Rainbow Electronics DS14287 - Manual

1 of 25 080400
FEATURES
Direct replacement for IBM AT computer
clock/calendar
Functionally compatible with the
DS1285/DS1287
Available as chip (DS14285, DS14285S, or
DS14285Q) or stand-alone module with
embedded lithium battery and crystal
(DS14287)
Automatic backup supply and write
protection to make external SRAM
nonvolatile
Counts seconds, minutes, hours, days, day of
the week, date, month, and year with leap
year compensation valid up to 2100
Binary or BCD representation of time,
calendar, and alarm
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 128 RAM
locations
–
14 bytes of clock and control registers
– 114 bytes of general purpose RAM
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
µ
s to 500 ms
– End of clock update cycle
Optional industrial temperature version
available DS14285 DIP, SOIC, and PLCC
PIN ASSIGNMENT
DS14285/DS14287
Real Time Clock with NV RAM Control
www.dalsemi.com
DS14285 24-Pin DIP
DS14285S 24-Pin SOIC
23
X2
AD1
AD3
AD4
AD5
AD6
AD7
GND
V
CC
CEI
V
BAT
IRQ
RESET
DS
GND
R/W
AS
CS
1
2
3
4
5
6
7
8
9
10
11
12
24
22
21
20
19
18
17
16
15
14
13
X1
AD0
AD2
SQW
CEO
DS14285Q 28-Pin PLCC
AD0
AD1
AD2
AD3
AD4
AD5
CEI
V
BAT
IRQ
RESET
DS
GND
NC R/W
X2 X1 MOT V
CCO
VC
C
SQ
W
CE
0
AD
6
NC
AD
7
GND
CS AS NC
25
24
23
22
21
20
19
5
6
7
8
9
10
11
4 3 2 1 28 27 26
12 13 14 15 16 17 18
23
NC
AD1
AD3
AD4
AD5
AD6
AD7
GND
V
CC
SQW
CEO
CEI
NC
IRQ
RESET
DS
NC
R/W
AS
CS
1
2
3
4
5
6
7
8
9
10
11
12
24
22
21
20
19
18
17
16
15
14
13
NC
AD0
AD2
V
CCO
DS14287 24-Pin
Encapsulated Package
V
CCO