Rtc Control Register (Rtc_Cr) - ST STM32F412 Reference Manual

Real-time clock (RTC)
22.6.3

RTC control register (RTC_CR)

Address offset: 0x08
Backup domain reset value: 0x0000 0000
System reset: not affected
31 30 29 28
Res. Res. Res. Res.
15 14 13 12
TSIE WUTIE ALRBIE ALRAIE
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Bits 31:24 Reserved, must be kept at reset value.
Bit 23 COE: Calibration output enable
Bits 22:21 OSEL[1:0]: Output selection
Bit 20 POL: Output polarity
Bit 19 COSEL: Calibration output selection
Bit 18 BKP: Backup
Bit 17 SUB1H: Subtract 1 hour (winter time change)
636/1163
27 26 25
Res. Res. Res.
11 10 9
TSE WUTE ALRBE ALRAE DCE
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This bit enables the RTC_CALIB output
0: Calibration output disabled
1: Calibration output enabled
These bits are used to select the flag to be routed to RTC_ALARM output
00: Output disabled
01: Alarm A output enabled
10:Alarm B output enabled
11: Wakeup output enabled
This bit is used to configure the polarity of RTC_ALARM output
0: The pin is high when ALRAF/ALRBF/WUTF is asserted (depending on OSEL[1:0])
1: The pin is low when ALRAF/ALRBF/WUTF is asserted (depending on OSEL[1:0]).
When COE=1, this bit selects which signal is output on RTC_CALIB.
0: Calibration output is 512 Hz
1: Calibration output is 1 Hz
These frequencies are valid for RTCCLK at 32.768 kHz and prescalers at their default
values (PREDIV_A=127 and PREDIV_S=255). Refer to
output
This bit can be written by the user to memorize whether the daylight saving time change has
been performed or not.
When this bit is set outside initialization mode, 1 hour is subtracted to the calendar time if the
current hour is not 0. This bit is always read as 0.
Setting this bit has no effect when current hour is 0.
0: No effect
1: Subtracts 1 hour to the current time. This can be used for winter time change.
24 23 22 21
Res. COE OSEL[1:0]
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8 7 6 5
FMT BYPSHAD REFCKON TSEDGE
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RM0402 Rev 6
20 19 18
POL COSEL BKP SUB1H ADD1H
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4 3 2
WUCKSEL[2:0]
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Section 22.3.14: Calibration clock
RM0402
17 16
w w
1 0
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