Datasheet
31.8.2 Control B Clear
Name: CTRLBCLR
Offset: 0x04
Reset: 0x00
Property: PAC Write-Protection, Write-Synchronized, Read-Synchronized
This register allows the user to change this register without doing a read-modify-write operation. Changes
in this register will also be reflected in the Control B Set (CTRLBSET) register.
Bit 7 6 5 4 3 2 1 0
CMD[2:0] IDXCMD[1:0] ONESHOT LUPD DIR
Access
R/W R/W R/W R/W R/W R/W R/W R/W
Reset 0 0 0 0 0 0 0 0
Bits 7:5 – CMD[2:0] TCC Command
These bits can be used for software control of re-triggering and stop commands of the TCC. When a
command has been executed, the CMD bit field will read back zero. The commands are executed on the
next prescaled GCLK_TCC clock cycle.
Writing zero to this bit group has no effect.
Writing a '1' to any of these bits will clear the pending command.
Value Name Description
0x0
NONE No action
0x1
RETRIGGER Clear start, restart or retrigger
0x2
STOP Force stop
0x3
UPDATE Force update of double buffered registers
0x4
READSYNC Force COUNT read synchronization
0x5
DMAOS One-shot DMA trigger
Bits 4:3 – IDXCMD[1:0] Ramp Index Command
These bits can be used to force cycle A and cycle B changes in RAMP2 and RAMP2A operation. On
timer/counter update condition, the command is executed, the IDX flag in STATUS register is updated
and the IDXCMD command is cleared.
Writing zero to these bits has no effect.
Writing a '1' to any of these bits will clear the pending command.
Value Name Description
0x0
DISABLE DISABLE Command disabled: IDX toggles between cycles A and B
0x1
SET Set IDX: cycle B will be forced in the next cycle
0x2
CLEAR Clear IDX: cycle A will be forced in next cycle
0x3
HOLD Hold IDX: the next cycle will be the same as the current cycle.
Bit 2 – ONESHOT One-Shot
This bit controls one-shot operation of the TCC. When one-shot operation is enabled, the TCC will stop
counting on the next overflow/underflow condition or on a stop command.
Writing a '0' to this bit has no effect
SAM D21 Family
TCC – Timer/Counter for Control Applications
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 748