DS1385/DS1387
DS1385/DS1387
RAMified Real Time Clock 4K x 8
FEATURES
PIN ASSIGNMENT
OER
X1
X2
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
GND
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
V
CC
SQW
AS0
AS1
V
BAT
IRQ
WER
RD
GND
WR
ALE
CS
OER
NC
NC
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
GND
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
V
CC
SQW
AS0
AS1
NC
IRQ
WER
RD
NC
WR
ALE
CS
•
Upgraded
IBM AT computer clock/calendar with
4K x 8 extended RAM
the absence of power
•
Totally nonvolatile with over 10 years of operation in
•
Counts seconds, minutes, hours,
day of the week,
date, month and year with leap year compensation
alarm
•
Binary or BCD representations of time, calendar and
•
12–
or 24–hour clock with AM and PM in 12–hour
mode
•
Daylight Savings Time option
•
Multiplex bus for pin efficiency
•
Interfaced with
software as 64 user RAM locations
plus 4K x 8 of static RAM
– 14–bytes of clock and control registers
– 50–bytes of general purpose RAM
– 4K x 8 SRAM accessible by using separate con-
trol pins
DS1385 24–PIN DIP
(600 MIL)
DS1387 24–PIN
ENCAPSULATED PACKAGE
(740 MIL FLUSH)
OER
X1
X2
NC
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
NC
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
CC
SQW
NC
AS0
AS1
V
BAT
IRQ
WER
RD
BGND
WR
ALE
CS
NC
•
Programmable square wave output signal
•
Bus–compatible interrupt signals (IRQ)
•
Three interrupts
and testable:
– Time–of–day alarm once/second to once/day
– Periodic rates from 122
µs
to 500 ms
– End–of–clock update cycle
are separately software–maskable
•
Available
as chip (DS1385 or DS1385S) or stand
alone module with embedded lithium battery and
crystal (DS1387)
DS1385S 28–PIN SOIC
(330 MIL)
ORDERING INFORMATION
DS1385
DS1385S
DS1387
RTC Chip; 24–pin DIP
RTC Chip; 28–pin SOIC
RTC Module; 24–pin DIP
ECopyright
1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
012496 1/20
DALLAS [ DALLAS SEMICONDUCTOR ]
