Rainbow Electronics DS1554 - Manual

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FEATURES
Integrated NV SRAM, real time clock,
crystal, power-fail control circuit and lithium
energy source
Clock registers are accessed identically to the
static RAM; these registers are resident in the
16 top RAM locations
Century byte register; i.e., Y2K complaint
Totally nonvolatile with over 10 years of
operation in the absence of power
Precision power-on reset
Programmable watchdog timer and RTC
alarm
BCD coded year, month, date, day, hours,
minutes, and seconds with automatic leap
year compensation valid up to the year 2100
Battery voltage level indicator flag
Power-fail write protection allows for
±
10%
V
CC
power supply tolerance
Lithium energy source is electrically
disconnected to retain freshness until power is
applied for the first time
PIN ASSIGNMENT
DS1554
256K NV Y2KC Timekeeping RAM
www.dalsemi.com
1 IRQ/FT
2
3
NC
NC
RST
V
CC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
4
5
6
7
8
9
10
11
12
13
14
15
16
17
NC
A14 33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
34 NC
X1 GND V
BAT
X2
34-Pin PowerCap ® Module Board
(Uses DS9034PCX PowerCap)
RST
13
1
2
3
4
5
6
7
8
9
10
11
12
14
31
A14
A7
A5
A4
A3
A2
A1
A0
DQ1
DQ0
V
CC
NC
IRQ/FT
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ5
DQ6
32
30
29
28
27
26
25
24
23
22
21
19
20
NC
A12
A6
DQ2
GND
15
16
18
17
DQ4
DQ3
32-Pin Encapsulated Package