12.5.6 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: The TUNE value is
locked if the Auto-Tune Enable (AUTOTUNE) bit in the Internal High-Frequency Oscillator
Control A (CLKCTRL.OSCHFCTRLA) register is enabled. When AUTOTUNE is disabled, it takes up
to 0.75 μs and three Main Clock cycles before the latest tune value from the auto-tune
operation has updated this bit field.