Datasheet

29. PTC - Peripheral Touch Controller

29.1 Features

• Low-power, high-sensitivity, environmentally robust capacitive touch buttons, sliders, and wheels

• Supports wake-up on touch from power-save Sleep mode

• Supports mutual capacitance and self-capacitance sensing

– 144 buttons in mutual-capacitance mode

– 24 buttons in self-capacitance mode

– Mix-and-match mutual-and self-capacitance sensors

• One pin per electrode – no external components

• Load compensating charge sensing

– Parasitic capacitance compensation and adjustable gain for superior sensitivity

• Zero drift over the temperature and V

range

– Auto calibration and recalibration of sensors

• Single-shot charge measurement

• Hardware noise filtering and noise signal desynchronization for high conducted immunity

• Selectable channel change delay allows choosing the settling time on a new channel, as required

• Acquisition-start triggered by command or through auto-triggering feature

• Low CPU utilization through interrupt on acquisition-complete

29.2 Overview

The Peripheral Touch Controller (PTC) acquires signals in order to detect a touch on the capacitive

sensors. The external capacitive touch sensor is typically formed on a PCB, and the sensor electrodes

are connected to the analog front end of the PTC through the I/O pins in the device. The PTC supports

both self- and mutual-capacitance sensors.

In the mutual-capacitance mode, sensing is done using capacitive touch matrices in various X-Y

configurations, including indium tin oxide (ITO) sensor grids. The PTC requires one pin per X-line and one

pin per Y-line.

In the self-capacitance mode, the PTC requires only one pin (Y-line) for each touch sensor.

The number of available pins and the assignment of X- and Y-lines is depending on both package type

and device configuration. Refer to the Configuration Summary and I/O Multiplexing table for details.

ATmega328PB

PTC - Peripheral Touch Controller

Datasheet Complete

DS40001906C-page 360