Explanation Of Circuit - Sanyo NV-E7500 - Navigation System With DVD Player Service Manual

EXPLANATION OF CIRCUIT

IN NAVI MODE, the power supply is supplied to NAVI BLOCK and SERVO PCB.
The NAVI signal from th microcomputer is Hi, and +3.3V and +5V are supplied to NAVI BLOCK from
Q36, Q38 and Q40.
+5V is supplied to SERVO PCB from Q120
a. CPU IC20)
IC20 controls ASIC, MEMORY and GRAPHIC CONTROLER etc. in MAIN CPU.
Taking in the key signal from GPS data and microcomputer are also performed by CPU.
And CPU detects the state of BEEP output, Parking brake and Disc cover etc.
b. ASIC IC30
ASIC performs output of the control signal at the time of memory access of CPU,
and communicates with DVD drive.
Voice guidance is outputted through IC31 DAC and IC32 LPF/AMP by ASIC.
c. MEMORY IC36, 37, 38
IC36 and IC37 are used for memory of Map data and calculation of NAVI microcomputer by SDRAM .
IC38 is used for memory of program software, font data, bit map data, and back up data
of course and initial setting by FRASH.
d. GRAPHIC CONTROLER IC25
The data sent from NAVI microcomputer of MEMORY is changed into the data for display.
IC26 is used as work memory by DRAM .
Graphic data is outputted by RGB data synchronizing with VCLK.
IC28 is inputted to pin 3 and pin 14 by PLL.
15.7KHz is compared and VCLK is outputted from pin4.
e. VIDEO DAC IC29
Digital RGB outputted from IC25 is synchronizes with VCLK and changed into ANALOG,
and RGB signal and Composite video signal are outputted.
f. GPS
GPS tuner is arranged on MAIN PCB.
Pin 9 is power supply for tuner, pin 10 is power supply fro antenna,
and pin 7 is power supply for backup.
Pin 4 receives data from NAVI microcomputer, and data is transmitted to
NAVI microcomputer from pin 3.
From GPS tuner, position/time data is outputted for every seconds,
and it is inputted into pin 145 of NAVI microcomputer.
a. Microcomputer part
Microcomputer manages the whole set, such as power supply management, change mode,
change image/audio, sensor input processing of remote control or dimmer.
Communication with parking brake input and NAVI BLOCK are also performed.
b. Image part
There are 3 kinds of images displayed by this set, NAVI image, DVD image, and VIDEO IN image.
Their signals are switched by VIDEO SW IC10, IC11 and outputted to LCD interface IC IC1002 .
However, since NAVI image is outputted from NAVI BLOCK and DVD image is outputted from
DVD BLOCK by RGB signal, so DVD image and NAVI image are switched by RGB SW IC8 ,
and RGB signal of OSD is switched by RGB SW IC9 , and then they are outputted to
LCD interface IC IC1002 .
Gamma correction and bright adjustment of the image signal inputted to LCD interface are performed,
and then the image signal is outputted to LCD side as RGB signal.
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