6-9
Other
circuit
6-9-1
Sound
generating
circuit
Sound
generating
circuit
is
described
in
fig.
6-44.
1.
By
he
rising
edge
of
the
system
I/O
address
decoder
output
MUSIC
SEL,eoLmd
signal
is
outputted
after
latching
MPU
data
D7
by
IC93.
Fig.
6-45
shows
the
timing
chart
of
Sound
generating
circuit.
2.
Sgund
signals
which
was
made
by
IC93
is
amplified
by
sound
amp.
circuit
(Q
transistors
Ql,
Q2
and
Q3)
then
outputted
to
the
speaker.
3.
To
enable
to
input
the
Sgund
from
expansion
connectors
I/F-1-I/F-6
and
to
play
from
the
speaker,
the
Sound
input
terminal
is
incorporated
before
the
sound
amplifier
circuit.
Fig,
6-I6
Light
Pen
Interface
JC,
I/O
pins
JCpin
nol
signal
|
content
1
I
fJTI‘_
pen
ir2
I
WW
lf$a§S§¥§sse
H
3
I
*_*
+
5
V
Power
;
E
U VCMP
;§§i§§i§3i¥3l§?g§h§51§§§%
Sin
e
e
er’
d
when
Y
e
EØgØ
pen
~.{
kiiØ
pin
¢ S . ‹ m l
(vertical
sync)
LPOUT
in
nczsri;
P~
p_‘
f
_»"’
3u|++-Q;-"‘~‘_‘
H
H H
(horizontal
sync)
-4--|-
63.5p|
| 6 . 6 m
LP
sfe
_
lC17‘5‘
P]-n
|6.6m|
me
_
|C1B’§’
pil
i
_
_
Fig
5-43
Light
pen
interface
circuit
I/O
timing
M - + 5 v
.I
D07
Z
DPS
CRO
5
Q35
AMP
Mus|csE|_
J
was
+-jfoq
CK
exam
’
’
|C93
74LS74AP
.
.
Q - 0 ? - 0 3
‘f?§S§
’i9§iE1/F6)
Fiq-
544
Sound
generating
circuit
D01
.
QkvØgzzyyz/3
,¢;5’>33f
M;
,
J
mesa
0
1
P u t
/
f
, 3 1 § 4 ~
’ 1 f % ?
"
4153;
Musfc
SEL
r
i
(ncaa
ca
input
H
U
U
"U
SQUUC1
signal
ncaa Q
output
Fig.
5"45
sound
generating
circuit
timing
chart
7
Summary of Contents for MB-6890
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