This register can be written only when ALRBE is reset in RTC_CR register, or in initialization mode.This register is write protected.The write access procedure is described in Section: RTC register write protection.
SS | Sub seconds value This value is compared with the contents of the synchronous prescaler counter to determine if Alarm B is to be activated. Only bits 0 up to MASKSS-1 are compared. |
MASKSS | Mask the most-significant bits starting at this bit … The overflow bits of the synchronous counter (bits 15) is never compared. This bit can be different from 0 only after a shift operation. |