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KRC-949D
CIRCUIT DESCRIPTION
Deck mircocomputer (7508G(M)-814-00)
@ Outline
This microprocessor is used for controlling the car audio
deck
and
is composed
of twin
(MASTER
and SLAVE)
CPUs.
As for roles of MASTER
and SLAVE
microcomputers,
all keys, mechanical sensors and display related to the deck
are assigned
to the MASTER
side, and the SLAVE
side
controls
mechanisms
in accordance
with the data trans-
mitted through serial data transmission.
© Port assignment diagram for 7508G(M)-814-00
ACC SW
TUNER POWER
COMMUNICATION
REQUEST
SCK
Duty
= 1/8
so
BCD DECODER
Ss!
(TC4028BF)
BUZZER
MASTER
MATRIX
(uPD7508G)
ACC CONT.
COMMUNICATION REQUEST
TO SLAVE
ELECTRONIC VOL.
dbx
12
Oo
®@
lomme)
e)
NUMBER
OF MUSIC
SETs
7 seg.
oe
BE
RE-
EJECT | peat
wi
VOL.
MUSIC
Fos! | CM
M2
SET
sw
LOAD-
Principal functions
Electronic VOL. data transmission:
VOLUME, BAL-
ANCE, FADER,
BASS, TREBLE
Key entry : entry of all KEYs related to deck.
LED display : ON/OFF of each mode, residual value,
electronic VOL.
Serial data transmission : Exchange of data with SLAVE
side.
LED OUTPUT
RESIDUAL
VALUE
DISPLAY
No.
1
ELECTRONIC
VOL.
DISPLAY
PLAY
MUTE
at
DOWN
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