23.2.3 Peripheral Multiplexing

SAM devices contain a peripheral MUX, which is individually controllable for each I/O pin of the device. The peripheral MUX allows you to select the function of a physical package pin - whether it will be controlled as a user controllable GPIO pin, or whether it will be connected internally to one of several peripheral modules (such as an I²C module). When a pin is configured in GPIO mode, other peripherals connected to the same pin will be disabled.