Datasheet

The counter will count up or down for each tick (clock or event) until it reaches TOP or ZERO. When it's
counting up and TOP is reached, the counter will be set to zero at the next tick (overflow) and the
Overflow Interrupt Flag in the Interrupt Flag Status and Clear register (INTFLAG.OVF) will be set. When
down-counting, the counter is reloaded with the TOP value when ZERO is reached (underflow), and
INTFLAG.OVF is set.
INTFLAG.OVF can be used to trigger an interrupt, or an event. An overflow/underflow occurrence (i.e. a
compare match with TOP/ZERO) will stop counting if the One-Shot bit in the Control B register is set
(CTRLBSET.ONESHOT). The One-Shot feature is explained in the Additional Features section.
Figure 49-3. Counter Operation
DIR
COUNT
MAX
"reload" update
TOP
COUNT writtenDirection Change
ZERO
"clear" update
It is possible to change the counter value (by writing directly in the COUNT register) even when the
counter is running. The COUNT value will always be ZERO or TOP, depending on direction set by
CTRLBSET.DIR or CTRLBCLR.DIR, when starting the TCC, unless a different value has been written to
it, or the TCC has been stopped at a value other than ZERO. The write access has higher priority than
count, clear, or reload. The direction of the counter can also be changed during normal operation. See
also Figure 49-3.
Stop Command
A stop command can be issued from software by using TCC Command bits in Control B Set register
(CTRLBSET.CMD=0x2, STOP).
When a stop is detected while the counter is running, the counter will maintain its current value. If the
waveform generation (WG) is used, all waveforms are set to a state defined in Non-Recoverable State x
Output Enable bit and Non- Recoverable State x Output Value bit in the Driver Control register
(DRVCTRL.NREx and DRVCTRL.NRVx), and the Stop bit in the Status register is set (STATUS.STOP).
Pause Event Action
A pause command can be issued when the stop event action is configured in the Input Event Action 1 bits
in Event Control register (EVCTRL.EVACT1=0x3, STOP).
When a pause is detected, the counter can stop immediatly maintaining its current value and all
waveforms keep their current state, as long as a start event action is detected: Input Event Action 0 bits in
Event Control register (EVCTRL.EVACT0=0x3, START).
Re-Trigger Command and Event Action
A re-trigger command can be issued from software by using TCC Command bits in Control B Set register
(CTRLBSET.CMD=0x1, RETRIGGER), or from event when the re-trigger event action is configured in the
Input Event 0/1 Action bits in Event Control register (EVCTRL.EVACTn=0x1, RETRIGGER).
SAM D5x/E5x Family Data Sheet
TCC – Timer/Counter for Control Applications
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1806