45.7.2 Control B Clear
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.
| Symbol | Description | Symbol | Description | Symbol | Description |
|---|---|---|---|---|---|
| R | Readable bit | HC | Cleared by Hardware | (Grey cell) | Unimplemented |
| W | Writable bit | HS | Set by Hardware | X | Bit is unknown at Reset |
| K | Write to clear | S | Software settable bit | — | — |
| Name: | CTRLBCLR |
| Offset: | 0x04 |
| Reset: | 0x00 |
| Property: | PAC Write-Protection, Read-Synchronized, Write-Synchronized |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| CMD[2:0] | LUPD | ||||||||
| Access | RW | RW | RW | RW | |||||
| Reset | 0 | 0 | 0 | 0 | |||||
Bits 7:5 – CMD[2:0] Command
These bits can be used for software control of the PDEC. When a command has been executed, the CMD bit group will read back zero. The commands are executed on the next prescaled GCLK_PDEC clock cycle.
Writing a zero to this bit group has no effect.
Writing a valid value to these bits will clear the corresponding pending command.
Writing a '0' to these bits has no effect.
Writing a '1' to an individual bit will clear the corresponding bit.
| Value | Name | Description |
|---|---|---|
| 0 | NONE | No action |
| 1 | RETRIGGER | Force a counter restart or re-trigger |
| 2 | UPDATE | Force update of double buffered registers |
| 3 | READSYNC | Force a read synchronization of COUNT |
| 4 | START | Start QDEC/HALL |
| 5 | STOP | Stop QDEC/HALL |
Bit 1 – LUPD Lock Update
This bit controls the update operation of the PDEC buffered registers.
When CTRLB.LUPD is set, no any update of the registers with value of its buffered register is performed on hardware UPDATE condition. Locking 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.
Writing a '0' to this bit has no effect.
Writing a '1' to this will disable the lock update.
| Value | Description |
|---|---|
| 0 | The PRESCBUF, FILTERBUF and CCBUFx buffer registers value are copied into CCx and PER registers on hardware update condition. |
| 1 | The PRESCBUF, FILTERBUF and CCBUFx buffer registers value are not copied into CCx and PER registers on hardware update condition. |