Self-Capacitance Touch Sensors Example Using QT7 Xplained Pro and PIC16F17146 Curiosity Nano

This example showcases a self-capacitance touch application using the PIC16F17146 Curiosity Nano board in combination with the QT7 Xplained Pro extension board. The project offers user feedback for touch events either through the on-board LEDs on the QT7 XPRO or by displaying data on a PC using MPLAB® Data Visualizer over USB.

Related Documentation

• PIC16F17146 Curiosity Nano Hardware User Guide
• QT7 Xplained Pro Extension Kit

Software Used

• MPLAB® X IDE v6.25.0 or newer
• MPLAB® XC8 v3.0.0 or newer compiler
• MPLAB® Code Configurator v5.6.2 or newer
• Microchip PIC16F1xxxx Series DFP v1.27.418 or newer

Hardware Used

• PIC16F17146 Curiosity Nano Evaluation Kit
• Curiosity Nano Touch Adapter
• QT7 Xplained Pro Extension Kit
• Type-B® Micro USB cable

Setup

The PIC16F17146 Curiosity Nano is mounted on the Curiosity Nano Touch Adapter which has two extension headers. The QT7 Xplained Pro is connected to the 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. Button/Slider touch events are indicated by LEDs on the QT7 XPRO and can also be monitored in the MPLAB® Data Visualizer.

Other Features

• The project supports bidirectional tuning

Monitoring Touch Data in MPLAB® Data Visualizer Touch Plugin

Prerequisite: MPLAB Data Visualizer and Touch Plugin. Procedure for Installation is available in Touch Plugin Installation.

1. Configure the COM Port:
   • Select the correct COM port in Connection tab
   • Update the Baud Rate to 115200 in COM Settings
   • Start streaming for COM data
2. COM Port on Touch:
   • Select Touch in Connection tab
   • For data source, from drop-down menu, select configured COM port as 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 QT7 Self-Capacitance extension header with the PIC16F17146 microcontroller. It leverages the Analog-to-Digital Converter (ADC) in Capacitive Voltage Divider (CVD) mode to enable touch sensing and supports Universal Asynchronous Receiver and Transmitter (UART) communication on the PIC16F17146. The application detects touch inputs from the self-capacitance buttons and slider on the QT7 XPRO board. When a touch is registered, the corresponding LED for each button or slider position lights up. Additional touch parameters can be monitored using the Touch Plugin in MPLAB® Data Visualizer.