STMPE321QTR STMicroelectronics

STMPE321 3-channel capacitive touchkey controller Features Up to 3 GPIOs Up to 3 capacitive touchkey inputs Operating voltage 1.65 - 1.95 V Interrupt output pin 2 I C interface (1.8 V operation, 3.3 V tolerant) 8 kV HBM ESD protection 40 fF resolution, 128-step capacitance QFN12 measurement (2.2 x 1.5 mm) Advanced data filtering (AFS) Environment tracking calibration (ETC) Individually adjustable touch variance (TVR) settings for all channels Description Adjustable environmental variance (EVR) for optimal calibration The STMPE321 is a 3-channel capacitive touchkey controller. Capacitance measurement is Capacitive key sensing capability in 27 A implemented in fully optimized hardware. sleep mode 2 All 3 I/Os can be configured via an I C bus to function as either capacitive touchkey, or as Applications GPIOs (general purpose I/O). Mobile phones and smartphones Portable media players Game consoles Table 1. Device summary Order code Package Packing STMPE321QTR QFN12 (2.2 x 1.5 mm) Tape and reel August 2009 Doc ID 15791 Rev 3 1/40 www.st.com 40Contents STMPE321 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 Noise filtering 8 2.1.2 Data filtering . 8 2.2 Power management 9 2 3I C interface . 10 4 Register map and function description . 12 5 System and identification registers 14 6 Interrupt controller module 17 7 GPIO controller 22 8 Capacitive touch module registers 24 9 Maximum rating 33 10 Electrical specifications . 34 10.1 Capacitive sensing characteristics 34 11 Package mechanical data 35 12 Revision history . 39 2/40 Doc ID 15791 Rev 3