DS1685 Maxim, DS1685 Datasheet - Page 9

• Manufacturer Part Number: DS1685
• Description: The DS1685/DS1687 are real-time clocks (RTCs) designed as successors to the industry-standard DS1285,DS1385, DS1485, and DS1585 PC RTCs
• Manufacturer: Maxim

“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)
2)
3)
Table 2A. Time, Calendar, and Alarm Data Modes—BCD Mode (DM = 0)
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.
ADDRESS
0CH
0DH
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
0AH
0BH
48H
49H
Registers C and D are read-only.
Bit 7 of Register A is read-only.
Bit 7 of the seconds byte is read-only.
AM/PM
AM/PM
BIT 7
IRQF
SET
VRT
UIP
0
0
0
0
0
0
0
0
0
BIT 6
DV2
PIE
PF
0
0
0
0
0
0
10 Year
10 Seconds
10 Seconds
10 Minutes
10 Minutes
BIT 5
DV1
AIE
AF
0
0
0
0
0
10 Hour
10 Date
10 Date
10 Hr
10 Month
10 Hour
10 Hour
BIT 4
DV0
UIE
UF
0
0
Century
SQWE
BIT 3
9 of 34
RS3
0
0
0
BIT 2
RS2
DM
0
0
Seconds
Seconds
Minutes
Minutes
Hours
Hours
Month
Date
Year
Date
24/12
BIT 1
RS1
Day
DS1685/DS1687 3V/5V Real-Time Clocks
0
0
BIT 0
DSE
RS0
0
0
FUNCTION
Date Alarm
Seconds
Seconds
Minutes
Minutes
Century
Control
Control
Control
Control
Bank 1
Bank 1
Month
Alarm
Alarm
Hours
Hours
Alarm
Date
Year
Day
+AM/PM
+AM/PM
RANGE
00-59
00-59
00-59
00-59
00-23
00-23
01-07
01-31
01-12
00-99
00-99
01-31
1-12
1-12