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Name Voltage For operation of
VDD +5 V CPU, Reset IC, Working storage RAM
DVDD +5 V DSP, Key touch LSI, Sound source ROM, Effect RAM, KO siginal generator
AVDD +5V DAC, Filter
LVDD +4.5 V LED Driver
VCC +9 V Power amplifier, Pilot lamp
VC +9 V Power amplifier
BUTTON MATRIX
KI1 KI2 KI3 KI4 KI5
KO0 3021
KO1 Control Demo Effect MIDI
KO2 +978
KO3 6-54
KO4 Tone
MIDI
Channel
Channel
On/Off
Octave
Shift
Modulation
POWER SUPPLY CIRCUIT
The power supply circuit generates six voltages as shown in the following table. VDD voltage is always
generated. The others are controlled by APO signal output from the CPU.
RESET CIRCUIT
When batteries are set or an AC adapter is connected, the reset IC provides a low pulse to the CPU.
The CPU then initializes its internal circuit and clears the working storage RAM.
When the power switch is pressed, the CPU receives a low pulse of POWER signal. The CPU provides
APO signal to the power supply circuit and raises RESET signal to +5V to reset the DSP, the key control-
ler and the KO signal generator.
VDD
Battery set
RESET
CPU
LSI106
HD6433298A42F
Reset IC
IC105
RH5VL36AA
Working Strage RAM
LSI105
SRM2264LM90
DSP
LSI102
HG51B155FD
Key Controller
LSI107
HG52E35P
DVDD
DVDD
DVDD
VDD
VDD
-RESET
POWER
From power switch
KO Signal Generator
IC102
TC74HC174AF
-NMI
To power supply circuit
APO
P42