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[ADV7480] About laptop audio output

Category: Software


We are evaluating the ADV780 product.

I am checking the video/audio output by connecting the HDMI output of a Windows 10 laptop (Dynabook R73)

to a monitor equipped with ADV7480.

The video from the PC is output, but the audio from the PC is not output.

(PC audio driver itself does not recognize)

What could be the cause?

For monitors without ADV7480, PC audio is output.

Best regards.

  • Hi Tatsuya San,

          Please find the below comments,

     ① Before connecting an HDMI device: HPD = L

           Generally the Sink device will supply a voltage on an HPD pin to signal to the video source device that it is connected So the video source device monitors the voltage on the HPD pin and then initiates EDID requests as it senses incoming voltage.

         If HDMI device is disconnected then the HPD would be in LOW State (The absences of a voltage on the HPD pin indicates disconnection).

    ② After connecting HDMI equipment: 

         In this case, how long should HPD=H be maintained in 1) ?

          There is no specific time duration that we need to maintained for the case "1. HPD=H" .

         Please note But "After HPD become low, We need to wait 100ms".