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Confuzzled: LCD / TFT / LCD / 12, 18, 24-bit/ NOT LVDS ???

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  • Confuzzled: LCD / TFT / LCD / 12, 18, 24-bit/ NOT LVDS ???

    Perhaps someone can shed some light on my situation. I'm very confused right now.

    What type of panel termination or signal support do I have?

    I currently have two Mini ITX boards and both support what I have always called "panel out" or TFT out.

    1) Advantech PCM 9575
    2) Adastra VNS-786

    (Copy From the user manual) Adastra VNS-786; The Flat Panel connectors consist of a 50-pin and a 20-pin connector. The 50-pin connector at J2 is a 2mm pitch, dual in-line connector and is solely used when integrating TFT or LCD displays up to 24-bit. The 20-pin connector at J3 is a 2mm pitch, dual in-line connector andis used in conjunction with J2 to drive 36-bit panels

    (Copy From the user manual) Advantech PCM 9575 :Extension flat panel connector CN10 consists of a 20-pin connector which is Hirose’s product no. DF13A-20DP-1.25V. The PCM-9575 supports a 36-bit LCD panel which must be connected to both the CN11 (40-pin) and the CN10 (20-pin). The pin assignments for both CN11and the CN10 can be found in Appendix C

    CN11 consists of a 40-pin connector which can support a 24-bit LCD panel. It is Hirose’s product no. DF13A-40DP-1.25 V. The PCM-9575 provides a bias control signal on CN11 that can be used to control the LCD bias voltage. It is recommended that the LCD bias voltage not be applied to the panel until the logic supply voltage (+5 V or +3.3 V) and panel video signals are stable. Under normal operation, the control signal (ENAVEE) is active high. When the PCM-9575’s power is applied, the control signal is low until just after the relevant

    This is NOT LVDS. So what is the proper terminology or nomenclature for this type of panel termination or signal support for these two boards?

    Reason I am asking is because I have an older high-bright 1100nit LCD that is supported by either of these boards. I am looking to upgrade to a faster CPU and I cant seem to find anything that supports this type of signal. All the new boards only support LVDS and I do not think they are compatible.

    Does anyone know of any boards that support this signal?
    Attached Files

  • #2
    It is often called as 'TTL RGB'. If you have about 30-40 wires, that means ttl rgb (R0-R5,G0-G5,B0-B5 or so ).
    If you have more than 50, it means odd-even ttl rgb (AR0-AR5, BR0-BR5, AG0-AG5, BG0-BG5 and so on...).
    If you have 2*8 (LD0-LD7,HD0-HD7) that means DSTN (older notebooks with contrast-regulation)
    Finally LVDS for notebooks is 4 pairs for single channel and 8 pairs for dual channel.

    Except LVDS, they all have vsync, hsync,clk
    Some have DE/M signal.

    FLM = Vsync
    LP = Hsync

    In your case those P-pins are configurable, they exact function depends on the dstn or ttl rgb.
    Alopecia perniciosa


    • #3

      Thanks for the reply!

      I have heard it called so many different names that I wasn’t sure of the true nomenclature of it. The tech at Advantech swore up and down to me that it was referred to as "Panel Out." searching for that drove me nuts as it yielded absolutely no results. I knew something was wrong. Searching for "TTL RGB" and "18 BIT TTL" or "24 bit TTL" as well as "Direct TTL" did help shed some light on the situation.

      So after some more research, it would appear that if I want to upgrade to a newer motherboard I will need to find a LVDS to TTL Converter (or LVDS to TTL Receiver Module). Does anyone know where I can purchase one? It looks like they are also being phased out and are becoming non-existent because “TTL RGB” is an old (outdated) technology and LVDS is what is the industry standard at the moment and soon to be succeeded by HDMI.

      Also, correct me if I'm wrong, but there isn’t any board that directly supports the older TTL or "TTL RGB" other than Pentium III and VIA C3 boards’ right? I'm looking for a Mini-itx form-factor that at least supports a P4 or Pentium M processors and TTL RGB displays. Otherwise, it looks like a core 2 duo board and LVDS to TTL Receiver Module is the only way to go if I want to use my existing sunlight viewable (1100 nit) monitor.

      If anyone has any advice, please let me know!


      Jason K
      (a.k.a. Distorted Axis)


      • #4
        search for 'LVDS receiver'

        This link shows you a transmitter/converter pair xxxx63 vs. xxx64
        It costs approx. 3 dollars, so it could be available around 6 dollars for mortals

        Those closing resistors are VERY important (around 100 ohms) on the receiver side, do not skip them!

        LVDS transmission is better, because it is just limited around 5m, unlike TTL is not noise-sensitive, less crosstalk, etc.

        Is that special high nits display also available? Just imagine, what happens, if that could break...or simply does not work any more...
        The life span of the CCFL is also limited, etc.
        Alopecia perniciosa


        • #5
          Originally posted by bbalazs View Post
          Is that special high nits display also available? Just imagine, what happens, if that could break...or simply does not work any more...
          The life span of the CCFL is also limited, etc.
          The high-nit display is and is not available... I supposed it depends on how you look at it? The screen is just a "backlight-less" LCD desinged to go with any backlight you throw on it.

          LCD: NEC NL6448AC33-30

          So, theoretically speaking, if I could find a high-contrast LCD that supports LVDS and re-use my existing backlight, then I can go a different route. Unfortunately, I have not found a screen that will work with the backlight dimensions for under $600. And those didn't even include an inverter... From a price standpoint, the LVDS receiver is the cheapest way to go.

          Basically these are data911 systems (MDS2000) that are being phased out of police cars and are somewhat readily available -- you just have to know where to look for them. I have 4 right now. This way I have spare parts if something fails.

          I've had them for 3-4 years now. I've used one as a screen for a friends CNC mill. They are very rugged and sunlight readable, so the possibilities are endless as long as I can find a way to have new boards support the older TFT RGB screens.

          Also, here is an old post on the back light.