Datasheet

Figure 48-3. Counter Operation
DIR
COUNT
MAX
"reload" update
TOP
COUNT writtenDirection Change
Period (T)
ZERO
"clear" update
Due to asynchronous clock domains, the internal counter settings are written when the synchronization is
complete. Normal operation must be used when using the counter as timer base for the capture
channels.
48.6.2.5.1 Stop Command and Event Action
A Stop command can be issued from software by using Command bits in the Control B Set register
(CTRLBSET.CMD = 0x2, STOP). When a Stop is detected while the counter is running, the counter will
not retain its current value. All waveforms are cleared and the Stop bit in the Status register is set
(STATUS.STOP).
48.6.2.5.2 Re-Trigger Command and Event Action
A re-trigger command can be issued from software by writing the Command bits in the Control B Set
register (CTRLBSET.CMD = 0x1, RETRIGGER), or from event when a re-trigger event action is
configured in the Event Control register (EVCTRL.EVACT = 0x1, RETRIGGER).
When the command is detected during counting operation, the counter will be reloaded or cleared,
depending on the counting direction (CTRLBSET.DIR or CTRLBCLR.DIR). When the re-trigger command
is detected while the counter is stopped, the counter will resume counting from the current value in the
COUNT register.
Note: When a re-trigger event action is configured in the Event Action bits in the Event Control register
(EVCTRL.EVACT=0x1, RETRIGGER), enabling the counter will not start the counter. The counter will
start on the next incoming event and restart on corresponding following event.
48.6.2.5.3 Count Event Action
The TC can count events. When an event is received, the counter increases or decreases the value,
depending on direction settings (CTRLBSET.DIR or CTRLBCLR.DIR). The count event action can be
selected by the Event Action bit group in the Event Control register (EVCTRL.EVACT=0x2, COUNT).
Note: If this operation mode is selected, PWM generation is not supported.
48.6.2.5.4 Start Event Action
The TC can start counting operation on an event when previously stopped. In this configuration, the event
has no effect if the counter is already counting. When the peripheral is enabled, the counter operation
starts when the event is received or when a re-trigger software command is applied.
The Start TC on Event action can be selected by the Event Action bit group in the Event Control register
(EVCTRL.EVACT=0x3, START).
SAM D5x/E5x Family Data Sheet
TC – Timer/Counter
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1717