I/O Expansion Techniques - Intel MCS48 User Manual

APPLICATION
EXAMPLES
I/O
Expansion Techniques
The
following are several
examples
of
how
the basic I/O capability
of
the
MCS-48™
microcomputers can
be
easily
expanded
externally using
either the
8243
I/O
expander
device or standard
logic circuits.
These techniques can be used
whenever
the
combination
memory/IO expanders
illustrated
on
the
preceeding pages
are not
required.
,40
,26 ,20
INPUT
-
^.
39
10
T1
6
_
*-
INT
VCC
V
DD
Vss
XTAL
1
8049
8048
8748
8035
8039
ALE
PSEN
PROG WR
RD
P10
P11
P12
P13
P14
P15
P16
P17
P20
P21
P22
P23
P24
P25
P26
P27
DB0
DB1
DB2
DB3
DB4
DB5
DB6
DB7
Vcc
P40
P41
P42
P43
P50
P51
8243
I/O
P52
P53
EXPANDER
P60
P20 P61
P21
P62
P22 P63
P23
P70
P71
P72
P73
-
I/O
ADDING AN
I/O
EXPANDER
5-11