ViewSonic Vx2235wm4 Service Manual

							
3. Front Panel Function Control Description 
 
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Main Menu
with OSD controls
Front Control Panel
shown below in detail
Scrolls through menu 
options and adjusts the 
displayed control.
Also a shortcut to display 
the Contrast adjustment 
control screen (T) / 
OptiColor  ( S) 
Displays the control screen for
the highlighted control.
Also toggles between two
controls on some screens.
Also a shortcut to Auto Image Adjust.Standby Power On/Off
Power light
Blue = ON
Orange = Power Saving
Displays the MainMenu or exits the
control screen and
saves adjustments. 
						

							
 
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Do the following to adjust the display setting:
1. To display the Main Menu, press button [1].
NOTE:  All OSD menus and adjustment screens  disappear automatically after about 15 
seconds. This is adjustable through the  OSD timeout setting in the setup menu.
2. To select a control to adjust, press SorT to scroll up or down in the Main Menu.
3. After the desired control is se lected, press button [2]. A cont rol screen like the one shown 
below appears.
4. To adjust the setting, press the up  S or down T  buttons.
5. To save the adjustments and  exit the menu, press button [1]  twice.
The following tips may help  you optimize your display:
• Adjust the computers graphics card so  that it outputs a 1680 x 1050 @ 60Hz video signal to 
the LCD display. (Look fo r instructions on “changing the refresh rate”  in the graphics cards 
user guide.)
• If necessary, make small adjustments using  H. POSITION and V. POSITION until the 
screen image is completely visible
. (The black border around the  edge of the screen should 
barely touch the illuminated “act ive area” of the LCD display.)
The command line at the bottom of the
control screen tells what to do next from
this screen. You can toggle between control
screens, adjust the selected option, or exit
the screen. 
						

							
 
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Main Menu Controls
Adjust the menu items shown below by using the up  S and down  T buttons.
Control Explanation
Auto Image Adjust  sizes and centers the screen image automatically.
Contrast  adjusts the difference between the image background  (black level) 
and the foreground (white level).
Brightness  adjusts background black level of the screen image.
Audio Adjust
Vo l u m e  increases the volume, decreases  the volume, and mutes the audio.
Mute  temporarily silences audio output.
Color Adjust  provides several color adjustment  modes, including preset color 
temperatures and a User Color mode wh ich allows independent adjustment of 
red (R), green (G), and blue (B). The  factory setting for this product is 6500K 
(6500 Kelvin).
sRGB- This is quickly becoming the industr y standard for color management, 
with support being included in many of th e latest applications. Enabling this 
setting allows the LCD display to more  accurately display colors the way they 
were originally intended. Enabling the sRGB  setting will cause the Contrast and 
Brightness adjustment s to be disabled.
9300K- Adds blue to the screen image for  cooler white (used in most office 
settings with fluorescent lighting).
7500K -  Adds blue to the screen image for  cooler white (used in most office
settings with fluorescent lighting).
6500K- Adds red to the screen image fo r warmer white and richer red.
5400K- Adds green to the screen image for a darker color. 
						

							
 
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Control Explanation
User Color Individual adjustments for red (R), green (G),  and blue (B).
1. To select color (R, G or B) press button [2].
2. To adjust selected color, press Sand T.
Important: If you select RECALL from the Main Menu when the product is 
set to a Preset Timing Mode, colors  return to the 6500K factory preset.
Information  displays the timing mode (vid eo signal input) coming from the 
graphics card in the computer, the LC D model number, the serial number, and 
the ViewSonic
® website URL. See your graphics card’s user guide for 
instructions on changing the resolution and refresh rate (vertical frequency).
NOTE:  VESA 1680 x 1050 @ 60Hz (recommended) means that the resolution 
is 1680 x 1050 and the refresh rate is 60 Hertz.
Manual Image Adjust
Horizontal Size  adjusts the width of the screen image.
H./V. Position (Horizontal/Vertical Position)  moves the screen image left or 
right and up or down. 
						

							
 
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Control Explanation
Fine Tune sharpens the focus by aligning te xt and/or graphics with pixel 
boundaries.
NOTE:  Try Auto Image Adjust first.
Sharpness  adjusts the clarity and focus of the screen image.
OptiColor Mode  provides an optimum display  environment depending on the 
contents displayed. It contains 7 user-selectable presets. These 7 presets are 
easily accessible from the short cut keys.
Standard  is for general windows environm ent and monitor default setting.
Te x t  optimized for text editing and view ing in a word processing environment.
Cinema  optimized for movie and video environment.
Game  optimized for PC/TV game environment.
Portrait  optimized for displaying indoor portraits and enhancing pictures.
Scenery  optimized for displaying outdoor scenery images.
Vivid  optimized for color luster and sharpness.
These 7 presets are carefully chosen by Vi ewsonic, but may not suit all users 
tastes. In that case, the user can eith er return to the Standard setting and 
manually adjust the brightness and contrast as desired.
OptiColor Skin Tone  includes 3 presets (Natural / Red Tone / Yellow Tone) 
which user can select according to users preference. 
						

							
 
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Control Explanation
Setup Menu displays the menu shown below:
Language  Select allows the user to choose th e language used in the menus and 
control screens.
Resolution Notice  allows the user to enable or disable this notice.
If you enable the Resolution Notice show n above and your computer is set at a 
resolution other than 1680 x 1050,  the following screen appears.
OSD Position  allows the user to move the OSD menus and control screens.
OSD Timeout  sets the length of time the OSD  screen is displayed. For example, 
with a “30 second” setting,  if a control is not pushed within 30 seconds, the 
display screen disappears.
OSD Background  allows the user to turn the OSD background On or Off.
Memory Recall  returns the adjustments back to fa ctory settings if the display is 
operating in a factory Preset Timing Mode listed in the Specifications of this 
manual. 
						

							
4. Circuit Description 
 
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RTD2553V 
LCD Monitor/MFM Controller 
General 
Embedded dual DDC with DDC1/2B/CI
　  
Zoom scaling up and down
　  
No external memory required.
　  
Require only one crystal to generate all timing.
　  
Programmable 3.3V/5V detection reset
　  output. 
Embedded crystal output to micro
　 -controller. 
3 channels 8 bits PWM output, and wide range
　  selectable PWM frequency. 
Analog RGB Input Interface  Integrated 8
　 -bit triple-channel 210/165 (optional) MHz ADC/PLL 
Embedded programmable Schmitt
　  trigger of HSYNC 
Support Sync On Green (SOG) and various kinds
　  of composite sync modes 
On
　 -chip high-performance hybrid PLLs 
High resolution true 64 phase ADC PLL
　  
Y/Pb/Pr support up to HDTV 1080i resolution
　  
Support 2/1 Analog input (optional
　 ) 
Digital Video Input Interface  Support 8
　 -bit video (ITU 656) format input 
Support 16
　 -bit video (ITU 601) format input (optional) 
Built
　 -in YUV to RGB color space converter & de-interlace 
DVI Compliant Digital Input  Interface (optional) 
Single l
　 ink on-chip TMDS receiver 
Support to 165Mhz with long cable
　  
Adaptive algorithm for TMDS capability
　  
Data enable only mode support
　  
High
　 -Bandwidth Digital Content Protection (HDCP 1.1) (optional only in H version) 
Enhanced protection of HDCP se
　 cret key (optional only in H version) 
Auto Detection /Auto Calibration  Input format detection
　  
Compatibility with standard VESA mode and
　  support user-defined mode 
Smart engine for Phase/Image position/Color
　  calibration 
Scaling  Fully programmable
　  zoom ratios 
Independent horizontal/vertical scaling
　  
Advanced zoom algorithm provides high image
　  quality 
Sharpness/Smooth filter enhancement
　  
Support non
　 -linear scaling from 4:3 to 16:9 or 16:9 to 4:3 
Vivid Color.  Dynamic Contrast Control (DC
　 C) 
Independent Color Management (ICM)
　  
True 10 bits color processing engine
　  
sRGB compliance
　  
Advanced Dithering logic for 18
　 -bit panel color depth enhancement 
Dynamic overshoot
　 -smear canceling engine 
Brightness and contrast control
　  
Progr
　 ammable 10-bit gamma support 
Output Interface  Fully programmable display timing generator
　  
Flexible data pair swapping for easier system
　  design. 
Programmable TCON function support
　  
Multi
　 -output interface (RSDS/ LVDS/TTL)on single PCB 
Spread
　 -Spectrum DPLL to reduce EMI
 
Fixed Last Line output for perfect panel
　  capability 
Host Interface  Support MCU serial/parallel bus interface.
　  
Support MCU dual edge data latch.
　   
						

							
 
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Embedded OSD 
Embedded 12K SRAM dynamically stores OSD
　  command and fonts 
Supp
　 ort multi-color RAM font, 1, 2 and 4-bit per pixel 
16 color palette with 24bit true color selection
　  
Maximum 8 window with alpha
　 -blending/gradient/dynamic fade-in/fade-out, bordering/shadow/3D       
window type 
Rotary 90,180,270 degree
　  
Independent r
　 ow shadowing/bordering 
Programmable blinking effects for each character
　  
OSD
　 -made internal pattern generator for factory mode 
Support 12x18~4x18 proportional font
　  
Decompress OSD font
　  
Power & Technology  3.3V power supplier
　  
0.18um CMOS process, 12
　 8-pin QFP package 
Embedded 3.3V to 1.8V voltage regulator
　
 
 
Analog Input 
RTD integrates three ADC ＇s (analog-to-digital converters), one fo r each color (red, green, and blue). 
The sync-processor can deal with  Separate-Sync, Composite-Sync, and Sync-On-Green. And the PLL 
can generate very low jitter clock from HS to sample  the analog signal to digital data. Input data is 
latched within a capture window defined in registers refer to VS and HS leading edge. RTD also has 2 
ADC input, we can switch these 2 input to choose which input we want to present on RTD embedded 
LCD monitor. 
RTD has a YPbPr input, we can connect DVD or some devices that has YPbPr input, YPbPr input can 
be 1st or 2nd ADC pins.
 
 
TMDS Input 
RTD integrates high-speed single li nk receiver function. It can operate up to 165 M at long cable. RTD 
integrates an equalizer to enhance the cable loss weakness in long cable application and the advanced 
tracking algorithm to have better performance in DVI RX.
 
 
Display Output Timing 
The display output port sends single/double pixel data transfer and synchronized display timing to an 
external device. The display port also support display panel with 6-bit per color, turn on the dithering 
function to enhance color depth. In single pixel  output mode, single pixel data (24-bit RGB) is 
transferred to display port A on each active edge of DC LK, the rate of DCLK is also equal to display 
pixel clock. The sync & enable signals are also se nt to display port on each active edge of DCLK. In 
double pixel output mode, doubl e pixel data (48-bit RGB) is transferred to display port A & B on each 
active edge of DCLK and the rate of DCLK is equal to half display pixel clock at this moment. 
The sync & enable signals are also sent  to display port on each active edge of DCLK.
 
 
Color Processing 
Digital color R & G & B independent channel sRGB,  contrast, brightness, gamma, dithering controls 
are built in RTD. sRGB compliance function is provided with 9 multipliers. The contrast control is 
performed a multiply value from 0 to 2 for each R/G/B ch annel. The brightness control is used to set an 
offset value from  –512 to +511 also for each R/G/B channel. Also RTD provided 10 bit gamma and a 
high performance dithering function.
 
 
Build-In OSD 
The detailed function-description of build-in OSD,  please refer to the application note for RTD 
embedded OSD.
 
 
Color LUT & Overlay Port 
The following diagram presents the data flow among the gamma correction, dithering, overlay MUX, 
OSD LUT and output format conversion blocks. 
Auto-Adjustment 
There are two main independent auto-adjustment functions supported by RTD, including 
auto-position & auto-tracking. The operation procedure is as following;  
						

							
 
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Auto-Position 
1. Define the RGB color noise margin: When the value of color channel R or G or B is greater than 
these noise margins, a valid pixel is found. 
2. Define the threshold-pixel for vertical boundary search 
3. Define the boundary window of searching for horizontal boundary search. 
4. Start auto-function. 
5. The result can be read from register. 
Auto-Tracking 
1. Setting the control-registers for the function (auto-phase,  auto-balance) according to the 
Control-Table. 
2. Define the Threshold 
3. Define the boundary window of searching for tracking window. 
4. Start auto-function. 
5. The result can be read from register 
PLL System 
Inside the RTD, there are four PLL systems for display clock and ADC sample clock (PLL1, 
PLL2,M2PLL, DPLL ). 
DCLK PLL 
DPLL frequency = F_IN * DPM / DPN * Divider. 
F_IN is input crystal frequency. DPM and DPN is in  DPLL_M and DPLL_N .  
DPLL_N , and it divide PLL frequency by 1, 2, 4 or 8. 
According to parameter DPN, you must set LPF Mode in DPLL_WD . If LPF Mode is 1, the charge 
pump current, Ich, must be DPM/17.6, while Ich mu st be DPM/1.67 if LPF Mode is 0. The charge 
pump current Ich is in  DPLL_CRNT. 
Spread-Spectrum function is also  build in DCLK to reduce EMI. You can control the SSP_I, SSP_W, 
and FMDIV to fine-tune the EMI. 
M2PLL is a PLL used to power-on reset, FIFO clock and Internal crystal clock. After power-on reset, 
M2PLL output 10 times frequency of crystal clock. According to crystal frequency, set M2PLL to keep 
FIFO clock frequency between 240MHz and 250MHz. 
ADC Pixel Sampling PLL 
The input pixel sampling PLL of RTD compose of PLL1 and PLL2 and DDS, the hybrid PLL system 
inherently has a process-independent advantages co mparing with pure analog PLL, DDS synthesizer is 
in charge of the phase-frequency control, PLL1 pr ovided a high frequency to get a larger bandwidth 
letting the system fast locking, PLL2 finally synthesize the desired pixel sampling clock. The block 
diagram shown below describes our high-performance tracking system.
 
Host Interface 
Parallel/Serial Port Determination: 
After RESET end, the status of pin 5 (TMDS_TST)  can be sensed to determine the interface mode: 
high for parallel port, low, low for serial port. 
Host Interface Location Determination: 
After the falling edge of RESET signal, the status of  pin 3 can be sensed to determine the host interface 
location: high for 112-115,118,119, and low for 52-57
 
Reset Output 
We have the RESET_OUT function, and also reserve the RESET_IN function. By the bounding of 
internal pins we can select two kinds of reset func tion. First of all is only reset-out, we can output the 
reset signal to MCU, and the MCU can reset the RT D by firmware. The second is RTD output reset and 
also reset itself. Notice that the reset output is positive polarity, besides, the reset output is open-drain 
pin, please don’t forget to attach a  pull-up resistor (10K). The reset function for 3.3V operating 
voltage detection is determined by  33VRST_REF voltage, No matter 5V or 3.3V MCU is been used, 
divider the input voltage on 33VRST_REF to 2.2V for internal power sensing circuit detecting, the 
divider resistor should be 10K level avoiding current leakage.
 
The Programmable Schmitt Trigger of HSYNC 
To get better waveform of the input HSYNC, we  have a programmable Schmitt Trigger circuit. For 
different HSYNC amplitude and polarity, we can select different setting of the threshold voltage. The 
Vt +  and the Vt - can be selected by register CR97 We can select the old mode or the new mode. When 
using the new mode we can directly determine the positive threshold voltage (1.4V, 1.6V … 2.6V), and 
we can choose the hysterias from 
the  Vt +  to determine the  Vt - (0.6V, 0.8V, 1.0V, 1.2V). We also can finely tune the voltage by minus 
0.1V. For application, we can select different threshold voltage by the polarity of the HSYNC. The 
control register is CR97  
						

							
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Crystal Frequency Output 
RTD can output crystal frequency or 1/2 crystal frequency to external MCU to save a crystal device. 
Once power state is on and reset is finished, we can  set crystal frequency by firmware and output to pin 
48 and pin 110 simultaneously, and then can turn off them in Pin Share Part. Pin 48 and PIN 110 is 
configurable, detail setting is listed in Pin-Share part 
 
RTD2120  8051 Embedded Micro-Controller for Monitor   
Overview  
This chip is the micro-processor of LCD monitor. It uses the design ware DW8051 of 
Synopsys as the 8051 core of this chip and is  compatible with other industry 8051 series. Also, 
96Kbyte FLASH with 8 bit bus is embedded in  this chip which is licensed from TSMC 0.18um 
e-FLASH process. Here we use the package of PLCC44/LQFP48 if we would like to have a 
discrete MCU controller or we make a multi-chip  package with our LCD monitor controller to 
form one chip package to save the  cost of package and PCB material.   
Features   　Operating voltage range : 3.0V to 3.6V   
　 8051 core, CPU operating frequency up to 50MHz   
　 4 clocks per machine cycle   
　 256-byte internal RAM   
　 512-byte external data RAM, including 256-byte DDC RAM(128-byte x 2) and 256-byte 
general purpose RAM   
　 96K-byte flash memory, 64k for program and 32k for saving parameter   
　 Two DDC ports compliant with VESA DDC1/2B/2Bi/CI   
　 Three channels of PWM DAC with programable frequency from 100K to 100Hz   
　 Watchdog timer with programmable interval   
　 Three 16-bit counters/timers (T0, T1, and T2)   
　 One PLL to provide programmable operating freque ncy and clock output, 2 clock output ports   
　 One full-duplex serial port   
　 Six interrupt sources with 2 external interrupts 
 
zFour channels of 6-bit ADC   
z Hardware In System Programming(I SP) capability, no boot code required   
z Built-in Low voltage reset circuit   
z Embedded 1.8V regulator   
z Code protection   
z Available in 44-pin PLCC or 48-pin LQFP package 
 
 
AUDIO    STEREO CLASS-D AUDIO POWER AMPLIFIER   
DESCRIPTION  
The TPA2008D2 is a third generation 5-V class-D amplifier from Texas Instruments. Improvements to 
previous generation devices include: dc volume con-tr ol, lower supply current, lower noise loor ,higher 
efficiency, smaller packaging, and fewer external  components. Most notably, a new filter-free class-D 
modulation technique allows the TPA2008D2 to directly drive the speakers, without needing a low-pass 
output filter consisting of two inducto rs and three capacitors per channel. Eliminating this output filter   
saves approximately 30% in system cost and 75% in PCB area.  
The improvements and functionality make this device ideal for LCD projectors, LCD on itors ,powered 
speakers, and other applications  that demand more battery life, re duced board space, and functionality   
that surpasses currently available class-D devices.   
A chip-level shutdown control limits total supply current to 1 µA, making the device ideal for bat-   
Tery powered applications. Protection circuitry in-c reases device reliability: thermal and short circuit. 
Under voltage shutdown saves battery power for more  essential devices when battery voltage drops to 
low leve.