Intel MCS48 User Manual page 194

intel
8243
MCS-48
T
"
INPUT/OUTPUT EXPANDER
Low
Cost
Simple
Interface to
MCS-48™
Micro-
computers
Four
4-Bit I/O Ports
AND
and
OR
Directly to Ports
24-Pin DIP
Single
5V Supply
High Output
Drive
Direct Extension
of
Resident 8048
I/O
Ports
The
Intel®
8243
is
an
input/output expander designed
specifically to
provide a low cost
means
of I/O
expansion
for
the
MCS-48
1
" family
of single chip
microcomputers.
Fabricated
in
5
volts
NMOS,
the
8243 combines
low
cost, single
supply
voltage
and
high
drive current
capability.
The
8243
consists
of
four
4-bit
bidirectional
static
I/O ports
and one
4-bit
port
which
serves as an
interface to the
MCS-48
microcomputers. The
4-bit
interface requires that only 4 I/O
lines of the
8048 be used
for I/O
expansion, and
also allows
multiple 8243s
to
be added
to the
same
bus.
The
I/O ports
of
the 8243 serve as a
direct
extension
of the resident I/O
facilities
of
the
MCS-48
microcomputers and
are
accessed by
their
own MOV,
ANL, and
ORL
instructions.
PIN
CONFIGURATION BLOCK DIAGRAM
P50C
y
24
3Vcc
P40C
2 23
DP51
P41C
3 22
DPS2
P42C
4 21
DP53
M3C
5 20
DP60
CSC
PROGC
6
8243
'
9
7
18
DP61
DP62
P23C
8 17
DP63
P22C
9 16
DP73
P21C
10 15
DP72
P20C
11
14
IJP71
GNDC
12 13
DP70
<x>
p INSTRUC.
DECODER
o
=tp
a
7>
TJ
:>
i>
RESET
CIRCUIT
:> 4
> PORT
5
a
2
>
4
>
PORT
6
P
NPUT
/*~^
JFFER
\
ATCH
4
\
'UT
/^
FER
V_J
INTEL
CORPORATION ASSUMES NO
RESPONSIBILITY
FOR THE USE
OF ANY CIRCUITRY
OTHER THAN
CRCUTRV EMBODED
M
AN KTEL
PRODUCT.
NO OTHER CKCUIT PATENT LICENSES ARE
MPLB).
c
INTEL
CORPORATION, 1979
6-42