24.4.3.1 Overrun Channel Detection

If events occur faster than the event user of channel n is able to service them EVSYS will detect this as a channel overrun, and the Overrun Channel n bit in the Interrupt Flag Status and Clear register (INTFLAG.OVRn) will be set. Overrun channel detection can occur when:

  • One or more event users on channel n are not ready when a new event occurs
  • An event occurs when the previous event on channel n is not yet been handled by all event users connected channel n

The flag will only be set when using synchronous or resynchronized paths. When using the asynchronous path, INTFLAG.OVRn will always read as ‘0’.

If several events are received by the event channel in less than three GCLK_EVSYS_CHn periods, the overrun will not be detected, and only the first event will be serviced.

When using the synchronous path, ensure that the generic clock (GCLK_EVSYS_CHn) is always on by writing the On Demand bit in the Channel n register (CHANNEL[n].ONDEMAND) to ‘0’.