Datasheet

Figure 24-3. Channel

The path is selected by writing to the Path Selection bit group in the Channel register (CHANNEL.PATH).

24.6.2.5.1 Asynchronous Path

When using the asynchronous path, the events are propagated from the event generator to the event

user without intervention from the Event System. The GCLK for this channel

(GCLK_EVSYS_CHANNEL_n) is not mandatory, meaning that an event will be propagated to the user

without any clock latency.

When the asynchronous path is selected, the channel cannot generate any interrupts, and the Channel

Status register (CHSTATUS) is always zero. No edge detection is available; this must be handled in the

event user. When the event generator and the event user share the same generic clock, using the

asynchronous path will propagate the event with the least amount of latency.

24.6.2.5.2 Synchronous Path

The synchronous path should be used when the event generator and the event channel share the same

generator for the generic clock and also if event user supports synchronous path. If event user doesn't

support synchronous path, asynchronous path has to be selected. If they do not share the same clock, a

logic change from the event generator to the event channel might not be detected in the channel, which

means that the event will not be propagated to the event user. For details on generic clock generators,

refer to GCLK - Generic Clock Controller.

When using the synchronous path, the channel is able to generate interrupts. The channel status bits in

the Channel Status register (CHSTATUS) are also updated and available for use.

If the Generic Clocks Request bit in the Control register (CTRL.GCLKREQ) is zero, the channel operates

in SleepWalking mode and request the configured generic clock only when an event is to be propagated

through the channel. If CTRL.GCLKREQ is one, the generic clock will always be on for the configured

channel.