DS1395/DS1397
DS1395/DS1397
RAMified Real Time Clock
FEATURES
PIN ASSIGNMENT
A0
A1
X2
X1
STBY
D0
D1
D2
D3
D4
D5
D6
D7
V
SS
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
A2
A3
VDD
SQW
A4
A5
VBAT
IRQ
RESET
RD
BGND
WR
XRAM
RTC
•
Ideal for EISA bus PCs
•
Functionally compatible
mode
with MC146818 in 32 KHz
•
Totally nonvolatile with over 10 years of operation in
the absence of power
•
Self-contained
•
Counts
subsystem includes lithium, quartz,
and support circuitry
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
•
Interfaced with software as 64 register/RAM locations
plus 4K x 8 of static RAM
– 14 bytes of clock and control registers
– 50 bytes of general and control registers
– Separate 4K x 8 nonvolatile SRAM
DS1395S 28-Pin SOIC (330 mil)
A0
A1
X2
X1
STBY
D0
D1
D2
D3
D4
D5
D6
D7
VSS
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
A2
A3
VDD
SQW
A4
A5
VBAT
IRQ
RESET
RD
BGND
WR
XRAM
RTC
•
Programmable square wave output signal
•
Bus-compatible interrupt signals (IRQ)
•
Three
interrupts are separately software-maskable
and testable:
– Time-of-day alarm once/second to once/day
– Periodic rates from 122
µs
to 500 ms
– End-of-clock update cycle
DS1395 28-Pin DIP (600 mil)
A0
A1
NC
NC
STBY
D0
D1
D2
D3
D4
D5
D6
D7
V SS
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
A2
A3
VDD
SQW
A4
A5
NC
IRQ
RESET
RD
NC
WR
XRAM
RTC
•
28-pin JEDEC footprint
•
Available as chip (DS1395/DS1395S) or stand alone
module with embedded lithium battery and crystal
(DS1397)
ORDERING INFORMATION
DS1395
DS1395S
DS1397
RTC Chip; 28–pin DIP
RTC Chip; 28–pin SOIC
RTC Module; 28–pin DIP
DS1397 28-Pin Encapsulated Package (720 mil)
ECopyright
1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor databooks.
020794 1/19
DALLAS [ DALLAS SEMICONDUCTOR ]
