pcf2123 NXP Semiconductors, pcf2123 Datasheet - Page 13

• Manufacturer Part Number: pcf2123
• Description: Spi Real Time Clock/calendar
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF2123_1
Product data sheet
Table 7.
Bits labeled as - are not implemented. Bits labeled as X are undefined at power-on and unchanged
by subsequent resets.
After reset, the following mode is entered:
Address Register name
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
•
•
•
•
•
•
32.768 kHz on pin CLKOUT active
24 hour mode is selected
Offset register is set to 0
No alarms set
Timer disabled
No interrupts enabled
Control_1
Control_2
Seconds
Minutes
Hours
Days
Weekdays
Months
Years
Minute_alarm
Hour_alarm
Day_alarm
Weekday_alarm
Offset_register
Timer_clkout
Countdown_timer
Register reset values
Rev. 01 — 19 November 2008
Bit
7
0
0
1
1
-
-
-
-
X
1
1
1
1
0
-
X
6
0
0
X
X
-
-
-
-
X
X
-
-
-
0
0
X
5
0
0
X
X
X
X
-
-
X
X
X
X
-
0
0
X
4
0
0
X
X
X
X
-
X
X
X
X
X
-
0
0
X
SPI Real time clock/calendar
3
0
0
X
X
X
X
-
X
X
X
X
X
-
0
0
X
2
0
0
X
X
X
X
X
X
X
X
X
X
X
0
-
X
PCF2123
© NXP B.V. 2008. All rights reserved.
1
0
0
X
X
X
X
X
X
X
X
X
X
X
0
1
X
0
0
0
X
X
X
X
X
X
X
X
X
X
X
0
1
X
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