18.7.9 DFLL48M Control B
Note: During a maximum 30 cycles of the
reference clock period, between lock flag asserted and frequency stabilization, DFLL
accuracy will be limited to +/-1.5%. After frequency stabilization has been
achieved, the accuracy will be +/-0.25%. Disabling Quick Lock plus reducing STEP
value at 4 (instead of the optimum 8) will eliminate this clock period of
inaccuracy.
| 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: | DFLLCTRLB |
| Offset: | 0x30 |
| Reset: | 0x00000000 |
| Property: | PAC Write-Protected, Write-Synchronized |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| Access | |||||||||
| Reset |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| Access | |||||||||
| Reset |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| WAITLOCK | QLDIS | CCDIS | LLAW | STABLE | LOOPEN | ||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | |||
| Reset | 0 | 0 | 0 | 0 | 0 | 0 |
Bit 7 – WAITLOCK Wait Lock
This bit controls the DFLL48M output clock, depending on lock status:
| Value | Description |
|---|---|
| 0 | Output clock before the DFLL is locked. |
| 1 | Output clock when DFLL is locked. |
Bit 5 – QLDIS Quick Lock Disable
| Value | Description |
|---|---|
| 0 | Quick Lock is enabled. |
| 1 | Quick Lock is disabled. |
Bit 4 – CCDIS Chill Cycle Disable
| Value | Description |
|---|---|
| 0 | Chill Cycle is enabled. |
| 1 | Chill Cycle is disabled. |
Bit 2 – LLAW Lose Lock After Wake
| Value | Description |
|---|---|
| 0 | Locks will not be lost after waking up from sleep modes if the DFLL clock has been stopped. |
| 1 | Locks will be lost after waking up from sleep modes if the DFLL clock has been stopped. |
Bit 1 – STABLE Stable DFLL48M Frequency
| Value | Description |
|---|---|
| 0 | Tune register tracks changes in output frequency. |
| 1 | Tune calibration register value will be fixed after a lock. |
Bit 0 – LOOPEN Operating Mode Selection
| Value | Description |
|---|---|
| 0 | The DFLL operates in open-loop operation. |
| 1 | The DFLL operates in closed-loop operation. |
