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DS90UB929-Q1EVM: HDMI not detected properly

Part Number: DS90UB929-Q1EVM

Hello all,

I have an issue where the Analog LaunchPAD does not detect my HDMI input properly. The windows itself detects that I connected a 1280x720p display, but the Analog LaunchPAD shows that the board is not linked to the video source. 

Under the HDMI tab I can see this:

If I am correct, when the HDMI is connected, than on the board D1 and D2 green LED's should be active, but on my board only the D1 LED is active.

Also when I first connected the board to my PC, and than started the Analog LaunchPAD than it asked for a firmware update:

I connected device to the SMA output, and tried to use the internal pattern generator, but it does not recognize it either. 

I tried to use an other PC, but the reaction was the same.

Do you  have any suggestions what else should I try to make it work?

  • Hey Laszlo,

    HDMI won't work by default if you don't have Ser and Des FPD-Link connection established.

    I'm not sure what Des you are using here, but Ds90Uh926 it looks gray which means it's not active. 

    Otherwise, without a Deserializer connection, you would need to set register 0x5C bit[6] high on the 929 to force link detection without a Deserializer connection present.

    Regards,
    Fadi A.

  • Hello Fadi

    Deserializer reference : DS90UB928

    The disabled back channel from Deserializer can be the root cause of HDMI link not detected by the Launch PAD ?

  • Hey Nabil,

    Yes, in order to get an HDMI signal detection, you need to connect a Deserializer to the DS90UB929 EVM Serializer. Otherwise, without a Deserializer connection, you would need to set register 0x5C bit[6] high - (board.WriteI2C(serAddr,0x5C,0x42)) to force link detection without a Deserializer connection present. This is how the 929 HDMI state machine works. 

    Regards,
    Fadi A.