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AVDD
470
AG
AG
1K
1K 1K
C333(H)
C332(H)
2SC1740SQ
1K
AG
AG
2SC1740SQ
AVDD
47K
22K
50V0.22µ
10V22µ
From the DAC
To main volume
Synch signal
Data
Word clock
Bit clock
Data
Word clock
Bit clock
DSP
LSI101
HG51B227FB
DAC
IC102
UPD6379GR
CPU
LSI105
UPD912GF-3BA
L OUT
R OUT
SI
LRCK
CLK
SO
WCKO
SCK1
SO
LRCK
BCK
SINC
SI
WCKI
BCKI
DAC (IC102: UPD6379GR)
The DAC receives 16-bit serial data output from the DSP. 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.
Pin No. Terminal In/Out Function
50 VSS3 In Ground (0 V) source
58 EA13 Out Not used
60 EWEB Out Write enable signal output for the effect RAM
61 EA14 Out Not used
62, 66, 70, 74, 78 VSS2 In Ground source
63, 67, 71, 75, 79 VDD2 In +5 V source
64, 65, 68, 69,
72, 73, 76, 77
PA0 ~ PA7 Out LED segment signal output
FILTER BLOCK
Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the
waveforms.