Datasheet

The decrement event action can be selected in the Event Control register (EVCTRL.EVACT1=0x4, DEC)
and can change the counter state when an event is received. When the TCE1 (TCCx_EV1) event is
received, the counter decrements, whatever the direction setting (CTRLBSET.DIR or CTRLBCLR.DIR) is.
Non-recoverable Fault Event Action
Non-recoverable fault actions can be selected in the Event Control register (EVCTRL.EVACTn=0x7,
FAULT). When received, the counter will be stopped and the output of the compare channels is
overridden according to the Driver Control register settings (DRVCTRL.NREx and DRVCTRL.NRVx).
TCE0 and TCE1 must be configured as asynchronous events.
Event Action Off
If the event action is disabled (EVCTRL.EVACTn=0x0, OFF), enabling the counter will also start the
counter.
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31.6.3.1 One-Shot Operation
31.6.2.5 Compare Operations
By default, the Compare/Capture channel is configured for compare operations. To perform capture
operations, it must be re-configured.
When using the TCC with the Compare/Capture Value registers (CCx) for compare operations, the
counter value is continuously compared to the values in the CCx registers. This can be used for timer or
for waveform operation.
The Channel x Compare/Capture Buffer Value (CCBx) registers provide double buffer capability. The
double buffering synchronizes the update of the CCx register with the buffer value at the UPDATE
condition or a force update command (CTRLBSET.CMD=0x3, UPDATE). For further details, refer to
31.6.2.6 Double Buffering. The synchronization prevents the occurrence of odd-length, non-symmetrical
pulses and ensures glitch-free output.
31.6.2.5.1 Waveform Output Generation Operations
The compare channels can be used for waveform generation on output port pins. To make the waveform
available on the connected pin, the following requirements must be fulfilled:
1. Choose a waveform generation mode in the Waveform Generation Operation bit in Waveform
register (WAVE.WAVEGEN).
2. Optionally invert the waveform output WO[x] by writing the corresponding Waveform Output x
Inversion bit in the Driver Control register (DRVCTRL.INVENx).
3. Configure the pins with the I/O Pin Controller. Refer to PORT - I/O Pin Controller for details.
The counter value is continuously compared with each CCx value. On a comparison match, the Match or
Capture Channel x bit in the Interrupt Flag Status and Clear register (INTFLAG.MCx) will be set on the
next zero-to-one transition of CLK_TCC_COUNT (see Normal Frequency Operation). An interrupt and/or
event can be generated on the same condition if Match/Capture occurs, i.e. INTENSET.MCx and/or
EVCTRL.MCEOx is '1'. Both interrupt and event can be generated simultaneously. The same condition
generates a DMA request.
There are seven waveform configurations for the Waveform Generation Operation bit group in the
Waveform register (WAVE.WAVEGEN). This will influence how the waveform is generated and impose
restrictions on the top value. The configurations are:
• Normal Frequency (NFRQ)
• Match Frequency (MFRQ)
SAM D21 Family
TCC – Timer/Counter for Control Applications
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 713