All and more about Sharp PC-1500 at http:/lwww.PC-1500.info
ADDENDUM
Differences
between
the
PC-1
SOOA
and
the
PC-1500
Take
notice o
f'
these differences when you use
the
mac
hine l
an
guage for t
he
PC
-1
500A.
Page
89
90
91
PC
-1500
© Chip select decoder
. . .
and
it
is used to select chip by
me
ans
o
fS0
~
4
.
S6.S7,
2Y2and
2Y3.
0 System RAM
Because the 4-bit X l K bytes
TC55
14
is used in a
pa
ir, the
da
ta bus is
divided i
nto
two
of
oo
~
DJ
and
D4
~
D7
and
the select signal S7 is
commonly
sh
ared
so
as
to
be
co
mp
atible
wi1
h 1he
8-
bil RAM.
Address is within 7800H to
7BFFH
of
the
MEO
ar
ea which is used for
the
system
memory
ar
ea
and
for
the
fixed
var
i
ab
le a rea.
© User RAM
It
is the u
ser
RAM
for which 8-bit X
2KB HM6
11
6 is used. Address
se
lected by
SO
is w
it
hin 4000H to
47
FF
H.
4-2-2. Block diagram
4-2-
3.
Chip select circuit
Do
not
sell this PDF !!!
PC-1500A
© Chip select decoder
...
and
it is u
se
d to select chip by
means
of
S0~7.
2Y2 and 2Y3
...
.
0 System
RAM
A
dd
ress is within 7800H to 7F
FFH
of
the M
EO
a r
ea
which
is
used for the
system m
emory
area, machine
l
anguag
e ar
ea
(7
CO
l H
~7 FFFH)
and
for the fixed va
ri
ab
le area.
© User RAM
It
is
the
us
er RAM for which 8-bit X
2KB H
M6I
16
is used. A
ddr
ess
se
le
cte
d by
so
~
S2
is within
4000H
to
57
FF
H.
4-2-2. Block diagram for the PC-
1500A
Refer
to
4-2-2 diagram for
th
e PC-
I
500A
4-2-3. Chip select circuit for the PC-
1
SOOA
Refer
to
4-
2-3
ci
rcuit for the PC-l 500A.
161
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