Real-time clock RTC 0x0 0x400 registers TR TR time register 0x0 0x20 read-write 0x00000000 PM AM/PM notation 22 1 HT Hour tens in BCD format 20 2 HU Hour units in BCD format 16 4 MNT Minute tens in BCD format 12 3 MNU Minute units in BCD format 8 4 ST Second tens in BCD format 4 3 SU Second units in BCD format 0 4 DR DR date register 0x4 0x20 read-write 0x00002101 YT Year tens in BCD format 20 4 YU Year units in BCD format 16 4 WDU Week day units 13 3 MT Month tens in BCD format 12 1 MU Month units in BCD format 8 4 DT Date tens in BCD format 4 2 DU Date units in BCD format 0 4 CR CR control register 0x8 0x20 read-write 0x00000000 COE Calibration output enable 23 1 OSEL Output selection 21 2 POL Output polarity 20 1 BKP Backup 18 1 SUB1H Subtract 1 hour (winter time change) 17 1 ADD1H Add 1 hour (summer time change) 16 1 TSIE Time-stamp interrupt enable 15 1 WUTIE Wakeup timer interrupt enable 14 1 ALRBIE Alarm B interrupt enable 13 1 ALRAIE Alarm A interrupt enable 12 1 TSE Time stamp enable 11 1 WUTE Wakeup timer enable 10 1 ALRBE Alarm B enable 9 1 ALRAE Alarm A enable 8 1 DCE Coarse digital calibration enable 7 1 FMT Hour format 6 1 REFCKON Reference clock detection enable (50 or 60 Hz) 4 1 TSEDGE Time-stamp event active edge 3 1 WCKSEL Wakeup clock selection 0 3 ISR ISR initialization and status register 0xC 0x20 0x00000007 ALRAWF Alarm A write flag 0 1 read-only ALRBWF Alarm B write flag 1 1 read-only WUTWF Wakeup timer write flag 2 1 read-only SHPF Shift operation pending 3 1 read-write INITS Initialization status flag 4 1 read-only RSF Registers synchronization flag 5 1 read-write INITF Initialization flag 6 1 read-only INIT Initialization mode 7 1 read-write ALRAF Alarm A flag 8 1 read-write ALRBF Alarm B flag 9 1 read-write WUTF Wakeup timer flag 10 1 read-write TSF Time-stamp flag 11 1 read-write TSOVF Time-stamp overflow flag 12 1 read-write TAMP1F Tamper detection flag 13 1 read-write TAMP2F TAMPER2 detection flag 14 1 read-write RECALPF Recalibration pending Flag 16 1 read-only PRER PRER prescaler register 0x10 0x20 read-write 0x007F00FF PREDIV_A Asynchronous prescaler factor 16 7 PREDIV_S Synchronous prescaler factor 0 15 WUTR WUTR wakeup timer register 0x14 0x20 read-write 0x0000FFFF WUT Wakeup auto-reload value bits 0 16 CALIBR CALIBR calibration register 0x18 0x20 read-write 0x00000000 DCS Digital calibration sign 7 1 DC Digital calibration 0 5 ALRMAR ALRMAR alarm A register 0x1C 0x20 read-write 0x00000000 MSK4 Alarm A date mask 31 1 WDSEL Week day selection 30 1 DT Date tens in BCD format 28 2 DU Date units or day in BCD format 24 4 MSK3 Alarm A hours mask 23 1 PM AM/PM notation 22 1 HT Hour tens in BCD format 20 2 HU Hour units in BCD format 16 4 MSK2 Alarm A minutes mask 15 1 MNT Minute tens in BCD format 12 3 MNU Minute units in BCD format 8 4 MSK1 Alarm A seconds mask 7 1 ST Second tens in BCD format 4 3 SU Second units in BCD format 0 4 ALRMBR ALRMBR alarm B register 0x20 0x20 read-write 0x00000000 MSK4 Alarm B date mask 31 1 WDSEL Week day selection 30 1 DT Date tens in BCD format 28 2 DU Date units or day in BCD format 24 4 MSK3 Alarm B hours mask 23 1 PM AM/PM notation 22 1 HT Hour tens in BCD format 20 2 HU Hour units in BCD format 16 4 MSK2 Alarm B minutes mask 15 1 MNT Minute tens in BCD format 12 3 MNU Minute units in BCD format 8 4 MSK1 Alarm B seconds mask 7 1 ST Second tens in BCD format 4 3 SU Second units in BCD format 0 4 WPR WPR write protection register 0x24 0x20 write-only 0x00000000 KEY Write protection key 0 8 SSR SSR sub second register 0x28 0x20 read-only 0x00000000 SS Sub second value 0 16 SHIFTR SHIFTR shift control register 0x2C 0x20 write-only 0x00000000 ADD1S Add one second 31 1 SUBFS Subtract a fraction of a second 0 15 TSTR TSTR time stamp time register 0x30 0x20 read-only 0x00000000 ALARMOUTTYPE AFO_ALARM output type 18 1 TSINSEL TIMESTAMP mapping 17 1 TAMP1INSEL TAMPER1 mapping 16 1 TAMPIE Tamper interrupt enable 2 1 TAMP1TRG Active level for tamper 1 1 1 TAMP1E Tamper 1 detection enable 0 1 TSDR TSDR time stamp date register 0x34 0x20 read-only 0x00000000 WDU Week day units 13 3 MT Month tens in BCD format 12 1 MU Month units in BCD format 8 4 DT Date tens in BCD format 4 2 DU Date units in BCD format 0 4 TSSSR TSSSR timestamp sub second register 0x38 0x20 read-only 0x00000000 SS Sub second value 0 16 CALR CALR calibration register 0x3C 0x20 read-write 0x00000000 CALP Increase frequency of RTC by 488.5 ppm 15 1 CALW8 Use an 8-second calibration cycle period 14 1 CALW16 Use a 16-second calibration cycle period 13 1 CALM Calibration minus 0 9 TAFCR TAFCR tamper and alternate function configuration register 0x40 0x20 read-write 0x00000000 ALARMOUTTYPE AFO_ALARM output type 18 1 TSINSEL TIMESTAMP mapping 17 1 TAMP1INSEL TAMPER1 mapping 16 1 TAMPPUDIS TAMPER pull-up disable 15 1 TAMPPRCH Tamper precharge duration 13 2 TAMPFLT Tamper filter count 11 2 TAMPFREQ Tamper sampling frequency 8 3 TAMPTS Activate timestamp on tamper detection event 7 1 TAMP2TRG Active level for tamper 2 4 1 TAMP2E Tamper 2 detection enable 3 1 TAMPIE Tamper interrupt enable 2 1 TAMP1TRG Active level for tamper 1 1 1 TAMP1E Tamper 1 detection enable 0 1 ALRMASSR ALRMASSR alarm A sub second register 0x44 0x20 read-write 0x00000000 MASKSS Mask the most-significant bits starting at this bit 24 4 SS Sub seconds value 0 15 ALRMBSSR ALRMBSSR alarm B sub second register 0x48 0x20 read-write 0x00000000 MASKSS Mask the most-significant bits starting at this bit 24 4 SS Sub seconds value 0 15 BKP0R BKP0R backup register 0x50 0x20 read-write 0x00000000 BKP BKP 0 32 BKP1R BKP1R backup register 0x54 0x20 read-write 0x00000000 BKP BKP 0 32 BKP2R BKP2R backup register 0x58 0x20 read-write 0x00000000 BKP BKP 0 32 BKP3R BKP3R backup register 0x5C 0x20 read-write 0x00000000 BKP BKP 0 32 BKP4R BKP4R backup register 0x60 0x20 read-write 0x00000000 BKP BKP 0 32 BKP5R BKP5R backup register 0x64 0x20 read-write 0x00000000 BKP BKP 0 32 BKP6R BKP6R backup register 0x68 0x20 read-write 0x00000000 BKP BKP 0 32 BKP7R BKP7R backup register 0x6C 0x20 read-write 0x00000000 BKP BKP 0 32 BKP8R BKP8R backup register 0x70 0x20 read-write 0x00000000 BKP BKP 0 32 BKP9R BKP9R backup register 0x74 0x20 read-write 0x00000000 BKP BKP 0 32 BKP10R BKP10R backup register 0x78 0x20 read-write 0x00000000 BKP BKP 0 32 BKP11R BKP11R backup register 0x7C 0x20 read-write 0x00000000 BKP BKP 0 32 BKP12R BKP12R backup register 0x80 0x20 read-write 0x00000000 BKP BKP 0 32 BKP13R BKP13R backup register 0x84 0x20 read-write 0x00000000 BKP BKP 0 32 BKP14R BKP14R backup register 0x88 0x20 read-write 0x00000000 BKP BKP 0 32 BKP15R BKP15R backup register 0x8C 0x20 read-write 0x00000000 BKP BKP 0 32 BKP16R BKP16R backup register 0x90 0x20 read-write 0x00000000 BKP BKP 0 32 BKP17R BKP17R backup register 0x94 0x20 read-write 0x00000000 BKP BKP 0 32 BKP18R BKP18R backup register 0x98 0x20 read-write 0x00000000 BKP BKP 0 32 BKP19R BKP19R backup register 0x9C 0x20 read-write 0x00000000 BKP BKP 0 32