49.8.3 Control B Set

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 (CTRLBCLR) register.

Name:	CTRLBSET
Offset:	0x05
Reset:	0x00
Property:	PAC Write-Protection, Write-Synchronized, Read-Synchronized


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 be read back as zero. The commands are executed on the next prescaled GCLK_TCCx clock cycle.

Writing zero to this bit group has no effect

Writing a value different from 0x0 to this bit field will issue a command for execution.

Important: This command requires synchronization before being executed.

A valid sequence is the following:

Issue CMD command (CTRLBSET.CMD = command)
Wait for CMD synchronization (SYNCBUSY.CTRLB = 0)
Wait for CMD read back as zero (CTRLBSET.CMD = 0)

Value	Name	Description
0x0	NONE	No action
0x1	RETRIGGER	Force start, restart or retrigger
0x2	STOP	Force stop
0x3	UPDATE	Force update of double buffered registers
0x4	READSYNC	Force a read synchronization of COUNT
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 a zero to these bits has no effect.

Writing a valid value to these bits will set a command.

Value	Name	Description
0x0	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 in one-shot operation, the TCC will stop counting on the next overflow/underflow condition or a stop command.

Writing a '0' to this bit has no effect.

Writing a '1' to this bit will enable the one-shot operation.

Value	Description
0	The TCC will count continuously.
1	The TCC will stop counting on the next underflow/overflow condition.

Bit 1 – LUPD Lock Update

This bit controls the update operation of the TCC buffered registers.

When CTRLB.LUPD is set, the hardware UPDATE registers with value from their buffered registers is disabled. Disabling the update ensures that all buffer registers are valid before an hardware update is performed. After all the buffer registers are loaded correctly, the buffered registers can be unlocked.

This bit has no effect when input capture operation is enabled.

Writing a '0' to this bit has no effect.

Writing a '1' to this bit will disable the registers updates on hardware UPDATE condition.

Value	Description
0	The CCBx, PERB, PGVB, and PGEB buffer registers values are copied into the corresponding CCx, PER, PGV, and PGE registers on hardware update condition.
1	The CCBx, PERB, PGVB, and PGEB buffer registers values are not copied into CCx, PER, PGV, and PGE registers on hardware update condition.

Bit 0 – DIR Counter Direction

This bit is used to change the direction of the counter.

Writing a '0' to this bit has no effect

Writing a '1' to this bit will set the bit and make the counter count down.

Note: When the TCC is counting down, the COUNT register must be initialized to the TOP value (PER or CC0 value depending on the mode).

Value	Description
0	The timer/counter is counting up (incrementing).
1	The timer/counter is counting down (decrementing).