22.5.6 Events

The TC can generate the following events:

Table 22-5. Event Generators in TC
Generator Name		Description	Event Type	Generating Clock Domain	Length of Event
Peripheral	Event	Description	Event Type	Generating Clock Domain	Length of Event
TCn	OVF	Overflow or Underflow	Pulse	GCLK_TCn	One GCLK_TCn period
TCn	MC_n	Compare Match or Capture on compare/capture channel n	Pulse	GCLK_TCn	One GCLK_TCn period

Note: The conditions for generating an event are identical to those that will raise the corresponding interrupt flag in the TCn.INTFLAGS register.

Writing a ‘1’ to an Event Output Enable bit in the Event Control Register (EVCTRL.xxEO) enables the corresponding output event. Writing a ‘0’ to this bit disables the corresponding output event.

The TC can connect to the following events:

Table 22-6. Event Users
User Name		Description	Input Detection	Channel Path Type
Peripheral	Input	Description	Input Detection	Channel Path Type
TCn	EVU	Event Input	Level	Asynchronous Synchronous Resynchronized

Writing a ‘1’ to an Event Input Enable bit in the Event Control register (EVCTRL.xxEI) enables the corresponding action on input event. Writing a ‘0’ to this bit disables the corresponding action on input event.

Note: EVn input detection depends on the configuration of the Timer/Counter Event n Invert Enable bit in the Event Control register (EVCTRL.TCINVn) and the Timer/Counter Event Input n Action bit fields in the Event Control register (EVCTRL.EVACTn).

The event users can trigger the following actions:

Table 22-7. Event Actions
Event Input	Event Action	Description
EVU	RETRIGGER	Counter retrigger
	COUNT	Count on event (increment or decrement, depending on counter direction)
	START	Counter start - Start counting on the event rising edge. Further events will not restart the counter; the counter will keep on counting using prescaled GCLK_TCn, until it reaches TOP or ZERO, depending on the direction.
	STAMP	Capture Time-stamp (overflow)
	PPW	Period and pulse width capture. The period is captured in CC0, and the pulse width is captured in CC1.
	PWP	Pulse width and period capture. The period is captured in CC1, and the pulse width is captured in CC0.
	PW	Pulse width capture

Refer to the EVSYS - Event System chapter for details on configuring the event system.