12.5.8 Internal High-Frequency Oscillator Frequency Tune
| Name: | OSCHFTUNE |
| Offset: | 0x09 |
| Reset: | 0x00 |
| Property: | - |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| TUNE[7:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
Bits 7:0 – TUNE[7:0] User Frequency Tuning
This bit field controls the manual tuning of the output frequency of the internal high-frequency oscillator (OSCHF). The frequency can be tuned 32 steps down or 31 steps up from the oscillator’s target frequency. Thus, the register’s acceptable input value range is -32 to +31.
Writing to bits 6 and 7 has no effect, as bit 5 will be mirrored to bits 6 and 7 due to the 6-bit value in this bit field being represented in a signed (two’s complement) form.
Note: If the Auto-Tune
Enable (AUTOTUNE) bit in the Internal High-Frequency Oscillator Control A
(CLKCTRL.OSCHFCTRLA) register is enabled, the TUNE value is locked. When AUTOTUNE is
disabled, it takes up to three µs and three Main Clock cycles before this bit field is
updated with the latest tune value from the auto-tune operation.