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5.6. Circuit Operation Theory
A-1) Interface board diagram:
(a) Circuit operation theory:
A basic operation theory for this interface board is to convert analog signals of Red, Green
and Blue to digital signals of Red, Green and Blue. The scaling IC has internal A/D
converter, internal OSD, built in LVDS transmitter and auto-detect input timing functions.
A/D converter is convert analog signal to digital data. OSD is offering adjustable functions to
end-user. Detect timing is for detect change mode. LVDS transmitter is used to compress
the digital RGB data, the Hsync, Vsync and pixel clock generated by Scaling then output to
LCD module. MCU stores source code and offers H/W DDC2Bi function & controls system
processing. EEPROM is stored DDC data, OSD common data and user mode data.
(b) IC introduction:
1.) DDC (Display Data Channel) function: We use DDC IC to support DDC2Bi function. DDC
data is store in 24C02 (EEPROM). Those data related to LCD monitor specification. PC
can read them by “SDA” and “SCL” serial communication for I²C communication for
DDC2Bi.
2.) Scalar IC: It is a total solution graphics processing IC for LCD monitors. It is configured
with an integrated triple-ADC/PLL, an integrated receiver, a display processing engine,
an integrated micro-controller and output display interface that can support LVDS panel
interface format. And it also integrates power management control capability for green-
mode requirements and spread-spectrum support for EMI management.
