Datasheet
PCF2127AT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6 — 11 July 2013 8 of 86
NXP Semiconductors
PCF2127AT
Integrated RTC, TCXO and quartz crystal
Table 5. Register overview
Bit positions labeled as - are not implemented and will return a 0 when read. Bit T must always be written with logic 0. Bits
labeled as X are undefined at power-on and unchanged by subsequent resets.
Address Register name Bit Reset value
7 6 5 4 3 2 1 0
Control registers
00h Control_1 EXT_
TEST
TSTOPTSF1POR_
OVRD
12_24 MI SI 0000 0000
01h Control_2 MSF WDTF TSF2 AF CDTF TSIE AIE CDTIE 0000 0000
02h Control_3 PWRMNG[2:0] BTSE BF BLF BIE BLIE 0000 0000
Time and date registers
03h Seconds OSF SECONDS (0 to 59) 1XXX XXXX
04h Minutes - MINUTES (0 to 59) - XXX XXXX
05h Hours - - AMPM HOURS (1 to 12) in 12 h mode - - XX XXXX
HOURS (0 to 23) in 24 h mode - - XX XXXX
06h Days - - DAYS (1 to 31) - - XX XXXX
07hWeekdays----- WEEKDAYS (0 to 6) - - - - - XXX
08h Months - - - MONTHS (1 to 12) - - - X XXXX
09h Years YEARS (0 to 99) XXXX XXXX
Alarm registers
0Ah Second_alarm AE_S SECOND_ALARM (0 to 59) 1XXX XXXX
0Bh Minute_alarm AE_M MINUTE_ALARM (0 to 59) 1XXX XXXX
0Ch Hour_alarm AE_H - AMPM HOUR_ALARM (1 to 12) in 12 h mode 1 - XX XXXX
- HOUR_ALARM (0 to 23) in 24 h mode 1 - XX XXXX
0Dh Day_alarm AE_D - DAY_ALARM (1 to 31) 1 - XX XXXX
0EhWeekday_alarmAE_W----WEEKDAY_ALARM (0 to 6) 1 - - - - XXX
CLKOUT control register
0FhCLKOUT_ctlTCR[1:0] ---COF[2:0] 00---000
Watchdog registers
10h Watchdg_tim_ctl WD_CD[1:0] TI_TP - - - TF[1:0] 000 - - - 11
11h Watchdg_tim_val WATCHDG_TIM_VAL[7:0] XXXX XXXX
Timestamp registers
12h Timestp_ctl TSM TSOFF - 1_O_16_TIMESTP[4:0] 00 - X XXXX
13h Sec_timestp - SECOND_TIMESTP (0 to 59) - XXX XXXX
14h Min_timestp - MINUTE_TIMESTP (0 to 59) - XXX XXXX
15h Hour_timestp - - AMPM HOUR_TIMESTP (1 to 12) in 12 h mode - - XX XXXX
HOUR_TIMESTP (0 to 23) in 24 h mode - - XX XXXX
16h Day_timestp - - DAY_TIMESTP (1 to 31) - - XX XXXX
17hMon_timestp---MONTH_TIMESTP (1 to 12) ---XXXXX
18h Year_timestp YEAR_TIMESTP (0 to 99) XXXX XXXX
Aging offset register
19h Aging_offset ----AO[3:0] ----1000