Overriding the automatic clock control system to ensure the LFCLK clock is started and kept running is possible, even if not requested.
This can be used to avoid associated LFCLK clock start-up times and have the highest clock accuracy after wake-up from sleep.
The register LFCLKALWAYSRUN can override the automatic clock control
system. This override is initiated by performing the following steps:
- Set LFCLKSRC.SRC to select the LFCLK source.
- Set LFCLKALWAYSRUN.ALWAYSRUN.
- Trigger the LFCLKSTART task.
Registers LFCLKSRC.SRC and LFCLKALWAYSRUN.ALWAYSRUN can be written at any time, but are only activated by the LFCLKSTART task.