Datasheet
36. Peripheral Touch Controller (PTC)
36.1 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.
Related Links
7. I/O Multiplexing and Considerations
2. Configuration Summary
36.2 Features
• Low-power, high-sensitivity, environmentally robust capacitive touch buttons, sliders, and wheels
• Supports wake-up on touch from Standby Sleep mode
• Supports mutual capacitance and self-capacitance sensing
– 6/10/16 buttons in self-capacitance mode, for 32-/48-/64- pins respectively
– 60/120/256 buttons in mutual-capacitance mode, for 32-/48-/64- pins respectively
– 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
DD
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
Related Links
7. I/O Multiplexing and Considerations
2. Configuration Summary
SAM D21 Family
Peripheral Touch Controller (PTC)
© 2018 Microchip Technology Inc.
Datasheet Complete
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