CPT112S-A02-GU - SILICON LABS

TouchXpress™ Family

CPT112S Data Sheet

The CPT112S device, part of the TouchXpress family, is designed

to quickly add capacitive touch via an I2C interface by eliminating

the firmware complexity and reducing the development time for ca-

pacitive sensing applications.

Supporting up to 12 capacitive sensor inputs in a 3 mm x 3 mm QFN package, the

CPT112S is a highly-integrated device that interfaces via I2C to the host processor to

provide a simple solution for adding capacitive touch. The device also comes with ad-

vanced features like moisture immunity, wake-on proximity, and buzzer feedback for an

enhanced user experience. No firmware development is needed, and all the capacitive

touch sense parameters can be configured using a simple GUI-based configurator. By

eliminating the need for complex firmware development, the CPT112S device enables

rapid user interface designs with minimal development effort.

The CPT112S device is ideal for a wide range of capacitive touch applications including

the following:

KEY FEATURES

• No firmware development required

• Simple GUI-based configurator

• 12 Capacitive Sensor inputs with

programmable sensitivity

• Configurable multi-button slider

• I2C interface to communicate to the host

• Lowest power capacitive sense solution

• Active — 200 µA

• Sleep — 1 µA

• Wake on proximity

• Superior noise immunity: SNR up to 270:1

• Moisture immunity

• Mutually-exclusive touch qualifier

• Button touch time-out to avoid false

touches

• Buzzer output for audible touch feedback

• Home appliances

• Instrument / Control panels

• White goods

• Medical equipment

• Consumer electronics

• Lighting control

Input

Features

Output

Features

Capacitive Touch Sensing

Features

Baselining

Low Power State

Machine

Configuration

Profile for each

Input

Touch Time-Out

Timer

Touch

Qualification

Mutually-

Exclusive Touch

Qualifier

Input Engine

with

12 Inputs

Proximity Wake

Input

Option for a

Multi-Button

Slider

Optimized Active

Lowest power mode with feature operational:

Active

Optional Buzzer

Output

I2C Output I2C Event Buffer

Interrupt Pin

Low Power Sleep

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2

This information applies to a product under development. Its characteristics and specifications are subject to change without notice.

1. Feature List and Ordering Information

Tape and Reel (Optional)

G M

Temperature Grade — –40 to +85 °C (G)

T–1 S A –

Package Type — QFN20 (M), QSOP24 (U)

Silicon Labs Xpress Product Line

Firmware Revision

Hardware Revision

Capacitive Sense Features — Slider (S)

Interface Type — GPO (0), I2C (1)

Number of Capacitive Sense Inputs

TouchXpress Family

Figure 1.1. CPT112S Part Numbering

The CPT112S has the following features:

• Capacitive sensing input engine with 12 inputs

• Post-sample touch qualification engine

• Configuration profile space in non-volatile memory

• I2C event buffer with interrupt pin to signal when new touch events have been qualified

• Low power state machine to minimize current draw in all use cases

• Capacitive proximity sensing input

• Buzzer output

• Mutually-exclusive touch qualifier

• Touch time-out timer

Table 1.1. Product Selection Guide

Ordering

Part Number

Pb-free

(RoHS Compliant)

Temperature Range

Package

CPT112S-A02-GM Yes -40 to +85 °C QFN20

CPT112S-A02-GU Yes -40 to +85 °C QSOP24

CPT112S Data Sheet

Feature List and Ordering Information

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 1

2. Typical Connection Diagrams

2.1 Signal, Analog, and Power connections

Figure 2.1 Connection Diagram on page 2 shows a typical connection diagram for the power pins of CPT112S devices.

CPT112S

Device

4.7 µF and 0.1 µF

bypass capacitors

required for the power

pins placed as close to

the pins as possible.

1.8-3.6 V (in)

Host

Processor

1.8-3.6 V (in)

...

1.8-3.6 V (in)

Electrode

GND

VDD

EB_SCL

EB_INT

CS10

CS00

Config Data

Config Clk / RSTb

EB_SDA

Figure 2.1. Connection Diagram

CPT112S Data Sheet

Typical Connection Diagrams

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 2

2.2 Configuration

The diagram below shows a typical connection diagram for the configuration connections pins. The ToolStick Base Adapter is available

on the evaluation board.

CPT112S Device

Config Clk

1 k

VDD

Config Data

GND

ToolStick

Figure 2.2. Configuration Connection Diagram

CPT112S Data Sheet

Typical Connection Diagrams

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 3

3. Electrical Specifications

3.1 Electrical Characteristics

All electrical parameters in all tables are specified under the conditions listed in Table 3.1 Recommended Operating Conditions on page

4, unless stated otherwise.

3.1.1 Recommended Operating Conditions

Table 3.1. Recommended Operating Conditions

Parameter Symbol Test Condition Min Typ Max Unit

Operating Supply Voltage on VDD VDD 1.8 2.4 3.6 V

Minimum RAM Data Retention

Voltage on VDD1

VRAM Not in Sleep Mode — 1.4 — V

Sleep Mode — 0.3 0.5 V

Operating Ambient Temperature TA–40 — 85 °C

Note:

1. All voltages with respect to GND.

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 4

3.1.2 Power Consumption

See 3.4 Typical Performance Curves for power consumption plots.

Table 3.2. Power Consumption

Parameter Symbol Test Condition Min Typ Max Unit

Active Mode Supply Current IDD — 3.1 — mA

Optimized Active Mode Supply

Current

IDD — 180 — µA

Sleep Mode Current1, 2 IDD 3 sensors or fewer — 0.78 — µA

4 sensors — 0.79 — µA

5 sensors — 0.81 — µA

6 sensors — 0.82 — µA

7 sensors — 0.84 — µA

10 sensors — 0.88 — µA

12 sensors — 0.95 — µA

System Current with Varying Scan

Time — Base with One Sensor1

IDD Scan period = 10 ms — 154 — µA

Scan period = 20 ms — 77 — µA

Scan period = 50 ms — 31 — µA

Scan period = 75 ms — 21 — µA

Scan period = 100 ms — 16 — µA

System Current with Varying Scan

Time — Each Additional Sensor1

IDD Scan period = 10 ms — 47 — µA

Scan period = 20 ms — 23 — µA

Scan period = 50 ms — 9 — µA

Scan period = 75 ms — 6 — µA

Scan period = 100 ms — 5 — µA

Note:

1. Measured with Free Run Mode disabled and sensors set to 4x accumulation, 8x gain.

2. Measured with scan period set to 250 ms.

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 5

3.1.3 Reset and Supply Monitor

Table 3.3. Reset and Supply Monitor

Parameter Symbol Test Condition Min Typ Max Unit

VDD Supply Monitor Threshold VVDDM Reset Trigger 1.7 1.75 1.8 V

VWARN Early Warning 1.8 1.85 1.9 V

Power-On Reset (POR) Monitor

Threshold

VPOR Rising Voltage on VDD — 1.75 — V

Falling Voltage on VDD 0.75 1.0 1.3 V

VDD Ramp Time tRMP Time to VDD ≥ 1.8 V — — 3 ms

RST Low Time to Generate Reset tRSTL 15 — — µs

Boot Time1tboot 1 sensor — 25 — ms

2 sensors — 40 — ms

3 sensors — 55 — ms

4 sensors — 70 — ms

5 sensors — 85 — ms

6 sensors — 100 — ms

7 sensors — 115 — ms

8 sensors — 130 — ms

9 sensors — 145 — ms

10 sensors — 160 — ms

11 sensors — 175 — ms

12 sensors — 200 — ms

Note:

1. Boot time is defined as the time from a power-on reset or /RST pin release until the first capacitive sense scan begins.

3.1.4 Configuration Memory

Table 3.4. Configuration Memory

Parameter Symbol Test Condition Min Typ Max Units

Endurance (Write/Erase Cycles) NWE 20 k 100 k — Cycles

Note:

1. Data Retention Information is published in the Quarterly Quality and Reliability Report.

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 6

3.1.5 Capacitive Sense

Table 3.5. Capacitive Sense

Parameter Symbol Test Condition Min Typ Max Unit

Scan Time Per Sensor1tSCAN Accumulation = 1x — 64 — µs

Accumulation = 4x — 256 — µs

Accumulation = 8x — 512 — µs

Accumulation = 16x — 1.024 — ms

Accumulation = 32x — 2.048 — ms

Accumulation = 64x — 4.096 — ms

Signal to Noise Ratio1, 2 SNR Accumulation = 1x — 90:1 — codes

Accumulation = 4x — 180:1 — codes

Accumulation = 8x — 182:1 — codes

Accumulation = 16x — 210:1 — codes

Accumulation = 32x — 230:1 — codes

Accumulation = 64x — 270:1 — codes

Conversion Time tCONV Gain = 1x — 205 — µs

Gain = 2x — 123 — µs

Gain = 3x — 98 — µs

Gain = 4x — 85 — µs

Gain = 5x — 76 — µs

Gain = 6x — 72 — µs

Gain = 7x — 67 — µs

Gain = 8x — 64 — µs

Total Processing Time3tPROC 1 sensor — 576 — µs

2 sensors — 796 — µs

3 sensors — 1.0 — ms

4 sensors — 1.2 — ms

5 sensors — 1.4 — ms

6 sensors — 1.7 — ms

7 sensors — 1.9 — ms

8 sensors — 2.1 — ms

9 sensors — 2.3 — ms

10 sensors — 2.6 — ms

11 sensors — 2.8 — ms

12 sensors — 3.0 — ms

Maximum External Capacitive

Load

CEXTMAX Gain = 8x — 45 — pF

Gain = 1x — 500 — pF

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 7

Parameter Symbol Test Condition Min Typ Max Unit

Maximum External Series Impe-

dance

REXTMAX Gain = 8x — 50 — kΩ

Note:

1. Measured with gain set to 8x.

2. Measured with an evaluation board with 1/16" overlay using Capacitive Sense Profiler.

3. Sensors configured to 8x gain, 1x accumulation with sensor sampling and system processing time included and mutually-exclu-

sive buttons, slider, buzzer, and touch time-outs disabled.

3.1.6 Buzzer Output

Table 3.6. Buzzer Output

Parameter Symbol Test Condition Min Typ Max Unit

Output High Voltage (High Drive) VOH IOH = –3 mA VDD – 0.7 — — V

Output Low Voltage (High Drive) VOL IOL = 8.5 mA — — 0.6 V

Output High Voltage (Low Drive) VOH IOH = –1 mA VDD – 0.7 — — V

Output Low Voltage (Low Drive) VOL IOL = 1.4 mA — — 0.6 V

Weak Pull-Up Current IPU VDD = 1.8 V

VIN = 0 V

— –4 — µA

VDD = 3.6 V

VIN = 0 V

–35 –20 — µA

3.2 Thermal Conditions

Table 3.7. Thermal Conditions

Parameter Symbol Test Condition Min Typ Max Unit

Thermal Resistance* θJA — 60 — °C/W

Note:

1. Thermal resistance assumes a multi-layer PCB with any exposed pad soldered to a PCB pad.

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 8

3.3 Absolute Maximum Ratings

Stresses above those listed in Table 3.8 Absolute Maximum Ratings on page 9 may cause permanent damage to the device. This is

a stress rating only and functional operation of the devices at those or any other conditions above those indicated in the operation list-

ings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. For

more information on the available quality and reliability data, see the Quality and Reliability Monitor Report at http://www.silabs.com/

support/quality/pages/default.aspx.

Table 3.8. Absolute Maximum Ratings

Parameter Symbol Test Condition Min Max Unit

Ambient Temperature Under Bias TBIAS –55 125 °C

Storage Temperature TSTG –65 150 °C

Voltage on VDD VDD GND–0.3 4.0 V

Voltage on I/O pins or RSTb VIN GND–0.3 VDD + 0.3 V

Total Current Sunk into Supply Pin IVDD — 400 mA

Total Current Sourced out of Ground

IGND 400 — mA

Current Sourced or Sunk by Any I/O

Pin or RSTb

IIO –100 100 mA

Maximum Total Current through all

Port Pins

IIOTOT — 200 mA

Operating Junction Temperature TJ–40 105 °C

Exposure to maximum rating conditions for extended periods may affect device reliability.

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 9

3.4 Typical Performance Curves

Figure 3.1. Active Mode Processing Time Per Sensor

Note: Active mode processing time per sensor measured with sensors configured to 1x accumulation, 8x gain. Sensor sampling and

system processing time is included with mutually-exclusive buttons, the buzzer, slider, and touch time-outs disabled.

Figure 3.2. Current vs. Active Mode Scan Period — Base Current Consumption

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 10

Figure 3.3. Current vs. Active Mode Scan Period — Current Consumption for Each Additional Sensor

Note: Active mode scan period current draw measured with free run mode disabled and all 12 sensors enabled at 4x accumulation, 8x

gain. In addition, the buzzer, slider, and mutually-exclusive button groups were disabled.

Figure 3.4. Typical VOH Curves

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 11

Figure 3.5. Typical VOL Curves

CPT112S Data Sheet

Electrical Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 12

4. Functional Description

4.1 Capacitive Sensing Input

4.1.1 Introduction

The capacitive to digital converter uses an iterative, charge-timing self-capacitance technique to measure capacitance on an input pin.

Sampling is configured and controlled by settings in the non-volatile configuration profile, which can be changed through the 2-pin con-

figuration interface.

Baseline

Active threshold

Touch delta Inactive threshold

Capacitance

Time

Figure 4.1. Capacitive Sense Data Types

4.1.2 Touch Qualification Criteria

The device detects a touch event when an inactive (untouched) input enabled by the input enable mask detects an sequence of meas-

urements that cross the active threshold.

The device detects a touch release event when an active (touched) input enabled by the input enable mask detects an sequence of

measurements that cross the inactive threshold.

The debounce configuration profile parameter defines how many measurements in a row must cross a threshold before a touch or re-

lease is qualified. In electrically noisy environments more heavily filtered data is used for qualification.

4.1.3 Thresholds

Capacitive sensing inputs use input-specific thresholds for touch qualification. Each input uses two thresholds, one to detect inactive-to-

active transitions on the input, and another to determine active-to-inactive transitions on the input. The inputs use two thresholds to add

hysteresis and prevent active/inactive ringing on inputs. Each threshold can be set through Simplicity Studio tools and all thresholds are

stored in non-volatile memory in the device's configuration profile.

Thresholds are defined as percentages of a capacitive sensing input's touch delta.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 13

4.1.4 Debounce Counter

Each capacitive sensing input maintains its own debounce counter. For an inactive sensor, this counter tracks the number of succes-

sive samples which have crossed that input's active threshold. For an active sensor, this counter tracks the number of successive sam-

ples which have crossed the inactive threshold. When the counter reaches a terminal value defined in the the configuration profile, the

touch/release event is qualified.

4.1.5 Touch Deltas

Each capacitive sensing input uses a stored touch delta value that describes the expected difference between inactive and active ca-

pacitive sensing output codes. This value is stored in the configuration profile for the system and is used by the touch qualification en-

gine, which defines inactive and active thresholds relative to the touch delta.

The touch deltas are stored in the configuration profile in a touch delta/16 format. For this reason, touch deltas must be configured as

multiples of 16.

4.1.6 Auto-Accumulation and Averaging

Capacitive sensing inputs have an auto-accumulate and average post-sample filter that can be used to improve signal strength if nee-

ded. Settings stored in the configuration profile can configure the engine to accumulate 1, 4, 8, 16, 32, or 64 samples. After the defined

number of samples have been accumulated, the result is divided by either 1, 4, 8, 16, 32, or 64, depending on the accumulation setting.

This auto-accumulated and averaged value is the sample output used for all touch qualification processing. Note that sample time per

sensor increases as the level of accumulation increases. To reduce current consumption, the engine should not be set to auto-accumu-

late unless it is required to achieve acceptable signal strength due to thick overlays or other system-level factors.

4.1.7 Drive strength

The drive strength of the current source used to charge the electrode being measured by the capacitive sensing input can be adjusted

in integer increments from 1x to 8x (8x is the default). High drive strength gives the best sensitivity and resolution for small capacitors,

such as those typically implemented as touch-sensitive PCB features. To measure larger capacitance values, the drive strength should

be lowered accordingly. The highest drive strength setting that yields capacitive sensing output which does not saturate the sensing

engine when the electrode is active (touched) should always be used to maximize input sensitivity.

4.1.8 Active Mode Scan Enable

Active mode scanning of capacitive sensing inputs is controlled by an enable setting for each capacitive sensing input. This setting is

stored in the configuration profile.

4.1.9 Active Mode Scan Period

The capacitive sensing input engine stays in active mode whenever one or more inputs have qualified as active. During this time, the

sensors scan at a periodicity defined by the active mode scan period, which is stored in the configuration profile. Every active mode

scan pushes new samples through the processing engine, which checks for new touch and release events on all enabled inputs.

If free run mode is enabled, the engine will repeatedly scan all enabled inputs during the active mode scan period. In this mode of

operation, the active mode scan period is used as a timer to determine how much time has passed since the last qualified active sensor

has been seen. When a defined amount of time without a qualified touch event has occurred, the engine switches to a low power mode

using the sleep mode scan period, and conserves current.

If free run mode is disabled, the engine will enter a low power state after completing one scan of all enabled inputs and processing the

resulting samples. The engine will remain in this low power state until it wakes, at a time defined by active mode scan period, to perform

another scan.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 14

4.1.10 Active Mode Scan Type

The active mode scan type, which is stored in the configuration profile, controls whether the capacitive sensing engine in active mode

will scan only once during the active mode scan period before going to sleep, or whether the engine will continue scanning as quickly

as possible during the active mode scan period, never entering a low power state.

For optimal responsiveness, the engine should be configured to run with free run mode enabled. Setting the scan mode to 'free run'

causes touch qualification on a new touch to occur as quickly as the scanning engine can convert and process samples on all sensors.

In this mode, qualification time is not bounded by active mode scan period, and is only bounded by scanning configuration factors such

as the debounce setting, the number of enabled sensors, the accumulation setting on each sensor, and the timing constraints of any

enabled component.

For optimal current draw when in active mode, the engine should be configured to use the 'one scan per period' mode setting. In this

case, touch qualification is bound by the scan period and the debounce setting of the device.

Touch Event

(t = 0 ms) 10 ms 20 ms 30 ms 40 ms

Optimized

Active sample sample

Active process additional

processing process additional

processing

Sleep sleep sleep

debounce

count = 1

touch

qualified

Figure 4.2. Timing and Current — One Sample Per Period Mode

Touch Event

(t = 0 ms) 10 ms 20 ms 30 ms 40 ms

Optimized

Active sample

Active process additional

processing

Sleep

debounce

count = 1

touch

qualified

sample

process additional

processing

Figure 4.3. Timing and Current — Free Run Mode

4.1.11 Sleep Mode Scan Period

The sleep mode scan period defines the rate at which a scan of the inputs enabled as wake-up sources are sampled. Each enabled

sensor can also be enabled as a wake-up source. After the sleep mode scan completes, the scan is processed for a qualified candidate

touch. If a candidate touch is qualified, the system wakes form sleep mode and enters active mode scanning.

The sleep mode scan period is stored in the configuration profile and is defined in units of ms.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 15

4.1.12 Active Mode and Sleep Mode Transitions

Capacitive sensing inputs will stay in active mode until no inputs detect qualified touches for a span of time defined by the counts until

sleep parameter stored in the configuration profile. The scan period of enabled inputs is defined by the active mode scan period, also

found in the configuration profile. If free run mode is enabled, the active mode sensing engine will remain awake and scanning the sen-

sors as fast as possible. If free run mode is disabled, the engine will put itself into a low power state for the remainder of the active

mode scan period, after a scan has completed.

When in sleep mode, the sensing engine will wake at a period defined by sleep mode scan period to do a scan on sensors that have

been enabled as wakeup sources. If the engine finds a candidate touch in this state, the system reverts to active mode to continue

scanning.

Note that in systems where a proximity input is selected, the sleep mode scan engine uses conversions on the proximity input instead

of sensors enabled as wakeup sources.

Devices configured to wake on a touch will attempt to qualify the candidate touch that initiated the sleep-to-active transition. If qualifica-

tion completes successfully, the device will signal this qualification to the external system. Touch qualification of this candidate touch

uses the same active mode thresholds, debounce setting, and active mode scan period settings as any touch that occurs during active

mode scanning.

qualified touch

release

Touch Delta

touch release new touch

Device Execution

no touch

counter = 1

no touch

counter = 2

...

no touch counter

= counts before

sleep

device enters

sleep

sleep scan sees

touch, wakes,

qualifies touch

no touch

counter = 0

Figure 4.4. Active and Sleep Transitions

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 16

4.2 I2C Event Buffer Interface

4.2.1 Introduction

The event buffer I2C interface provides an event-driven, packetized communication system describing newly qualified events generated

by the capacitive sensing input engine.

The interface provides access to a first-in-first-out buffer of data packets. When the sensing engine generates these packets and push-

es them onto the buffer. The interface then signals a host to indicate that one or more packets are available in the buffer by activating

the event buffer interrupt pin.

The interrupt pin is defined as active-low and operates as a push-pull digital output.

The host reads the packets through an I2C interface, with the host acting as an I2C master. Once all packets have been fully transmit-

ted across the I2C interface, the event buffer interrupt pin is de-activated. The device will remain in active mode until no packets remain

in the buffer, even if no sensors have been qualified as active for the period of time defined by the active mode scan period and the

counts before sleep value.

4.2.2 Packet retrieval in operational mode

When the least significant byte of the CRC of an event packet has been transferred during a master read transaction, that event is

popped from the device's buffer. If only a part of the event is read, the event will stay in the buffer and will be transmitted again by the

device during the next read.

If the host initiates a master read when the device is in operational mode but the interrupt pin is not active, signifying that the device has

no events in its buffer to transmit, the device will NACK its slave address on the bus.

If the I2C master sends a stop condition on the bus before the entire three-byte packet has been read, the device will not pop the pack-

et from its internal buffer. Instead, the I2C state machine will reset, and the next transaction will begin with the first byte of the same

event that was being read in the previous, prematurely-terminated transaction.

The I2C event buffer has a depth of 22 events. If the host does not read events promptly after seeing the interrupt pin go active, there is

the possibility of a buffer overflow. In the event of an overflow, the I2C engine will discard the oldest events first.

New I2C packets will only be generated at the active mode sample rate, and so the buffer will only fill at a maximum of 12 packets (in

the case of 12 simultaneous touch/releases) per sample period. If the host runs the I2C bus at 400kHz and reads packets as soon as

the interrupt pin activates, all packets can be read from the buffer in 1 to 2 ms, which is faster than the rate at which a new active mode

scan sequence can complete.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 17

4.2.3 Event Packet Structure

Every qualified event detected by the capacitive sensing input engine generates a single packet that can be retrieved by the host pro-

cessor through the event buffer I2C interface. The packet is an atomic data unit that fully describes the generated event.

Note: The bytes in the packet are transmitted MSB first.

Each packet has a standard structure that can be parsed by the host.

Table 4.1. Standard Packet Structure

Byte # Designator

0 I2C Slave Address + read bit

1 Packet counter and event type

2 Event description (byte 1)

3 Event description (byte 2)

The packet counter is a 4-bit number stored in the upper bits of byte 1. Each new event will be assigned a counter value that is +1 from

the last qualified event. After event 15, the counter wraps back to 0 for the next event. The counter captures the temporal nature of

touch events so that a host can reconstruct a sequence of events over time. Also, the host can use the counter value to determine if a

packet has been lost due to a buffer overflow.

The event type is a 4-bit value describes the originator of the event. For instance, the source could be a capacitive sensing button. The

event type is stored in the lower 4 bits of byte 1.

The event description bytes define characteristics of the event that have been qualified. Event descriptions are defined relative to the

event source. An event source that is a capacitive sensing input will have a defined set of valid event description values. Those same

values will mean something different for a different type of event source, such as a slider. Event description values are defined relative

to the event type field of byte 1.

Touch

Event

I2C Slave Address

+ read bit CSxx index reserved

byte 0 byte 1 byte 2 byte 3

Touch

Release

Event

I2C Slave Address

+ read bit CSxx index reserved

byte 0 byte 1 byte 2 byte 3

Slider

Event

I2C Slave Address

+ read bit

slider position

(MSB)

slider position

(LSB)

byte 0 byte 1 byte 2 byte 3

packet

counter

0010

event

type

0000

packet

counter

0011

event

type

0001

packet

counter

0100

event

type

0010

Figure 4.5. I2C Event Buffer Packet Structure

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 18

4.2.4 Defined Event Types

The device assigns the following event types to events.

Table 4.2. Event Type Mapping

Event Type Value Mapping

0 Sensor activity - touch event

1 Sensor activity - release event

2 Slider activity

Note that this event type value is stored in the lower 4 bits of the first byte of a packet. The upper 4 bits are a packet counter value.

4.2.5 Description Bytes for Touch Events

A touch or release event uses only one byte of the description field. That field identifies which sensor caused the touch or release event

as shown below.

Table 4.3. Touch or Release Event Sensor Mapping

Value Mapping

0 Capacitive sensing input 0

1 Capacitive sensing input 1

2 Capacitive sensing input 2

3 Capacitive sensing input 3

4 Capacitive sensing input 4

5 Capacitive sensing input 5

6 Capacitive sensing input 6

7 Capacitive sensing input 7

8 Capacitive sensing input 8

9 Capacitive sensing input 9

10 Capacitive sensing input 10

11 Capacitive sensing input 11

4.2.6 Description Bytes for Slider Events

The slider activity description field uses two bytes to describe the position of the slider, which can be any value between 0 (0x0000) and

65534 (0xFFFE). The most-significant byte of this value is transmitted in the first byte (byte 2 of the event packet), and the least-signifi-

cant byte is transmitted second (byte 3 of the event packet).

When the slider is released, a final slider event will be transmitted with 0xFFFF in the two-byte field.

4.2.7 Event Buffer I2C Slave Address

The device's I2C slave address is configurable through the configuration profile. The device will ACK its slave address only when the

interrupt pin is low, signalling that a packet is ready to be read by the host. If the interrupt pin is logic high, the device will not ACK its

slave address.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 19

4.3 Capacitive Proximity Sensing

4.3.1 Wake on Proximity

The wake on capacitive proximity detection engine monitors for the presence of a conductive object such as a hand to move within

detectable range of the sensor. When the engine detects an object, the device wakes from sleep and can begin qualifying touch events

on all sensors enabled for active mode sensing.

4.3.2 Proximity Configuration

The proximity sensing feature uses a single sensor input for proximity qualification. The configuration profile stores the pin chosen by

the user. The sensor used for proximity qualification should also have a drive strength setting that is as high as possible without saturat-

ing the input when no conductive object is in proximity to the proximity sensor. The accumulation setting of the input is also configura-

ble.

The proximity threshold controls the sensitivity of the input. A lower threshold setting increases sensitivity and increases the range of

the sensor.

A proximity sensing input cannot be used for touch qualification, and so the active and inactive thresholds are not used for proximity

sensors. Additionally, the proximity input has no effect on other components of the device such as mutually exclusive button groups,

buzzer output, touch time out timers, and sliders.

4.4 Slider

The device supports creation of a single slider that is composed of two or more capacitive sensing input pins. The pins chosen as slider

inputs are assigned to the slider feature through the configuration profile.

The configuration profile also stores a value designated as the highest positional value that can be derived by the slider engine. That

highest value is used to derive the values of all intermediate positions on the slider array.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 20

When a capacitive sensing input pin is designated as a slider input, it will no longer function as a 'button' input and will not generate

button style touch/release events across the I2C buffer interface.

Touching the slider pads and moving a finger along a slider pad generates an event packet of type Slider, with the remaining two bytes

of the packet describing the calculated active position of the slider.

The range of possible reported slider active positions can be 0 to the maximum value of the slider as defined in the configuration profile,

which can be any value between 40 and 65534. The 65535 (0xFFFF) value is reserved for a slider untouched event.

Position 0 is always assigned to the lowest CSxx sensor enabled as a slider input. The maximum position value of the slider is assigned

to the highest CSxx sensor enabled as a slider input. All slider inputs in between are assumed to be routed to the slider contiguously,

lowest to highest.

Invalid

Configuration

Valid

Configuration CS00 CS02 CS04 CS05

increasing slider

position

Valid

Configuration CS03 CS02 CS01 CS00

increasing slider

position

CS00 CS02 CS01 CS03

Figure 4.6. Slider Behavior and Layout Constraints

Slider touch qualification uses the same touch deltas and thresholds that are defined in the configuration profile for all enabled sensors.

The user should configure slider sensors through the configuration profile, just as one would configure a sensor assigned to a capaci-

tive button.

For optimal performance, each sensor used in the slider should have roughly the same touch surface area dimensions.

If the touch-timeout feature is enabled, slider-assigned inputs will also be subject to being qualified as releases by the touch-timeout

feature.

The mutually exclusive button grouping feature does not affect slider-assigned sensors. Even if the mutually exclusive button grouping

feature is enabled, multiple slider-assigned sensors can still be used to resolve a finger's position on the slider.

4.5 Touch Time-Out

The touch time-out feature can be enabled and disabled through the configuration profile. When enabled, the device will monitor touch

event duration on each input independently.

When a touch event exceeds a duration specified in the configuration profile, the device forces a release event, even if the user is still

actively touching the sensor.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 21

The feature qualifies a touch release by adding the configured touch delta value for that sensor to the sensor's current baseline value.

By doing this, the raw data-to-baseline delta created by the touch will be removed, and the touch qualification engine will see this as a

touch release event.

When the user removes a finger from a sensor that had been qualified active but has been qualified released through touch timeout, the

resulting raw-to-baseline negative delta will be aggressively tracked downward by the baseline, resulting in a sensor that remains sensi-

tive to successive touches.

The touch timeout duration is configured globally, so all inputs are monitored for the same touch duration.

If both the touch timeout feature and the mutually exclusive button group feature are enabled, the timeout timer will only run on the

touch that is externally reported as being active.

4.6 Buzzer Output

4.6.1 Introduction

The buzzer output engine produces a square wave of a configurable duration and frequency when a capacitive sensing input goes from

inactive to active. The feature can be enabled and disabled through the configuration profile. The configuration profile also includes the

settings for active duration and frequency.

No Touch, Buzzer Inactive

Device Execution

Optimized

Active sample sample

Active process additional

processing process additional

processing

Sleep sleep sleep

Figure 4.7. Effects of the Buzzer on Current Draw — Active Mode, No Touch, Buzzer Inactive

Touch Detected, Buzzer Active

Device Execution

Optimized

Active

Active additional

processing

Sleep

sleep

(stall)

sample

process additional

processing

sleep

(stall)

sample

process

Figure 4.8. Effects of the Buzzer on Current Draw — Active Mode, Touch Detected, Buzzer Active

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 22

4.6.2 Buzzer Configuration

When enabled, buzzer output will appear on the CS11/buzzer pin (pin 10) of the device. When buzzer output is enabled, CS11 is not

available for capactive input sensing.

When activated, the buzzer will remain active for either the duration specified in the configuration profile, or until the last active sensor

has qualified a touch release.

The configuration profile supports configuration of output frequencies ranging from 1 kHz to 4 kHz.

The configuration profile can configure the buzzer output pin to either push pull mode or open drain mode.

4.7 Mutually Exclusive Buttons

When enabled through the configuration profile, this system allows one and only one capacitive sensing input to be qualified as active

at a time. The first sensor active will remain the only sensor active until released. The device will internally qualify multiple touch and

release events but will not report them.

If multiple sensors have been internally qualified as active, the first sensor's touch event will be reported. If a touch event occurs simul-

taneously on more than one sensor, the touch with the highest touch delta will be reported.

If two sensors are qualified as active and the sensor being reported as active qualifies a touch release, the device will report that re-

lease and then report a touch qualification on the still-active second sensor.

In the case where a device has simultaneously qualified more than two active sensors and the reported active sensor qualifies and

reports a release, the remaining qualified sensor with the highest sensor name will then be reported. For example, if sensors CS00,

CS01, and CS02 are active with CS00 externally reported as active, after CS00's release, CS02 would be externally reported as an

active sensor unless the device has already qualified a touch release on CS02.

If both the touch timeout feature and the mutually exclusive button group feature are enabled, the timeout timer will only run on the

touch that is externally reported as being active.

CS00

Device Execution

CS01 CS02

physical touch on pad

touch reported by CPT device

release reported by CPT device

Figure 4.9. Mutually-Exclusive Button Operation

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 23

4.8 Self Testing

4.8.1 Introduction

When the self-test feature is enabled through the configuration profile, the device performs a check on all enabled capacitive sensing

inputs upon startup to determine whether the sensing input pins are erroneously shorted to ground or supply. If a short or open is found

on a sensor, the self test feature will signal that an error has been found through a port pin. The feature will then disable that sensor

before beginning touch qualification scans on all sensors left enabled.

4.8.2 Test Failure Signaling

If the self test check reveals an error, the device will toggle the I2C buffer interrupt pin at a frequency of 2 Hz. This toggling will persist

for two seconds if the device detects one or more self test errors.

4.9 Configuration Profile

The configuration interface is used by the device to configure default values and performance characteristics that effect capacitive

sensing. The configuration data can be programmed through the Configuration interface (Config Clk and Config Data pins) using [Con-

figurator] in Simplicity Studio.

Several configuration profile templates are available in Simplicity Studio to provide a starting point for development.

CPT112S Data Sheet

Functional Description

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 24

5. Pin Definitions

5.1 CPT112S QFN20 Pin Definitions

20 pin QFN

(Top View)

CS01

CS00

GND

VDD

RSTb /

Config Clk

Config Data

CS06

CS07

CS08

CS09

GND

CS10

CS02

CS03

CS04

CS05

GND

6 11

EB_INT

EB_SCL

EB_SDA

CS11 /

BUZZER

Figure 5.1. CPT112S QFN20 Pinout

Table 5.1. Pin Definitions for CPT112S QFN20

Number

Pin Name Description

1 CS01 Analog input

Capactive sensing input 1

2 CS00 Analog input

Capacitive sensing input 0

3 GND Ground

4 VDD Supply power input

5 RSTb /

Config Clk

Active-low reset /

Configuration clock

6 Config Data Configuration data

CPT112S Data Sheet

Pin Definitions

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 25

Number

Pin Name Description

7 EB_INT Push-pull digital output

Event buffer interrupt pin

8 EB_SCL Open drain digital output

Event buffer I2C SCL

9 EB_SDA Open drain digital input

Event buffer I2C SDA

10 CS11 /

Buzzer

Analog input, capacitive sensing input 11

Digital output for buzzer

11 CS10 Analog input

Capacitive sensing input 10

12 GND Ground

13 CS09 Analog input

Capacitive sensing input 9

14 CS08 Analog input

Capacitive sensing input 9

15 CS07 Analog input

Capacitive sensing input 7

16 CS06 Analog input

Capacitive sensing input 6

17 CS05 Analog input

Capacitive sensing input 5

18 CS04 Analog input

Capacitive sensing input 4

19 CS03 Analog input

Capacitive sensing input 3

20 CS02 Analog input

Capacitive sensing input 2

CPT112S Data Sheet

Pin Definitions

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 26

5.2 CPT112S QSOP24 Pin Definitions

CS02

CS01

CS00

GND

VDD

RSTb /

Config Clk

Config Data

N/C

CS04

CS05

CS06

CS07

CS08

CS09

CS10

CS11 /

BUZZER

N/C

24 pin QSOP

(Top View)

EB_SCL

EB_INT

CS03

N/C

EB_SDA

Figure 5.2. CPT112S QSOP24 Pinout

Table 5.2. Pin Definitions for CPT112S QSOP24

Number

Pin Name Description

1 CS02 Analog input

Capacitive sensing input 2

2 CS01 Analog input

Capactive sensing input 1

3 CS00 Analog input

Capacitive sensing input 0

4 N/C No Connect (leave this pin floating)

5 GND Ground

CPT112S Data Sheet

Pin Definitions

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 27

Number

Pin Name Description

6 VDD Supply power input

7 N/C No Connect (leave this pin floating)

8 N/C No Connect (leave this pin floating)

9 RSTb /

Config Clk

Active-low reset /

Configuration clock

10 Config Data Configuration data

11 EB_INT Push-pull digital output

Event buffer interrupt pin

12 EB_SCL Open drain digital output

Event buffer I2C SCL

13 N/C No Connect (leave this pin floating)

14 EB_SDA Open drain digital input

Event buffer I2C SDA

15 N/C No Connect (leave this pin floating)

16 CS11 /

Buzzer

Analog input, capacitive sensing input 11

Digital output for buzzer

17 CS10 Analog input

Capacitive sensing input 10

18 CS09 Analog input

Capacitive sensing input 9

19 CS08 Analog input

Capacitive sensing input 9

20 CS07 Analog input

Capacitive sensing input 7

21 CS06 Analog input

Capacitive sensing input 6

22 CS05 Analog input

Capacitive sensing input 5

23 CS04 Analog input

Capacitive sensing input 4

24 CS03 Analog input

Capacitive sensing input 3

CPT112S Data Sheet

Pin Definitions

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 28

6. QFN20 Package Specifications

6.1 QFN20 Package Dimensions

Figure 6.1. QFN20 Package Drawing

Table 6.1. QFN20 Package Dimensions

Dimension Min Typ Max

A 0.50 0.55 0.60

A1 0.00 — 0.05

b 0.20 0.25 0.30

b1 0.275 0.325 0.375

D 3.00 BSC

D2 1.6 1.70 1.80

e 0.50 BSC

e1 0.513 BSC

E 3.00 BSC

E2 1.60 1.70 1.80

L 0.35 0.40 0.45

CPT112S Data Sheet

QFN20 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 29

Dimension Min Typ Max

L1 0.00 — 0.10

aaa — 0.10 —

bbb — 0.10 —

ddd — 0.05 —

eee — — 0.08

Note:

1. All dimensions shown are in millimeters (mm) unless otherwise noted.

2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.

3. This drawing is based upon JEDEC Solid State Product Outline MO-248 but includes custom features which are toleranced per

supplier designation.

4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.

CPT112S Data Sheet

QFN20 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 30

6.2 QFN20 PCB Land Pattern

Figure 6.2. QFN20 PCB Land Pattern Drawing

Table 6.2. QFN20 PCB Land Pattern Dimensions

Dimension Min Max

C1 2.70

C2 2.70

C3 2.53

C4 2.53

E 0.50 REF

X1 0.20 0.30

X2 0.24 .034

X3 1.70 1.80

Y1 0.50 0.60

Y2 0.24 0.34

Y3 1.70 1.80

CPT112S Data Sheet

QFN20 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 31

Dimension Min Max

Note:

1. All dimensions shown are in millimeters (mm) unless otherwise noted.

2. Dimensioning and Tolerancing is per the ANSI Y14.5M-1994 specification.

3. This Land Pattern Design is based on the IPC-7351 guidelines.

4. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be 60 µm

minimum, all the way around the pad.

5. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release.

6. The stencil thickness should be 0.125 mm (5 mils).

7. The ratio of stencil aperture to land pad size should be 1:1 for the perimeter pads.

8. A 2x2 array of 0.75 mm openings on a 0.95 mm pitch should be used for the center pad to assure proper paste volume.

9. A No-Clean, Type-3 solder paste is recommended.

10. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.

6.3 QFN20 Package Marking

112S

TTTT

YWW+

Figure 6.3. QFN20 Package Marking

The package marking consists of:

• 112S – The part number designation.

• TTTT – A trace or manufacturing code. The first letter of this code is the hardware revision.

• Y – The last digit of the assembly year.

• WW – The 2-digit workweek when the device was assembled.

• + – Indicates the device is RoHS-compliant.

CPT112S Data Sheet

QFN20 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 32

7. QSOP24 Package Specifications

7.1 QSOP24 Package Dimensions

Figure 7.1. QSOP24 Package Drawing

Table 7.1. QSOP24 Package Dimensions

Dimension Min Typ Max

A — — 1.75

A1 0.10 — 0.25

b 0.20 — 0.30

c 0.10 — 0.25

D 8.65 BSC

E 6.00 BSC

E1 3.90 BSC

e 0.635 BSC

L 0.40 — 1.27

theta 0º — 8º

CPT112S Data Sheet

QSOP24 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 33

Dimension Min Typ Max

aaa 0.20

bbb 0.18

ccc 0.10

ddd 0.10

Note:

1. All dimensions shown are in millimeters (mm) unless otherwise noted.

2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.

3. This drawing conforms to JEDEC outline MO-137, variation AE.

4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.

CPT112S Data Sheet

QSOP24 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 34

7.2 QSOP24 PCB Land Pattern

Figure 7.2. QSOP24 PCB Land Pattern Drawing

Table 7.2. QSOP24 PCB Land Pattern Dimensions

Dimension Min Max

C 5.20 5.30

E 0.635 BSC

X 0.30 0.40

Y 1.50 1.60

Note:

1. All dimensions shown are in millimeters (mm) unless otherwise noted.

2. This land pattern design is based on the IPC-7351 guidelines.

3. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder mask and the metal pad is to be 60 µm

minimum, all the way around the pad.

4. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used to assure good solder paste release.

5. The stencil thickness should be 0.125 mm (5 mils).

6. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pads.

7. A No-Clean, Type-3 solder paste is recommended.

8. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.

CPT112S Data Sheet

QSOP24 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 35

7.3 QSOP24 Package Marking

CPT112S

YYWWTTTTTT

Figure 7.3. QSOP24 Package Marking

The package marking consists of:

• CPT112S – The part number designation.

• TTTTTT – A trace or manufacturing code. The first letter of this code is the hardware revision.

• YY – The last two digits of the assembly year.

• WW – The 2-digit workweek when the device was assembled.

• e3 – Indicates the device is RoHS-compliant.

CPT112S Data Sheet

QSOP24 Package Specifications

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 36

8. Relevant Application Notes

The following Application Notes are applicable to the CPT112S devices:

•AN957: TouchXpress™ Configuration and Profiling Guide — This application note guides developers through the evaluation and

configuration process of TouchXpress devices using Simplicity Studio [Xpress Configurator] and [Capacitive Sense Profiler].

•AN447: Printed Circuit Design Notes for Capacitive Sensing Performance — This document describes hardware design guidelines

specifically for capacitive sensing applications, including button placement and other layout guidelines.

•AN949: TouchXpress™ Programming Guide — This application note discusses the production programming options available for

TouchXpress devices.

Application Notes can be accessed on the Silicon Labs website (www.silabs.com/interface-appnotes) or in Simplicity Studio using the

[Application Notes] tile.

CPT112S Data Sheet

Relevant Application Notes

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 37

9. Revision History

9.1 Revision 0.2

August 12th, 2016

Added new revision devices (A02).

Added QSOP24 devices, including pinout information and package drawings.

Added a paragraph to 4.1.12 Active Mode and Sleep Mode Transitions describing the wake-on-touch behavior.

9.2 Revision 0.1

November 21st, 2015

Initial release.

CPT112S Data Sheet

Revision History

silabs.com | Smart. Connected. Energy-friendly. Preliminary Rev. 0.2 | 38

Table of Contents

1. Feature List and Ordering Information ......................1

2. Typical Connection Diagrams .........................2

2.1 Signal, Analog, and Power connections .....................2

2.2 Configuration ..............................3

3. Electrical Specifications ...........................4

3.1 Electrical Characteristics ..........................4

3.1.1 Recommended Operating Conditions .....................4

3.1.2 Power Consumption ...........................5

3.1.3 Reset and Supply Monitor .........................6

3.1.4 Configuration Memory ..........................6

3.1.5 Capacitive Sense ............................7

3.1.6 Buzzer Output .............................8

3.2 Thermal Conditions ............................8

3.3 Absolute Maximum Ratings .........................9

3.4 Typical Performance Curves .........................10

4. Functional Description........................... 13

4.1 Capacitive Sensing Input ..........................13

4.1.1 Introduction ..............................13

4.1.2 Touch Qualification Criteria.........................13

4.1.3 Thresholds ..............................13

4.1.4 Debounce Counter ...........................14

4.1.5 Touch Deltas .............................14

4.1.6 Auto-Accumulation and Averaging ......................14

4.1.7 Drive strength .............................14

4.1.8 Active Mode Scan Enable .........................14

4.1.9 Active Mode Scan Period .........................14

4.1.10 Active Mode Scan Type .........................15

4.1.11 Sleep Mode Scan Period .........................15

4.1.12 Active Mode and Sleep Mode Transitions ...................16

4.2 I2C Event Buffer Interface ..........................17

4.2.1 Introduction ..............................17

4.2.2 Packet retrieval in operational mode......................17

4.2.3 Event Packet Structure ..........................18

4.2.4 Defined Event Types ...........................19

4.2.5 Description Bytes for Touch Events ......................19

4.2.6 Description Bytes for Slider Events ......................19

4.2.7 Event Buffer I2C Slave Address .......................19

4.3 Capacitive Proximity Sensing.........................20

4.3.1 Wake on Proximity ...........................20

4.3.2 Proximity Configuration ..........................20

4.4 Slider .................................20

4.5 Touch Time-Out .............................21

Table of Contents 39

4.6 Buzzer Output ..............................22

4.6.1 Introduction ..............................22

4.6.2 Buzzer Configuration ...........................23

4.7 Mutually Exclusive Buttons .........................23

4.8 Self Testing ..............................24

4.8.1 Introduction ..............................24

4.8.2 Test Failure Signaling ..........................24

4.9 Configuration Profile............................24

5. Pin Definitions .............................. 25

5.1 CPT112S QFN20 Pin Definitions .......................25

5.2 CPT112S QSOP24 Pin Definitions .......................27

6. QFN20 Package Specifications........................ 29

6.1 QFN20 Package Dimensions ........................29

6.2 QFN20 PCB Land Pattern .........................31

6.3 QFN20 Package Marking ..........................32

7. QSOP24 Package Specifications ....................... 33

7.1 QSOP24 Package Dimensions ........................33

7.2 QSOP24 PCB Land Pattern .........................35

7.3 QSOP24 Package Marking .........................36

8. Relevant Application Notes ......................... 37

9. Revision History ............................. 38

9.1 Revision 0.2 ..............................38

9.2 Revision 0.1 ..............................38

Table of Contents .............................. 39

Table of Contents 40

http://www.silabs.com

Silicon Laboratories Inc.

400 West Cesar Chavez

Austin, TX 78701

USA

Simplicity Studio

One-click access to MCU and

wireless tools, documentation,

software, source code libraries &

more. Available for Windows,

Mac and Linux!

IoT Portfolio

www.silabs.com/IoT

SW/HW

www.silabs.com/simplicity

Quality

www.silabs.com/quality

Support and Community

community.silabs.com

Disclaimer

Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using

or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and

"Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Laboratories reserves the right to

make changes without further notice and limitation to product information, specifications, and descriptions herein, and does not give warranties as to the accuracy or completeness of the

included information. Silicon Laboratories shall have no liability for the consequences of use of the information supplied herein. This document does not imply or express copyright licenses

granted hereunder to design or fabricate any integrated circuits. The products are not designed or authorized to be used within any Life Support System without the specific written consent

of Silicon Laboratories. A "Life Support System" is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected to result in significant

personal injury or death. Silicon Laboratories products are not designed or authorized for military applications. Silicon Laboratories products shall under no circumstances be used in

weapons of mass destruction including (but not limited to) nuclear, biological or chemical weapons, or missiles capable of delivering such weapons.

Trademark Information

Silicon Laboratories Inc.® , Silicon Laboratories®, Silicon Labs®, SiLabs® and the Silicon Labs logo®, Bluegiga®, Bluegiga Logo®, Clockbuilder®, CMEMS®, DSPLL®, EFM®, EFM32®,

EFR, Ember®, Energy Micro, Energy Micro logo and combinations thereof, "the world’s most energy friendly microcontrollers", Ember®, EZLink®, EZRadio®, EZRadioPRO®, Gecko®,

ISOmodem®, Precision32®, ProSLIC®, Simplicity Studio®, SiPHY®, Telegesis, the Telegesis Logo®, USBXpress® and others are trademarks or registered trademarks of Silicon Laborato-

ries Inc. ARM, CORTEX, Cortex-M3 and THUMB are trademarks or registered trademarks of ARM Holdings. Keil is a registered trademark of ARM Limited. All other products or brand

names mentioned herein are trademarks of their respective holders.