16.3.2.3 Pin Configuration

The Pin n Configuration register (PORT.PINnCTRL) is used to configure inverted I/O, pullup, and input sensing of a pin.

All input and output on the respective pin n can be inverted by writing a '1' to the Inverted I/O Enable bit (INVEN) in PORT.PINnCTRL.

Toggling the INVEN bit causes an edge on the pin, which can be detected by all peripherals using this pin, and is seen by interrupts or Events if enabled.

Pullup of pin n is enabled by writing a '1' to the Pullup Enable bit (PULLUPEN) in PORT.PINnCTRL.

Changes of the signal on a pin can trigger an interrupt. The exact conditions are defined by writing to the Input/Sense bit field (ISC) in PORT.PINnCTRL.

When setting or changing interrupt settings, take these points into account:
  • If an INVEN bit is toggled in the same cycle as the interrupt setting, the edge caused by the inversion toggling may not cause an interrupt request.
  • If an input is disabled while synchronizing an interrupt, that interrupt may be requested on re-enabling the input, even if it is re-enabled with a different interrupt setting.
  • If the interrupt setting is changed while synchronizing an interrupt, that interrupt may not be accepted.
  • Only few pins support full asynchronous interrupt detection, see I/O Multiplexing and Considerations. These limitations apply for waking the system from sleep:
    Interrupt Type Fully Asynchronous Pins Other Pins
    BOTHEDGES will wake system will wake system
    RISING will wake system will not wake system
    FALLING will wake system will not wake system
    LEVEL will wake system will wake system