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WinEC 7 AM35x lcd driver rotation problem RRS feed

  • Question

  • Hello,

    I'm using the Adeneo BSP for TI AM35x. The LCD driver supports screen rotation via setting [HKEY_LOCAL_MACHINE\System\GDI\Drivers] "Angle" to 1 for 90°.

    It works, but the screen is flickering and I get the debug message:

    DSS pipeline underflow error.Intrstatus:40

    In the *.reg file I found the following note: Rotation should not be used with the flat frame buffer, memory/bus bandwidth may be exceeded by display scanning requirements causing display to flicker and/or lock up.

    What means flat frame buffer?

    Does anybody have experience with rotate AM35x screen?

    Best regards,

    Andreas

    Thursday, November 8, 2012 12:33 PM

Answers

All replies

  • Are you using VRFB or DMA for display rotation?

    Vinoth.R

    www.e-consystems.com

    http://vinoth-vinothblog.blogspot.com

    • Marked as answer by Andreas_1981 Tuesday, November 13, 2012 1:44 PM
    Thursday, November 8, 2012 4:01 PM
  • Hi Vinoth,

    I found, that I don't have add VRFB driver. Now it works.

    But I don't understand the difference. If I don't add VRFB, the rotation is done with DMA and if I add the driver the rotation is done with VRFB. Is this correct?

    What is the difference? And why do I get disruptions on the display if I use DMA mode?

    Best regards,

    Andreas

    Friday, November 9, 2012 7:37 AM
  • See the recommendation in the TRM.


    Vinoth.R

    www.e-consystems.com

    http://vinoth-vinothblog.blogspot.com


    • Edited by Vinoth[MCTS] Friday, November 9, 2012 2:21 PM
    • Marked as answer by Andreas_1981 Tuesday, November 13, 2012 1:44 PM
    Friday, November 9, 2012 2:18 PM
  • May be the AM35xx documentation is not good enough for this expatiation Check any OMAP data sheet of TI or something else for the better explanation for the same.

    --- Misbah


    Senior Design Engineer T.E.S Electroni Solutions (Bangalore-India) www.tes-dst.com email-misbah.khan@tes-dst.com



    • Edited by Misbah Khan Sunday, November 11, 2012 8:57 PM
    Sunday, November 11, 2012 6:30 PM