Service manual
•
.
-
PC- l600
Pin
Svmbol
I
n/Out
Actill.
SI.t.
FU
ne1l
on
No.
'w.
It
AC
l
~
V
~
*
lQRJ
Z\S
o-
J
KH
ZIB
~
1J
V
I I
KH
IL.Jl
20
Z12
0,,,
L
~
'"
F
or
the
PC
-l
600,'
high signa'
n.lIls
normallv issued
(.t
ONI.
21
Zl1
,.
,.
NC.
22
ZIO
Cu,
High
,.
Tnil ligna
ll
l used
to
Interface with
tht
main C
PU
. il
goel
high when the
sub CPU
_I"
for.
commend
(r
..
dyl,
and
gaes
lowwhen
bulY.
23
Z.
0,,,
High
,.
This signel
i.
, lso used
to
inte
rf_
with
the
mein CPU. A high pulse i.
i$$ued
whe
n t
ht
s
ub
CPU
lerm
i
n.
!
••
comme
nd
execution,
2.
Z8
Cu,
,.
Used
to
$IIt
up
the
tn.
log
input
mode
.
11
1
VO
l
l
'~
i.
AID
conv.rted when low !initi
al
valuel.
The
input
impedance
i.
100
K ohm
••
121
Current
I.
AID
cOlli/M
ud
wh
ln
high,
T
h.
PC
-l
600
I
Upporu
t111n BASI
C,
but
it
needs
to
pr
ogr
ltn
In m
.:
hine
Ienguegt
for
121.
26
Z7
0,,,
H igh
,.
The
sub
CPU
uu
this
sign,
l high
when
th
e
com
m
and
$peelfled
In
t
er
rupt
has
been acknowledged, This
sign,l
is
con
nected
to
IN
T6
input
at
the
SC7852.
There ere
fcu
re.u.s
which force
thl
sslgn.
ll
evel
to
high.
)I)
Th
e
wek.up
time
metch
ed
thl
rl
l l·
time
timer.
(1
)
Th
e
time
of
Ill
rm·1
or
·2
mlt
ch
ld
the
rlel
·time
timer
.
(III)
Rl"Clipt of I n
input
from
thl
llIIternl l keyboard.
(I
V) At O.S second cycle
of
the
real·
time
timer.
Th
is
sig
na
l
goft
l
ow
when
thl
int
lr
r
upt
caUK status
is
read
or
whln
all inpul1
from
the
eIItlrnal keyboa
rd
have been read.
2B
GNO
'
OV
27
Z'
Cu,
L
ow
,.
A
1/64
t8COnd
pulSi
of
SO%
duty
Is
se
nt
.
Connected 10
iFif4 end P
BS
inp
u
ll
of
lhl
SC78S2
.
2B
Z'
0..,
H
igh
,.
As
t~
r
ef.,.encl
lIoltage
is
required
whl
n
the
w b
CPU
AID
corwensthe
sig""
input
to
KCG-
KC2, ZS
iSKt
high only d.oring
the
AID cotlllllt"llon to obtain
the CornlCt Y
RH
.
Th
is
1$
u$ed for Y
RH
accuracy IS well
1$
powe
r lIVing.
29
Z'
0"'
Hi
gh
,.
Used for handshaking of
the
IIlIternal keyboard
input
thr
ough the analog
input
connector.
Shoned
with
the
anal~
i
nput
KC1.
Normally an open
output
.
30
Z3
,.
,.
31
Z'
,.
,.
32
ZI
,. ,.
N
ot
used.
33
ZO
,. ,.
34
SOU
T
Cu,
35 SCLOCK InlOu t
,.
"
F
Cu,
t:lsecI
10f"
genlf"ttion
of
cli
ck
and alarm sounds.
37
V
R"
,.
AID
corwersion h
igh
side reference voltage
(2.47S
V In 5Upply ).
-
28
-
.