Casio CTK-731 Service Manual page 15

DIGITAL SIGNAL PROCESSOR (LSI4:HG51B155FD)
Upon receipt of note numbers and their velocities, the DSP (Digital Signal Processor) reads sound and
velocity data from the sound source ROM in accordance with the selected tone; the DSP can read rhythm
data simultaneously when a rythm pattern is selected. Then it provides 16-bit serial signals containing data
of the melody, chord, bass, and percussion to the DAC. The DSP also adds the selected effect to the sound
data using a 256k-bit RAM.
The following table shows the pin functions of the DSP.
Pin No. Terminal
1 ~ 8 CD0 ~ CD7
9, 10
11 GND7
12 CK16
13 VCC6
14 CK0
15 TCKB
16 VCC1
17 GND1
18, 19 XT0, XT1
20 SGL
21 CCSB
22 ~ 25 CA0 ~ CA3
26 CE0
27 CWRB
28 CRDB
29 ~ 32
33 RESB
34 TESB
35 ~ 39
40 ~ 49
RD0 ~ RD15
52 ~ 57
58 RA23
59 RA22
60 RA21
61 ~ 73
RA0 ~ RA20
75 ~ 82
74 GND5
83 WOK2
84 VCC3
85 GND3
86 WOK1
87 SOLM
88 SOLP
89 BOK
In/Out
In/Out Data bus
Not used.
In Ground (0 V) source
Out 24.576 MHz clock output
In +5 V source
In Clock input. Connected to terminal CK16.
Not used.
In +5 V source
In Ground (0 V) source
In/Out 24.576 MHz clock input/output. Connected to a crystal oscillator.
In System control terminal. Single chip system: Open
In Chip select signal input
In Address bus
In Not used. Connected to ground.
In Write enable signal
In Read enable signal
Not used.
In Reset signal input
In Not used. Connected to +5 V
Not used.
In Data bus for the ROM1 and ROM2
Out Chip select signal for the ROM1
Out Chip select signal for the ROM2
Out Not used.
Out Address bus for the ROM1 and ROM2
In Ground (0 V) source
Out Word clock output. Not used.
In +5 V source
In Ground (0 V) source
Out Word clock for the DAC
Out Serial data output. Not used.
Out Serial data output for the DAC
Out Bit clock output for the DAC
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Function