Service manual
PC
-
l600
9-3.
Sub CPU (LU57813P)
pin
description
Pin
Symbol
I
n/Out
Active
State
Function
No
. level
atACL
,
ao
'"
L
~
'"
When t
he
system -off
command
is
received fr
om
the
Z.aO,
the
SV
$1:1IITl
is
turnad
off
after
this signal
g0e5
low. It hes PCTA L
output
from
the
SC7852
as its Input.
2
vaa
High side VGG is supplied.
3 ACL
'"
High
The
pulJe widt h of
AC
L
must
be
IIreeter
thin
1 microsecond in
duratio
n
to
be
recognized by the h.rdware. It
likes
.bout
80
microseeonds befoll! the
LSI
s1
8rt
S
10
operate
after
inp!Jt
of
ACL. This
pin
i. u
ted
IS r
eset
input
from
the
ALL RESET switch of
the
PC-1600.
4
CLl
'"
Th
.
system
clock
generating
ceramic
oscillator
is
atteched
ecross
these
two
5 CL2
Qu,
lines. With
the
PC
·1600, 8 1.229MHz oscillator
is
used for
the
basic clock of
the
RS-232C
baud
rata.
•
F
OU
T
Qu,
System clock
output.
Not
used .
7
PO
Qu,
L
~
'"
-
Reset input
to
the
SC7852.
T his line
is
maintain
ed
low
for
30
milliseconds
during
system-on
and
reset.
S
P1
Qu,
Low
'"
In a low sUite whan
the
main
CPU
is
permitted
to
access
the
memory
and
I/O.
9 P2
0"
High
'"
In
an
opposite
level
of
Pl.
In
put
to
SLCT
of
the
SC7852.
10 P3
Qu,
Low
'"
In a low
state
during
system-on
.
Used
to
turn
on
th
e
system.
11
KH
'"
High
Thi
s signal goes high
with
an
input
of
the
ON key. When
the
system
is
off,
this LSI is in
the
stendby
m
ode,
and
it
tums
on
the
system
with
e high
KH
J
S13te.
12
K'
'"
High
A
command
request
from
the
main
CPU. I
nterrupt
is
caused
by
a high
Kl
sta
te.
13
T
'"
Te
st
pin
which
is NC.
14
OSCOUT
Qu,
The
32.768
KHl
timer
crystal
oscillator
is
attached
across
thes
e lines.
15
OSCIN
'"
,.
KL
'"
High
Reset
input
from
the
perip
heral
unit.
As
monitored
by
the
software,
if this
in
put
is high
for
more
than
tha
given.timl,
the
reset
is
executed.
17
Z15
00,
High
'"
Z15
and
KL
are
shorted
outside
and
externally
pulled
down
by
the
resistor.
Z15
is
turned
high for 1
mill
i
second
in
the
reset
routine
to
be
convened
into
the
RSTE signal,
and
sent
to
peripherals as
the
reset signal via
the
system
bus.
So,
both
Z15
and
KL
can
be
handled
as
an
input/output
line,
which
may
be used
to
apply
reset
to
the
peripheral
or
to
receive reset
from
the
peripheral.
This signal is
used
as
the
rlset
input
of
the
CE·1
600
P.
18
Z14
Qu,
High
'"
The
sub
CPU
monitors
the
state
of
the
BREAK/ON
key via
the
KH
input
line
and
its
state
is
sent
throu!t1 Z14
and
supplied
to
PB7
of
the
SC7852.
Therefore,
key
chatte
ring
and
bouncing
of
the
BREAK/ON
key are
com·
pl
etely
controlled
the
s
ub
CPU.
19
Z13
Qu,
Low
'"
The
sub
CPU goes
into
the
powar-down
mode
except
when
one
of
the
co
nditions
mentioned
below
hold
s
true.
111
When 8
command
Is
received
from
the
ma
in CPU.
121
When
iii
timer
interrupt
is
received.
13'
If
the
BREAK/ON
key
sensing
KH
i
nput
is
at
II
high level.
To
prevent
these
conditions
from
occur
ring, Z13 is
set
low
8t
every
time
interrupt!1/128
second). If KH is
at
a high level, depression
of
the
BREAK/ON
key
is
sensed.
- :r/ -