The following table shows the pin functions of the key touch LSI.
Pin No. | Terminal | In/Out | Function | |
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|
| |
1 | REQB | Out | Interrupt request. Not used. | |
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| |
2, 3 | FI10, SI10 | In | Key input signal | |
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|
| |
4 | VCC | In | +5V source | |
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| |
5 | CRDB | In | Read enable signal | |
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| |
6 | CWRB | In | Write enable signal | |
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| |
7 | CCBB | In | Chip select signal | |
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| |
8, 9 | T, STBY | In | Not used. Connected to +5V. | |
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| |
10 | RESB | In | Reset signal | |
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| |
11 | W | In | Not used. Connected to +5V. | |
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| |
12 | CKI | In | 10 MHz clock input | |
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| |
13, 14 | TMD, TST | In | Not used. Connected to ground. | |
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| |
15 | CKO | Out | Not used. | |
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| |
16 | GND | In | Ground (0V) source | |
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| |
17 | XIN | In | Not used. Connected to ground. | |
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| |
18 | XOUT | Out | Not used. | |
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| |
19 | TRES | In | Not used. Connected to ground. | |
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| |
20 ~ 23, 25 ~ 28 | CD0 ~ CD7 | In/Out | Data bus | |
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24 | GND | In | Ground (0V) source | |
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|
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| |
29 ~ 31 | CR0 ~ CR2 | In | Address bus | |
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| |
32 | VCC | In | +5V source | |
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| |
33 ~ 39, 41 ~ 43 | FI0 ~ FI9, | In | Key input signal | |
53 ~ 55, 57 ~ 63 | SI0 ~ SI9 | |||
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| |||
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40 | VCC | In | +5V source | |
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| |
44 ~ 47, 49 ~ 52 | KC0 ~ KC7 | Out | Key scan signal | |
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| |
48, 56 | GND | In | Ground (0V) source | |
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|
|
| |
64 | VCC | In | +5V source | |
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|
|
|
Filter Block
Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the waveforms.
10V22µ-
+
To main volume
M5218APR
C104(H) |
| AVDD |
|
| |
| 2SC1740SQ | |
1K | 1K | 1K |
C182(H) | C152(H) | 1K |
AG | AG | AG |
AVEE
10K
10V22µ
From the DAC
— 11 —
