5.4.6 Peripheral Touch Controller (PTC)
The AVR and PIC32CM Peripheral Touch Controller (PTC) is used for capacitive touch sensing, supporting both self-capacitance and mutual-capacitance modes. It enables robust, low-power detection of touch buttons, sliders, wheels and 2D surfaces, with high sensitivity and environmental resilience. The AVR and PIC32CM PTCs are designed for easy integration, requiring only one pin per electrode and no external components, and are supported by development tools such as the QTouch® Configurator. Table 5-19 shows a comparison of features between AVR and PIC32CM.
| Feature | AVR® PTC | PIC32CM PTC: Standard/ Enhanced |
|---|---|---|
| Self-Capacitance Buttons | Up to 46 |
Standard: Up to 16 Enhanced: Up to 36, mix-and-match |
| Mutual-Capacitance Buttons | Up to 529 |
Up to 256, mix-and-match with self-capacitance |
| Driven Shield+ | Any X/Y line | Enhanced: Any X/Y line |
| Boost Mode | Supported | Supported |
| Window Monitor | Supported | Supported |
| Analog/Digital Accumulation | Supported | Supported |
| Polarity Control | Supported | Supported |
| Power Consumption |
Low power Wake-up on touch |
Low power Wake-up on touch |
| Channel Change Delay | Selectable | Selectable |
| Noise Immunity |
Hardware filtering Desynchronization Driven Shield |
Hardware filtering Desynchronization Enhanced: Driven Shield |
| Auto-Calibration | Supported | Supported |
| QTouch® Library | Supported | Supported |