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Problems outputting digital and analog video simultaneously with DM355

R&D10371
Intellectual 730 points

I'm working with DM355 and I would like to output analog and digital video simultaneously through the VPBE, My application already outputs analog video without any trouble. Then I added a couple of ioctl callings (FBIO_QUERY_TIMING and FBIO_SET_TIMING) and managed to output digital video perfectly. But at this point the analog video had disappeared.

What could I do to get both of them at the same time? I'm studying the situation but I just can't see the way to do it.

Thanks in advance!

  • 0
    TI__Mastermind 37340 points

    I believe the only way to do this is to place VPBE hardware is standard timing mode (BT.656 mode).  You see, the video back end has a single video timing generator that feeds into both analog and digital output interfaces.  Therefore, you cannot support one resolution via analog output interface and a different one via digital video output interface; both interfaces need to support the same exact resolution in order to view both simultaneously.  Since analog interface only supports standard timing (NTSC or PAL), it implies that digital output interface should be placed in standard timing mode (BT656 for NTSC or PAL).

  • 0 in reply to Juan Gonzales
    Intellectual 730 points

    Thanks for your answer Juan.

    I forgot to say it, but we are already using BT.656 for the digital video. Anyway, you have confirmed our initial suspects: both video outputs (analog and digital) must be the same size. Anyway I'm still working on it because I can't find the point why the analog video disappears. I'll be back as soon as I can give more information about it.

    Meanwhile, any idea is welcome.

  • 0 in reply to R&D10371
    Intellectual 730 points

    Ok, I got it! I had the DAC set in power-down mode. Now it works. Thanks again Juan!

  • 0 in reply to R&D10371
    TI__Mastermind 37340 points

    that is great news!