12.6.6 OSCHF Control
| Name: | OSCHFCTRL |
| Offset: | 0x24 |
| Reset: | 0x00000C80 |
| Property: | Local Write-Protection |
| 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 | |
| FRQSEL[3:0] | AUTOTUNE | ||||||||
| Access | R/W | R/W | R/W | R/W | R/W | ||||
| Reset | 0 | 0 | 1 | 1 | 0 | ||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| ONDEMAND | |||||||||
| Access | R/W | ||||||||
| Reset | 1 |
Bits 13:10 – FRQSEL[3:0] Frequency Select
This bit field controls the OSCHF frequency.
| Value | Name | Description |
|---|---|---|
| 0x00 | 1M | 1 MHz output clock |
| 0x01 | 2M | 2 MHz output clock |
| 0x02 | 3M | 3 MHz output clock |
| 0x03 | 4M | 4 MHz output clock (default) |
| 0x04 | — | Reserved |
| 0x05 | 8M | 8 MHz output clock |
| 0x06 | 12M | 12 MHz output clock |
| 0x07 | 16M | 16 MHz output clock |
| 0x08 | 20M | 20 MHz output clock |
| 0x09 | 24M | 24 MHz output clock |
| 0x0A - 0x0F | — | Reserved |
Bit 8 – AUTOTUNE Automatic oscillator tune
Enable automatic tuning using 32.768 kHz from XOSC32K.
| Value | Name | Description |
|---|---|---|
| 0 | OFF | Automatic oscillator frequency tune disabled |
| 1 | ON | Automatic oscillator frequency tune enabled |
Bit 7 – ONDEMAND On-Demand Operation
The On-Demand Operation (ONDEMAND) bit allows the OSCHF to be enabled or disabled depending on peripheral clock requests. If ONDEMAND is set, the OSCHF will only be running when requested by a peripheral. If there is no peripheral requesting the OSCHF clock source, the OSCHF will not be running.
For details, refer to the Sleep Mode Operations section.
| Value | Name | Description |
|---|---|---|
| 0 | DISABLE | The OSCHF is always running |
| 1 | ENABLE | The OSCHF On-Demand Operation is enabled and the oscillator will be running when requested |