QT8

Self-Capacitance Touch Surface Example Using QT8 Xplained Pro and ATtiny3217 Xplained Pro Kit

This example showcases a self-capacitance touch surface application using the ATtiny3217 Xplained Pro board in combination with the QT8 Xplained Pro extension board. The project offers user feedback for touch events either through the on-board LEDs on the QT8 XPRO or by displaying data on a PC using MPLAB® Data Visualizer over USB.

Related Documentation

• ATtiny3217 Xplained Pro User Guide
• QT8 Xplained Pro Extension Kit

Software Used

• MPLAB® X IDE v6.25.0 or newer
• MPLAB® XC8 v3.0.0 or newer
• MPLAB® Code Configurator (MCC) v5.6.2 or newer
• Microchip ATtiny Series DFP v3.3.272 or newer

Hardware Used

• ATtiny3217 Xplained Pro
• QT8 Xplained Pro Extension Kit
• USB Type-C® cable

Setup

The ATtiny3217 Xplained Pro features two Xplained Pro Extension Headers, supporting both Self- and Mutual-Capacitance Touch Extension Kits, along with two power configuration options. In this project, the ATtiny3217 Xplained Pro serves as the circuit interface, connecting to the QT8 Xplained Pro board through extension header 1, as shown below.

Operation

Once the setup is ready, open the application project in IDE, build the project and program the target board. Surface touch events are indicated by LEDs on the QT8 XPRO and can also be monitored in the MPLAB® Data Visualizer.

Other Features

• The project supports bidirectional tuning
• The Driven Shield option has been enabled

Monitoring Touch Data in the MPLAB® Data Visualizer Touch Plugin

Prerequisite: MPLAB Data Visualizer and Touch Plugin. For the installation procedure, refer to Touch Plugin Installation.

1. Configure the COM Port:
   • Select the correct COM port in the Connection tab
   • Update the Baud Rate to 38400 in COM Settings
   • Start streaming for COM data
2. COM Port on Touch:
   • Select Touch in the Connection tab
   • For data source, from the drop-down menu, select the configured COM port as the source
   • Start streaming on Touch

For a more detailed procedure for Data Visualization, refer to Visualize Touch Data Using MPLAB® Data Visualizer.

Known Issues

None.

Summary

This example project showcases how to interface the QT8 Self-Capacitance extension header with the ATtiny3217 microcontroller. It leverages the Peripheral Touch Controller (PTC) to enable touch sensing and supports Universal Asynchronous Receiver and Transmitter (UART) communication on the ATtiny3217. The application detects touch inputs from the self-capacitance touch surface on the QT8 XPRO board. When a touch is registered, the corresponding LED for each surface position lights up. Additional touch parameters can be monitored using the Touch Plugin in MPLAB® Data Visualizer.