Real-time clock (RTC) RM0091
554/742 Doc ID 018940 Rev 1
Note: Bits 7, 6 and 4 of this register can be written in initialization mode only (RTC_ISR/INITF = 1).
It is recommended not to change the hour during the calendar hour increment as it could
mask the incrementation of the calendar hour.
ADD1H and SUB1H changes are effective in the next second.
This register is write protected. The write access procedure is described in RTC register
write protection on page 540.