Service manual
l
1\
Syltltm-(lff
(dow
nl
in
th
t
Norm.1
system-off
03
Itltt
1
The
real
-time timer is n
ot
A timet'
interrupt
is i$Sued
relliled. every 0.5 second
to
revise
the
real-time
timer
.
2
FOUT
is
not
Issued.
FOUT
is
Issu
ed
every
0.5
second.
3
Th.
rynem
can
Ia
turned
The ry
""'"
ean
be
turned on
on
by
one
of
the
foll
ow
ing
by
one
of
the
following
oPM"ions
.ft.r
cle.
rl
ng
the
oper.tions.
_k
bettery
c
ondition
.
(j)
Depression
of
the
<D
~res
llo
n
of
Ihe
BREAK
/ON key
BREAK/ON key @ Depressi
on
of
the
ALL
® Oepression
of
tht
ALL
HESET
SWITCH located
on
A ESET .witCh
loe.ted
the
back of
the
PC
-
l600
on
the
back
of
the
®
Depression
of
the
RESET
PC
·l
600
switc
h lOCated
on
the
back
of
tht
CE·1600P
ill
Wh
en
the
Wilke-up
tim
e
meet
s
Ihe
real
time
as
programmed
bV
the
WAKES/Oj statement
®
When Ihe AS-232C
interface
CI inp!Jl is
set
high
by
the
WAKES(1)
s
tatement
Th
e figure below shows the timings when the system turns
off
.
= -
-----,
l ........
.....
..................... .
'"
_____
--'rn
..
-nn.
_____
__________
n
____
n_
voo
:~
~';.-_';.';.';.
';.:
';:
;;:;
:;
___ • _______ ____________
__
_
__
____ _
;'~:~:
,
.~
..
~
...
~
..
.
~
....
~t
..
~
...
~
.
..
~
.
..
~
....
~
...
~
...
~
...
~
....
~
....
1'2.
SLCT
".
SlCB
PO_ASTIN
215
~
lO,
Rll
- R20 I
ell(·3.58M
H.
WU1fHlfL
_
__
•.
____
______
•
__
. _. _. ___ .•
__
•.
_____
_
CKO- 211I<H. Jl....JL.
__
__
______
.
______________________
_
Wi!
001
FOUT
0.
5_
'"
CD
When
the subcontroller rece
ives
the system-off com-
mand from the main
CPU
, it confirms
that
both
ao
and KH are
at
a low level. Then,
P2
and SLCT
are
forced to low to disable
the
memory selection.
If
KH
is
at
high, the control proceeds to the system
in
sequence.
® Then,
P3
and
BFO
are set to high
to
tum
off
the
system power supply. With this, all inputs and outputs
of
the SC7852 and LH·5803
are
turned
to
a low
or
high
impedance.
® The subcontro
ll
er goes into the standby mode,
but
the real
-ti
mer issues a timer interrupt ever 0,5 second,
second,
(a)
11
the wake-up timer has been set,
the
time on
the real·timer
is
checked for whether it coincides
-
11
-
with the wakeup time. If it coincides, the system
is turned on.
(b)
If
the wake-up timer
is
set to turn on the system
with
the
RS
-23
2C interface
CI
input, the system
is turned on with
the
input
of
the
CI
signal
as
it
has been monitored.
If
the
weak battery signal
Q3
goes high when the
system
is
off,
the
system down
is
established.
7
-2
. System-on operation
The figure below
~ows
the timing sequence when the
system
is
turned on by the BREAK/ON key.
"'
_
__
--.;._---.J----f
--
--
.:. P
rohi:>
't
_
'fIg
IC
C'
''''''''
to
eSR
ol
T857t1F
PRIME _
_________
______
-'---:::::::::c!-.~o,,;""~~.,
••
~.~""
~~
-:::::;;;;:
.
"""-
-
C
I.
IC.J
.&8
~H
.
•
::::::
-_._----_
..
_----
--
:-
-_
....
, ,
MREO :
~
------_._----_
..
_-
-,-----_. :
.:.
':==
========j
:
~'~
..
~.~.~.========
!~T~
:~:
~ ~ ~
~-_
~
~~:::
_j
VDD
_____
_
••
________
~
_
___
_ •
___
•
___
:.
- - -
--- ---
-
-----
_.
-
-----
--
---
---
--.;
CD
When
the BREAK/ON key
is
pushed while
the
system
is
off. the
ON
input
of
the
LR38041 converU to low.
As
Z13 is low.
KH
goes high.
®
When
KH
goes high, the subcontroller starts
to
operate
assumi
ng
the sta
rt
of
the system. First, P3 is set low,
P2
low, Pl high , and
PO
low. Now,
VCC
is
activated
because
P3
and BFO are low, and the system reset
is
applied with low
PO
and RSTIN states. The mem
ory
and I
/O
selections are prohibited
in
low
P2
and SLCT
states_
(§)
Low
PO
and RSTIN' states are issued for
30
milli·
seconds.
(j)
The Z15 peripheral reset
output
is
issued for 1
mil-
lisecond to reset peripherals.
® First, P2 and SLCT are set to high
to
select memory
and I/O, then the system reset
is
cleared.
®
In
order
to supp
ly
stable clocking
to
the Z-80, it takes
about 0.3 millisecond before supplying the system
clock.