— 10 —
The following table shows the pin functions of the key touch LSI.
Filter Block
Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the
waveforms.
AVDD
1K
1K
1K
C222(H)
C103(H)
AG
AG
1K
AG
To main volume
-
+
IC105
M5218APR
10V22µ
C333(H)
Q107/108
2SC1740
18K
AVEE
50V1µ
From the DAC
Pin No.
Terminal
In/Out
Function
1
REQB
Out
Interrupt request. Not used.
FI8 ~ FI10
SI8 ~ SI10
4
VCC
In
+5 V source
5
CRDB
In
Read enable signal
6
CWRB
In
Write enable signal
7
CCBB
In
Chip select signal
8, 9, 11
T, STBY, W
In
Not used. Connected to +5 V.
10
RESB
In
Reset signal
12
CKI
In
10 MHz clock input
13, 14
TMD, TST
In
Not used. Connected to ground.
15
CKO
Out
Not used
16
GND
In
Ground (0 V) source
17
XIN
In
Not used. Connected to ground.
18
XOUT
Out
Not used
19
TRES
In
Not used. Connected to ground.
20 ~ 23, 25 ~ 28
CD0 ~ CD7
In/Out
Data bus
24
GND
In
Ground (0 V) source
29 ~ 31
CR0 ~ CR2
In
Address bus
32
VCC
In
+5 V source
33 ~ 39, 41 ~ 43
FI0 ~ FI7,
53 ~ 55, 57 ~ 59
SI0 ~ SI7
40
VCC
In
+5 V source
44 ~ 47, 49 ~ 52
KC0 ~ KC7
Out
Key scan signal
48, 56
GND
In
Ground (0 V) source
64
VCC
In
+5 V source
In
Key input signal. Connected to + 5 V.
2, 3, 60 ~ 63
In
Key input signal
Содержание Oriental Maestro AT1
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