6.5.3 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. 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.