Casio CZ-1 Service Manual And Spare Parts List page 88

(3)
SUB
CPUc£>MAIN
CPU.
In
tht
same procedures as stated in
tht item
(2),
MAIN CPU
sends
"Request
Command"
that inquires
SUB CPU
to transmit data.
(5)
SUB CPU puts data
on
data
bus
DSO
-
DS7 and
sets
the data
in
Latch
4 by
signal
W1.
SUB CPU
then
presets
F/F 2 by pulse *4. causing signal
X896
to
be entered
in
MAIN
CPU.
Acknowledging
that data
is
set in
Latch 4
by
signal
X896,
MAIN CPU
generates clock
pulse
V.
causing data
from
SUB CPU
to
be put
on
MAIN CPU
data
bus
DO -
D7.
(4)
After
receiving data,
MAIN CPU
sends
SUB CPU
an interrupt
signal
from terminal
PB2, and
by
interrupt
signal,
SUB CPU
confirms
that the data
is
received
by
MAIN
CPU.
Repeating the
above procedures
(f)~
®
SUB CPU sends the next data to
MAIN
CPU.
Dummy
data
to
ot ntrata
signal
Rtqunt
Command
1
Latch
2 y«aqut»t
Command
)(
IT
A
x
SYC
n
n
n
n
U<eh4
"^""lit
data X
2nd
data //
X
Lait data
MAIN CPU n
PB2
M
n
n n )
n_
X898
|
|
n n
n
)
n
((
CONT
|
L
-27-