26.6.2 Control B
| Name: | CTRLB |
| Offset: | 0x04 |
| Reset: | 0x00000080 |
| Property: | PAC Write-Protection |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| CACHEDIS[1:0] | READMODE[1:0] | ||||||||
| Access | R/W | R/W | R/W | R/W | |||||
| Reset | 0 | 0 | 0 | 0 | |||||
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| SLEEPPRM[1:0] | |||||||||
| Access | R/W | R/W | |||||||
| Reset | 0 | 0 | |||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| MANW | RWS[3:0] | ||||||||
| Access | R/W | R/W | R/W | R/W | R/W | ||||
| Reset | 1 | 0 | 0 | 0 | 0 | ||||
Bits 19:18 – CACHEDIS[1:0] Cache Disable
This bit is used to disable the cache.
| Value | Description |
|---|---|
| 0x0 | The Data Flash cache is disabled, the main array cache is enabled |
| 0x1 | The Data Flash cache is disabled, the main array cache is disabled |
| 0x2 | The Data Flash cache is enabled, the main array cache is enabled |
| 0x3 | The Data Flash cache is enabled, the main array cache is disabled |
Bits 17:16 – READMODE[1:0] NVMCTRL Read Mode
| Value | Name | Description |
|---|---|---|
| 0x0 | NO_MISS_PENALTY | The NVM Controller (cache system) does not insert wait states on a cache miss. Gives the best system performance. |
| 0x1 | LOW_POWER | Reduces power consumption of the cache system, but inserts a wait state each time there is a cache miss. This mode may not be relevant if CPU performance is required, as the application will be stalled and may lead to increased run time. |
| 0x2 | DETERMINISTIC | The cache system ensures that a cache hit or miss takes the same amount of time, determined by the number of programmed Flash wait states. This mode can be used for real-time applications that require deterministic execution timings. |
| 0x3 | Reserved |
Bits 9:8 – SLEEPPRM[1:0] Power Reduction Mode during Sleep
| Value | Name | Description |
|---|---|---|
| 0x0 | WAKEONACCESS | NVM block enters low-power mode when entering sleep. NVM block exits low-power mode upon first access. |
| 0x1 | WAKEUPINSTANT | NVM block enters low-power mode when entering sleep. NVM block exits low-power mode when exiting sleep. |
| 0x2 | Reserved | |
| 0x3 | DISABLED | Auto power reduction disabled. |
Bit 7 – MANW Manual Write
Note that reset value of this bit is '1'.
| Value | Description |
|---|---|
| 0 | Writing to the last word in the page buffer will initiate a write operation to the page addressed by the last write operation. This includes writes to the memory and Configuration Rows. |
| 1 | Write commands must be issued through the CTRLA.CMD register. |
Bits 4:1 – RWS[3:0] NVM Read Wait States
This register is initialized to 0 wait states. Software can change this value based on the NVM access time and system frequency. Refer to 46.27 Flash NVM Electrical Specifications in the 46 Electrical Characteristics at 85°C chapter.