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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. When the power switch is pressed, the CPU receives a low pulse of POWER signal.The CPU raises APO signal to +5 V to turn power on.
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Pin No. Terminal In/Out Function 15, 16 XLT0, XLT1 In/Out 20 MHz clock input/output +5 V source 18, 19 MD0, MD1 Mode selection terminal. Connected to ground. RSTB Reset signal input Power ON signal input — Not used. Connected to ground. FI0 ~ FI3 23 ~ 30 Key input signal...
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DAC (IC105: UPD6379GR) The DAC receives 16-bit serial data output from the CPU. The data contains digital sound data of the melody, chord, bass, and percussion for the right and left channels. The DAC converts the data into analog waveforms and output them to each channel separately.
MAJOR WAVEFORMS 50 µs 0.1 s CH1: CH2: 5 V CH1: CH2: 5 V CH3: 5 V 1 POWER ON signal 3 Key scan signal KC0 UPD912GF-3BA pin 21 UPD912GF-3BA pin 31 2 APO signal 4 Key scan signal KC1 UPD912GF-3BA pin 3 UPD912GF-3BA pin 32 5 Key scan signal KC2...
PCB VIEW AND CHECK PRINTS 3 4 5 A 1 ms A 1 ms Tone: Piano-1 Key: Touch response: Volume: Maximum CH1: 50 mV CH2: 50 mV CH1: 0.1 V CH2: 0.1 V A Equalizer output (R-ch) 9 DAC output (R-ch) UPD6379GR pin 5 B Equalizer output (L-ch) 0 DAC output (L-ch)
PARTS LIST CPS-7 Notes: Prices and specifications are subject to change with- out prior notice. As for spare parts order and supply, refer to the "GUIDEBOOK for Spare parts Supply", published seperately. The numbers in item column correspond to the same...