Open hugglesfox opened 7 months ago
If you need the feature I'd be happy to accept a PR :). How does the calibration period work though? Do you set a flag and it calibrates in the background for CalibrationPeriod
seconds, or is it something the application has to wait for? Would it make sense for the API to be something like rtc.start_calibration(period: CalibrationPeriod);
?
Sorry I probably should've added some explanation. The way the calibration works (as I understand it from reading RM0367 section 27.4.12) is you specify the number of rtc clock cycles to be masked (ignored) in CALM
, thus slowing down the RTC. Setting the CALP
bit will add a clock pulse every 32 seconds and conversely speed up the RTC by a fixed amount. So by setting CALP
then offsetting it with CALM
you can set a specific speed up.
I'm still trying to wrap my head around the calibration period however the number of usable bits in CALM
depends on the calibration period. Longer the calibration period, the more bits available in CALM
and therefore the finer the control on how much the rtc is slowed down. By default the period is 32 seconds (matching the period of which pulses are added by CALP
) but the CALW8
and CALW16
bits allow that to be changed to a period of 8 and 16 seconds respectively. I'm not sure exactly what the use case for changing the period is but the functionality is there.
So to answer your questions (finally :sweat_smile:)
RECALPF
bit in the rtc interrupt register returns to 0).rtc.start_calibration(period: CalibrationPeriod);
does make some sense however I don't see the use case for changing the calibration period after it's been initially set. It possibly could be something which is set as apart of Rtc::new
but I don't know if we want to further convolute it.Hope this clears things up!
Just wondering if there's interest in providing methods to control the
RTC_CALR
register in the RTC register block. If so any suggestions as to what that api should look like? My thoughts are something along the lines ofI'm happy to write the decided on implementation.
Thanks!