Panasonic gp6d th-42px20u th-50px20u th-42pa20u th-37pa20u update information Service Manual

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 System Control Circuit  
 
Panel Operations 
 
Figure 22 
 
This main CPU, IC9701 uses three different I
2
C bus lines to control peripheral 
devices. Bus line 1 controls the operation of the EEPROM. Programmable setting 
such as drive settings or white balance is stored in the EEPROM, IC9702. Bus 
line 2 controls the video processing, main tuner and the sub tuner. Examples of 
video processing include on-screen display, tint or contrast as well as many other 
picture adjustments. Bus line 3 reads the data from the Stand-by CPU for front 
panel and remote control operation. Additionally bus line 3 reads the condition of 
the SOS protection lines and transfers this information to the Main CPU.  
 
In all cases, the Main CPU, is the master of the bus, all other devices are slaves. 
This means that all commands are generated from the Main CPU.  
 
 
 
 
 
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