Wpd43257C-15L - Epson LQ-2550 Technical Manual

The wPD43257C-15L is a CMOS static RAM, features low power consumption, and has
so that the memory can be backed up with a battery.
Features:
32768 words X 8 bits
TTL compatible input/output
+5 V single power supply
. CE access time: 150 nS (max.)
28 pins (DIP)
Battery back-up is possible
Standby power consumption: 2 PA (typ.)
Terminal Functions:
. AO to Al 4: Address input
WE: Write enable
CE1: Chip enable 1 input
. CE2: Chip enable 2 input
GND: Ground
H
x
L
L
NOTE: X... Don't care
A s -
—
—
— ~
Row
A
D
—
,
1/01
c o n t r o l
1/04
Figure A-1 7. pPD43257C-15L Block Diagram
Table A-7. pPD43257C-15L Signal Status
WE
x x
x
L
H H
H L
A
T
A4
As
A4
A l
A t
1/01
Figure A-1 6. IAPD43257C-15L Pin Diagram
262, 144 ens
X
Control
I
Suffer
I
I
I 1
I
Mode
Deselect
High impedance
(Power down)
Read
Write
A-1 5
a
standby mode
A4
A4
CE4
1/07
I/o*
1/04
Output Status
D
OUT
D
IN
REV.-A