ADV7842 CVBS to RGB Out

I've been using the AVES scripts for the ADV7842/AD7511 eval board to successfully setup up my custom ADV7842 board to handle analog RGB inputs.  I've moved onto CVBS (NTSC) inputs and I'm not having the same success.  I started with the 1-1e script (NTSC to 480i HDMI) and I was able to get video out of my board but the colors where all messed up.  Specifically, black is coming out as purple and white is coming out as a lime color.  As I dug into it I saw the script sets up the ADV7511 to accept YCrCb so the ADV7842 must output YCrCb.  However, the DVI Transmitter on my board only accepts RGB so I need the ADV7842 to output RGB as it did with the analog RGB input scripts.  I thought that should be as simple as switching 0x40 (IO) 0x02[1] from '0' to '1' but that seemed to have no impact.  I realize the analog RGB inputs use CP and the CVBS inputs use SDP but other than the register I just mentioned I don't see anything related to SDP color output specifically.

I've been analyzing scripts all day and I can't seem to figure out why the analog RGB input scripts work but the CVBS input scripts don't.  Do you have any ideas or things for me to check that might help me diagnose because I'm pretty stumped?

By the way, I tried disabling the 3D comb filter to take the SDRAM on my board out of the equation and it didn't resolve my issue.

Thanks,

Nathan

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  • I see, I was thinking by setting the RGB_OUT bit I was automatically informing the SDP to execute color space conversion.  But it sounds like I have to manually setup the color space conversion.

    I skimmed through 7.22.7 and I'm assuming to execute a YCrCb to RGB conversion I need to alter the coefficients.  Any chance you have example register settings for that exact conversion?  I know you said you can't test CVBS 480i -> RGB 480i because your monitor doesn't support RGB 480i.  However, I assume your monitor supports RGB 480p so a CVBS 480i -> RGB 480p would be possible.  And in order to execute that the color space conversion would be setup the same as what I need.

    Thanks,

    Nathan

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  • I see, I was thinking by setting the RGB_OUT bit I was automatically informing the SDP to execute color space conversion.  But it sounds like I have to manually setup the color space conversion.

    I skimmed through 7.22.7 and I'm assuming to execute a YCrCb to RGB conversion I need to alter the coefficients.  Any chance you have example register settings for that exact conversion?  I know you said you can't test CVBS 480i -> RGB 480i because your monitor doesn't support RGB 480i.  However, I assume your monitor supports RGB 480p so a CVBS 480i -> RGB 480p would be possible.  And in order to execute that the color space conversion would be setup the same as what I need.

    Thanks,

    Nathan

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