Table 212. Effect Of Low-Power Modes On Rtc; Table 213. Rtc Pins Functionality Over Modes - ST STM32WL55JC Reference Manual

RM0453
32.6.2 RTC date register (RTC_DR)
The RTC_DR is the calendar date 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: 0x04
Backup domain reset value: 0x0000 2101
System reset value: 0x0000 2101 when BYPSHAD = 0. Not affected when BYPSHAD = 1.
31 30 29
Res. Res. Res. Res.
15 14 13
WDU[2:0]
rw rw rw
Bits 31:24 Reserved, must be kept at reset value.
Bits 23:20 YT[3:0]: Year tens in BCD format
Bits 19:16 YU[3:0]: Year units in BCD format
Bits 15:13 WDU[2:0]: Week day units
Bit 12 MT: Month tens in BCD format
Bits 11:8 MU[3:0]: Month units in BCD format
Bits 7:6 Reserved, must be kept at reset value.
Bits 5:4 DT[1:0]: Date tens in BCD format
Bits 3:0 DU[3:0]: Date units in BCD format
Note: The calendar is frozen when reaching the maximum value, and can't roll over.
999.
28 27 26 25
Res. Res. Res.
12 11 10 9
MT MU[3:0]
rw rw rw rw
000: forbidden
001: Monday
...
111: Sunday
Calendar initialization and configuration on page 999
1001.
24 23 22
Res. YT[3:0]
rw rw
8 7 6
Res. Res.
rw
RM0453 Rev 2
Real-time clock (RTC)
RTC register
21 20 19 18
YU[3:0]
rw rw rw rw
5 4 3 2
DT[1:0] DU[3:0]
rw rw rw rw
and
17 16
rw rw
1 0
rw rw
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