30.8.3 Control B Clear
This register allows the user to clear bits in the CTRLB register without doing a read-modify-write operation. Changes in this register will also be reflected in the Control B Set register (CTRLBSET).
| Name: | CTRLBCLR |
| Offset: | 0x04 |
| Reset: | 0x00 |
| Property: | PAC Write-Protection, Read-Synchronized, Write-Synchronized |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| CMD[1:0] | ONESHOT | DIR | |||||||
| Access | R/W | R/W | R/W | R/W | |||||
| Reset | 0 | 0 | 0 | 0 | |||||
Bits 7:6 – CMD[1:0] Command
These bits are used for software control of the TC. The commands are executed on the next prescaled GCLK_TC clock cycle. When a command has been executed, the CMD bit group will be read back as zero.
Writing 0x0 to these bits 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 | Force a start, restart or retrigger |
| 0x2 | STOP | Force a stop |
| 0x3 | - | Reserved |
Bit 2 – ONESHOT One-Shot on Counter
This bit controls one-shot operation of the TC.
Writing a '0' to this bit has no effect
Writing a '1' to this bit will disable one-shot operation.
| Value | Description |
|---|---|
| 0 | The TC will wrap around and continue counting on an Overflow/Underflow condition. |
| 1 | The TC will wrap around and stop on the next Underflow/Overflow 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 clear the bit and make the counter count up.
| Value | Description |
|---|---|
| 0 | The timer/counter is counting up (incrementing). |
| 1 | The timer/counter is counting down (decrementing). |