Service manual
Pin
Symbol
Inl OuI
Act;"',
No.
lllYe'
10
VGG
11
VM
'0
"
VOis
'"
13
VA
'0
14
VB
'0
15
NM'
'0
\6
M'
'"
17
H'N
'0
18
HA
0."
19
OISP
0."
20-27
H7-HO
0."
28
00
Qu.
29
MEO
0"
30
MEl
0"
31
-38
00-07
In/
Out
39-46
AO-A7
0"
Power
$lJpply
(system's
vee
in
put
).
LCD
~kp
l
at.
power
supplv
input.
LCD
backplate
power
supply
input.
LCD
backpl.l.
power
supp
ly inPlII.
LCD
backp
l
ate
power
supply
inPlJl.
function
Not used
by
the
P
C,
'6
00.
-
PC
- l600
Non
-m
sskabll1
interrupt
input.
A
hi
gh
Input
state causes
en
Interrupt
to
th.
CPU.
The
CPU
unconditionally
accepls
Ih.
request and
staru
to
'''Icult
the
interrupt
routine
from
th
e
addr..,
whose
high
order
idd,ess
is
represented
by
the
con
t
ents
of
the
address
FF
F
CH
end
the
low
o rder acidness
by
the
contents
of
FFFDH
.
Maskabl.
interrupt
inpu
t.
When
th,
IE flag
(I
nte
rrupt Enable'
II
set
on,
an
interrupt
request
is
caused
by
a high
Ml
input
lIate,
e
nd
the
CPU $IafU 10
execute
Ihe
inte
r-
rupt
routine
from
the
address whose high
order
address is represented
by
th
e
contenu
of the address F FFSH and
the
l
ow
order
Idd
ress by the
contints
of
FFF9H.
I
nput
to th
e
counter
by
which
the
LCD
and
backplate signals,
HO
-
H7
. are generated.
Normally
connected
to
the
HA pin of
the
CPU. With
the
PC
·
1600,
this functi
on
is
not
,
.....
CPU internal d ivider
ootput
through which
is
de
livered
the
ba1ic clock for
the
LCD
driver
and
co
nn
ected
to
HiN
and
the
regment signal generator LSI.
LCD display o n
/off
control
signal
output.
Can
be
set and res
at
by
mean,
of a
command.
With
the
PC
·
1600,
this fu n
ction
is
not
used.
LCD back
plate
signal
output
.
When
the
LCD
is
driven
by
the
backplate
signal
and
the
segme
nt
signal.
the
backplate
signal
is
iss
ued by
the
CPU.
OutpUt disable lignll. When
00
is
I t I high level,
the
CPU disables
the
data
outpUt
onto
the
dati
bus for
the
externa
l device.
This
signal
is
issued
when
writing data in
the
memory.
.as ,
:
AOO-
::;::::::x
A01S
:
X
:
x:=
MEOo.
I
\
I
\
M"
RIW
:
\
i
oo
=::J>
:
I
:
'C
00
-
07
:
(
MemOry
mola
>----{CPU
Int
.....
1 data
Memory
rtad cycle Memory write iignal
Memory enable lignal. This signal il e
nabled
10
direclly
Kcns
the
128K8
memory area;
MEO
accesses a 64KB area and
ME'
accelln
a
64K8
arel
.
Th
e
memory
area accessible
by
the
program
COUnter
P
and
s
teek
pointer
S
is64KB,
fO(
MEO
is
used by
the
felch
Ind
sl8<:k
co
m
mand
s.
FO(
aceening
dati,
both
ME.
and
ME
l
memory
arees
can
be
acclHSlld
by
the
CPU
command
.
Bidirectional
dala
bus
which
is
used
to
write
data
in the external
memory
or
to
read
data
from Ihe aXlernal memory.
Address bus which
may
be
in three
nates.
Goes
to
high impedance with
the
8Ra
(bos
requntl
signal . It
is
possible
to
access
the
memory
arel
of 64KB. It
is
al
so
pO$sibla
to
access
th
e memory
of
'28KB
USing
the
M
EO
or
MEl signal.
-
25
-