PCF2127AT/1 NXP [NXP Semiconductors], PCF2127AT/1 Datasheet - Page 7

• Manufacturer Part Number: PCF2127AT/1
• Description: Integrated RTC, TCXO and quartz crystal
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
Table 4.
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.
PCF2127A_2
Product data sheet
Address Register name
Control registers
00h
01h
02h
Time and date registers
03h
04h
05h
06h
07h
08h
09h
Alarm registers
0Ah
0Bh
0Ch
0Dh
0Eh
CLKOUT control register
0Fh
Watchdog registers
10h
11h
Timestamp registers
12h
13h
Control_1
Control_2
Control_3
Seconds
Minutes
Hours
Days
Weekdays
Months
Years
Second_alarm
Minute_alarm
Hour_alarm
Day_alarm
Weekday_alarm
CLKOUT_ctl
Watchdg_tim_ctl
Watchdg_tim_val WATCHDG_TIM_VAL[7:0]
Timestp_ctl
Sec_timestp
Register overview
When one of the RTC registers is written or read, the content of all counters is temporarily
frozen. This prevents a faulty writing or reading of the clock and calendar during a carry
condition (see
•
•
Address registers 1Ah and 1Bh define the RAM address. Address register 1Ch
(RAM_wrt_cmd) is the RAM write command; address register 1Dh (RAM_rd_cmd) is
the RAM read command. Data is transferred to or from the RAM via the serial
interface (see
The registers Seconds, Minutes, Hours, Days, Months, and Years are all coded in
Binary Coded Decimal (BCD) format to simplify application use. Other registers are
either bit-wise or standard binary.
Bit
7
EXT_
TEST
PWRMNG[2:0]
OSF
-
-
-
-
AE_S
AE_M
AE_H
AE_D
AE_W
TCR[1:0]
WD_CD[1:0]
TSM
MSF
-
-
WDTF
-
-
-
-
-
-
TSOFF
6
T
-
-
SECOND_TIMESTP (0 to 59)
Section
All information provided in this document is subject to legal disclaimers.
Section
TSF2
TI_TP
-
5
STOP
HOURS (0 to 23) in 24 h mode
-
-
HOUR_ALARM (0 to 23) in 24 h mode
-
-
8.9.8).
AMPM HOURS (1 to 12) in 12 h mode
AMPM HOUR_ALARM (1 to 12) in 12 h mode
Rev. 02 — 7 May 2010
8.5).
-
1_O_16_TIMESTP[4:0]
4
TSF1
AF
BTSE
-
-
-
SECOND_ALARM (0 to 59)
MINUTE_ALARM (0 to 59)
YEARS (0 to 99)
SECONDS (0 to 59)
MINUTES (0 to 59)
DAY_ALARM (1 to 31)
-
3
POR_
OVRD
CDTF
BF
-
-
-
DAYS (1 to 31)
MONTHS (1 to 12)
Integrated RTC, TCXO and quartz crystal
-
2
12_24
TSIE
BLF
COF[2:0]
WEEKDAY_ALARM (0 to 6) 1 - - - - XXX
WEEKDAYS (0 to 6)
1
MI
AIE
BIE
TF[1:0]
PCF2127A
0
SI
CDTIE
BLIE
© NXP B.V. 2010. All rights reserved.
Reset value
0000 0000
0000 0000
0000 0000
1XXX XXXX
- XXX XXXX
- - XX XXXX
- - XX XXXX
- - XX XXXX
- - - - - XXX
- - - X XXXX
XXXX XXXX
1XXX XXXX
1XXX XXXX
1 - XX XXXX
1 - XX XXXX
1 - XX XXXX
00 - - - 000
000 - - - 11
XXXX XXXX
00 - X XXXX
- XXX XXXX
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