The TCB is an event generator. Any condition that causes the CAPT flag in TCBn.INTFLAGS to be set will also generate a one-cycle strobe on the event channel output.
The peripheral accepts one event input. If the Capture Event Input Enable bit (CAPTEI) in the Event Control register (TCBn.EVCTRL) is written to '1', incoming events will result in an event action as defined by the Event Edge bit (EDGE) in TCBn.EVCTRL. The event needs to last for at least one CLK_PER cycle to ensure that it is recognized.
If the Asynchronous mode is enabled for Single-Shot mode, the event is edge triggered and will capture changes on the event input shorter than one system clock cycle.