DS1685_10 Datasheet, PDF (9/34 Pages) Maxim Integrated Products – 3V/5V Real-Time Clocks

DS1685/DS1687 3V/5V Real-Time Clocks
“don’t care” codes in all three time alarm bytes create an interrupt every second. The three time-alarm bytes can be
used with the date alarm as described in the Wake-Up/Kickstart section. The century counter is discussed later in
this text.
All registers can be directly written or read except for the following:
1) Registers C and D are read-only.
2) Bit 7 of Register A is read-only.
3) Bit 7 of the seconds byte is read-only.
Table 2A. Time, Calendar, and Alarm Data Modes—BCD Mode (DM = 0)
ADDRESS BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0 FUNCTION
00H
0
01H
0
02H
0
03H
0
10 Seconds
10 Seconds
10 Minutes
10 Minutes
Seconds
Seconds
Minutes
Minutes
Seconds
Seconds
Alarm
Minutes
Minutes
Alarm
AM/PM
04H
0
0
0
10 Hour
10 Hour
Hours
Hours
AM/PM
05H
0
0
0
10 Hour
10 Hr
Hours
Hours
Alarm
06H
0
0
0
0
0
07H
0
0
10 Date
08H
0
0
0
10 Month
09H
10 Year
Day
Date
Month
Year
Day
Date
Month
Year
0AH
UIP
DV2
DV1
DV0
RS3
RS2
RS1
RS0
Control
0BH
SET
PIE
AIE
UIE
SQWE
DM
24/12
DSE
Control
0CH
IRQF
PF
AF
UF
0
0
0
0
Control
0DH
VRT
0
48H
49H
0
0
0
Century
10 Date
0
0
Date
0
Control
Bank 1
Century
Bank 1
Date Alarm
RANGE
00-59
00-59
00-59
00-59
1-12
+AM/PM
00-23
1-12
+AM/PM
00-23
01-07
01-31
01-12
00-99
00-99
01-31
X = Read/Write Bit.
Note 1: Unless otherwise specified, the state of the registers is not defined when power is first applied.
Note 2: Except for the seconds register, 0 bits in the time and date registers can be written to a 1, but may be modified when the clock updates.
0 bits should always be written to 0 except for alarm mask bits.
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