaced through USB to a PC and utilized
in the Keil Integrated Development Environment (IDE) by running nRFProbe found in the nRFgo develop-
ment kits or dedicated HW from First Silicon Solutions.
23.1 Features
• Read/write all processor registers, SFR, program and data memory.
• Go/halt processor run control.
• Single step by assembly and C source instruction.
• Four independent HW execution breakpoints.
• Driver software for Keil µVision debugger interface.
The features listed below are for the Keil µVision debugger only:
• Load binary, Intel Hex or OMF51 file formats.
• Symbolic debug.
• Load symbols, including code, variables and variable types.
• Support C and assembly source code.
• Source window can display C source and mixed mode.
• Source window provides execution control; go, halt; goto cursor; step over/into call.
• Source window can set or clear software and hardware breakpoints.
23.2 Functional description
The JTAG debug interface is enabled by writing (through the flash SPI slave interface) to address 0x24 in
the InfoPage. Any byte value other than 0xFF enables debug. The Flash Status Register (FSR bit 7, 17.3.6
on page 139) shows the current status of the interface.
The GPIO allocated in debug mode is summarized in Table 147.
Table 147. HW debug physical interface for nRF24LU1+
Note: A pull-up on OCITCK is required for the MCU to run (in debug mode) without the system nav-
igator cable plugged in.
A separate "Trigger Out" is available on the OCITO pin. This output can be activated when certain address
and data combinations occur.
OCITO P0.4
OCITDO P0.3
OCITDI P0.2
OCITMS P0.1
OCITCK P0.0
Revision 1.1 Page 176 of 187
nRF24LU1+ Product Specification
24 Peripheral information
This chapter describes peripheral circuitry and PCB layout requirements that are important for achieving
optimum RF performance from the nRF24LU1+.
24.1 Antenna output
The ANT1 and ANT2 output pins provide a balanced RF output to the antenna. The pins must have a DC
path to VDD_PA, either through a RF choke or through the center point in a balanced dipole antenna. A
load of 15 Ω+j88 Ω is recommended for maximum output power (0dBm). Lower load impedance (for
instance 50 Ω) can be obtained by fitting a simple matching network between the load and ANT1 and
ANT2. A recommended matching network for 50Ω load impedance is illustrated in Chapter 25 on page
178.
24.2 Crystal oscillator
A crystal being used with the nRF24LU1+ must fulfil the specifications given in Table 10. on page 24.
You must use a crystal with a low load capacitance specification to achieve a crystal oscillator solution with
low power consumption and fast start-up time. A lower C0 also gives lower current consumption and faster
start-up time, but may increase the cost of the crystal. Typically C0=1.5pF at a crystal specified for
C0max=7.0pF.
The crystal load capacitance, CL, is given by:
, where C1’ = C1 + CPCB1 +CI1 and C2’ = C2 + CPCB2 + CI2
C1 and C2 are SMD capacitors as shown in the application schematics, see Chapter 25 on page 178.
CPCB1 and CPCB2 are the layout parasitic on the circuit board. CI1 and CI2 are the capacitance seen into
the XC1 and XC2 pins respectively; the value is typically 1pF for each of these pins.
24.3 PCB layout and decoupling guidelines
A well designed PCB is necessary to achieve good RF performance. A poor layout can lead to loss of per-
formance or functionality. A fully qualified RF-layout for the nRF24LU1+ and its surrounding components,
including matching networks, can be downloaded from www.nordicsemi.no.
A PCB with a minimum of two layers including a ground plane is recommended for optimum performance.
The nRF24LU1+ DC supply voltage should be decoupled as close as possible to the VDD pins with high
performance RF capacitors.See the schematics layout in Chapter 25 on page 178 for recommended
decoupling capacitor values. The nRF24LU1+ supply voltage should be filtered and routed separately from
the supply voltages of any digital circuitry.
Long power supply lines on the PCB should be avoided. All device grounds, VDD connections and VDD
bypass capacitors must be connected as close as possible to the nRF24LU1+ IC. For a PCB with a topside
RF ground plane, the VSS pins should be connected directly to the ground plane. For a PCB with a bottom
ground plane, the best technique is to have via holes as close as possible to the VSS pads. A minimum of
one via hole should be used for each VSS pin.
''
''
21
21
CC
CC
L
C+
⋅
=
Revision 1.1 Page 177 of 187
nRF24LU1+ Product Specification
Full swing digital data or control signals should not be routed close to the crystal or the power supply lines.
The exposed die attach pad is a ground pad connected to the IC substrate die ground and is intentionally
not used in our layouts. It is recommended to keep it unconnected.
Revision 1.1 Page 178 of 187
nRF24LU1+ Product Specification
25 Application example
25.1 Schematics
25.2 Layout
A double sided FR-4 board of 1.6 mm thickness is used. This PCB has a ground plane on the bottom layer.
There are ground areas on the component side of the board to ensure sufficient grounding of critical com-
ponents. A large number of via holes connect the top layer to ground areas to the bottom layer ground
plane.
No components
in bottom layer
Top silk screen
Revision 1.1 Page 179 of 187
nRF24LU1+ Product Specification
25.3 Bill Of Materials (BOM)
Table 148. Bill Of Materials
Top view Bottom view
Designator Value Footprint Comment
C1 15pF 0402 NP0 +/-2%
C2 15pF 0402 NP0 +/-2%
C3 2.2nF 0402 X7R +/-10%
C4 Not mounted 0402
C5 1.2pF 0402 NP0 +/-0.1pF
C6 1.0pF 0402 NP0 +/-0.1pF
C7 10nF 0402 X7R +/-10%
C8 10nF 0402 X7R +/-10%
C9 33nF 0402 X7R +/-10%
C10 33nF 0402 X7R +/-10%
C11 100nF 0402 X7R +/-10%
C12 10uF 0805 X5R +/-10%
L1 6.8nH 0402 Chip inductor +/-5%
L2 6.8nH 0402 Chip inductor +/-5%
L3 4.7nH 0402 Chip inductor +/-5%
R2 22k 0402 1%
R3 22R 0402 1%
R4 22R 0402 1%
R5 10k 0402 1%
R6 10R 0402 1%
R7 10k 0402 1%
U1 nRF24LU1+ QFN32L/5x5 nRF24LU1+
X1 16 MHz BT-XTAL 16 MHz, CL=9pF +/-60ppm
Revision 1.1 Page 180 of 187
nRF24LU1+ Product Specification
26 Mechanical specifications
nRF24LU1+ is packaged in a QFN32 5 x 5 x 0.85 mm, 0.5 mm pitch.
Table 149. QFN32 dimensions in mm (Bold dimension denotes BSC)
Package AA1 A3 bD, E D2, E2 e K L
QFN32 0.80
0.85
0.90
0.00
0.02
0.05
0.20
0.18
0.23
0.30
5
3.20
3.30
3.40
0.5
0.20 0.35
0.40
0.45
Min.
Typ.
Max
D
A
D2
E2
E
A1 A3
SIDE VIEW
TOP VIEW
1
2
32 31
b
L
2
1
e
K
32
BOTTOM VIEW
E2/2
D2/2
Revision 1.1 Page 181 of 187
nRF24LU1+ Product Specification
27 Ordering information
27.1 Package marking
nRF24LU1P-F32 option:
nRF24LU1P-F16 option:
27.1.1 Abbreviations
Table 150. Abbreviations
nRF BX
24LU1P
YYWWLL
nRF BX
LU1P16
YYWWLL
Abbreviation Definition
LU1P16 Product number, F16 option
24LU1P Product number, F32 option
B Build Code, that is, unique code for production sites, package type and, test platform.
X "X" grade, that is, Engineering Samples (optional).
YY Two digit Year number
WW Two digit week number
LL Two letter wafer lot number code
Revision 1.1 Page 182 of 187
nRF24LU1+ Product Specification
27.2 Product options
27.2.1 RF silicon
Table 151. nRF24LU1+ RF silicon options
27.2.2 Development tools
Table 152. nRF24LU1+ solution options
Ordering code Flash memory
size Package Container MOQa
a. Minimum Order Quantity
nRF24LU1P-F32Q32-T 32 kB 5x5mm 32-pin QFN,
lead free (green)
Tray 490
nRF24LU1P-F32Q32-R7 32 kB 5x5mm 32-pin QFN,
lead free (green)
7” reel 1500
nRF24LU1P-F32Q32-R 32 kB 5x5mm 32-pin QFN,
lead free (green)
13” reel 4000
nRF24LU1P-F32Q32-SAMPLE 32 kB 5x5mm 32-pin QFN,
lead free (green)
Sample box 5
nRF24LU1P-F16Q32-T 16 kB 5x5mm 32-pin QFN,
lead free (green)
Tray 490
nRF24LU1P-F16Q32-R7 16 kB 5x5mm 32-pin QFN,
lead free (green)
7” reel 1500
nRF24LU1P-F16Q32-R 16 kB 5x5mm 32-pin QFN,
lead free (green)
13” reel 4000
nRF24LU1P-F16Q32-SAMPLE 16 kB 5x5mm 32-pin QFN,
lead free (green)
Sample box 5
Type Number Description
nRF24LU1P-FxxQ32-DK nRF24LU1+ Development kit
nRF6700 nRFgo Starter Kit
nRF6704 nRFgo nRF24LU1P Flash/OTP Programming
Adapter Kit (requires nRFgo Starter Kit)
Revision 1.1 Page 183 of 187
nRF24LU1+ Product Specification
28 Glossary of terms
Table 153. Glossary
Term Description
ACC Accumulator
ACK Acknowledgement
ART Auto Re-Transmit
BSC Basic Spacing between Centers
Cclk MCU Clock
CRC Cyclic Redundancy Check
CSN Chip Select NOT
DPS Data Pointer Select register
ESB Enhanced ShockBurst™
FCR Flash Command Register
FPCR Flash Protect Config Register
FSR Flash Status Register
GFSK Gaussian Frequency Shift Keying
HAL Hardware Abstraction Layer
HID Human Interface Device
IRQ Interrupt Request
ISM Industrial-Scientific-Medical
LNA Low Noise Amplifier
LSB Least Significant Bit
LSByte Least Significant Byte
MCU Microcontroller
Mbps Megabit(s) per second
MISO Master In Slave Out
MoQ Minimum Order Quantity
MOSI Master Out Slave In
MSB Most Significant Bit
MSByte Most Significant Byte
PCB Printed Circuit Board
PER Packet Error Rate
PID Packet Identity Bits
PLD Payload
PRX Primary RX
PSW Program Status Word Register
PTX Primary TX
pwrdwn Power Down
PWR_UP Power Up
RAM Random Access Memory
RDSR Read Status Register
rfce Radio transceiver chip enable
RX Receive
RX_DR Receive Data Ready
SDK Software Development Kit
SP Stack Pointer
SPI Serial Peripheral Interface
TX Transmit
TX_DS Transmit Data Sent
USB Universal Serial Bus
WO Write Only
Revision 1.1 Page 184 of 187
nRF24LU1+ Product Specification
Appendix A - (USB memory configurations)
The USB buffer memory has a total size of 512 bytes. Bulk/control buffer size can be 2, 4, 8, 16, 32 or, 64
bytes, while ISO buffers (if used) must be multiples of 16 bytes.
Some example configurations are given below.
Configuration 1
Endpoint 0-5 Bulk/control IN/OUT, each of size 32 bytes.
Endpoint 8 ISO IN/OUT, each of size 32 bytes (with double buffering).
Total buffer area: 448 bytes.
Table 154. Configuration 1
Configuration 2
Endpoint 0-2 bulk/control IN/OUT, each of size 32 bytes
Endpoint 3-4 bulk IN/OUT, each of size 16 bytes
Endpoint 8 ISO IN/OUT, each of size 32 bytes (with double buffering).
Total buffer area: 320 bytes
Register Value (hex) Calculation Comment
bout1addr 0x10 (ep0 out size)/2 Start addr. of bulk 1 OUT
bout2addr 0x20 bout1addr + (ep1out size)/2 Start addr. of bulk 2 OUT
bout3addr 0x30 bout2addr + (ep2 out size)/2 Start addr. of bulk 3 OUT
bout4addr 0x40 bout3addr + (ep3 out size)/2 Start addr. of bulk 4 OUT
bout5addr 0x50 bout4addr + (ep4 out size)/2 Start addr. of bulk 5 OUT
binstaddr 0x30 (bulk out size)/4 Start addr. of bulk 1 IN
bin1addr 0x10 (ep0 in size)/2 Start addr. of bulk 1 IN
bin2addr 0x20 bin1addr + (ep1 in size)/2 Start addr. of bulk 2 IN
bin3addr 0x30 bin2addr + (ep2 in size)/2 Start addr. of bulk 3 IN
bin4addr 0x40 bin3addr + (ep3 in size)/2 Start addr. of bulk 4 IN
bin5addr 0x50 bin4addr + (ep4 in size)/2 Start addr. of bulk 5 IN
isostaddr 0x18 (bulk size)/16 Start addr. of iso
out8addr 0x00 0 Start addr. of iso OUT
in8addr 0x08 (ep8 out size)/4 Start addr. of iso IN
isosize 0x04 (iso size)/16
Register value (hex) Calculation Comment
bout1addr 0x10 (ep0 out size)/2 Start addr. of bulk 1 OUT
bout2addr 0x20 bout1addr + (ep1 out size)/2 Start addr. of bulk 2 OUT
bout3addr 0x30 bout2addr + (ep2 out size)/2 Start addr. of bulk 3 OUT
bout4addr 0x38 bout3addr + (ep3 out size)/2 Start addr. of bulk 4 OUT
binstaddr 0x20 (bulk out size)/4 Start addr. of bulk 1 IN
bin1addr 0x10 (ep0 in size)/2 Start addr. of bulk 1 IN
bin2addr 0x20 bin1addr + (ep1 in size)/2 Start addr. of bulk 2 IN
Revision 1.1 Page 185 of 187
nRF24LU1+ Product Specification
Table 155. Configuration 2
Unused bout5addr and bin5addr shall be 0x00.
Configuration 3
Endpoint 0-3 bulk IN/OUT, each of size 16 bytes
Endpoint 4-5 bulk IN/OUT, each of size 32 bytes
Endpoint 8 iso IN/OUT, each of size 32 bytes (with double buffering)
Total buffer area: 320 bytes.
Table 156. Configuration 3
bin3addr 0x30 bin2addr + (ep2 in size)/2 Start addr. of bulk 3 IN
bin4addr 0x40 bin3addr + (ep3 in size)/2 Start addr. of bulk 4 IN
isostaddr 0x10 (bulk size)/16 Start addr. of iso
out8addr 0x00 0 Start addr. of iso OUT
in8addr 0x08 (ep8 out size)/4 Start addr. of iso IN
isosize 0x04 (iso size)/16
Register Value (h) Calculation Comment
bout1addr 0x08 (ep0 out size)/2 Start addr. of bulk 1 OUT
bout2addr 0x10 bout1addr + (ep1 out size)/2 Start addr. of bulk 2 OUT
bout3addr 0x18 bout2addr + (ep2 out size)/2 Start addr. of bulk 3 OUT
bout4addr 0x20 bout3addr + (ep3 out size)/2 Start addr. of bulk 4 OUT
bout5addr 0x30 bout4addr + (ep4 out size)/2 Start addr. of bulk 5 OUT
binstaddr 0x20 (bulk out size)/4 Start addr. of bulk 1 IN
bin1addr 0x08 (ep0 in size)/2 Start addr. of bulk 1 IN
bin2addr 0x10 bin1addr + (ep1 in size)/2 Start addr. of bulk 2 IN
bin3addr 0x18 bin2addr + (ep2 in size)/2 Start addr. of bulk 3 IN
bin4addr 0x20 bin3addr + (ep3 in size)/2 Start addr. of bulk 4 IN
bin5addr 0x30 bin4addr + (ep4 in size)/2 Start addr. of bulk 5 IN
isostaddr 0x10 (bulk size)/16 Start addr. of iso
out8addr 0x00 0 Start addr. of iso OUT
in8addr 0x08 (ep8 out size)/4 Start addr. of iso IN
isosize 0x04 (iso size)/16
Register value (hex) Calculation Comment
Revision 1.1 Page 186 of 187
nRF24LU1+ Product Specification
Configuration 4
Endpoint 0-1 bulk/control IN/OUT, each of size 32 bytes
Endpoint 8 ISO IN/OUT, each of size 32 bytes (with double buffering).
Total buffer area: 192 bytes.
Table 157. Configuration 4
Unused bout2addr to bout5addr and bin2addr to bin5addr shall be 0x00.
Register Value (h) Calculation Comment
bout1addr 0x10 (ep0 out size)/2 Start addr. of bulk 1 OUT
binstaddr 0x10 (bulk out size)/4 Start addr. of bulk 1 IN
bin1addr 0x10 (ep0 in size)/2 Start addr. of bulk 1 IN
isostaddr 0x08 (bulk size)/16 Start addr. of iso
out8addr 0x00 0 Start addr. of iso OUT
in8addr 0x08 (ep8 out size)/4 Start addr. of iso IN
isosize 0x04 (iso size)/16
Revision 1.1 Page 187 of 187
nRF24LU1+ Product Specification
Appendix B - Configuration for compatibility with nRF24XX
How to setup the radio module in nRF24LU1+ to receive from an nRF2401/nRF2402/nRF24E1/nRF24E2/
nRF24LE1:
1. Use the same CRC configuration as the nRF2401/nRF2402/nRF24E1/nRF24E2/nRF24LE1.
2. Set the PWR_UP and PRIM_RX bit to 1.
3. Disable auto acknowledgement on the addressed data pipe.
4. Use the same address width as the PTX device.
5. Use the same frequency channel as the PTX device.
6. Select data rate 1 Mbps on both nRF24LU1+ and nRF2401/nRF2402/nRF24E1/nRF24E2/
nRF24LE1.
7. Set correct payload width on the addressed data pipe.
8. Set rfce high.
How to setup the radio module in nRF24LU1+ to transmit to an nRF2401/nRF24E1/nRF24LE1:
1. Use the same CRC configuration as the nRF2401/nRF24E1/nRF24LE1.
2. Set the PRIM_RX bit to 0.
3. Set the Auto Retransmit Count to 0 to disable the auto retransmit functionality.
4. Use the same address width as the nRF2401/nRF24E1/nRF24LE1.
5. Use the same frequency channel as the nRF2401/nRF24E1/nRF24LE1.
6. Select data rate 1 Mbps on both nRF24LU1+ and nRF2401/nRF24E1/nRF24LE1.
7. Set PWR_UP high.
8. Clock in a payload that has the same length as the nRF2401/nRF24E1/nRF24LE1 is configured
to receive.
9. Pulse rfce to transmit the packet.
