STMPE1208SQTR

STMPE1208S S-Touch™ 12-channel capacitive touchkey controller Features ■ 12 touchkey capacitive sensor inputs ■ 12-bit general purpose input/output (GPIO) ■ Operating voltage 3.0 − 5.5 V ■ 98 µA in active mode, 60 µA in idle mode ■ Dual interrupt output pin ■ I2C interface (up to 400 kHz) ■ 7 kV HBM ESD protection ■ Idle and sleep mode for low power operation ■ Advanced data filtering (AFS) ■ Environment tracking calibration (ETC) ■ Individually adjustable touch variance (TVR) setting for all channels ■ Adjustable environmental variance (EVR) for optimal calibration Applications Notebook computers ■ Monitors ■ Set-top boxes ■ Televisions ■ Portable media players and game consoles ■ Mobile and smart phones ■ Home entertainment systems u d o t e l o u d o r P e let o s b QFN40 O ) Description s ( t c ■ r P e ) s ( ct The STMPE1208S is a 12-channel GPIO capacitive touchkey sensor able to interface a main digital ASIC via the two-line bidirectional bus (I2C). It senses changes in capacitance using a fully digital architecture, giving fast and accurate results at very low power consumption. Automatic impedance calibration ensures that changes in environment will never affect the correct operation of the capacitive touchkeys. s b O ■ Domestic appliances Table 1. Device summary Order code Package Packing STMPE1208SQTR QFN40 Tape and reel December 2009 Doc ID 14438 Rev 5 1/47 www.st.com 47 Contents STMPE1208S Contents 1 Pin configuration and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1 Power management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2 Clock setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 I2C interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ) s ( ct 3.1 Start condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2 Stop condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.3 Acknowledge bit (ACK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4 Data Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.5 Slave device address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.6 Memory addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 u d o r P e t e l o s b O 4 Power schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5 Capacitive sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 b O 6 Capacitive sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.2 Capacitance compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.3 Setting of TVR and EVR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 t c u d o r 5.3.1 3-stage data filtering system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 5.3.2 Noise filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.3.3 BEEP output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.3.4 Interrupt system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 P e let so ) (s 5.1 Register map and function description . . . . . . . . . . . . . . . . . . . . . . . . . 20 7 Command registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 8 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 8.1 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 9 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 10 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2/47 Doc ID 14438 Rev 5 STMPE1208S 11 Contents Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 ) s ( ct u d o r P e t e l o ) (s s b O t c u d o r P e t e l o s b O Doc ID 14438 Rev 5 3/47 List of tables STMPE1208S List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Pin assignments and description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Clocking system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 I2C addresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Operation modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Calibration action under different scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Register summary map table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Command registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 DC electrical characteristics (-40 - 85 °C unless otherwise stated) . . . . . . . . . . . . . . . . . . 40 QFN40 (5 x 5 mm) mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 ) s ( ct u d o r P e t e l o ) (s s b O t c u d o r P e t e l o s b O 4/47 Doc ID 14438 Rev 5 STMPE1208S List of figures List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. STMPE1208S pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 STMPE1208S block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 STMPE1208S operating states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Read and write modes (random and sequential) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Power using the internal regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Power bypassing the internal regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Capacitive sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Capacitive sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Capacitance compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3-stage data filtering system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Interrupt system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Software interface (G_INT based) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Software interface (T_INT based). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 QFN40 (5 x 5 mm) package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 QFN40 recommended footprint without ground pad VIA . . . . . . . . . . . . . . . . . . . . . . . . . . 43 QFN40 recommended footprint with ground pad VIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 QFN40 tape information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Reel information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 ) s ( ct u d o r P e t e l o ) (s s b O t c u d o r P e t e l o s b O Doc ID 14438 Rev 5 5/47 Pin configuration and function Pin configuration and function S_IN_ 8 S_IN_ 7 S_IN_ 6 GND V25 VREG VPH S_IN_ 5 STMPE1208S pin configuration S_IN_3 Figure 1. S_IN_ 4 1 STMPE1208S S_IN_2 S_IN_ 9 S_IN_1 S_IN_ 10 S_IN_0 S_IN_ 11 u d o GND ID_1 STMPE1208S ID_0 e t e ol GPIO_ 5 GPIO_ 4 t e l o bs O 6/47 GPIO_6 GPIO _7 GPIO _8 GPIO _9 GPIO_11 u d o Table 2. VPH 6 GPIO_10 5 TCLK SDATA GPIO_0 GPIO_1 ) s ( ct -O 4 BEEP 3 G_INT 2 T_INT 1 SCLK GPIO_ 2 Pr bs GPIO_ 3 r P e ) s ( ct S_ RE F RESET_N CS00037 Pin assignments and description Pin number Pin name Description 1 GPIO_1 General purpose I/O 2 GPIO_0 General purpose I/O 3 SDATA I2C data 4 SCLK I2C clock 5 T_INT Touch interrupt 6 G_INT General interrupt 7 BEEP Beep output 8 TCLK Test pin (to be grounded) 9 GPIO_11 General purpose I/O 10 GPIO_10 General purpose I/O 11 GPIO_9 General purpose I/O Doc ID 14438 Rev 5 STMPE1208S Pin configuration and function Table 2. Pin assignments and description (continued) Pin number Pin name 12 GPIO_8 General purpose I/O 13 GPIO_7 General purpose I/O 14 GPIO_6 General purpose I/O 15 VPH 3 − 5.5 V power supply (regulator input) Supply to this pin is also used for powering the GPIO 16 GND Ground 17 S_REF 18 S_IN_11 Capacitance sensing input 11 19 S_IN_10 Capacitance sensing input 10 20 S_IN_9 Capacitance sensing input 9 21 S_IN_8 Capacitance sensing input 8 22 S_IN_7 Capacitance sensing input 7 23 S_IN_6 Capacitance sensing input 6 24 GND Ground 25 V25 2.5 V supply 26 VREG 27 VPH 28 S_IN_5 Capacitance sensing input 5 29 S_IN_4 ct Capacitance sensing input 4 S_IN_3 Capacitance sensing input 3 S_IN_2 Capacitance sensing input 2 S_IN_1 Capacitance sensing input 1 33 S_IN_0 Capacitance sensing input 0 34 RESET_IN 35 ID_1 I2C address 36 ID_0 I2C address 37 GPIO_5 General purpose I/O 38 GPIO_4 General purpose I/O 39 GPIO_3 General purpose I/O 40 GPIO_2 General purpose I/O du 30 o r P 31 32 s b O ol ete Description Touch sensing reference. ) s ( ct u d o r P e t e l o s b O Internal regulator output ) (s 3 − 5.5 V power supply (regulator input) Active low reset pin. This pin should be held ‘low’ for 10 mS from power stable state. Recommended: 47 K resistor with 0.47 μF capacitor Doc ID 14438 Rev 5 7/47 Pin configuration and function Figure 2. STMPE1208S STMPE1208S block diagram S_Ref Automatic calibration unit Data filtering unit 12-input capacitive sensor ID_0 S_In 0 - 11 ID_1 RESET Host interface unit G_INT ) s ( ct T_INT SDAT SCLK BEEP generator BEEP 12-bit GPIO Regulator & power control Clock control unit TCLK Figure 3. VPH bs e t e ol V REG u d o Pr V25 O ) CS00038 s ( t c Application diagram u d o s b O System host t e l o RESET G_INT T_INT SDAT STMPE1208S SCLK GPIO 0-11 Up to 12 GPIO for system usage 8/47 Doc ID 14438 Rev 5 Up to 12 touch pads r P e GPIO 0 - 11 STMPE1208S 1.1 Pin configuration and function Power management The STMPE1208S operates in 3 states. Figure 4. STMPE1208S operating states RESET ACTIVE Host command Time out ) s ( ct Touch or host command u d o Host command r P e SLEEP t e l o s b O IDLE CS00039 On reset, the STMPE1208S enters the active state immediately. ) (s Upon a fixed period of inactivity, the device enters into the IDLE state. Any touch activity in IDLE state would cause the device to go back to active state. t c u In IDLE state, the calibration will not run. If the calibration is required at all time, set F2A bit to ‘1’. d o r If no touch activity is expected, the host may set the device into SLEEP state to save power. P e t e l o s b O Doc ID 14438 Rev 5 9/47 Clock setting 2 STMPE1208S Clock setting The STMPE1208S uses a flexible clocking system that allows the user to adjust the clock speed for optimization of power consumption. Table 3. Clocking system Active OSC PDIV Clock Idle NDIV Sensor clock 00 0 20 kHz 100 Hz 1 10 kHz 50 Hz 0 10 kHz 50 Hz 1 5 kHz 0 5 kHz 1 2.5 kHz Pr 12.5 Hz 2.5 kHz 12.5 Hz 1.25 kHz 6.25 Hz 1.6 MHz 01 800 kHz u d o 1.6 MHz 10 400 kHz e t e ol 0 11 200 kHz 1 ) s ( ct 25 Hz 25 Hz The clock frequency must be set to value higher than the expected I2C frequency. ) (s s b O t c u d o r P e t e l o s b O 10/47 Doc ID 14438 Rev 5 STMPE1208S I2C interface I2C interface 3 The features that are supported by the I2C interface are the following ones: ● I2C slave device ● Compliant to Philips I2C specification version 2.1 ● Supports standard (up to 100 kbps) and fast (up to 400 kbps) modes. ● 7-bit and 10-bit device addressing modes ● General call ● Start/restart/stop ) s ( ct The address is selected by the state of 2 pins.The state of the pins is read upon reset and then the pins can be configured for normal operation.The pins have a pull-up or down to set the address.The I2C interface module allows the connected host system to access the registers in the STMPE1208S. I2C Table 4. u d o r P e addresses ID_1 ID_0 0 0 0 1 1 0 1 1 t e l o 7-bit address Write Read 0xB0 0xB1 0xB2 0xB3 0x5A 0xB4 0xB5 0x5B 0xB6 0xB7 s b O 0x58 0x59 )- s ( t c 7-bit address u d o 3.1 Start condition r P e A start condition is identified by a falling edge of SDATA while SCLK is stable at high state. A start condition must precede any data/command transfer.The device continuously monitors for a start condition and will not respond to any transaction unless one is encountered. s b O t e l o 3.2 3.3 Stop condition A stop condition is identified by a rising edge of SDATA while SCLK is stable at high state. A stop condition terminates communication between the slave device and bus master. A read command that is followed by NoAck can be followed by a stop condition to force the slave device into idle mode. When the slave device is in idle mode, it is ready to receive the next I2C transaction. A Stop condition at the end of a write command stops the write operation to registers. Acknowledge bit (ACK) The acknowledge bit is used to indicate a successful byte transfer. The bus transmitter releases the SDATA after sending eight bits of data. During the ninth bit, the receiver pulls Doc ID 14438 Rev 5 11/47 I2C interface STMPE1208S the SDATA low to acknowledge the receipt of the eight bits of data.The receiver may leave the SDATA in high state if it would to not acknowledge the receipt of the data. 3.4 Data Input The device samples the data input on SDATA on the rising edge of the SCLK. The SDATA signal must be stable during the rising edge of SCLK and the SDATA signal must change only when SCLK is driven low. 3.5 Slave device address ) s ( ct The slave device address is a 7 or 10-bit address, where the least significant 3-bit are programmable. These 3-bit values will be loaded in once upon reset and after that these 3 pins no longer be needed with the exception during general call. Up to 4 STMPE1208S devices can be connected on a single I2C bus. 3.6 u d o r P e Memory addressing t e l o For the bus master to communicate to the slave device, the bus master must initiate a start condition and followed by the slave device address. Accompanying the slave device address, there is a read/bit (R/ ). The bit is set to 1 for read and 0 for write operation. s b O If a match occurs on the slave device address, the corresponding device gives an acknowledgement on the SDA during the 9th bit time. If there is no match, it deselects itself from the bus by not responding to the transaction. Table 5. Operation modes Mode Read s b O Byte d o r P e t e l o t c u ) (s ≥1 Programming sequence Start, device address, R/W = 0, register address to be read Restart, device address, R/W = 1, data read, stop If no stop is issued, the data read can be continuously performed. If the register address falls within the range that allows an address autoincrement, then the register address auto-increments internally after every byte of data being read. For those register addresses that fall within a non-incremental address range, the address will be kept static throughout the entire write operations. Refer to the memory map table for the address ranges that are auto and non-increment. An example of such a non-increment address is FIFO Start, device address, R/W = 0, register address to be written, data write, stop Write 12/47 ≥1 If no stop is issued, the data write can be continuously performed. If the register address falls within the range that allows address autoincrement, then the register address auto-increments internally after every byte of data being written in. For those register addresses that fall within a non-incremental address range, the address will be kept static throughout the entire write operations. Refer to the memory map table for the address ranges that are auto and non-increment. Doc ID 14438 Rev 5 STMPE1208S I2C interface Data to Write + 2 ) s ( ct u d o Ack Stop Ack Data to Write + 1 Stop Data Read + 2 Ack Data Read + 1 No Ack Stop No Ack Data Read Ack Ack R/W=1 Ack R/W=1 Data to Write Ack Data to be written Data Read Ack Stop Ack Restart Ack Restart Reg Address Device Address Ack Reg Address Device Address Ack Ack R/W=0 Ack R/W=0 R/W=0 Device Address Reg Address Ack Device Address Reg Address Ack More than one byte Read Device Address R/W=0 One byte Write Start More than one byte Read Device Address Start One byte Read Start Read and write modes (random and sequential) Start Figure 5. r P e t e l o Master Slave ) (s s b O t c u d o r P e t e l o s b O Doc ID 14438 Rev 5 13/47 Power schemes 4 STMPE1208S Power schemes The STMPE1208S can be powered by a 2.5 V supply directly, or 3.0 - 5.5 V supply through the internal voltage regulator. Figure 6. Power using the internal regulator u d o VREG STMPE1208S r P e V25 2.2uF GND ) (s 1. REG_DISABLE bit in CTRL_2 register = 0 Figure 7. so b O t e l o s b O CS00041 t c u Power bypassing the internal regulator d o r P e let ) s ( ct 3 - 5.5V VPH 3 - 5.5V VPH VREG NC STMPE1208S V25 2.25 - 2.75V GND CS00042 1. REG_DISABLE bit in CTRL_2 register = 1 14/47 Doc ID 14438 Rev 5 STMPE1208S 5 Capacitive sensors Capacitive sensors The STMPE1208S capacitive sensor is based on fully digital, impedance change detection engine that is capable of detecting very small change in capacitance. Figure 8. Capacitive sensors Touchkey Calibrated impedance 7-bit impedance value of each channel Automatic calibration Unit Impedance sensor Touched keys ) s ( ct Data filtering u d o r P e Calibration control parameters Data filtering control Parameters t e l o 5.1 Capacitive sensing ) (s s b O The STMPE1208S senses a human touch by the additional capacitance introduced to the pad (with respect to ground). This capacitance causes a delay in a clock signal on the sensing pad, and the delay in the sensing pad is compared with a reference clock and the difference is a direct representation of the additional capacitance introduced by the proximity/touch of finger. t c u Figure 9. P e d o r Capacitive sensing t e l o s b O Doc ID 14438 Rev 5 15/47 Capacitive sensors 5.2 STMPE1208S Capacitance compensation The STMPE1208S is capable to measuring up to 7.2 pF in capacitance difference between the reference point (Zref) and the individual channels. In the case where the PCB connection between the sensor pads and the device is too long, the "reference delay" register is able to shift the reference by up to 6.0 pF, allowing the touch channels to measure added capacitance 7.2 pF with offset of 6.0 pF, as shown in following diagram. In case this is still not enough to compensate for the capacitance on sensor lines (due to very long sensor trace), an external capacitor of up to 30 pF can be connected at the A_Ref pin. This allows to further shift up the dynamic range of the capacitance measurement. Figure 10. Capacitance compensation 6.0 pF 6.0 pF ) s ( ct Reference delay register = 0 Dynamic range = 0 - 7.2 pF 7.2 pF u d o 7.2 pF Reference delay register = 6.0 pF Dynamic range = 6.0 - 13.2 pF t e l o 7.2 pF 30.0pF Increasing capacitance ) (s r P e Reference delay = 6.0 pF S_REF external capacitance = 30 pF Dynamic range = 36 - 43.2 pF s b O t c u CS00043 The sensed capacitance is accessible to host through the "IMPEDANCE" registers. 5.3 d o Setting r of TVR and EVR P e t e l o s b O The STMPE1208S uses 2 main parameters to control the sensitivity and calibration of the capacitive sensing system. TVR (touch variance) is a channel-specific value, that specifies the number of steps the sensed capacitance must be above the internal reference, to be considered a touch. Generally, this should be set as 4 −10, but it must be bigger than EVR. The EVR (environment variance) is a shared value that is applied to all the channels. This specifies the maximum change in capacitance that can be considered due to the shifting of the environmental factor. Generally, this should be set to 1 −5, but it must be less than TVR. Environment tracking calibration On power up, a calibration is executed. The initial calibration takes about 150 clock cycles of sensor clock for completion. Using 5 kHz sensor clock, this would be 30 mS. However, if any of the sensors are touched during powering up, calibration is delayed, until all sensors are untouched. In this case, the time taken for calibration, from the time when all sensors are untouched is: 2 * calibration interval + 150 * sensor clock period 16/47 Doc ID 14438 Rev 5 STMPE1208S Capacitive sensors The STMPE1208S maintains 2 parameters for each touch channels: TVR and calibrated impedance. calibrated impedance is an internal reference of which, if the currently measured impedance exceeds the calibrated impedance by a magnitude of TVR, it is considered a touch. If the impedance is more than the calibrated impedance, but the magnitude does not exceed calibrated impedance by TVR, it is not considered a TOUCH. In this case, 2 scenarios are possible: 1. Environmental changes has caused the impedance to increase 2. Finger is near the sensing pad, but not near enough In case 1, the change in impedance is expected to be small, as environmental changes are normally gradual. A value "EVR" is maintained to specify the maximum impedance change that is still considered an environmental change. Table 6. Calibration action under different scenarios Scenario u d o Touch sensing and calibration action r P e IMP>CALIBRATED IMP + TVR Touch, no calibration IMP>CALIBRATED IMP + EVR No touch, no calibration t e l o bs IMP calibrated impedance + TVR), the corresponding bit in this register will read '1'. Reading touch_byte_l and touch_byte_h will clear the TINT assertion. TOUCH_BYTE_H 7 ) s ( ct Touch byte H 6 5 4 RESERVED 3 2 CH11 CH10 1 u d o CH9 0 CH8 r P e Address: 0x76 Type: R Reset: 0x00 Description: CH n: Reads the touch status of channel n (n=8-11). If the key is touched (impedance > calibrated impedance + TVR), the corresponding bit in this register will read '1'. Reading touch_byte_l and touch_byte_h will clear the TINT assertion. t e l o ) (s [7:4] RESERVED [3] CH11: t c u [2] CH10: [1] CH9: s b O d o r [0] CH8: P e t e l o s b O 34/47 Doc ID 14438 Rev 5 STMPE1208S Register map and function description INT_PENDING 7 Interrupt pending 6 5 4 RESERVED 3 2 1 0 EOC I2A A21 TOUCH Address: 0x77 Type: R Reset: 0x00 Description: This register reflects the status of various possible interrupt sources. Upon the occurrence of an event, the corresponding bit in this register will be set to '1' by the hardware. ) s ( ct [7:4] Reserved u d o [3] EOC: End of calibration r P e [2] I2A: Sleep to active transition t e l o [1] A21: Active to sleeptransition [0] Touch: Touch detect )- GPIO_IN_L Address: 0x79 Type: R Reset: 0x0 t e l o s b O s ( t c GPIO input state (lower) register u d o r P e Description: GPIO_IN_H s b O Reads the current logical level of corresponding DIO if it is set as GPIO input. GPIO input state (higher) register Address: 0x7A Type: R Reset: 0x00 Description: Reads the current logical level of corresponding DIO if it is set as GPIO input. Doc ID 14438 Rev 5 35/47 Command registers 7 STMPE1208S Command registers The command registers do not have a data field. The device carries out a predetermined operation upon receiving a write access to these address offset. However, a dummy dataphase is used to complete the I2C transaction. Table 8. Command registers Command Operation 0xF8 CLK_SRC_INTERNAL Use internal OSC as clock source 0xF9 CLK_SRC_EXTERNAL Use TCLK pin as clock source 0xFA BIAS_OFF u d o r P e 0xFB BIAS_ON Turns ON biasing for internal LDO 0xFC Wake up Exits from sleep and enters active mode 0xFD Enter sleep Enter sleep mode t e l o bs 0xFE Cold reset Resets all states and registers 0xFF Warm reset O ) s ( t c u d o Resets internal state machines, register values remain the same NOTE: I2C WRITE TO THIS REGISTER WILL NOT BE ACKNOWLEDGED. However as long as I2C timing is followed, the writing to this register will work correctly r P e t e l o s b O 36/47 ) s ( ct Turns OFF biasing for internal LDO When external supply is used for V25, turning OFF the biasing for internal LDO reduces current consumption Doc ID 14438 Rev 5 STMPE1208S Command registers Figure 13. Software interface (G_INT based) Initialization GPIO configuration, direction and output Calibration interval ETC wait Feature select EVR setting EVR setting Integration time TVR setting Integration treshold setting Control 1, control 2 ) s ( ct u d o r P e t e l o s b O Wait for interrupt ) (s od t c u r P e t e l o Interrupt service routine Read interrupt pending register Write interrupt mask (to mask all) Write interrupt clear register Read “touch” byte register Read calibrated impedance registers Write interrupt mask (To unmask all) s b O Post processing (optional) Doc ID 14438 Rev 5 37/47 Command registers STMPE1208S Figure 14. Software interface (T_INT based) Initialization GPIO configuration, direction and output Calibration interval ETC wait Feature select EVR setting EVR setting Integration time TVR setting Integration treshold setting Control 1, control 2 r P e u d o t e l o s b O Wait for interrupt ) (s t c u d o r P e Interrupt service routine Read touch byte register t e l o s b O Post processing (optional) 38/47 Doc ID 14438 Rev 5 ) s ( ct STMPE1208S 8 Maximum rating Maximum rating Stressing the device above the rating listed in the “Absolute maximum ratings” table may cause permanent damage to the device. These are stress ratings only, and operation of the device at these or any other conditions above those indicated in the operating sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 9. Absolute maximum ratings Value Symbol Unit Typ Max 5.5 Power supply 3.0 - V25 Power supply 2.15 - VIN Digital input -0.3 TJ Operating temperature -40 TS Storage temperature ete -55 ol HBM on capacitive sensor pins s b O ) s ( ct Min Vph ESD 8.1 Parameter - du V 2.90 V VPH +0.3 V 85 °C - 95 °C 7 - kV o r P - - Recommended operating conditions Table 10. ct Symbol Vph V25 e t e l TJ ) (s Recommended operating conditions u d o Value Parameter Unit Min Typ Max Power supply 3.0 - 5.5 V Power supply 2.25 2.5 2.75 V Operating temperature -40 25 85 °C Pr o s b O Doc ID 14438 Rev 5 39/47 Electrical specifications 9 STMPE1208S Electrical specifications DC electrical characteristics (-40 −85 ° C unless otherwise stated) Table 11. Value Symbol Iout Iactive Iidle Isleep Parameter Test condition Typ Max GPIO driving current Vout = 0.75*VPH - - 2 mA Active current Touch present - 98 160 µA Idle current No-touch - 60 80 µA Sleep current Sleep mode - 0.1 ) s ( ct 1 µA 1.0 V - V 1.0 V - - V - 2 mA VIL Digital input low - - VIH Digital input high 0.7Vph - VOL Digital output low - VOH Digital output high Vph-0.5 Iout GPIO drive current - Iin GPIO sink current Total sink current on all GPIOs 〈 80 mA - - 10 mA Input leakage VIN = 5.5 V VPH = 5.5 V - 0.2 2 µA Ileakage ) (s e t e ol s b O t c u d o r P e t e l o s b O 40/47 Unit Min Doc ID 14438 Rev 5 u d o - Pr STMPE1208S 10 Package mechanical data Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Table 12. QFN40 (5 x 5 mm) mechanical data Millimeters Symbol Min Typ A 0.80 0.85 A1 0.00 - A3 0.15 0.20 D u d o Pr 5.00 BSC e t e ol E ) s ( ct 0.90 -0.203 ref b 0.05 0.25 5.00 BSC D2 3.70 E2 3.70 e L ) s ( ct L1 P u d o aaa Pr ccc e t e ol Max bs 3.80 3.90 3.80 3.90 -O 0.40 BSC 0.30 0.35 0.40 - - 0.10 - 45° BSC - - 0.15 - - 0.10 - s b O Doc ID 14438 Rev 5 41/47 Package mechanical data STMPE1208S Figure 15. QFN40 (5 x 5 mm) package outline ) s ( ct u d o r P e t e l o ) (s s b O t c u d o r P e t e l o s b O 8072802_A 42/47 Doc ID 14438 Rev 5 STMPE1208S Package mechanical data Figure 16. QFN40 recommended footprint without ground pad VIA ) s ( ct u d o r P e t e l o s b O Figure 17. QFN40 recommended footprint with ground pad VIA ) (s t c u d o r b O so let P e 0.68 0.30 0.68 1.27 1.27 Via Doc ID 14438 Rev 5 43/47 Package mechanical data STMPE1208S Figure 18. QFN40 tape information ) s ( ct u d o r P e t e l o ) (s s b O t c u d o r P e t e l o s b O 44/47 Doc ID 14438 Rev 5 STMPE1208S Package mechanical data Figure 19. Reel information ) s ( ct u d o r P e t e l o ) (s s b O t c u d o r P e t e l o s b O Doc ID 14438 Rev 5 45/47 Revision history 11 STMPE1208S Revision history Table 13. Document revision history Date Revision 14-Feb-2008 1 Initial release. 2 Modified title in cover page and ETC_WAIT register description. Updated: Table 5: Operation modes on page 12 Added Figure 16: QFN40 recommended footprint without ground pad VIA on page 43. 3 Document status promoted from preliminary data to datasheet. Modified: Beep_period and beep_frequency registers description, HBM ESD protection value, Table 2: Pin assignments and description on page 6 and Chapter 10: Package mechanical data on page 41. Updated: Section 8: Maximum rating on page 39 and Section 9: Electrical specifications on page 40. 04-Jun-2008 18-Jul-2008 Changes ) s ( ct u d o t e l o 26-May-2008 4 Modified: Table 9 and Table 10. 18-Dec-2009 5 Modified: title, operating voltage in the features and power supply values in Table 9 and Table 10. ) (s s b O t c u d o r P e t e l o s b O 46/47 r P e Doc ID 14438 Rev 5 STMPE1208S ) s ( ct Please Read Carefully: u d o Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. r P e All ST products are sold pursuant to ST’s terms and conditions of sale. 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All other names are the property of their respective owners. © 2009 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com Doc ID 14438 Rev 5 47/47