Rtc Alarm B Register (Rtc_Alrmbr) - STMicroelectronics STM32F405 Reference Manual

Real-time clock (RTC)
Note: This register can be written only when ALRAWF is set to 1 in RTC_ISR, or in initialization
mode.
This register is write protected. The write access procedure is described in
write protection on page
26.6.9

RTC alarm B register (RTC_ALRMBR)

Address offset: 0x20
Backup domain reset value: 0x0000 0000
System reset: not affected
31 30 29
MSK4 WDSEL DT[1:0]
rw rw rw
15 14 13
MSK2 MNT[2:0]
rw rw rw
Bit 31 MSK4: Alarm B date mask
Bit 30 WDSEL: Week day selection
Bits 29:28 DT[1:0]: Date tens in BCD format
Bits 27:24 DU[3:0]: Date units or day in BCD format
Bit 23 MSK3: Alarm B hours mask
Bit 22 PM: AM/PM notation
Bits 21:20 HT[1:0]: Hour tens in BCD format
Bits 19:16 HU[3:0]: Hour units in BCD format
Bit 15 MSK2: Alarm B minutes mask
Bits 14:12 MNT[2:0]: Minute tens in BCD format
Bits 11:8 MNU[3:0]: Minute units in BCD format
Bit 7 MSK1: Alarm B seconds mask
Bits 6:4 ST[2:0]: Second tens in BCD format
Bits 3:0 SU[3:0]: Second units in BCD format
816/1731
794.
28 27 26 25
DU[3:0]
rw rw rw rw
12 11 10 9
MNU[3:0]
rw rw rw rw
0: Alarm B set if the date and day match
1: Date and day don't care in Alarm B comparison
0: DU[3:0] represents the date units
1: DU[3:0] represents the week day. DT[1:0] is don't care.
0: Alarm B set if the hours match
1: Hours don't care in Alarm B comparison
0: AM or 24-hour format
1: PM
0: Alarm B set if the minutes match
1: Minutes don't care in Alarm B comparison
0: Alarm B set if the seconds match
1: Seconds don't care in Alarm B comparison
DocID018909 Rev 11
24 23 22 21
MSK3 PM
rw rw rw rw
8 7 6 5
MSK1 ST[2:0]
rw rw rw rw
RTC register
20 19 18
HT[1:0] HU[3:0]
rw rw rw
4 3 2
SU[3:0]
rw rw rw
RM0090
17 16
rw rw
1 0
rw rw