Service manual
I
--,
PC
1600
- -
- - -
T
-4. Gate array (LR38041)
pin
description
I
h
is
gafe array
is
an
integration of I
Cs
required for connec·
;
9
ion of _LSls.
-
Pin
Symbol
I
n/Out
Active
Fu nction
No. level
1
SLCB
1
~
It
Is
an
input
of
the
sub CPU·
iuued
signal PI
wh
i
ch
indicat es
com
men
cement
01
Ihe
system
operetio
n.
-
PI ISLe B)
goes
h
ig
h
when
the
sys
tem
is
off
and
doe
s
the
fol1owir'lg.
"'
Data bullts,
02-
DO
.
are
fixed
at
iii low level.
12'
EXc:&pt
for
A
1lA,
all outpUt levels are fixed
10
t
ow
or
high.
Z
Q3
'"
Hardware
WIIak
blIttery
detett
signal.
1
11
W
hen
a
weak
battery
con
dit
ion is
detected,
it forces
Q3
high; SI ,
S2,
S3,
KO,
Kl ,
and
K2 outputs&re
sel
high; KH
outpUt
is
set
low
;
and
AD
is
set
to
high impedance
(inecli...,).
121
Q3 is
at
a low level
when,
w,",k
battery
is
"01
est
ablished.
3
Z12
I,
When on,
tM
input
is high.
4
213
"
L
~
The
sub
CPU is n
orma
ll
y in
the
SII'Idby m
ode
10
AVe
power
when
8
eommand
is
nOl
received.
But
,
lt
would
not
go
into
t
he
power
save
mode
if
the
BREAK/ON
key
I,
cont
inuOllily depressed, n
it
goa.
OUt
of
the
n.ndby
m
ode
if
KH
i,
..
I hi
gh
I_I
.
To
prwent
thi
S,
the
nate
of
the
BREAK/ON
key
must
be
i
nte
rrogated with
Z13
when
~
ired
.
During
the
pOWllr
save
mode
, Z 13 is
set
to
high
to
keep
th
e
KH
output
...
l
ow
leve
l.
5 ON
"
L
ow
BREAK/ ON
key
input.
The
l i
gnalllO"
low when
the
BREAK
/ON key il d!lpreued ; otherwise,
it il
in I h
igh
ltat
•.
S KCl
I,
Signal
input
from
th
e analog Input
co
nn
ector.
7 C
Ll
'"
Sub
CPU 1.
229M
Hz cl
ock
In
put.
•
AD
Qu,
L
~
R
eid
signal cr
Mted
by
f
jy&
lignels (MEO, MEl , 0 0 ,
CKOS
.
and
BRO) which ara
ex
ternally
wired
OR
with
Ro
of
thl
Z-80
.
When
the
Z-aO Is
In
operation,
AD
;'
at a hi
gh
Impedance.
....
,.
A
2D-
R33
"
Ret
urn
data
from
t
he
sub
CPU.
The
data
becomes
the
Z-ao
date
when
the Z-aO reeds
33
H
of
110 .
17
PA
lM
'"
The
PC-1600
ha
l
two
serill
inputloutpu
t
interf
acl
:
thl
RS·232C
interface
and
t
he
SID
interface. But, ei
ther
one
mUlt
be
assigned
al
onlv
on&
hardwar
e i. for
the
se
rial inpu
t/
OU
tPUI.
Ii
III
Th
e
510
Interface
illtllected
with
I
low
PAlM
nlte.
121
The
R
5-232C
interface
Is
M
ltcted
with
a high PR IM
lUte.
PRIME - "
Lo
w"
PRIME · " H
igh"
Output
SoA
LOW
TXo
Output
SoF
TXl5
LOW
In
put
R
XD
ADF
AD
A
,.
TXD
"
~
Transmit
da"
which is
an
outp
ut
from
the
T
B576F
UART.
,.
AXD
Qu,
L
ow
Receive d
at.
which
is
an
input
to
the
T
8576F
UAR
T.
20 A
DA
'"
L
ow
R
eceivl
dati
wh ich
i.
an
input
from
th
. A
5-232C
Interf
acl.
21
SDA
Ou'
High Transmit
dati
outp
Ut is
sent
Ihrou
gh
the
RS·
232C
interface
connector.
A l
ow
,i
gn&1
state
Is
sent
w
hen
PR
1M
is
at
• l
ow
level.
2Z
ADF
'"
Hi
gh Receive
data
wh ich i.
an
input
from
thl
SID i
nurface.
23
SDF
"",
H
igh
Tr
ansmit
dall
which is
an
outpUt
10
the
SID interface
connec
t
or
.
A low
s.i
gnal
nate
Is
sent
when PR 1M i,
at
a high level.
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