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Basic LVDS question

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  • Basic LVDS question

    Right, this isn't exaclty a car pc project but I figure you guys might be able to help. I'm building a compact all in one pc (with added STUFF) and I was giving some thought to the screen.
    Now this is the mobo I've got my eye on
    I notcied it had an lvds option which I vaguely knew was some way of running an lcd from a mobo.
    So I did some research and now I'm somewhat confused. Now I reckon I'll need an LVDS module like this

    but I have a couple of questions.
    I have an old lcd here and also a laptop that's doing nothing, how can I tell if they're suitable for LVDS?

    Do I need any other hardware?

    Driver software? is it hard to come by? do you have to write your own?

    This might be basic stuff to some of you folks but I've not been able to find decent answers anywhere, any advice greatly appreciated.

  • #2
    Is this meant to be portable? I'm working on a portable/UMPC myself. I believe the integrated graphics controller on most VIA boards will work without the need to add the LVDS controller. I could be wrong. Most OEM LCDs tend to include some controlling hardware as well. As I understand it though LVDS OEM LCDs are difficult to find. I'm trying to understand more about using the LVDS interface myself. I've tried reading the VIA documentation and find that it explains some, but I really just need to know exactly what it takes to interface on-board LVDS to LCD. What type of connection does it use, is it similar to/compatible with TTL/Hirose? Is there a need for extra HW, do I have to write my own driver, etc., etc. Everything I can find is either geared toward an electrical engineer with a degree or a total hardware n00b.

    By the way if you want a small and fully portable solution you may consider waiting for the next gen fanless Pico-ITX due in Sept. (from what VIA's sales guy tells me). The new fanless will have the power circuitry built in so it won't need a wall-wart anymore. Good news for CarPC enthusiasts too!

    BTW, if your Laptop is a Dell it may use an LVDS interface. A lot of the Inspirons do. The suitability of the screen depends on what you want to do with it. Luckily if you go here
    and pick your Dell or enter the service tag. You can find an online service manual that'll give you a pretty good idea.


    • #3
      More on the LVDS

      Suspicion confirmed! You do not need to use a daughter card, the LVDS panel can be connected directly. See the UM_EPIA-PX_120.pdf link here.

      To make it easy on you, the .pdf is the user's manual and under LVDS it says:

      "The LVDS/DVI Panel connector allows you to connect the panel's LVDS cable directly to support LVDS panel without any need of a daughter card. Matching connector: ACES 87219-4000"

      I figure the VIA chipset drivers may be able to handle LCD/Video control via LVDS. So the only remaining question is: what LCD panels have the matching connector listed in the user's manual? I'm thinking of straight up asking VIA if they can point me in the right direction, stay tuned.


      • #4
        Originally posted by Squidge View Post
        Suspicion confirmed! You do not need to use a daughter card, the LVDS panel can be connected directly. See the UM_EPIA-PX_120.pdf link here.
        That's the pico-itx board, not the mini-itx originally linked to. The pico-itx has the lvds transmitters on board. Look at the pinout of the "lvds" connector on the mini-itx board (for example : )

        Does that connector pinout look even slightly like lvds? You do need the daughter board.

        I am running lvds from a pcm-9373, to an lvds receiver on the back of an ltm08c351, I have been doing so for quite a while.
        Old Systems retired due to new car
        New system at design/prototype stage on BeagleBoard.


        • #5
          That's the pico-itx board, not the mini-itx originally linked to.
          True. My bad. Yes, most of the mini-ITX boards from VIA and others DO require a daughter board. I got a little carried away...again....

          There are basically two types of LVDS if I understand it correctly, 18-bit single and 24-bit dual. If my research is correct an 18-bit single can still be connected to a 24-bit dual socket, but you need to know the pinouts of the LCD and the board. If you can find a model number on the LCD, the best thing to do is put the model number into google and look for a tech/data sheet/user's guide. There's a chance the LCD could also be TTL depending on how old it is.

          You'll also need to check and see that the LCD's native resolution (i.e. 800 x 600 or 1024 x 768) is supported by the BIOS. You might find more helpful info on the VIA Arena forums. I also recommend searching through posts on this forum by Giuliano.

          By the way, After reading more about things yesterday, it appears that a few people have tried asking VIA tech support and haven't gotten a helpful response, if at all. I guess it still never hurts to try.