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PCM9211: optical input detection

Downey Kim
Expert 2675 points

Part Number: PCM9211

Hi TI experts,

I have a few questions about optical signal detection.

1. When the optical is connected and the file is not played, does the PCM9211 recognize it as a no signal?

2. How is pcm9211 recognized when optical is connected and a silent file is played (ex:TDC784, track #7)?

Thank you.

  • 0
    TI__Mastermind 23030 points

    i shall respond on March 28

  • +1
    Genius 3945 points

     "File is not played." That depends entirely on the hardware driven the optical transmitter on the other side of the fiber. If that driver decides to turn off and stop toggling, then the receiver will unlock and should mute and set a status indicating such.  That hardware thing might also just decide to send all zeros as data, so in that case there would be no recognition that a "file" is not being played.

    Now if your driver hardware is fancy, it could send information on the S/PDIF subcode indicating track being played and all of that, and your 9211-based hardware needs to be able to recognize and handle such codes.

  • 0 in reply to Andy Peters
    Expert 2675 points

    Hi Andy,

    We confirmed that the int0 pin was changed when the optical cable was connected or disconnected.

    When optical is connected, we need to check whether there is data or not with optical input. Does PCM9211 have a detection function?

    I played/stopped the sound source on the source device, but int0 does not change. 

    Thank you.

  • 0 in reply to Downey Kim
    TI__Mastermind 23030 points

    Have you looked at pin 2?  NPCM/INT1