Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f1/STM32F100/RTC/CRL#0x0
RTC Control Register Low
Second Flag
Alarm Flag
Overflow Flag
Registers Synchronized Flag
Configuration Flag
RTC operation OFF
https://github.com/modm-io/cmsis-svd-stm32