MSM81 C55RSlGS
2048-Bit CMOS Static
RAM
with
110
Ports and Timer
General
The
hlSX181C55RS is a static
RAM
in combination with
110
ports and timer. for use with
microprocessors. The
XlSh18IC55RS is made from silicon-gate CMOS teck~ology. It
features very low power dissipation of up to 100
pA
as standby current when not selected.
The
MSM81C55 has 2K-bit of static KAh.1. configured as
256
x
8 bits.
The
MSh,I81C55RS
has an access time of 400 ns at maximum so that it can be usetl also in the 80C85A systern
without wait states.
The
hlSh18
1
C55RS has three general purpose
I/O
ports: two 8-bit porls and one 6-bit port.
rcspectively. ports
A.
B.
and C.
Port C is used to enable and set the modes for the other
two ports.
hlSXl8lC55RS also has a 14-bit built-in programmable counterltimer which can be used to
generate square pulses for timers or count pulses.
Features
High-speed operation
and
low power dissipation
RAM configuration of 256
x
8-bit bytes
Single power supply of
3
V
to
6
V
Completely static operation
Built-in address latch circuitry
8-bit programmable 110 ports (ports A and
B)
6-bit prograrnmablc 110 port (port C)
I
-!-bit programmable binary counter/timer
!vlultiplexed addressldata buses
40-pin
DIP
(JlShl8 1C55RS)
44-pin flat package (XIShl81C55CS)
Compatible with Intel
8
155
APX-E-
17
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