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CPU (LSI14: HD6433294A19F)
The 16-bit CPU contains a 32k-bit ROM, a 1k-bit RAM, seven 8-bit I/O ports, an A/D convertor and MIDIl
interfaces. The CPU accesses to the working storage RAM, the DSP and the key touch LSI. The CPU
interprets MIDI message using the working storage RAM. The CPU also controls buttons and LEDs.
The following table shows the pin functions of LSI14.
Pin No.
Terminal
1
P50/TXD
2
P51/RXD
3
P52/SCK
4
-RESET
5
-NMI
6
VCC
7
-STBY
8
VSS
9, 10
XTAL, EXTAL
11, 12
MD1, MD0
13
AVSS
14
P70
15 ~ 21
P71 ~ P77
22
AVCC
23 ~ 30
P60 ~ P67
31
VCC
32 ~ 48
A0 ~ A15
40
VSS
49 ~ 56
D0 ~ D7
57
P40
58
P41
59
P42
60
P43
61
P44
62
P45
63
P46
64
P47
DIGITAL SIGNAL PROCESSOR (LSI11: HG51B155FD-1)
Upon receipt of note numbers and their velocities, the DSP 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
rhythm pattern is selected. Then it provides 16-bit serial signal containing data of the melody, chord,
bass, and percussion to the DAC. When an effect selected, the DSP adds the effect to the sound data
using a 256k-bit RAM.
The following table shows the pin functions of LSI11.
I n / O u t
Out
MIDI signal output
In
MIDI signal input
Out
Reset signal output
In
Reset signal input
In
Power ON trigger signal input
In
+5 V source
In
Standby signal input. Connected to +5 V.
In
Ground (0 V) source
In
20 MHz clock input
In
Mode selection input
In
Ground (0 V) source
In
Analog input terminal for the pitch bend wheel
Out
Input terminals from keys (KI1 ~ KI7)
In
+5 V source
Out
LED drive signal output
In
+5 V source
Out
Address bus
In
Ground (0 V) source
In/Out
Data bus
Out
Clock for KO signal generator
Out
KO signal data
Out
APO signal output
Out
Read enable signal output
In
Write enable signal output
—
Not used
Out
10 MHz clock output
—
Not used. Connected to +5 V source.
— 7 —
Function
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