Introduction

In the past two decades, smart gadgets led to the popularity of capacitive touch surface, or touchpad, as a Human Machine Interface (HMI) for a wide range of applications. The increase in demand for touch also led to the development of reliable, robust touch-sensing technology. Consequently, the capacitive touch interface is an essential user requirement in numerous consumer electronic, wearable, home appliances, home automation, industrial, medical, and automotive products. Many devices use capacitive touch surface as a replacement for mechanical buttons.

This application note demonstrates 2D touch surface implementation for an AVR® DA microcontroller with integrated gesture recognition using the on-chip Peripheral Touch Controller (PTC) and the Microchip Touch Library. It showcases the advanced low-power touch measurement capabilities of the AVR DA microcontroller and how to use the PTC peripheral with CPU in Standby sleep mode to minimize power consumption.

A basic Snake Game demonstrator is implemented to showcase the 2D touch surface gestures with the help of the Microchip AVR128DA48 Curiosity Nano, Curiosity Nano Touch Adapter, QT2 Xplained Pro extension board, and the Microchip Touch Library. The supplemented firmware is developed with the help of Microchip’s Atmel START, and the QTouch® configurator (embedded into Atmel START) is used to configure the touch surface parameters.