ST STM32F301 6 Series Reference Manual page 627

RM0366
24.6.4 RTC initialization and status register (RTC_ISR)
Address offset: 0x0C
Backup domain reset value: 0x0000 0007
System reset: not affected except INIT, INITF, and RSF bits which are cleared to '0'
31 30 29
Res. Res. Res.
15 14 13
Res. TAMP2F TAMP1F TSOVF
rc_w0 rc_w0
Bits 31:17 Reserved, must be kept at reset value.
Bit 16 RECALPF: Recalibration pending Flag
The RECALPF status flag is automatically set to '1' when software writes to the RTC_CALR
register, indicating that the RTC_CALR register is blocked. When the new calibration settings
are taken into account, this bit returns to '0'. Refer to
Bit 15 Reserved, must be kept at reset value.
Bit 14 TAMP2F: RTC_TAMP2 detection flag
This flag is set by hardware when a tamper detection event is detected on the RTC_TAMP2
input.
It is cleared by software writing 0
Bit 13 TAMP1F: RTC_TAMP1 detection flag
This flag is set by hardware when a tamper detection event is detected on the RTC_TAMP1
input.
It is cleared by software writing 0
Bit 12 TSOVF: Time-stamp overflow flag
This flag is set by hardware when a time-stamp event occurs while TSF is already set.
This flag is cleared by software by writing 0. It is recommended to check and then clear
TSOVF only after clearing the TSF bit. Otherwise, an overflow might not be noticed if a time-
stamp event occurs immediately before the TSF bit is cleared.
Bit 11 TSF: Time-stamp flag
This flag is set by hardware when a time-stamp event occurs.
This flag is cleared by software by writing 0.
Bit 10 WUTF: Wake-up timer flag
This flag is set by hardware when the wake-up auto-reload counter reaches 0.
This flag is cleared by software by writing 0.
This flag must be cleared by software at least 1.5 RTCCLK periods before WUTF is set to 1
again.
Bit 9 ALRBF: Alarm B flag
This flag is set by hardware when the time/date registers (RTC_TR and RTC_DR) match the
Alarm B register (RTC_ALRMBR).
This flag is cleared by software by writing 0.
28 27 26 25
Res. Res. Res. Res.
12 11 10 9
TSF WUTF ALRBF ALRAF
rc_w0 rc_w0 rc_w0 rc_w0
24 23 22
Res. Res. Res. Res.
8 7 6
INIT INITF RSF
rc_w0 rw r rc_w0
RM0366 Rev 5
Real-time clock (RTC)
21 20 19 18
Res. Res. Res.
5 4 3 2
INITS SHPF WUTWF
r r r
Re-calibration on-the-fly.
17 16
Res. RECALPF
r
1 0
ALRB
ALRAWF
WF
r r
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