Real-Time Clock
Table 2B. Time, Calendar, and Alarm Data Modes—Binary Mode (DM = 1)
ADDRESS
BIT 7
BIT 6 BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
FUNCTION
RANGE
00–3B
00–3B
00–3B
00–3B
00H
0
0
0
0
0
0
0
0
Seconds
Seconds
Minutes
Minutes
Seconds
01H
Seconds Alarm
Minutes
02H
03H
Minutes Alarm
AM/PM
0
0
Hours
01–0C +AM/PM
00–17
04H
05H
0
0
0
0
Hours
0
AM/PM
0
Hours
Hours
Month
01–0C +AM/PM
00–17
Hours Alarm
Hours
06H
07H
08H
09H
0AH
0
0
0
0
0
0
0
0
0
0
0
0
Date
Day
Day
Date
Month
Year
01–07
01–1F
01–0C
00–63
—
0
Year
RS3
UIP
DV2
PIE
PF
0
DV1
AIE
AF
0
DV0
UIE
UF
0
RS2
RS1
RS0
DSE
0
Control
0BH
0CH
SET
IRQF
VRT
X
SQWE
DM
0
24/12
Control
Control
Control
RAM
—
—
—
—
—
—
0
0
X
0
0
X
0DH
0
0
0EH-31H
32H
X
X
X
X
X
N/A
N/A
Century*
RAM
33H-7FH
X
X
X
X
X
X
X
X
X = Read/Write Bit.
*DS12C887, DS12C887A only. General-purpose RAM on DS12885, DS12887, and DS12887A.
Note: Unless otherwise specified, the state of the registers is not defined when power is first applied. Except for the seconds regis-
ter, 0 bits in the time and date registers can be written to 1, but may be modified when the clock updates. 0 bits should always be
written to 0 except for alarm mask bits.
5/DS12C87A
14
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