STMPE821QTR STMicroelectronics, STMPE821QTR Datasheet
STMPE821QTR
Specifications of STMPE821QTR
Available stocks
Related parts for STMPE821QTR
STMPE821QTR Summary of contents
Page 1
... Portable media players ■ Game consoles Table 1. Device summary Order code STMPE821QTR April 2009 8-channel capacitive touch key controller Description The STMPE821 is an 8-channel capacitive touch key controller. The capacitance measurement is implemented fully in optimized hardware. All 8 I/Os could be configured via I function as either capacitive touch key, or GPIO (general purpose I/O) ...
Page 2
Contents Contents 1 STMPE821 functional overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 ...
Page 3
STMPE821 List of tables Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
Page 4
List of figures List of figures Figure 1. Functional block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
Page 5
STMPE821 1 STMPE821 functional overview The STMPE821 consists of the following blocks: ● GPIO controller ● PWM controller ● Impedance sensor ● Touch key controller 2 ● interface 1.1 STMPE821 block diagram Figure 1. Functional block diagram INT ...
Page 6
STMPE821 functional overview 1.2 Pin assignment and function Figure 2. STMPE821 pin assignment (top view) Table 2. Pin assignments and function Pin number 6/55 ...
Page 7
STMPE821 1.3 STMPE821 typical application The STMPE821 is able to support channel capacitive sensors. Figure 3. Typical application diagram STMPE821 functional overview 7/55 ...
Page 8
STMPE821 functional overview 1.4 Calibration algorithm The STMPE821 maintains 2 parameters for each TOUCH channel: 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 ...
Page 9
STMPE821 1.4.1 Noise filtering When the STMPE821 is operating in the vicinity of highly emissive circuits (DC-DC converter, PWM controller/drive etc), the sensor inputs will be affected by high-frequency noise. In this situation, the time-integrating function could be used to ...
Page 10
STMPE821 functional overview 1.5 Power management The STMPE821 operates in 3 states. Figure 4. STMPE821 operating states On RESET, the STMPE821 enters the ACTIVE state immediately. Upon a fixed period of inactivity, the device enters into the SLEEP state. Any ...
Page 11
STMPE821 2 Power schemes The STMPE821 is powered by a 2.7 - 3.6 V supply. An internal LDO regulates this supply into 1.8 V for core operation. All GPIOs operates at V Figure 5. Power using the internal regulator * ...
Page 12
I2C interface interface The features that are supported by the I 2 ● slave device ● Compliant to Philips I ● Supports standard (up to 100 kbps) and fast (up to 400 kbps) modes. ...
Page 13
STMPE821 Table 4. Operation modes Mode Read Write Figure 6. Read and write modes (random and sequential) One byte Read More than one byte Read One byte Write More than one byte Read Byte Programming sequence Start, Device address, R/W ...
Page 14
Register map and function description 4 Register map and function description This section lists and describes the registers of the STMPE821 device, starting with a register map and then provides detailed descriptions of register types. Table 5. Register summary map ...
Page 15
STMPE821 Table 5. Register summary map table (continued) Address Register name 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 0xB0 ...
Page 16
System and identification registers 5 System and identification registers Table 6. System and identification registers map Address Register name 0x00 CHIP_ID_0 0x01 CHIP_ID_1 0x02 ID_VER 0x03 SYS_CFG_1 0x04 SYS_CFG_2 CHIP_ID_x Address: 0x00, 0x01 Type: R Reset: 0x08, 0x21 Description: 16-bit ...
Page 17
STMPE821 SYS_CFG_1 RESERVED Address: 0x03 Type: R/W Reset: 0x00 Description: The reset control register enables to reset the device [7:4] RESERVED [3] SLEEP: Write ‘1’ to enable sleep mode. hardware resets this bit to ‘0’ after it ...
Page 18
System and identification registers Table 7. Sensor clock setting Mode Operational (6.5 MHz) Autosleep (200 KHz) 18/55 Sensor clock Divider [2:0] 1 000 2 001 4 010 8 011 16 1xx 1 000 2 001 4 010 8 011 16 ...
Page 19
STMPE821 6 Interrupt controller module Figure 7. Interrupt controller module block diagram INT pending INT mask GPIO interrupt status GPIO interrupt enable Interrupt status Interrupt enable AND Interrupt controller module INT AND CS00053 19/55 ...
Page 20
Interrupt controller module INT_CTRL 7 6 Address: 0x08 Type: R/W Reset: 0x00 Description: This register is used to enable control the polarity, edge/level and enabling of the interrupt system.device [7:3] RESERVED [2] POLARITY: '0' for active low '1' for active ...
Page 21
STMPE821 INT_EN GPIO PWM3 PWM2 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 ...
Page 22
Interrupt controller module INT_STA GPIO PWM3 PWM2 Address: 0x0A Type: R Reset: 0x00 Description: This register is used to enable the interruption from a system related interrupt source to the host. Regardless whether the IESYSIOR bits are ...
Page 23
STMPE821 GPIO_INT_EN 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[7:0] bits and the interrupt enable ...
Page 24
GPIO controller 7 GPIO controller A total of 8 GPIOs are available in the STMPE821. The GPIO controller contains the registers that allow the host system to configure each of the pins into either a GPIO, direct output of a ...
Page 25
STMPE821 The function of each bit is shown in the following table: Table 9. GPIO control bits function Register name GPIO monitor pin state GPIO set pin state GPIO set pin direction GPIO function Function Reading this bit yields the ...
Page 26
Capacitive touch module registers 8 Capacitive touch module registers Table 10. TOUCH_FIFO summary table TOUCH_FIFO Address: 0x19, 0x18 Type: R Reset: 0x00 Description: TOUCH_FIFO is the access port for the internal 4-level FIFO used ...
Page 27
STMPE821 FEATURE_SELECT 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 ...
Page 28
Capacitive touch module registers CAL_INTERVAL Address: 0x22 Type: R/W Reset: 0x30 Description: Calibration interval [7:0] CALIBRATION INTERVAL: Interval between calibration = Calibration Interval [7:0] * sensor clock period * 50 Range 28/55 ...
Page 29
STMPE821 INTEGRATION TIME 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 Capacitive touch ...
Page 30
Capacitive touch module registers CTRL 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 ...
Page 31
STMPE821 INT_MASK RESERVED Address: 0x26 Type: R/W Reset: 0x08 Description: Writing '1' to this register disables the corresponding interrupt source. [7:4] RESERVED [3] EOC: End of calibration This interrupt occurs on both automatic and forced calibration [2:0] ...
Page 32
Capacitive touch module registers INT_CLR RESERVED Address: 0x27 Type: R/W Reset: 0x00 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 ...
Page 33
STMPE821 FILTER_PERIOD 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 ...
Page 34
Capacitive touch module registers FILTER_THRESHOLD Address: 0x29 Type: R/W Reset: 0x00 Description: Filter threshold. [7:0] FILTER_THRESHOLD: An internal "Filter Counter" is compared with Filter Threshold [7:0] to determine if a valid touch has occurred. REFERENCE_DELAY 7 6 ...
Page 35
STMPE821 TVR RESERVED Address: 0X30 - 0x3B Type: R/W Reset: 0x08 Description: Touch variance setting. [7] RESERVED [6:0] TVR: Setting TVR between 0-99 A high TVR value decreases sensitivity of the sensor, but increasing its tolerance to ...
Page 36
Capacitive touch module registers EVR RESERVED Address: 0x40 Type: R/W Reset: 0x04 Description: Environmental variance setting. [7] RESERVED [6] EVR: EVR is used to detect "Non-Touch" condition 36/55 Environmental variance TVR STMPE821 1 0 ...
Page 37
STMPE821 STRENGTH_THRESHOLD Address: 0x50 - 0x5B 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 - 0x67 Type: R Reset: ...
Page 38
Capacitive touch module registers CALIBRATED_IMPEDANCE 7 6 Address: 0x70 - 0x77 Type: R Reset: 0x00 Description: Calibrated impedance is a reference value maintained by the device. [7:0] CALIBRATED IMPEDANCE: Calibrated reference impedance IMPEDANCE 7 6 Address: 0x80 - 0x87 Type: ...
Page 39
STMPE821 TINT_PENDING 7 6 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 Interrupt pending EOC Capacitive touch module registers 2 1 ...
Page 40
Basic PWM controller 9 Basic PWM controller The advanced PWM allows complex brightness and blinking control of a LED. The basic PWM controller allows simpler brightness control and basic blinking patterns. The STMPE821 is fitted with a 4-channel basic PWM ...
Page 41
STMPE821 Figure 9. Ramps with programmable brightness, ON/OFF period and repetition Duty cycle ON period “On” period = period 0[1:0] * time unit [3:0] “Off” period = period 1[1:0] * time unit [3:0] Duty cycle during “on” period = brightness ...
Page 42
Basic PWM controller 9.1 PWM function register map Table 11. PWM function register map summary table Register name PWM_OFF_OUTPUT MASTER_EN PWM0_SET PWM0_CTRL PWM0_RAMP_RATE PWM1_SET PWM1_CTRL RAMP1_RATE PWM2_SET PWM2_CTRL RAMP2_RATE PWM3_SET PWM3_CTRL PWM3_RATE MASTER_EN 7 6 AF3 AF2 Address: 0xA1 Type: ...
Page 43
STMPE821 PWM_OFF_OUTPUT 7 6 Address: 0xA0 Type: R/W Reset: 0x00 Description: PWM group control register. [7:4] RESERVED [3:0] OUT3:0: Default is '0' '1' - PWM channel outputs '1' when disabled '0' - PWM channel outputs '0' when disabled RAMP_RATE 7 ...
Page 44
Basic PWM controller PWM_n_SETUP 7 6 BRIGHTNESS Address: 0xB0 Type: R/W Reset: 0x00 Description: PWM setup register. [7:4] BRIGHTNESS: This defines the duty cycle during the ON period of the PWM channel output which in turn determines the brightness level ...
Page 45
STMPE821 PWM_CTRL_n 7 6 PERIOD_0 Address: 0xB1, 0xB5, 0xB9, 0xBD Type: R/W Reset: 0x00 Description: This register controls the sequence and repetition of blinking. [7:6] PERIOD_0: This defines the ON period time which is when the PWM channel output is ...
Page 46
Basic PWM controller 9.2 Interrupt on basic PWM controller The basic PWM controller can be programmed to generate interrupts on completion of the blinking sequence. a) Each basic PWM controller has its own bit in interrupt the enable/status registers. b) ...
Page 47
STMPE821 10 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 ...
Page 48
Electrical specifications 11 Electrical specifications Table 13. DC electrical characteristics (- °C unless otherwise stated) Symbol Core supply V CC voltage IO supply V IO voltage I Active current active I Active current active I Active current active ...
Page 49
STMPE821 Table 13. DC electrical characteristics (- °C unless otherwise stated) Symbol Input voltage high state V IH (GPIO) Output voltage V low state OL (GPIO) Parameter Test condition V = 2.7-3 2.7-3.6 V, ...
Page 50
Package mechanical data 12 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 ...
Page 51
STMPE821 Table 14. Mechanical data for QFN16 (2.6 x 1.8 x 0.55 mm) - 0.40 mm pitch Symbol Figure 12. Footprint recommendations for QFN16 (2.6 x 1.8 x 0.55 mm) - 0.40 mm ...
Page 52
Package mechanical data Figure 13. Carrier tape for QFN16 (2.6 x 1.8 x 0.55 mm) - 0.40 mm pitch 52/55 STMPE821 785978-J ...
Page 53
STMPE821 Figure 14. Reel information for QFN16 (2.6 x 1.8 x 0.55 mm) - 0.40 mm pitch 1. Drawing not to scale. 2. Dimensions are in millimeters Package mechanical data 7875978 53/55 ...
Page 54
Revision history 13 Revision history Table 15. Document revision history Date 26-Feb-2008 10-Jun-2008 15-Sep-2008 06-Apr-2009 54/55 Revision 1 Initial release. Modified: operating voltage range included support for 5.5 V, Section 1.3 on page Section 4 on page ...
Page 55
... STMPE821 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. All ST products are sold pursuant to ST’s terms and conditions of sale. ...