24.4.2.4 Channel Path

There are three different paths for an event to propagate through an event system channel: Asynchronous, Synchronous or Resynchronized. The path is configured by writing to the Path Selection bit field of the Channel register (CHANNEL[n].PATH).

Asynchronous Path

When using the asynchronous path, events are propagated from the event generator to the event user without intervention from the Event System. The GCLK for this channel (GCLK_EVSYS_CHn) is not required.

When the asynchronous path is selected, the channel will not generate any interrupts, and the Channel Status register (CHSTATUS) will always read as zero. The Edge detection is non-functional and must be disabled. For further details, refer to the Event Users section and the description in each peripheral chapter description.

Synchronous Path

The synchronous path must only be used when the event generator and the event channel use the same generic clock generator, and the event user supports the synchronous path. For details on generic clock generators, refer to the GCLK – Generic Clock Controller chapter.

Resynchronized Path

The resynchronized path can be used when the event generator, the event channel, and the event user do not use the same clock source. The resynchronization of the event from the event generator to channel n, and from channel n to the event user, is automatically handled by EVSYS. For details on generic clock generators, refer to the GCLK – Generic Clock Controller chapter.