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DS90UB947-Q1: How to set single link for port1

Ansel Song
Expert 3890 points
Part Number: DS90UB947-Q1

Hi team,

As shown in the following 947 0x5A register, it can be detected to work on single link port1, but how to set 947 to work in single Link port1 mode? It looks like just for port 0.

Best regards,

Ansel Song

  • 0
    TI__Guru** 103215 points

    Hello Ansel,

    Single link with transmit port 1 will be enabled automatically if port 1 is connected to the deserializer and port 0 is left unconnected. 

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Expert 3890 points

    Hi Casey,

    If  port 0 and port 1 are both connected, is possible to just use port ? 

    Take 947-948 as an example (port0 and port1) are connected, can only use port1 be transmitted in the following ways?

    UB947 0x1e 0x02 //select port 1
    UB947 0x5b 0x01 //Forced Single FPD-LinkIII mode
    UB948 0x34 0x1a //Forced Single FPD-LinkIII mode (948-Single link, secondary input)
    Best regards,
    Ansel
  • 0 in reply to Ansel Song
    TI__Guru** 103215 points

    Hello Ansel,

    What is the reason to do this? If both port 0 and port 1 are connected and you force single mode it will use port 0. What is the reason for needing to force port 1 only in this system configuration if both are connected?

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Expert 3890 points

    Hi Casey,

    Just for debug, the test as below,


    1.947 Forced dual channel mode, black screen appears;
    2. 947 forced single-channel mode, returned to normal;


    Inferred that the data transmission of port1 failed, so I want to confirm that only port1 is used to confirm the phenomenon. This failure occurred in the actual car, and the oscilloscope test waveform method basically does not work.

    BR,

    Ansel Song

  • 0 in reply to Ansel Song
    TI__Guru** 103215 points

    Hello Ansel,

    There is no way to do this through register config. What is the PCLK value for the video? Also are you sure both sides of the link have both channel 0 and channel 1 connected?

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Expert 3890 points

    Hi Casey,

    The PCLK is 75MHz. Yes, I am sure for both sides of the link have both channel 0 and channel 1 connected.  If there is a black screen, the dual-channel transmission is still black, but the single-channel port 0 transmission is normal. How can we confirm that the port 1 channel is abnormal?  Thank you.

    BR,

    Ansel

  • 0 in reply to Ansel Song
    TI__Guru** 103215 points

    Hello Ansel,

    What programming steps are being used to force dual FPD mode where the black screen appears?

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Expert 3890 points

    Hi Casey,

    947 is configured to force dual channels, and 948 is automatically detected. At this time, if it is in the black screen state, configure the 947 single channel, the black screen will disappear, so it is presumed that the transmission of port1 is abnormal.


    In addition, why can't the Port 1 of 947 be forced to use only when the port 0 is floating, what is this judgment mechanism?

    BR,

    Ansel

  • 0 in reply to Ansel Song
    TI__Guru** 103215 points

    Hello Ansel,

    Yes I understand - but what I'm asking is specifically what register programming is being used to force dual FPD-Link on the 947 here?

    If port 0 is floating, the port 1 will be used automatically but that is not the system configuration you are saying you have, correct? 

    Best Regards,

    Casey