ST STM32WL55JC Reference Manual page 1010

Real-time clock (RTC)
32.6 RTC registers
Refer to
register descriptions.
The peripheral registers can be accessed by words (32-bit).
32.6.1 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
Reading the calendar on page
This register is write protected. The write access procedure is described in
write protection on page
Address offset: 0x00
Backup domain reset value: 0x0000 0000
System reset value: 0x0000 0000 when BYPSHAD = 0. Not affected when BYPSHAD = 1.
31 30 29
Res. Res. Res. Res.
15 14 13
Res. MNT[2:0]
rw rw
Bits 31:23 Reserved, must be kept at reset value.
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 Reserved, must be kept at reset value.
Bits 14:12 MNT[2:0]: Minute tens in BCD format
Bits 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
Bits 3:0 SU[3:0]: Second units in BCD format
1010/1454
Section 1.2 on page 58
999.
28 27 26 25
Res. Res. Res.
12 11 10 9
MNU[3:0]
rw rw rw rw
0: AM or 24-hour format
1: PM
of the reference manual for a list of abbreviations used in
Calendar initialization and configuration on page 999
1001.
24 23 22
Res. Res. PM
rw
8 7 6
Res.
rw rw
RM0453 Rev 2
21 20 19 18
HT[1:0]
rw rw rw rw
5 4 3
ST[2:0]
rw rw rw rw
RM0453
and
RTC register
17 16
HU[3:0]
rw rw
2 1 0
SU[3:0]
rw rw