Events

The TCA can generate the events described in the table below. All event generators except TCAn_HUNF are shared between Normal mode and Split mode operation.

Table 1. Event Generators in TCA
Generator Name		Description	Event Type	Generating Clock Domain	Length of Event
Peripheral	Event	Description	Event Type	Generating Clock Domain	Length of Event
TCAn	OVF_LUNF	Normal mode: Overflow Split mode: Low byte timer underflow	Pulse	CLK_PER	One CLK_PER period
	HUNF	Normal mode: Not available Split mode: High byte timer underflow	Pulse	CLK_PER	One CLK_PER period
	CMP0	Normal mode: Compare Channel 0 match Split mode: Low byte timer Compare Channel 0 match	Pulse	CLK_PER	One CLK_PER period
	CMP1	Normal mode: Compare Channel 1 match Split mode: Low byte timer Compare Channel 1 match	Pulse	CLK_PER	One CLK_PER period
	CMP2	Normal mode: Compare Channel 2 match Split mode: Low byte timer Compare Channel 2 match	Pulse	CLK_PER	One CLK_PER period

Note: The conditions for generating an event are identical to those that will raise the corresponding interrupt flag in the TCAn.INTFLAGS register for both Normal mode and Split mode.

The TCA has one event user for detecting and acting upon input events. The table below describes the event user and the associated functionality.

Table 2. Event User in TCA
User Name		Description	Input Detection	Async/Sync
Peripheral	Input	Description	Input Detection	Async/Sync
TCAn	CNT	Count on a positive event edge	Edge	Sync
		Count on any event edge	Edge	Sync
		Count while the event signal is high	Level	Sync
		The event level controls the count direction, up when low and down when high	Level	Sync

Notes:

1.Event inputs are not used in Split mode.
2.Event actions with level input detection only work reliably if the event frequency is less than the timer’s frequency.

The specific actions described in the table above are selected by writing to the Event Action (EVACT) bit field in the Event Control (TCAn.EVCTRL) register. Input events are enabled by writing a ‘1’ to the Enable Count on Event Input (CNTEI) bit in the Event Control (TCAn.EVCTRL) register.

Refer to the Event System (EVSYS) chapter for more details regarding event types and Event System configuration.