30.1 Description

The QTouch Peripheral Touch Controller (PTC) subsystem offers built-in hardware for capacitive touch measurement on sensors that function as buttons, sliders and wheels. The PTC subsystem supports both mutual and self-capacitance measurement without the need for any external component. It offers sensitivity and noise tolerance, as well as self-calibration, and minimizes the sensitivity tuning effort by the user.

The PTC subsystem is intended for autonomously performing capacitive touch sensor measurements. The external capacitive touch sensor is typically formed on a PCB, and the sensor electrodes are connected to the analog charge integrator of the PTC using the device I/O pins. The PTC supports mutual capacitance sensors organized as capacitive touch matrices in different X-Y configurations. In Mutual Capacitance mode, the PTC requires one pin per X line (drive line) and one pin per Y line (sense line). In Self-capacitance mode, the PTC requires only one pin with a Y-line driver for each self-capacitance sensor.