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OMAPL138 Graphic LCD LIDD

Alex Amin
Prodigy 60 points

Hello All, 

 

Thank you all very much for providing such active and informative forums. Unfortunately, I am having an issue with interfacing a graphical display to the OMAP using LIDD in place of the Raster mode. To give some background regarding my build, I am using a modified build of the Arago project on custom boards. Ideally I would like to drive the display using the LCD controller on the OMAP while utilizing the frame buffers and dma for optimal performance. I have reviewed the LCDC pdf (http://www.ti.com/lit/ug/sprufm0b/sprufm0b.pdf) and understand the functionality. The primary problem being the optimized Linux drivers are only provided for graphical displays utilizing the Raster mode, while the LIDD mode drives assume the use of character displays and are not optimized. I would highly appreciate it if anyone could provide an example driver of a graphical display utilizing the LIDD mode or point me in the right direction for implementing an optimized driver. 

 

Thank you, 

Amin 


  • 0
    Prodigy 120 points

    Hi Amin,

    I have a similar problem. I want to interface a 12" display LCD TFT Sharp LQ121S1DG41 with eXperimenter-kit L138 but I have not example driver of graphical display (LIDD mode or Raster mode prefered). Do you have resolve your problem ? If yes, can you explain shortly ?

    Thanks a lot

    Regards

    Eric



  • 0 in reply to Eric LOUVEL
    Prodigy 60 points

    Hi Eric,

     

    I looked up the datasheet for your display (http://media.digikey.com/pdf/Data%20Sheets/Sharp%20PDFs/LQ121S1DG41.pdf), it seems Raster Mode would work very well. There are several Rater mode Linux drivers included in the kernel which you can easily modify the signal trimming and resolution to match any display. Just make sure you enable the graphical display mode in the kernel xconfig (look at the links below). Moreover, since you are using the eXperimenter-kit it probably is not an issue at the moment but in the near future when you spin a custom board, make sure to assign the display to the designated OMAP LCD Controller pins. Look in this (http://www.ti.com/lit/ug/sprufm0b/sprufm0b.pdf) document for more information on the LCD Controller details. Lastly, you should not have to implement the Raster Driver from scratch as I did for the LIDD mode. Feel free to ask any follow-up questions if things aren’t working out.

     

    http://processors.wiki.ti.com/index.php/Omapl137_linux_lcd_driver

    http://processors.wiki.ti.com/index.php/Using_Linux_PSP_on_OMAP-L1#Graphical_LCD

    http://processors.wiki.ti.com/index.php/OMAP-L1x/C674x/AM1x_LCD_Controller_%28LCDC%29_Throughput_and_Optimization_Techniques

  • 0 in reply to Alex Amin
    Intellectual 625 points

    The LCD interfacing problem I am currently addressing is quite similar to your:

    OMAP-L137 LIDD interfaced to LCD "smart" controller in 8080 mode, 8 bit.
    (Formike KWH018TG02-F01, embedding HIMAX HX8353-D)
    I am working on  linux-arago 2.3.37, and could find myself that such distibution covers only raster mode LCD models.
    I would like to get driver relying on 8080 mode LIDD, possibly framebuffer-like.
    In any case I would be glad if you could help me to find some driver references for my project.

    Thank you for your attention.