Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Keil/AT32F413xx_v2/BPR/RTCCAL#0x0
RTC clock calibration register (BPR_RTCCAL)
Calibration value
Calibration Clock Output
Output enable
Output selection
https://github.com/cmsis-svd/cmsis-svd-data