There are two self capacitance buttons available on the SAM D11 Xplained Pro board that can be used as I/O. These QTouch buttons are intended to be driven by the built-in Peripheral Touch Controller (PTC) of the device.
0Ω resistors are added on the board to easily disconnect either the onboard touch buttons or the connection to the extension header, as the I/O lines are shared between the two. These resistors can be found on the back side of the board, marked "QTBTN1" and "QTBTN2" for disconnecting the touch buttons, and "EXT-3" and "EXT-4" for disconnecting the lines to the extension header.
| Pin on SAM D11 | Silkscreen text |
|---|---|
| PA02 | QT BTN1 |
| PA03 | QT BTN2 |