Circuit Description - Casio Realistic Concertmate 500 Service Manual

CIRCUIT DESCRIPTION
CPU (MSM6283
01GS;
LSI
Y)
• Generates
pitch
and envelope
signals for
melody,
chord,
bass,
and
obbligato sounds.
•
Provides percussion sounds.
•
Controls keys, switches,
RAMs,
and
ROM.
The
following
is
a
list
of pin functions of the CPU.
PinNo.
Terminal
Name
In/Out Functkon
1
BOND
Ground
iOV) source
ror
AOC
iAnalog
to Dignal Converter)
2
'
VAOC
*
-5V
source
tor
AOC
3.4
T
No
fur^citon.
5-11
1
100-106
»
In/Out Data bus
<100-
106).
"^12
'
AO
Out
.
Address bus
(AO).
13
:
107
•
*
1
m/Out
Data bus
(107).
14
A1
1
Out
Address bus
(A1).
is'
'
CE
¥
^
'
Out
Chip
enable
sigr>al
for
the
memory
devices.
16-18
A2. A10.
A3
T
•
Out Address bus <A2, A3.
A
10).
19
idE
•
«
Out Output
enable
signal
for the
memory
devices.
^20-30
I
A4-9. All-15
Out
Address bus (A4
-
A9,
A1
1
-
A15).
A
"
'31*
*
I
wt
W w
Out
Write
signal
output.
1
When
"L". the
CPU
writes data into the
memory
devices.
32
1
RPSH
1
Out Refresh
signal output.
When
'X*'.
the
CPU
refresh the
memory
data of
RAMs.
~33-39
f
r~
No
function.
40
[gno
^
Ground
(OV)
source.
"'41.42*
r
1
No
function.
43 VDD1
1
1
-5V
source.
"44-66*"
No
function.
"stTbs
"
,
OSI.OSO
'
Irt/Out
7.24
MHz
clock pulse
inputs.
59
'
1
»
—
1
No
function.
60
1
1
RESET
In Reset
signal input.
"H"
active.
At power ON,
the terminal receives
art
''H"
level
pulse so that the CPU's
internal
[
circuits are initialized.
61
'k015
1
t
Out
|~Control
signal for external
filter circuit.
"62-66"^
No
function.
~67-76"
K09
- KOO
Out
^
Key
ar>d
switch
common
signals output.
77~84
1
KI1
-kl8
In
Key
and
switch input
signals
input.
85
No
function.
86 *P01
*
j
Out
APO
(Auto Power
Off)
signal.
When
the
instrumertt
is
left
unoperated
for
approximately 7 minutes, the
terminal drops to
"V
level to shut the voltages
off.
87
1
.
No
function.
88
P03
r Out
'
Control
signal
for external
filter
circuit.