RM0090: Reference manual - STMicroelectronics

Real-time clock (RTC) RM0090
23.6 RTC registers
Refer to Section 1.1 of the reference manual for a list of abbreviations used in register
descriptions.
The peripheral registers can be accessed by words (32 bits).
23.6.1 RTC time register (RTC_TR)
The RTC_TR is the calendar time shadow register. This register must be written in
initialization mode only. Refer to Calendar initialization and configuration on page 625 and
Reading the calendar on page 626.
Address offset: 0x00
Power-on reset value: 0x0000 0000
System reset: 0x0000 0000 when BYPSHAD = 0. Not affected when BYPSHAD = 1
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Reserved
Note: This register is write protected. The write access procedure is described in RTC register
write protection on page 625.
637/1416 Doc ID 018909 Rev 3
PM HT[1:0] HU[3:0]
rw rw rw rw rw rw rw
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Reserv
ed
MNT[2:0] MNU[3:0] Reserv
ST[2:0] SU[3:0]
rw rw rw rw rw rw rw ed rw rw rw rw rw rw rw
Bits 31-24 Reserved
Bit 23 Reserved, must be kept at reset value.
Bit 22 PM: AM/PM notation
0: AM or 24-hour format
1: PM
Bits 21:20 HT[1:0]: Hour tens in BCD format
Bit 16:16 HU[3:0]: Hour units in BCD format
Bit 15 Reserved, must be kept at reset value.
Bits 14:12 MNT[2:0]: Minute tens in BCD format
Bit 11:8 MNU[3:0]: Minute units in BCD format
Bit 7 Reserved, must be kept at reset value.
Bits 6:4 ST[2:0]: Second tens in BCD format
Bit 3:0 SU[3:0]: Second units in BCD format