BenQ GL2055 Product Service Manual page 69

GL2055/ GL2055M
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. The MCU
is built-in on the Scalar IC, and offers H/W DDC2Bi function & controls system
processing.. The Flash ROM stores source code. 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: RTD2270L (GL2055A) and TSUMU58VHJ (GL2055/GL2055M)
are total solution graphics processing IC for LCD monitors. It is configured
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