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video signal detection on TVP5146

HiPer
Prodigy 200 points
Other Parts Discussed in Thread: TVP5146

I would like to detect when video source is connected to or disconnected from composite input on DM365EVM.

How can I setup TVP5146 video decoder and what registers need to be inspected afterwards in order to detect presence/absence of video signal ?

Thanks.

  • 0
    TI__Expert 4685 points

    Pl refer to video standard status register in (sub address;0x3Fh) tvp5146 data manual. Looks like you need to configure this register for your requirement.

  • 0 in reply to Nagabhushana
    Prodigy 200 points

    The Video Standard Status Register(VSSR) shouldn't be configured. It should be tested in order to determine current standard. Anyway it is not the point.

    I have modified standard Video Loopback example from Spectrum Digital's "DM365 EVM Target Content" archive by adding

        while(1) {
            tvp5146_rset( 0x02, 0x00 ); // set Video Standard Register to Autoswitch mode
            test = tvp5146_rget( 0x3F ); // read status from Video Standard Status Register
        }

    Then I performed such test:

    1) No video source connected. Video Standard Status Register displays 0x81 (which means NTSC).

    2) PAL video source is connected. Video Standard Status Register changes to 0x82 (which means PAL).

    3) NTSC video source is connected. Video Standard Status Register changes to 0x81 (which means NTSC).

    4) No video source connected. Video Standard Status Register remains equal to 0x81 (which means NTSC).

    To sum up, it is easy to detect Video Standard change from NTSC to PAL and back.

    But impossible to detect whether video source is connected or disconnected.

    The problem is still open.

  • 0 in reply to HiPer
    TI__Expert 4685 points

    HiPer,

    Looks like decoder takes NTSC as default. Even in the document, feature is mentioned as 'auto switch'. Nowhere, there is a mention of video source present or not. Looks like you cant use tvp514x to find whether video source is connected or not.