I need help designing this board to drive LCD

Discussion in 'Embedded Systems and Microcontrollers' started by Ali.Soliman, Sep 17, 2012.

  1. Ali.Soliman

    Thread Starter New Member

    Sep 14, 2012
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    Hi everyone,

    I am working on designing a board that will house an AM3517-M2 SOM, the main function of the board is to drive the HITACHI TX13D04VM2CAA 5" LCD. I will also make use of other IOs on the SOM.

    I am having a problem deciding about the LCD connections. There are no VSYNC, HSYNC on the LCD only a DE - Data Enable and a DCLK - DOT Clock.

    I am confused because I thought the VSYNC and HSYNC signal are quite essential to drive an LCD. looking at most other LCDs they do use the VSYNC and HSYNC signals.

    Can someone tell me if I am missing something here? Will it be ok to drive this LCD without the VSYNC,HSYNC signals ?

    Attached are data sheet for LCD and the SOM.

    any advice or link to tutorial will be very appreciated.

    Cheers.
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Looking at Figure 9.2 Timing chart for the TX13D04VM2CAA seems to indicate the traditional VSYNC and HSYNC signals are not required. You'll be inputting the display data at the display bit rate and the controller inside is just directing the pixel data as received to the display. I would imagine if you don't hit their recommended data rates something would still appear on the display, though it may be a poor (jumpy, flash, etc.) image.

    Sorry I don't know of any tutorials on this. The TFT displays I use you only update once, and the driver chip holds the entire image data and updates the display as it needs.
     
  3. Ali.Soliman

    Thread Starter New Member

    Sep 14, 2012
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    Thanks Ernie,

    your words are reassuring. I have attached the schematics if you can look at it.

    I am a bit confused about the Display On/Off circuit bit, this bit of circuit was taken from a working driving board but I wanted to make sure its the same for my LCD.
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Seems you want me to guess what part of another projects schematic shown in very low resolution might be applicable here. What part of the spec covers this "Display On/Off" control?
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Most of those larger LCDs have a minimum dot clock rate, it's usually in the Mhz. They need an extremely specialised high speed driver IC.

    If the driver IC is onboard, the pinout usually accepts hsync, vsync etc and RGB pixel data in real time (like a VGA signal).
     
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