17.3.3.1 Asynchronous Sensing Pin Properties

All PORT pins support asynchronous input sensing with interrupts for selectable pin change conditions. Fully asynchronous pin change sensing can trigger an interrupt and wake the device from all sleep modes, including modes where the Peripheral Clock (CLK_PER) is stopped, while partially asynchronous pin change sensing is limited as per the table below. See the I/O Multiplexing and Considerations section for further details on which pins support fully asynchronous pin change sensing.

Table 17-4. Behavior Comparison of Sense Pins
PropertyPartially Asynchronous PinsFully Asynchronous Pins
Waking the device from sleep modes with CLK_PER runningFrom all interrupt sense configurationsFrom all interrupt sense configurations
Waking the device from sleep modes with CLK_PER stoppedOnly from BOTHEDGES or LEVEL interrupt sense configurations
Minimum pulse-width to trigger an interrupt with CLK_PER runningMinimum one CLK_PER cycleLess than one CLK_PER cycle
Minimum pulse-width to trigger an interrupt with CLK_PER stoppedThe pin value must be kept until CLK_PER has restarted(1)
Interrupt “dead-time”No new interrupt for three CLK_PER cycles after the previous
Note:
  1. If a partially asynchronous input pin is used for wake-up from sleep with CLK_PER stopped, the required level must be held long enough for the MCU to complete the wake-up to trigger the interrupt. If the level disappears, the MCU can wake up without any interrupt generated.