STMPE321 ST Microelectronics, STMPE321 Datasheet
STMPE321
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STMPE321 Summary of contents
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... Table 1. Device summary Order code STMPE321QTR June 2009 3-channel capacitive touch key controller Description The STMPE321 is a 3-channel capacitive touch key controller. Capacitance measurement is implemented in fully optimized hardware. A µ All 3 I/Os can be configured via an I function as either capacitive touch key GPIOs (general purpose I/O). ...
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... Contents Contents 1 STMPE321 functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 STMPE321 block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Pin assignment and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 STMPE321 typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Capacitance compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1 Calibration algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.1 2.1.2 2.2 Power management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4 Register map and function description . . . . . . . . . . . . . . . . . . . . . . . . . 12 5 System and identification registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 6 Interrupt controller module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7 GPIO controller ...
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... STMPE321 1 STMPE321 functional overview The STMPE321 consists of the following blocks: ● GPIO controller ● Impedance sensor ● Touch key controller 2 ● interface 1.1 STMPE321 block diagram Figure 1. Functional block diagram IO controller Impedance RST SCLK Host interface SDA Touch key INT ...
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... STMPE321 functional overview 1.2 Pin assignment and function Figure 2. Table 2. Pin number 4/40 QFN12 pin assignment (top view Pin assignment and function Pin name GPIO_2 / touch 2 GPIO 2 GPIO_1 / touch 1 GPIO 1 GPIO_0 / touch 0 GPIO 0 ...
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... STMPE321 1.3 STMPE321 typical application The STMPE321 is capable of supporting capacitive sensors channels. Figure 3. Typical application diagram Doc ID 15791 Rev 1 STMPE321 functional overview 5/40 ...
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... Capacitance compensation 2 Capacitance compensation The STMPE321 is capable of measuring capacitance differences between the reference point (Zref) and the individual channels. In cases where the PCB connection between the sensor pads and the device is too long, the REFERENCE DELAY register is able to shift the reference 5.0 pF, allowing the touch channels to measure added capacitance of 5 ...
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... STMPE321 2.1 Calibration algorithm The STMPE321 maintains 2 parameters for each touch channel: TVR and CALIBRATED IMPEDANCE. CALIBRATED IMPEDANCE is an internal reference which, if the currently measured IMPEDANCE exceeds the CALIBRATED IMPEDANCE by a magnitude of TVR, is considered a “TOUCH”. If the IMPEDANCE is higher than the CALIBRATED IMPEDANCE, but the magnitude does not exceed CALIBRATED IMPEDANCE by TVR not considered a TOUCH ...
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... Capacitance compensation 2.1.1 Noise filtering When the STMPE321 is operating in the vicinity of highly emissive circuits (DC-DC converters, PWM controllers/drives etc.), the sensor inputs can be affected by high- frequency noise. In this situation, the time-integrating function can be used to distinguish between a real touch emission-related false touch. ...
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... Power management The STMPE321 operates in 3 states, as described below: Figure 5. On RESET, the STMPE321 enters the ACTIVE state immediately. Upon a fixed period of inactivity, the device enters a SLEEP state. Any touch activity occurring during a SLEEP state causes the device to return to an ACTIVE state. ...
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... 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. 10/ interface specification version 2.1 Doc ID 15791 Rev 1 STMPE321 ...
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... STMPE321 Table 4. Mode Read Write Figure 6. One byte Read More than one byte Read One byte Write More than one byte Read Operation modes Byte Start, Device address, R Register address to be read Restart, Device address, R 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 auto- ≥ ...
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... Register map and function description 4 Register map and function description This section lists and describes the registers in the STMPE321 device starting with a register map, and then provides detailed descriptions of the register types. Table 5. Address 0x00 CHIP_ID_0 0x01 CHIP_ID_1 0x02 ID_VER ...
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... STMPE321 Table 5. Address 0x40 EVR 0x50 - STRENGTH_THRES 0x57 [0-7] 0x60 - STRENGTH [0-7] 0x67 0x70 - CAL_IMPEDANCE 0x77 [0-7] 0x80 - IMPEDANCE [0-7] 0x87 0x92 INT_PENDING 0xA0 PWM_OFF_OUTPUT 0xA1 MASTER_EN Register summary map table (continued) Register name Bit Type 8 R R/W 8 R/W 8 R/W Doc ID 15791 Rev 1 ...
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... CHIP_ID_x Address: 0x00, 0x01 Type: R Reset: 0x03, 0x21 Description: 16-bit device identification 14/40 Bit Type R/W 8 R/W Doc ID 15791 Rev 1 STMPE321 Reset Function Device 0x03 identification Device 0x21 identification 0x03 Revision number System 0x00 configuration 1 System 0xEF configuration 2 Device identification ...
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... STMPE321 ID_VER Address: 0x02 Type: R Reset: 0x0F Description: 16-bit revision number SYS_CFG_1 7 6 RESERVED Address: 0x03 Type: R/W Reset: 0x00 Description: The reset control register enables the reset of the device [7:4] RESERVED [3] SLEEP: Write ‘1’ to enable sleep mode. Hardware resets this bit to ‘0’ after it successfully enters sleep mode ...
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... Sensor clock setting Sensor clock Divider [2:0] 1 000 2 001 4 010 8 011 16 1xx 1 000 2 001 4 010 8 011 16 1xx Doc ID 15791 Rev 1 STMPE321 Active Calibration 12.8 kHz 100 kHz 6.4 kHz 50 kHz 3.2 kHz 25 kHz 1.6 kHz 12.5 kHz 800 Hz 6.25 kHz 400 Hz 3.2 kHz 200 Hz 1.6 kHz 100 Hz 800 400 200 Hz ...
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... STMPE321 6 Interrupt controller module Figure 7. INT MASK interrupt Interrupt controller module block diagram INT pending GPIO interrupt status AND GPIO enable Doc ID 15791 Rev 1 Interrupt controller module Interrupt status INT AND Interrupt enable 17/40 ...
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... V [1] TYPE: '0' for level trigger '1' for edge trigger (pulse width is 200 nS) [0] INT_EN: '0' to disable all interrupts '1' to enable all interrupts 18/ the device when there is a pending interrupt. CC Doc ID 15791 Rev 1 STMPE321 Interrupt control register POLARITY TYPE INT_EN ...
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... STMPE321 INT_EN 7 6 GPIO Address: 0x09 Type: R/W Reset: 0x00 Description: This register is used to enable the interruption from a system related interrupt source to the host. Writing ‘1’ in this register enables the corresponding interrupt event to generate interrupt signal at the INT pin. Note that even if the interrupt is not enabled, an interrupt event is still reflected in the interrupt status register ...
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... Some of these bits might be set to '1' by hardware during normal operation. The content of these bit is for internal operation and are not required for normal use of device. [2] GEN: System INT (A21, I2A, EOC) [1] FIFO: Data available in FIFO [0] POR: Power-on reset 20/ RESERVED Doc ID 15791 Rev 1 STMPE321 Interrupt status register 2 1 GEN FIFO POR 0 ...
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... STMPE321 GPIO_INT_EN 7 6 RESERVED Address: 0x0B, 0x0C Type: R/W Reset: 0x00 Description: The GPIO interrupt enable register is used to enable the interruption from a particular GPIO interrupt source to the host. The IEg[2:0] bits and the interrupt enable mask bits correspond to the GPIO[7:0} pins. ...
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... GPIO controller 7 GPIO controller A total of 3 GPIOs are available in the STMPE321. The GPIO controller contains the registers that allow the host system to configure each of the pins into either a GPIO or Touch input. Unused GPIOs should be configured as outputs to minimize power consumption. A group of registers is used to control the exact function of each of the 8 GPIOs. The registers and their respective addresses are listed in Table 8 ...
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... STMPE321 The function of each bit is shown Table 9. Register name GPIO monitor pin state GPIO set pin state GPIO set pin direction GPIO function inTable 9: GPIO control bits function Reading this bit yields the current state of the bit. Writing has no effect. ...
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... While it is possible to access each byte in the data structure directly recommended that the FIFO is accessed only via the 0x18 address. The FIFO must be accessed in multiples of 2 bytes (LSB, MSB). For the STMPE321, MSB is reserved and LSB contains a snapshot of the recent touch event. The FIFO must be accessed in multiples of 2 bytes (LSB, MSB) ...
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... STMPE321 FEATURE_SELECT 7 6 RESERVED Address: 0x20 Type: R/W Reset: 0x04 Description: Controls AFS (advanced filtering system and second level filtering feature) [7:3] RESERVED [2:1] AFS[1:0]: “00’: reserved “01’ AFS mode 1 (only 1 strongest key) ‘10’: AFS mode 2 (all keys that are above threshold) ‘ ...
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... Range INTEGRATION TIME 7 6 Address: 0x23 Type: R/W Reset: 0x0F Description: Integration time [7:0] Integration time in AFS mode Total period of integration = sensor clock period * integration time [7:0] 78 µs - 320 ms 26/ CAL_INTERVAL INTEGRATION_TIME[7:0] Doc ID 15791 Rev 1 STMPE321 Calibration interval 2 1 Integration time ...
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... STMPE321 CTRL 7 6 RESERVED Address: 0x25 Type: R/W Reset: 0x00 Description: Control [7:4] RESERVED [3] F2A: Write '1' to force device to remain in ACTIVE state at all times [2] HDC_U: Write '1' to perform unconditional host driven calibration Cleared to '0' when calibration is completed Only applicable HOLD is '1' [1] HDC_C: ...
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... Description: Writing '1' to this register clears the corresponding interrupt source in INT_PENDING register. [7:4] RESERVED [3] EOC: End of calibration This interrupt occurs on both automatic and forced calibration [2:0] RESERVED 28/ EOC EOC Doc ID 15791 Rev 1 STMPE321 Interrupt mask 2 1 RESERVED Interrupt clear 2 1 RESERVED 0 0 ...
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... STMPE321 FILTER_PERIOD 7 6 Address: 0x28 Type: R/W Reset: 0x00 Description: Filter period. [7:0] FILTER_COUNT: Additional filter to stabilize touch output in AFS mode. AFS touch output is monitored for Filter Count [7:0] times every integration time. For each time a "touch status" is detected, an internal "Filter Counter" is incremented once. This counter ...
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... A small TVR value increases the sensitivity EVR 7 6 RESERVED Address: 0x40 Type: R/W Reset: 0x04 Description: Environmental variance setting. [7] RESERVED [6] EVR: EVR is used to detect "Non-Touch" condition 30/ TVR TVR Doc ID 15791 Rev 1 STMPE321 Touch variance setting 2 1 Environmental variance ...
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... STMPE321 STRENGTH_THRESHOLD 7 6 Address: 0x50 - 0x52 Type: R/W Reset: 0x01 Description: Strength threshold. [7:0] STRENGTH_THRESHOLD: Setting threshold to be used in AFS mode to determine valid touch STRENGTH 7 6 Address: 0x60 - 0x62 Type: R Reset: 0x00 Description: The number of times a sensed capacitance exceeds the calibrated reference ...
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... RESERVED Address: 0x92 Type: R/W Reset: 0x00 Description: Reflects the status of each interrupt source. [7:4] RESERVED [3] EOC: End of calibration [2:0] RESERVED ss [7:4] Number of cycles = repetition [3:0] 32/ CAL_IMPEDANCE IMPEDANCE EOC Doc ID 15791 Rev 1 STMPE321 Calibrated impedance Impedance Interrupt pending RESERVED ...
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... STMPE321 9 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 ...
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... Linearity of sensor calculated from full scale capacitance measurement data Doc ID 15791 Rev 1 Value Min Typ 1. 1 280 -0.3V - 0.2V 0.8Vcc - V CC -0.3V - 0.25V V, 0.75Vcc - V CC -0.3V - 0.25V - - = 1. Value Min Typ - STMPE321 Unit Max 1.95 V 3.0 µA 43 µA 470 µ +0. +0. 0.5 µA 0.5 µA Unit Max - ...
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... STMPE321 11 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK specifications, grade definitions and product status are available at: www.st.com. ® ECOPACK Figure 8. 1. Drawing not to scale. 2. Dimensions are in millimeters. packages, depending on their level of environmental compliance. ECOPACK trademark ...
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... Drawing not to scale. 2. Dimensions are in millimeters. 36/40 Mechanical data for QFN12 (2.2 x 1.5 x 0.5 mm) - 0.40 mm pitch Min A 0. 0.15 − D − E − 0.35 Footprint recommendations for QFN12 (2.2 x 1.5 x 0.5 mm) - 0.40 mm pitch Doc ID 15791 Rev 1 STMPE321 Millimeters Typ Max − 0.60 − − − 0.25 − 1.50 − 2.20 − 0.40 − 0.45 ...
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... STMPE321 Figure 10. Carrier tape for QFN12 (2.2 x 1.5 x 0.5 mm) - 0.40 mm pitch Doc ID 15791 Rev 1 Package mechanical data 785978-J 37/40 ...
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... Package mechanical data Figure 11. Reel information for QFN12 (2.2 x 1.5 x 0.5 mm) - 0.40 mm pitch 1. Drawing not to scale. 2. Dimensions are in millimeters 38/40 Doc ID 15791 Rev 1 STMPE321 7875978 ...
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... STMPE321 12 Revision history Table 15. Date 19-Jun-2009 Document revision history Revision 1 Initial release. Doc ID 15791 Rev 1 Revision history Changes 39/40 ...
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... 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 40/40 Please Read Carefully: © 2009 STMicroelectronics - All rights reserved STMicroelectronics group of companies www.st.com Doc ID 15791 Rev 1 STMPE321 ...