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All
and more about Sharp PC-1500
at
http://www.PC-1500.info
PC-1500
•
so~s1
is
selected by the
decode:
r
IC (TC40H138F)
when
the gate
signal input MEO (G1)
Is high,
Y1
(G2A)
low,
and
G2B
is low
(normally low).
PC-1
500A
•
so~s1
is
selected
by the
decoder
IC (TC40H138F)
wh@n
the
gate
signal
Input MEO
(G 1)
is high, Y1
(G2A) low, and
G2B
is low
(normally
low).
S
I .
...
..
With
high
.
... low
so
as
to
SI ...
...
With high
.
...
low so
as
to
(Y
I
)
sclc,1 thc optional user
RAfv1
(Y
I
)
select
the
user
RAM area
.
..
.
area
.
...
S2
...
.
.
. With low ..
.
. the
S2
output
S2
..
.... With
low
..
..
the S2
<)utpu1
(Y2)
goes low so
as
t(>
select
the
(Y2)
goes
low
so as to select the
opt
ional
user
RAM
area. .
.
.
user RAM
area
..
..
S3 ......
With low
.
.
.
•
the
S3 output
S3
.....
.
With low
.
...
the
S3
outpul
(Y3)
goes low so
as to
select the
(Y3)
goes low so as
to
select
the
user
RAM
area. . . .
optional
user
RAM
a rea .
.
.•
$4
...
.
.. With
high
..
..
the
$4
output
S4
.
.
..
..
With
high
.
...
the S4 outplll
(Y4)
goes
low so as
to
select
the
(Y4)
goes low
so
as
to select the
user
RAM
area.
.
.
.
optional user RAM
area .
..
•
S5
..
..
..
Do
not
use
S7 ...
...
so as to select the system
(Y7)
RAM
(TC5514)
...
Chip
select signal
SS .
...
.
.
Optional user RAM
area
(VS)
(Add
ress
assignment
of
6800H~6FFFH)
$7 ......
so
as
to select the system
(Y?)
RAM
(H
M
61
1
6)
...
Chip select signal
for
the PC-1
SOOA
Refer
to
following chart for
the
PC-
I
500A.
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