6.5.5.1.1 Enabling Remappable Peripheral Inputs

With PPS, each remappable input pin function (EXTINT0, SERCOM0_PAD3 and so on) is assigned to be driven from a specific device pin by programming the corresponding <INPUT>R[3:0] register (meaning, EXTINT0R[3:0], SCOM0P3R[3:0] and so on) with a value defined in the Input Pin Selection Group 1, Input Pin Selection Group 2, Input Pin Selection Group 3, Input Pin Selection Group 4, Input Pin Selection Group 5 tables and [pin name]R register. See these tables in the Remappable Input Example and [pin name]R from Related Links.

Assigning a remappable input pin function does not automatically enable the digital input buffer on the pin. The buffer must be enabled for each remap pin (RPx) by disabling all higher priority pin functions on that pin. In general, all functions other than GPIO are considered higher priority than remap pins. For the list and priority of pin functions on each pin, see Function Priority for Device Pins from Related Links.

When transitioning the pin usage from one peripheral to another, it is mandatory to make sure the pins are not configured for any other peripheral. Therefore, to avoid glitching outputs, the user is responsible for turning off the appropriate peripherals before remapping the pin functions associated with that peripheral. On Reset, all inputs are mapped to a default value and all outputs are disabled; therefore, the mapping may be safely performed after any device Reset. After Reset, all inputs are mapped to a default value and all outputs are disabled, the user can safely perform the mapping after any device Reset.