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VPBE byte swap at 16 bit boundary in first line of video frame.

Ali Ahmed
Prodigy 120 points


Hi,

I am using DM6437 EVM to send out a constant image out of the VPBE in non standard timing. I experiencing byte swap at 16 bit boundary on the first line of the frame. The swap only happens on the first line and then the rest of the lines are showing the data in correct order. My setup is as follows.

 DM6437 EVM

CCS 3.3

DSP BIOS 5.41.10.36

CGT 7.2.4

I am attaching screen shots and an example program to demonstrate this issue.

 

Regards,

Ali

VPBE.zip
  • 0
    TI__Genius 14405 points

    Hi Ali,

    Have you tried this configuration on a simple CCS test case w/o any OS support? We should simplify the testcase. i.e., a testcase that is simply displaying a fixed pattern.

    Please also make sure the frame buffer has the correct data.

    I don't have a good answer at the moment, but the 1st thing I would try if I were debugging this would be check the vertical timing setup.

    regards,

    Paul 

  • 0 in reply to Paul.Yin
    Prodigy 120 points

    Hi Paul,

    The attached example program is sending a fixed output buffer(I am sending a grey scale ram in the first 86 pixel locations on first four lines). The timing have been verified using logic analyzer. The Vsync and Hsync period and frequency are according to the programmed value. The data swap and timing is also verified in a frame grabber. The frame grabber shows the swap in the first line and not on the subsequent lines. The frame grabber also shows the correct image resolution and frame rate. 

    I doubt that OS has anything to do with this issue as I am not using any PSP drivers for VPBE. The OS layer is there as the attached example program is a stripped down version of our application that is currently running on DSP. I will however try to do this exercise again without DSP/BIOS just in case.

    Thanks,

    Ali