The
Parallel
Port
in General
Purpose
1/0
Mode
When you want to
use
the
parallel
port
as
a
general purpose
1/0
port, you have to
control
the
data
lines
directly
with
data
bit
5
of the control
register:
Most Significant Bit 7
Least Significant
Bit
0
Xx
XXXXXX
Commands should be sent to 3BE,
37A,
2BE,
or
27A
depending
upon
the port
address you
have
chosen
for the
parallel port.
Before
a
write
to
the parallel
port, you should
enable the
output buffer
by
setting
bit
5
of
the
control register to
0.
Before
a
read
from the parallel port,
you
should
disable
the
output buffer
by
setting
bit
5
of the control register
to
1.
You should
refer
to more detailed
documents
on
the printer
port
if you want to
tailor the parallel port for your
own
specific applications.
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