Hi! Working with the STM32F746ZG RTC. Clock, Calendar, and wakeup interrupt working fine. Have Battery Backup for RTC. I'm trying to perform a Smooth Calibration which does work but I find that not all of the CALM[0:8] bits in RTC_CALR seem to work. I did some experiments and found that CALM[0:4] bits don't affect the calibration, CALM[5:8] bits do. The finest step change seems to be approx. 31 micro Hz.
Another thought, does the calibration get lost upon losing battery power?
Great Processor but what a learning curve!