24.3.3.1.3 Input Capture on Event Mode
In the Input Capture on Event mode, the counter will count from BOTTOM to MAX continuously. When an event is detected the Count (TCBn.CNT) register value is transferred to the Compare/Capture (TCBn.CCMP) register and a CAPT interrupt and event is generated. The Event edge detector that can be configured to trigger a capture on either rising or falling edges.
This mode requires TCB to be configured as an event user, and is explained in Events section.
The figure below shows the input capture unit configured to capture on the falling edge of the event input signal. The CAPT Interrupt flag is automatically cleared after the low byte of the Compare/Capture (TCBn.CCMP) register has been read. An OVF interrupt and event is generated when the CNT is MAX.