6.2.5 Available Peripherals

The peripherals managed by the PPS are all digital-only peripherals. These include general serial communications (SERCOM), general purpose timer clock inputs, timer-related peripherals (input capture and output compare), interrupt-on-change inputs and reference clocks (input and output).

In comparison, some digital-only peripheral modules are never included in the PPS feature. This is because the peripheral’s function requires special I/O circuitry on a specific port and cannot be easily connected to multiple pins. These modules include I²C among others. A similar requirement excludes all modules with analog inputs, such as the ADC.

A key difference between remappable and non-remappable peripherals is that remappable peripherals are not associated with a default I/O pin. The peripheral must always be assigned to a specific I/O pin before it can be used. In contrast, non-remappable peripherals are always available on a default pin, assuming that the peripheral is active and not conflicting with another peripheral.

When a remappable peripheral is active on a given I/O pin, it takes priority over all other digital I/O and digital communication peripherals associated with the pin. Priority is given regardless of the type of peripheral that is mapped. Remappable peripherals never take priority over any analog functions associated with the pin.