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Interface
Circuit
6-8-3
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Pen
Interface
Circuit
Fig.
6-42
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the
Light
Pen
interface
circuit.
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circuit
is
the
interface
circuit
to
read
the
position
of
the
Light
Pen
on
the
CRT.
The
content
of
each
terminal
of
I
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1
JC
is
shown
in
Table
6-16.
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the
light
pen
is
pressed
LP-SW
becomes
L
leve
and
LP
OUT
which
indicates
the
timing
is
outputted.
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LP-SW
and
LP
OUT
are
inputted
to
pin
12
and
13
of
IC25,
inputted
as
light
pen
output
data
to
pin
3
of
IC17.
After
that,
LP
STB
signal
from
5
pin
of
IC17
to
CRTC
and
the
IRQ
signal
which
is
the
light
pen
interrupt
signal,
from
6
pin
of
IC22
to
MPU
are
outputted.
Fig
6-42
shows
the
timing
of
each
input/output
signals.
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Summary of Contents for MB-6890
Page 1: ...HITACHI PERSONAL COMPUTER MB 6890 SERVICE MANUAL I R 0 3012 98 ...
Page 2: ...HITACHI PERSONAL COMPUTER MB 6890 SERVICE MANUAL ev O 30 1 2 1 ...
Page 42: ... one of page 40 44 missing ...
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