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7" LCD display controller choice

Horatiu
Prodigy 180 points

Other Parts Discussed in Thread: TM4C129XNCZAD

Hi there, I have an 800x480 LCD and I'm trying to find an LCD controller suitable for it. My intention is to connect it to the a Tiva TM4C129XNCZAD. One I could find was the popular but outdated SSD1963 controller. Are there other choices that have RAM embedded in them? Here are the LCD specs: Type: TFT Resolution: 800 x 480 Pins: Backlight Cathode Backlight Anode Display On/Off Horizontal Sync Vertical Sync Data Enable Data-R[0-7] Data-G[0-7] Data-B[0-7] Touch Plane [X+, X-, Y+, Y-] NOTE 1: I know that the Tiva 129 has 256k RAM and an LCD controller. I tried making the LCD work using only that (without buying the extra RAM). I got it to work - the buffer displays over and over again on the screen. However, there is still the issue of color correction (eg. blue is teal) and another issue where the buffer should fill a tenth of the screen and it only fills about a 20th.
  • 0
    TI__Guru**** 244440 points
    Hello Horatiu

    Did you check the Mikroelectronika (though it is a 5" instead of 7")

    www.mikroe.com/.../tiva

    The RAM required for RGB888 format with compressing is 1.152MB which is more than what the size of internal RAM. You would need external SDRAM (from speed of operation perspective). I am not sure if there is a smart panel for such a panel. We have used smart panel for 320x240 in the DK-TM4C129

    Regards
    Amit
  • 0
    Guru 47900 points

    Horatiu said:
    the popular but outdated SSD1963 controller

    SSD1963 did not capture too many, "cell phone sockets" did it?   Might that speak to the absence of SSD replacement?

    Your 800x480 TFT seems a bit "pixel sparse" does it not?    (realize that cell phones, 5/7 or 4.3/7 that size - often have 2x+ that number pixels!)

    Was the MCU you've chosen (really) designed to accommodate that size/capacity TFT?   This maker - others - have superior MCUs - with greater emphasis placed upon the TFT interface.

    Pushing a large rock - "up" a tall hill - using (only) your nose - can be done.    Is it worthwhile?    (may warrant your consideration...)

  • 0 in reply to cb1
    TI__Guru**** 244440 points
    Hello cb1,

    May be on the higher processing cores... Internal RAM is going to be limitation for most of them (if not all).

    Regards
    Amit
  • 0 in reply to cb1
    Prodigy 180 points
    First, thank you for your reply. Next, I'm sorry for the poor formatting on my part.

    Third, to be honest, I should have let you guys know what my intentions were first, then ask for your advice.
    The final product will be a 7 inch LCD with a user interface built using the grlib library. It will be driven by a Tiva TM4C micro that can also support CAN communication. Cost is very important.

    With that said, the mikromedia boards are extremely expensive. I'm looking at spending a max of $30-$40/unit (LCD+micro).
  • 0 in reply to Amit Ashara
    Guru 47900 points

    Amit Ashara said:
    Internal RAM is going to be limitation for most of them (if not all).

    My reply placed no restrictions upon the "extent" of TFT drive solution.   Suggested was the "modeling" of the techniques/components/methods of those w/maximum experience & success in TFT application.    (that clearly - cell & tablet makers)

    Poster should be prepared for extremely S   L   O   W   screen updates - noticeably so - especially when compared to cell or tablet!   Your users will notice - and squawk (as they should) of that I assure you!

    May prove worthwhile for you to procure & gut a "lesser" tablet (which you can acquire in volume) and see if that can be "massaged" into service.   Parts w/in will always (far) exceed those resident - this forum.  

  • 0 in reply to cb1
    Prodigy 180 points
    Thank you cb1 and Amit.
  • 0 in reply to Horatiu
    Guru 47900 points
    Thank you - if you can find "lesser" tablet (NOT EBay) available in your required volume (you must inquire of tablet maker) AND you can "hijack" the existing code "provisioning" - you've got an enormous, "head-start!" (i.e. you've a case, a screen, a "real" TFT controller, adequate storage, connectors etc.)

    Often it does not pay to try and, "Reinvent the wheel." You'll find NO Cortex M4s w/in tablets - might there be a reason?

    Just as vendor (likely) over-states w/use of "launch" - suggesting that this MCU's 16-24 bit TFT performance may "approach" (cell/tablet (standard") may prove a "reach."

    And - that's your (unfortunate) reality - user's will always note - and register their displeasure - and then what???
  • 0 in reply to cb1
    TI__Guru**** 244440 points
    Hello cb1

    We have in the past used a 800x480 24bpp with external SDRAM and dual buffers to be able to run images. However having said that, I like your suggestion. Jump start rather than to reinvent the wheel.

    Regards
    Amit
  • 0 in reply to Amit Ashara
    Guru 47900 points

    Amit Ashara said:
    Jump start rather than to reinvent the wheel.

    Thank you - your firm, others produce MCUs far more oriented toward "real" TFT control/management.   Forcing Cortex M4s into this role (almost always) fails to meet user expectations.   (users will "naturally" compare to cells/tablets - where up-scale MCUs reign - M4s "have no chance!")

    This is an unfortunate - yet very strong/impacting - reality!    Unless the screen will (primarily) be used for, "Fixed images" or text selections - the update speed will be most notable - and will be rejected!   (imho - yet I'm past co-founder of public display firm...)

    Poster (thus far) seeks to combine a, "pixel-starved" screen with a, "SLOW (in comparison) screen update MCU" - that's sure to Sell!

    Look even at TV - larger screens - even more pixels - and 120Hz.   (some even faster!)

    That's the strong trend - again reality - and M4 (despite the LCD add-on) may not prove, "best/brightest."   (to be kind)