20.3.3.4 Compare Channel

Each Compare Channel n continuously compares the counter value (TCA.CNT) with the Compare n register (TCA.CMPn). If TCA.CNT equals TCA.CMPn, the comparator n signals a match. The match will set the Compare Channel's interrupt flag at the next timer clock cycle, and the optional interrupt is generated.

The Compare n Buffer register (TCA.CMPnBUF) provides double buffer capability equivalent to that for the period buffer. The double buffering synchronizes the update of the TCA.CMPn register with the buffer value to either the TOP or BOTTOM of the counting sequence, according to the UPDATE condition. The synchronization prevents the occurrence of odd-length, non-symmetrical pulses for glitch-free output.