NEC AccuSync LCD72VM, Руководство пользователя

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7-2
1. General Description
The LCD MONITOR contains a panel, a main board, an inverter/power board, audio board and keyboard.
2. Main Board
The main board contains panel control logic, brightness control logic, DDC and DC convert DC circuit etc.
2.1 Description of Main Chips
MCU: 8051 SCM, main function is power control, OSD control, frequency calculation, RS232 communication and
etc.
GMZAN3XL: integrate ADC, OSD, SCALER, convert analog RGB into digital and zoom and shrink scaling output
to timing control circuit of LCD panel.
AIC1084: DC power converter, used to convert 5v to 3.3v.
AIC1777A: DC power converter, used to convert 3.3v to 1.8v.
24C02: 1K EEPROM, is used to save DDC date which contains the basic parameter of production facility, supplier,
product name, maximum H-frequency, support resolution and so on.
24C16: 4K EEPROM, is used to save Auto configuration data, white balance data, the state of power key and
power on time counting data.
2.2 MCU
Oscillator: Provides clock frequency of 14.318MHZ for U101, C147, C148 is used for compensating frequency.
Capacitance for both is 33PF/50V.
Reset: Consists of R122, R188, active low.
Communication: Contains AD0-AD3 (DATA), ALE (HCLK), AD4 (HFS), INT0 (INTERRUPT REQUEST) in the
series communication between MCU and GMZAN3XL, because of some TIMING input
condition, the GMZAN3XL causes interruption and then it exports INT0 to MCU.
OSD control: PIN 25-29 is keyboard OSD function control.
White-balance adjust control: PIN 11 (RXD) and PIN 13 (TXD) are used for adjusting white-balance while in the
factory mode.
VGA-CON: PIN 24 is no signal test pin, it is high level at no signal, and low when connected to signal.
Power supply, Ground: PIN 44, PIN 35 are the power supply pins, PIN 22 connects ground.
2.3 GMZAN3XL
The GMZAN3XL is a graphics display processor and provides all the key display functions required good quality
image on a LCD panel. The integrated functions include a high-speed triple-ADC and PLL, a high quality zoom
and shrink scaling engine, an on-screen display (OSD) controller, digital color controls and LVDS Transmitters.
The GMZAN3XL provides a front-end analog interface with standard VGA compliance and an output at industry
standard LVDS interface for speed up to XGA and SXGA respectively.