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TVP7002 component input through VGA connector

Steven Weng1
Expert 2200 points

Other Parts Discussed in Thread: TVP7002, THS7368

Hello All,

I have used TVP7002 to capture PC graphic input from VGA connector successfully.

Now I want to capture the component input through the same VGA connector(there is no IC converter only circuit connected Y->G, Pb->B, Pr->R)

Is possible to detect VGA RGB and Component YPbPr signal from the same VGA connector?

As I know, component input use sync on green(SOG) to detect signal, so all I have to do is connect Gin to SOGin in hardware circuit?

And read sync detect register(0x14h) in the TVP7002 to determine which sync is active? SOG sync acitve is componet in and hsync active is VGA in?

I have tried above methods and I could capture 480P60 video from component input successfully. But when change resolution to others(720P60, 1080P60), it cant lock to a specific resolution because clocks per line and lines per frame are varied all the time. why ?

BTW, I take a look at DM8168 EVM IO daugther board, video filter such as THS7368  is necessary for component input? 

Thanks in advance!

BR

Steven

  • 0
    TI__Mastermind 43875 points

    Steven, You are on the right track.

    Please check the datasheet for an example schematic for connecting YPbPr syncs.

    Clocks per line will vary slightly since the internal reference clock is only 6MHz and not very accurate. Lines per frame should not change though.

    You can get more accurate clocks per line by adding an external 27MHz reference clock.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Expert 2200 points

    Hi Steve,

    Thank you so much for so quick reply :)

    The variation is very huge!! (only 480P varied slightly)

    So I get "resolution change event" in my program but it is out of my support standard video(I think I have sufficient  buffer in clocks per line and lines per frame to detect which video standard it is)

    I have checked the schematic for connecting YPbPr syncs and datasheet:

    The G or Y input containing the composite sync must be ac coupled to the SOG input pin using a
    1-nF capacitor.

    I dont have 1-nF capacitor now.

    I will find one and try again.

    Thanks again!

    BR,

    Steven

  • 0 in reply to Steven Weng1
    Expert 2200 points

    Hi Steve,

    The component Y input coupled to the SOG input pin using a 1-nF capacitor will solve this issue.

    Thanks for you help again.

    BR

    Steven