STMPE821 S-Touch 8-channel capacitive touchkey controller Features Up to 8 GPIOs Up to 8 capacitive touch key inputs Operating voltage 2.7- 3.6 Internal regulator Interrupt output pin 2 I C interface (1.8 V operation, 3.3 V tolerant) 8 kV HBM ESD protection 50 fF resolution, 128 steps capacitance measurement QFN16 (2.6x1.8mm) Advanced data filtering (AFS) Environment tracking calibration (ETC) Individually adjustable touch variance (TVR) setting for all channels Adjustable environmental variance (EVR) for optimal calibration Description Capacitive key sensing capability in 25 A sleep mode The STMPE821 is an 8-channel capacitive touch key controller. The capacitance measurement is Applications implemented fully in optimized hardware. Mobile and smartphones 2 All 8 I/Os could be configured via I C bus to Portable media players function as either capacitive touch key, or GPIO (general purpose I/O). Game consoles Table 1. Device summary Order code Package Packing STMPE821QTR QFN16 (2.6 x 1.8 mm) Tape and reel November 2010 Doc ID 14478 Rev 5 1/50 www.st.com 50 Obsolete Product(s) - Obsolete Product(s)Contents STMPE821 Contents 1 STMPE821 functional overview 5 1.1 STMPE821 block diagram . 5 1.2 Pin assignment and function . 6 1.3 STMPE821 typical application 7 1.4 Calibration algorithm . 8 1.4.1 Noise filtering 9 1.4.2 Data filtering . 9 1.5 Power management . 10 2 Power schemes 11 3 I2C interface . 12 4 Register map and function description . 14 5 System and identification registers 16 6 Interrupt controller module 19 7 GPIO controller 24 8 Capacitive touch module registers 26 9 Basic PWM controller . 35 9.1 PWM function register map . 37 9.2 Interrupt on basic PWM controller 41 10 Maximum rating 42 11 Electrical specifications . 43 12 Package mechanical data 45 13 Revision history . 49 2/50 Doc ID 14478 Rev 5 Obsolete Product(s) - Obsolete Product(s)