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4. THEORY OF OPERATION

This section describes the function of the LCD monitor per functional block.

button board.

1. MB BOARD

The MB board is a four-layer, single-landed design with ground and internal planes provided.

The VGA cable is a signal cable that contains video signal, sync signal and DDCsignal from PC VGA adapter.

This system board consists of 3 functional areas : flat panel controller, flash ROM and LVDS transmitter.

1.1 Flat panel controller...... gm2120 (U8)

The heart of the system board is Genesis gm2120. The gm2120 is a graphics processing IC for LCD

monitor. It provides all key IC functions required for LCD panel. On-chip functions include a

high-speed triple-ADC , PLL, high sacling engine, OSD controller and on-chip microcontroller.

a) Clock Generation :

Crystal Input Clock (TCLK and XTAL). This is the input pair to an internal crystal oscillator and

corresponding logic. A 14.318 MHz crystal is recommended.

b) Hardware Reset ( Pin 5 )

Hardware Reset signal is generated by MAX809 (U10).It assert a reset signal at least 100 ms.

c) Analog to Digital Converter

The gm2120 chip has three ADC's (analog-to-digital converters), one for each color (red, green and blue)

The analog RGB signals are connected to gm2120 as described below

Pin Name

Red +

Red -

Green +

Green -

Blue +

Blue -

d) OSD :

The gm2120 has a fully programmable ,high-quality OSD controller.The on-chip static RAM(4096 words

by 24 bits) stores the cell map and the cell definitions.

e) On-Chip Microcontroller (OCM)

The gm2120 on-chip microcontroller(OCM) serves as the system microcontroller.That is , it programs the

gm2120 and manages other devices in the system such as the keypad, the backlight, LED, audio and

non-volatile RAM.using general purpose input/output (GPIO) pins.

AL718

Pin Number

171

170

167

166

163

162

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