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ST Solution for Touch Sensing

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Presentation on theme: "ST Solution for Touch Sensing"— Presentation transcript:

1 ST Solution for Touch Sensing
Industrial & Multi-Market Competence Center ST Solution for Touch Sensing 1

2 Overview Touch Sensing positioning S-Touch™
RC and CT Firmware for STM8S/L STM8T14x single key with proximity Demoboards available on ESICOM Support request

3 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 Wheel Slider Wireless Communication Mobile Phone PDA PND Car Radio Remote Controller Touch Screen Touch Keypad Portable Device MP3 Player Portable Media Player Digital Photo Frame Medical Equipment Wheel, Slider Home Appliances Air Conditioner Refrigerator Microwave Oven Cooker White Goods Food Processor

4 Port expander with capacitive sensing capability
S-Touch™ Port expander with capacitive sensing capability

5 S-Touch™ Technology S-Touch touch sensing controller implements highly innovative signal processing techniques to correctly detect, process and pass the touch information to the main MCU. Finite State Machine Patented Techniques Low Power Consumption High Sensitive Level Small Package Size

6 S-Touch™ Product Roadmap
Capacitive Multi Touch Screen Capacitive Touch Screen Capacitive Touch Key Slider & Wheel Resistive Touch Screen 2008 2009 2010

7 S-Touch™ Product Portfolio
Touch Key Touch Screen Capacitive Capacitive Resistive STMPE321 STMPE632 STMPE821 STMPE1208S STMPE16M31 STMPE24M31 STMPE16M31PX STMPE24M31PX Dual-Touch STMPE28M18 STMPE36M28 4 Wire Resistive Touch STMPE811 STMPE610 STMPE812 Multi-Touch More Sensing Channels with Enhanced Features With Proximity Sensing Available in 2010

8 Capacitive Touch Key Controllers
STMPE321 STMPE821 STMPE1208S Package Size QFN12 (2.2x1.5 mm) QFN16 (2.6x1.8 mm) QFN40 (5x5 mm) Operating Voltage V V V No of Sensing Channels 3 8 12 No of GPIO Channels No of PWM Channels - 4 Slider/Wheel Capability Yes Hardware Tuning Required Interface Type I2C Sensitivity 40 fF 50 fF 60 fF No. of Capacitive Steps 128 ESD (HBM) 8 kV 7 kV

9 STMPE1208S 12-bit Key Controller
Key Features 12 capacitive touch key inputs 12 GPIOs 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 Data Filtering Data Calibration C_ Ref 12-Input Capacitive Sensor ID_0 G_INT SCLK T_INT ID_1 SDAT RESET Host I2C Interface Touch Key Controller 12-Input GPIO Clock Control Unit Power Management Voltage Regulator VinReg Vin

10 S-Touch™ Product Evolution
31-Mar-17 Evolved Products (M-Series) High Performances Application Hardware tuning NOT required 4x Better Sensitivity (15fF Resolution) Superior Noise Immunity Embedded Hardware Ratio Engine Proximity Sensing Capability STMPE16/24M31 STMPE16/24M31PX Basic Products (x21 Series) Portable Application Moderate Sensitivity & Noise Immunity Hardware Tuning Requirement Basic Slider/Wheel Functionality STMPE321 STMPE821 STMPE1208S 10

11 Touch Key Controllers: M31 Series
Single chip solution for highly sensitive and flexible capacitive sensing capabilities. Hardware PWM Controller 8 independent PWM controllers Control up to 16 PWM outputs Ramping/Blinking capable Touch-triggered PWM sequence 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 STMPE16M31/24M31

12 Capacitive Touch Key Controllers
STMPE16/24M31 STMPE16/24M31PX Package Size QFN32 (4x4 mm) / QFN40 (5x5 mm) Operating Voltage V Sensing Channels 16 / 24 No of GPIO 16 No of PWM Slider/Wheel Capability Yes Hardware Tuning Required No (Auto-Tuning) Auto-Calibration Interface Type I2C Sensitivity 15 fF No. of Capacitive Steps 512 Proximity Sense No ESD (HBM) 8 kV

13 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 Key Features Capacitive 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 V (VCC) 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

14 Resistive Touch Screen Controllers
STMPE811 STMPE610 STMPE812 Package Size QFN16 (3x3 mm) CSP12 (2.2x1.7 mm) Operating Voltage V Touch Screen Controller Fully Autonomous Median Averaging Filter No Yes Motion Tracking Window Masking Data Buffer 128 level 1 level Interface 400 KHz I2C 1 MHz SPI Programmable Settling Time No of Wires 4 Extra I/O 4 GPIO 4 ADC (MUX) 2 GPIO 2 ADC (MUX) 4 GPIO 1 ADC (MUX) 1 PWM (MUX) Sensitivity Levels Fixed 4 levels ESD (HBM) 4 kV 8 kV Available in 2010

15 Advance Features Motion Tracking Window Masking Data Buffer
With Data Buffer Without Data Buffer The host may set a value from 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. 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. 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.

16 STMPE811 8-GPIOs Screen Controller
I2C SDAT, SCLK RESET, INT 4-wire Resistive Touch Screen MCU Key Features 12-bit ADC for high-resolution resistive touch screen 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) GPIO Controller Driver & Switch Control Unit RC Oscillator Power Management Host I2C/SPI Interface Touch Screen Controller Thermal Sense VREF INT A0/DATA OUT SDAT/CS SCLK/CLK DATA IN REF-, REF+, GPIO Vin

17 S-Touch™ Additions in 2010 STMPE28M18 STMPE36M28 STMPE12M31RPX
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 STMPE36M28 True multi-touch capability Up to 36 capacitive sensing inputs Touch shape sensing capability Supports multi touches without “ghosting” effect STMPE12M31RPX 12 Channel Touch Key Controller with Ratio Proximity Sensor STMPE12M31MX 12 Channel Touch Key Controller with 6x6 capacitive/mechanical keypad controller

18 RC & CT Firmware Library for STM8S/L

19 STM8 Touch Sensing Library 2.x
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 Setup file

20 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)

21 Capacitive Sensing Acquisitions Overview
There are many ways to measure capacitance. ST Firmware is based on the followings: Charge Transfer RC Charging Time

22 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

23 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

24 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

25 Charge Transfer Acquisition Principle
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 25 25

26 Charge Transfert Library with STM8L101
x2 To comparator input STM8L101 The STM8L101 can handle 2 groups of 3 keys each, for a total of 6 keys.

27 Charge Transfert Library with STM8L151
To ADC input x8 STM8L151 The STM8L151 can handle 8 groups of 2 keys each, for a total of 16 keys.

28 With proximity detection
STM8T14x Single key device With proximity detection

29 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 SO8 5x6x 1.75mm UFDFPN 8 2x3x 0.65mm

30 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 R2 Shield pull-up resistor 100KΩ VSS Cs Cx SHLDin OUT VDD SHLDout VREG Vin GND C1 C2 C3 R1 Sensing electrode Shield R2 C2’ R LD Optional LED indicator

31 STM8T141 Output modes Active mode Toggle mode 3s latch mode

32 Power modes and reaction time
4 Output modes Normal Low power with zoom Extreme low power with zoom 2 selectable charge transfer frequency: 125KHz: Optimum power consumption 250KHz: Fast response time 2 selectable conversion time Fast: 10ms (100Hz) Slow: 20ms (50Hz)

33 Demoboards Available in ESICOM

34 STM8T141 Evaluation board Evaluation kit (STM8T141-EVAL)
Low cost and easy to use tool to demonstrate STM8T141 touch/proximity features Touch detection Proximity detection

35 STM8T141 Programming tools
STVP standard programming tool for product configuration Specific USB dongle Socket programming board for SO8,DFN8 and modules STVP Socket board STM8T1X1-SB Programming dongle ST-TSLINK

36 Demoboards available in ESICOM

37 STMPE321 Device and Sensor Board ST7 USB-I2C Interface Board
Demoboards available in ESICOM STMPE811 STMPE1208S STMPE321 Device and Sensor Board ST7 USB-I2C Interface Board STMPE (not in ESICOM)

38 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

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