st solution for touch sensing industrial & multi-market competence center

ST Solution for Touch Sensing

Industrial & Multi-Market Competence Center

I&MMCC - April 2010 2

Touch Sensing positioning

S-Touch™

RC and CT Firmware for STM8S/L

STM8T14x single key with proximity

Demoboards available on ESICOM

Support request

Overview


Touch Sensing Positioning

Computer & Peripherals

Notebook Printer Mouse Keyboard Monitors

Multimedia Bar Control Panel Blinking and Brightness

Digital Consumer

Set-Top Box DVD Player Digital TV Digital Camera Digital Audio Remote Control

Control Panel Wheel Slider Blinking and Brightness

WirelessCommunication

Mobile Phone PDA PND Car Radio Remote Controller

Touch Screen Touch Keypad Blinking and Brightness

Portable Device

MP3 Player Portable Media Player Digital Photo Frame Medical Equipment

Touch Screen Touch Keypad Blinking and Brightness Wheel, Slider

HomeAppliances

Air Conditioner Refrigerator Microwave Oven Cooker White Goods Food Processor

Control Panel Touch Keypad Blinking and Brightness Wheel, Slider


S-Touch™Port expander with capacitive sensing capability


S-Touch™ Technology

Finite State Machine

Patented Techniques

Low Power Consumption

High Sensitive Level

Small Package Size

S-Touch touch sensing controller implements highly innovative signal processing techniques to correctly detect, process and pass the touch information to the main MCU.


Resistive Touch Screen

Resistive Touch Screen

Capacitive Multi Touch

Screen

Capacitive Touch Screen

Capacitive Touch Key Slider & Wheel

Capacitive Touch Key Slider & Wheel

2008 2009 2010

S-Touch™ Product Roadmap


S-Touch™ Product Portfolio

CapacitiveCapacitive CapacitiveCapacitive ResistiveResistive

STMPE321 STMPE632 STMPE821 STMPE1208S STMPE16M31 STMPE24M31 STMPE16M31PX STMPE24M31PX

STMPE28M18 STMPE36M28

STMPE811 STMPE610 STMPE812

S-Touch™S-Touch™

Touch Key

Touch Key

Touch Screen

Touch Screen

Available in 2010With Proximity Sensing

More Sensing Channels with Enhanced Features

Dual-Touch

Multi-Touch

4 Wire Resistive Touch


Capacitive Touch Key Controllers

STMPE321 STMPE821 STMPE1208S

Package Size QFN12 (2.2x1.5 mm) QFN16 (2.6x1.8 mm) QFN40 (5x5 mm)

Operating Voltage 1.65 - 1.95 V 2.7 - 3.6 V 2.5 - 5.5 V

No of Sensing Channels 3 8 12

No of GPIO Channels 3 8 12

No of PWM Channels - 4 -

Slider/Wheel Capability Yes Yes Yes

Hardware Tuning Required Yes Yes Yes

Interface Type I2C I2C I2C

Sensitivity 40 fF 50 fF 60 fF

No. of Capacitive Steps 128 128 128

ESD (HBM) 8 kV 8 kV 7 kV


STMPE1208S 12-bit Key Controller Key Features

12 capacitive touch key inputs 12 GPIOs 3.0 - 5.5 V Operating Voltage Dual Interrupt output pin I2C interface 7 kV HBM ESD protection Individually adjustable touch

variance (TVR) setting for all channels

Adjustable environmental variance (EVR) for optimal calibration

Package QFN40 (5x5 mm)

Applications Portable Media Player Gaming Console Multimedia Bar (MMB) Control Panel for TV, LCD monitor

and consumer electronics

C_ Ref

VinReg Vin

Data Filtering

12-Input

Capacitive Sensor

Data Calibration

Host I2C Interface

Clock

Control Unit

Voltage

Regulator

Power Management

12-Input

GPIO

ID_0

G_INT

SCLK

T_INT

ID_1

SDAT

RESET

Touch

Key

Controller


High Performances Application Hardware tuning NOT required 4x Better Sensitivity (15fF

Resolution) Superior Noise Immunity Embedded Hardware Ratio Engine Proximity Sensing Capability

Portable Application Moderate Sensitivity & Noise

Immunity Hardware Tuning Requirement Basic Slider/Wheel Functionality

Evolved Products (M-Series)

Basic Products (x21 Series)

STMPE321STMPE321

STMPE821STMPE821

STMPE16/24M31STMPE16/24M31

STMPE16/24M31PXSTMPE16/24M31PX

STMPE1208SSTMPE1208S

S-Touch™ Product Evolution


Touch Key Controllers: M31 Series

Single chip solution for highly sensitive and flexible capacitive sensing capabilities.

Capacitive Sensing Engine 15 fF sensitivity with 512 steps 30 pF of auto-tuning Pseudo-random sampling Auto calibration with tuning Fault-tolerant calibration algorithm

Hardware Ratiometric Engine Supports 2 sliders/wheels with 3-8 sensors each 256 steps resolution per slider/wheel Reports position and movement No external computation

Hardware PWM Controller 8 independent PWM controllers Control up to 16 PWM outputs Ramping/Blinking capable Touch-triggered PWM sequence

STMPE16M31/24M31


Capacitive Touch Key Controllers

STMPE16/24M31 STMPE16/24M31PX

Package Size QFN32 (4x4 mm) / QFN40 (5x5 mm) QFN32 (4x4 mm) / QFN40 (5x5 mm)

Operating Voltage 2.7 - 5.5 V 2.7 - 5.5 V

Sensing Channels 16 / 24 16 / 24

No of GPIO 16 16

No of PWM 16 16

Slider/Wheel Capability Yes Yes

Hardware Tuning Required No (Auto-Tuning) No (Auto-Tuning)

Auto-Calibration Yes Yes

Interface Type I2C I2C

Sensitivity 15 fF 15 fF

No. of Capacitive Steps 512 512

Proximity Sense No Yes

ESD (HBM) 8 kV 8 kV


Key FeaturesCapacitive Sensing Up to 16/24 Capacitive Sensor inputs Configurable Automatic Impedance Calibration 15 fF resolution, 512 steps with 30 pF Auto-Tuning 2 hardware ratiometric engines

PWM and GPIO Up to 16 General Purpose Input/Outputs 8 independent PWM controllers, up to 16 PWM outputs 12mA sourcing/sinking on GPIO for LED driving (at 3.3 V VIO)

Others Operating voltage 1.65-1.95 V (VCC) 2.7-5.5 V (VIO) I2C interface (Up to 400 KHz). I2C is 3.3 V tolerant. 8 kV HBM ESD protection on all sensing pins

Package QFN32 4x4 mm / QFN40 5x5 mm

STMPE16/24M31 16-bit Key Controller

INT

RST

SCLK

SDAT

C_ Ref

A1

A0

VinReg

Vin

Clock Control Unit

Voltage

Regulator

Power

Management

GPIO Controller

Capacitance

Sensor

PWM Controller

Host I2C Interface

Ratio Engine

PWM

Array

Controller

Noise Filter

Calibration

MUX


Resistive Touch Screen Controllers

STMPE811 STMPE610 STMPE812

Package Size QFN16 (3x3 mm) QFN16 (3x3 mm) CSP12 (2.2x1.7 mm)

Operating Voltage 1.65 - 3.6 V 1.65 - 3.6 V 1.65 - 3.6 V

Touch Screen ControllerFully

AutonomousFully

AutonomousFully Autonomous

Median Averaging Filter No No Yes

Motion Tracking Yes Yes No

Window Masking Yes Yes No

Data Buffer 128 level 128 level 1 level

Interface400 KHz I2C1 MHz SPI

400 KHz I2C1 MHz SPI

400 KHz I2C

Programmable Settling Time Yes Yes Yes

No of Wires 4 4 4

Extra I/O4 GPIO

4 ADC (MUX)2 GPIO

2 ADC (MUX)

4 GPIO 1 ADC (MUX)1 PWM (MUX)

Sensitivity Levels Fixed Fixed 4 levels

ESD (HBM) 4 kV 4 kV 8 kV


The host may set a value from 4-127 as the distance, from which the new touch position must be away from the previous position, to be considered a valid new position. This reduces redundant, nearby data positions.

Advance Features Motion Tracking Window Masking

The host may define a rectangle within the full window, of which, if the touch position falls outside of the defined window, the touch is simply ignored.

With Data Buffer Without Data Buffer

Data Buffer

128 sets of data buffer in the touch screen controller ensures that no data will be missing, even if the CPU is busy. Each data buffer contains a 12-bit X-coordinate, 12-bit Y-coordinate and an 8-bit touch pressure.

Interrupt on FIFO full, FIFO empty and FIFO reaching programmable threshold.


Key Features 12-bit ADC for high-resolution

resistive touch screen 1.65 - 3.6 V Operating Voltage 128-depth data buffer Advance movement tracking to

reduce CPU/Bus utilization Window-Masking Function Fast I2C (400 KHz) or SPI (1 MHz)

serial interface Up to 8 GPIOs 4 Additional ADC inputs 4 kV Contact/15 kV HBM ESD

Protection

Package QFN16 (3x3 mm)

STMPE811

I2C SDAT, SCLK

RESET, INT

4-wire Resistive Touch

ScreenMCUMCU

STMPE811 8-GPIOs Screen Controller

Vin

GPIO Controller

Driver & Switch Control Unit

RC Oscillator

Power Management

Host

I2C/SPI

InterfaceTouch Screen

Controller

Thermal

SenseVREF

INT

A0/DATA OUT

SDAT/CS

SCLK/CLK

DATA IN

REF-, REF+,

GPIO


STMPE36M28 True multi-touch capability

Up to 36 capacitive sensing inputs

Touch shape sensing capability

Supports multi touches without “ghosting” effect

S-Touch™ Additions in 2010STMPE28M18 Dual touch capability

Up to 28 capacitive sensing inputs

Configurable automatic calibration

I2C Interface

8 kV HBM ESD protection on all sensing pins

Support gestures such as rotation, zoom in/out and panning

STMPE12M31RPX 12 Channel Touch Key Controller with Ratio Proximity Sensor

STMPE12M31MX 12 Channel Touch Key Controller with 6x6 capacitive/mechanical

keypad controller


RC & CT FirmwareLibrary for STM8S/L


Setup file available @ http://www.st.com/mcu

Updated STM8 touch sensing library revision 2.x It brings a new acquisition principle to the existing library The principle is still to provide the source code for free The license agreement remains the same as previous

version: usage restricted to ST MCUs The acquisition selection is done using the configuration

file (.h) The library is delivered with two configuration file example:

One for RC acquisition, one for the CT acquisition

STM8 Touch Sensing Library 2.x


Package contents

The touch sensing library is delivered together with several packages: The last revisions of the standard peripheral libraries for

STM8S, STM8L101 and STM8L151

A few examples demonstrating both acquisitions techniques for each STM8 subfamily supported

RC and CT examples STM8S and STM8L examples Buttons and wheels

Evaluation boards firmware STM8S plug-in board STM8L151 9 keys + 1 Wheel + 1 slider board

Documentation in windows help format (.chm)


Capacitive Sensing Acquisitions Overview

There are many ways to measure capacitance.ST Firmware is based on the followings:

Charge TransferRC Charging Time


RC Charging Time Acquisition

Advantages of the RC acquisition: Available to any STM8S and STM8L product Almost any IO can be used as electrode Low cost external components (2 resistors per key) Simple driven shield implementation


RC Charging Time Acquisition Principle

The electrode capacitance is charged through a pull-up resistor or an internal current source

The time necessary to charge the capacitor from one reference voltage to another is measured with a timer

The variations of this time is used to detect the finger proximity

untouched

touched

t


Charge Transfer Acquisition

Advantages: Good sensitivity: three channels wheels and sliders possible. Good immunity to conducted noise Low cost external components (1 resistors/key + 1capacitor per

group of keys)

Available on STM8L products Number of touch sensor electrode :

STM8L: up to 6 channels STM8L15x: up to 16 channels


Charge transfer uses the electrical properties of the capacitor charge Q.

It uses a sampling capacitor (CS) in which the electrode (Cx) charges are transferred to

Charge Transfer is done through analog switches embedded in STM8L I/O structure (in “red” in the schematic below).

The operation is repeated N times until the voltage on the sampling capacitor reaches a given threshold.

The number N of transfer cycles required to reach the threshold represents the size of Cx. N varies when the electrode is touched.

Cx

CS

Analog switch

Charge Transfer Acquisition Principle


Charge Transfert Library with STM8L101

x2

The STM8L101 can handle 2 groups of 3 keys each, for a total of 6 keys.

STM8L101

To comparator input


Charge Transfert Library with STM8L151

x8

STM8L151

To ADCinput

The STM8L151 can handle 8 groups of 2 keys each, for a total of 16 keys.


STM8T14xSingle key device

With proximity detection


STM8T141 key features

Single channel capacitive sensor for touch or proximity detection

Few centimeters detection range (up to 5 cm) 8-pin device in SO8 narrow or UFDFN8 (3*2mm) packages 1 configurable output to report touch or proximity detection Configurable sensitivity levels (2 for touch + 2 for proximity) On chip voltage regular and power-on reset (POR) Built-in driven shield function

Enhance proximity detection and protect sensing electrode from noise

4 selectable power modes 11µA in extreme low power mode, 30µA in run mode

2.9V to 5.5V voltage range

Environment compensation filter and automatic calibration

UFDFPN 8 2x3x 0.65mm

SO85x6x 1.75mm


STM8T141 Bill of material

Components Function Typ. value Comment

C1 Sampling capacitor 33nF COG or better suggested for zoom modes

C2 + C2’ VREG capacitor 1µF + 100nF Optional (shorted to VDD with a good supply or ext regulator)

C3 VDD capacitor 1µF Optional

R1 ESD Protection resistor 2KΩ Optional

R2 Shield pull-up resistor 100KΩ Optional

OptionalLEDindicator

VSS

Cs

Cx

SHLDin

OUT

VDD

SHLDout

VREG

Vin GND

C1

C2 C3

R1

Sensingelectrode

ShieldR2

C2’ R

LD


STM8T141 Output modes

Active mode Toggle mode

3s latch mode 30s latch mode


Power modes and reaction time

2 selectable charge transfer frequency: 125KHz: Optimum power consumption 250KHz: Fast response time

2 selectable conversion time Fast: 10ms (100Hz) Slow: 20ms (50Hz)

4 Output modes

Normal

Low power with zoom

Extreme low powerwith zoom

Extreme low power


DemoboardsAvailable in ESICOM


STM8T141 Evaluation board

Evaluation kit (STM8T141-EVAL) Low cost and easy to use tool to demonstrate STM8T141 touch/proximity features

Touch detectionProximity detection


STM8T141 Programming tools

Tools STVP standard programming tool for product configuration Specific USB dongle Socket programming board for SO8,DFN8 and modules

Programming dongleST-TSLINK

Socket boardSTM8T1X1-SB

STVP


Demoboards available in ESICOM

NEW

NEW

STMPE1208S

STMPE821

STMPE811

STMPE1208S


Demoboards available in ESICOM

STMPE811

STMPE1208S

STMPE321 (not in ESICOM)

ST7 USB-I2C Interface BoardSTMPE321 Device and Sensor Board


Library Evaluation boards

STM8L151CxT-TS1 Evaluation Board 10 keys + 1 Wheel + 1 slider Two-sided PCB with ground shield for better noise

immunity 1 Plexiglas panel (1.5mm thin dielectric) 1 LCD display for Touch Sensing parameters

visualization and modification 1 buzzer 1 SWIM connector for MCU programming &

debugging 1 STM8L pre-programmed device

Board available in September 2010

st solution for touch sensing industrial & multi-market competence center

Documents

touch information

capacitive touch key

wire resistive touch

stouch product roadmap

stouch port expander

adjustable touch variance

slider slide

sensing channels