ST STM32F207 Series Reference Manual page 586

Real-time clock (RTC)
Bit 14 WUTIE: Wakeup timer interrupt enable
Bit 13 ALRBIE: Alarm B interrupt enable
Bit 12 ALRAIE: Alarm A interrupt enable
Bit 11 TSE: Time stamp enable
Bit 10 WUTE: Wakeup timer enable
Note: When the wakeup timer is disabled, wait for WUTWF=1 before enabling it again.
Bit 9 ALRBE: Alarm B enable
Bit 8 ALRAE: Alarm A enable
Bit 7 DCE: Coarse digital calibration enable
Bit 6 FMT: Hour format
Bit 5 Reserved, must be kept at reset value.
Bit 4 REFCKON: Reference clock detection enable (50 or 60 Hz)
Note: PREDIV_S must be 0x00FF.
Bit 3 TSEDGE: Timestamp event active edge
Bits 2:0 WUCKSEL[2:0]: Wakeup clock selection
586/1381
0: Wakeup timer interrupt disabled
1: Wakeup timer interrupt enabled
0: Alarm B Interrupt disable
1: Alarm B Interrupt enable
0: Alarm A interrupt disabled
1: Alarm A interrupt enabled
0: Time stamp disable
1: Time stamp enable
0: Wakeup timer disabled
1: Wakeup timer enabled
0: Alarm B disabled
1: Alarm B enabled
0: Alarm A disabled
1: Alarm A enabled
0: Digital calibration disabled
1: Digital calibration enabled
PREDIV_A must be 6 or greater
0: 24 hour/day format
1: AM/PM hour format
0: Reference clock detection disabled
1: Reference clock detection enabled
0: TIMESTAMP rising edge generates a timestamp event
1: TIMESTAMP falling edge generates a timestamp event
TSE must be reset when TSEDGE is changed to avoid unwanted TSF setting.
000: RTC/16 clock is selected
001: RTC/8 clock is selected
010: RTC/4 clock is selected
011: RTC/2 clock is selected
10x: ck_spre (usually 1 Hz) clock is selected
11x: ck_spre (usually 1 Hz) clock is selected and 2
(see note below)
RM0033 Rev 9
16
is added to the WUT counter value
RM0033