Service manual
--
PC-l600
5·2. Chip select signal
(1)
CSOOl
This signal must
be
low
to
access the memory space in
OOOOH-7FFFH
of
bank
O.
The
sign
al
is
also an
input
to
the
~
line
of
the
ADM
.
(2) CS123
Th
is
signal must be low
to
access the memory space
of
SOOOtt-BFFFH
of
bank
6.
The remaining
l6Ke
area
of
the second half
is
for the LH·5803 control
ROM
.
Th
is
signal
is
also an
input
to
the
CS
line of
the
ROM
.
The
ROM
(64K
B)
se
lected
bV
CSOOl
or
Csm
is
cleared when a high signal
is
given
to
the
INH
line
which
is
connected
to
the
system bus and slot (pulled
down
to
low
within
the main un
it),
(3) CS24
This
sig
nal
mu
st
be low
to
access an
yone
of
the
l6KS
spaces.
(a)
For
accessing
of
bank 3
of
the memory sp
ace
in
4000H
-7
FFFH.
• CS24
is
an
input
to
the
CS
li
ne
of
256K
biu
ROM
.
• A 15
is
connected
to
DE
of
the
ROM.
• This l eKB space
is
further banked by another
port signal
to
compose a
32KB
ar
ea.
(4)
RAM3
This signal must be high
to
access
the memory
space
in
COOOH
......
FFFF
H
of
bank O. This signal
is
connected
to
CE2
of
the
two
8KB
RAMs. A 13
is
used
to
determine which RAM is
to
be selected.
5·3. Memory map
as
seen
from
the LH·5803
ooooH
51
51
51
51
= =
RAMf
RAI!T
4000H
R
AM
1
6KS
RAM3
8000
H
---- --
-------
CE-l50
CE
-
I58
P
VQU
T - 0
PVQUT- l
COOOH
ROM
1
6KB
(C$1
231
FFFFH
Bank 0
Sank 1 Bank 2 Bank 3
- 8 -
aKB
RAM
m
input
Memory space chosen
A13
COOO
H-
DFFFH
A13A
linve
ned
A13
~a
arrav
output)
EOOOH-
FFFFH
(5) RAM2
Memory select signal
for
the memory slot 1 (51
).
This signal must be
low
to
access
the
memory
space
in
BOOO
H
......
BFFFH
of
either bank 0
or
bank 1.
1.
(6) RAM1
Memory
se
lect signal
for
the memory slot 2 (S2).
This signal must
be
low
to
access
the memory
space
in 8000H-"'
SFFFH
of
either bank 2
or
ba
nk 3.
It
is
possible by
means
of
software
to
copy 16KB
of
memory
space
in 8000H
......
BFFFH onto 16KS
of
memory
space
in 4000H
......
7FFFH
of
bank
1.
(This
area
is
reserved
for
the applica
ti
on modu
le
which is
expected
to
be
made
avaiJabel
soon.)
m;
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Bank 7