ST STM32G0 1 Series Reference Manual page 893

RM0444
Bits 31:17 Reserved, must be kept at reset value.
Bit 16 RECALPF: Recalibration pending Flag
Bits 15:8 Reserved, must be kept at reset value.
Bit 7 INIT: Initialization mode
Bit 6 INITF: Initialization flag
Bit 5 RSF: Registers synchronization flag
Bit 4 INITS: Initialization status flag
Bit 3 SHPF: Shift operation pending
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
0: Free running mode
1: Initialization mode used to program time and date register (RTC_TR and RTC_DR), and
prescaler register (RTC_PRER). Counters are stopped and start counting from the new
value when INIT is reset.
When this bit is set to 1, the RTC is in initialization state, and the time, date and prescaler
registers can be updated.
0: Calendar registers update is not allowed
1: Calendar registers update is allowed
This bit is set by hardware each time the calendar registers are copied into the shadow
registers (RTC_SSRx, RTC_TRx and RTC_DRx). This bit is cleared by hardware in
initialization mode, while a shift operation is pending (SHPF = 1), or when in bypass shadow
register mode (BYPSHAD = 1). This bit can also be cleared by software.
It is cleared either by software or by hardware in initialization mode.
0: Calendar shadow registers not yet synchronized
1: Calendar shadow registers synchronized
This bit is set by hardware when the calendar year field is different from 0 (Backup domain
reset state).
0: Calendar has not been initialized
1: Calendar has been initialized
This flag is set by hardware as soon as a shift operation is initiated by a write to the
RTC_SHIFTR register. It is cleared by hardware when the corresponding shift operation has
been executed. Writing to the SHPF bit has no effect.
0: No shift operation is pending
1: A shift operation is pending
RM0444 Rev 5
Real-time clock (RTC)
Re-calibration on-the-fly.
893/1390
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