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DS90UB947-Q1: Fault connection between DS90UB947-Q1 and DS90UB926Q-Q1

Eric Vo
Prodigy 495 points
Part Number: DS90UB947-Q1
Other Parts Discussed in Thread: DS90UB926Q-Q1

Hi INTERFACE team,

I am Eric, analog FAE based in Vietnam.

  • Project background: My customer in automotive field is working on a MHU project.
  • Issue: The customer uses DS90UB947-Q1 and DS90UB926Q-Q1 to transmit image data. When they test the link between the two devices, the register successfully detected "Remote device". However, the communication cannot be LOCKED and the data (values) on remote device cannot be read.

Do you have any solutions for this issue?

Thank you for your help!

Best regards,

Eric. 

  • 0
    TI__Intellectual 1905 points

    Hi Eric,

    Thanks for reaching out,

    Here few things you may need to consider:

    1. Make sure that the serializer (DS90UB947-Q1) is configured correctly to match the capabilities of the deserializer (DS90UB926Q-Q1), such as PCLK rate, supported resolution ....

    2. After confirming the configuration is correct, check to make sure that PCLK is stable and meeting the spec. Also, check if the power supplies are stable and meeting the spec.

    3. If it is still not able to link, you can share your specific configuration and we will try to replicate in our side and we will let you know the result.

    Best Regards,

    Solomon

          

  • 0 in reply to Solomon Ali
    TI__Prodigy 495 points

    Hi Solomon,

    Thank you for your answer.

    Customer checked the config, they use DS90UB926 with LPMODE=1 (PCLK5 - < 15MHz). They wonder if they can config the device at that low clock mode?

    Please advice them.

    Best regards,

    Eric. 

  • 0 in reply to Eric Vo
    TI__Prodigy 495 points

    Hi Solomon,

    Here are some add-in input from customer:

    Target out of UB926 device: 

    -          Resolution: 800 x 293
    -          Frame Rate: 30
    Pixel clock is calculated at around 7.7-8MHz.
    Also they want to ask some more questions:
    1.          Can UB947 device accept that pixel clock? Accordance to the datasheet, the device's compatibility mode of its clock is around 25MHz-85MHz.
    2.          In case the answer for 1st question is YES, can you please provide us the config for UB947 to support this case and its testing result (UB926 with LFMODE=H) ?
    3.          In case the answer for 1st question is NO, can you please provide a p2p replaceable solution for UB974 that can connect with UB926 for this application?
    Best regards,
    Eric.
  • 0 in reply to Eric Vo
    TI__Intellectual 1905 points

    Hi Eric,

    Re: "Can UB947 device accept that pixel clock?"

    No, 7.7-8MHz is below the minimum PCLK spec for UB947. 

    Re: "In case the answer for 1st question is NO, can you please provide a p2p replaceable solution for UB974 ..."

    Actually, there is no pin-2-pin replacement for UB947.

    One possibility is for you to see if it possible to increase the PCLK by increasing the frame rate, the resolution, or both to meet the 25MHz min spec for UB947.

    Also, you may consider visiting FPD-Link page on TI.com and use the "Quick Search" tool to check the other available options that could meet your requirement:

    www.ti.com/.../overview.html

    Best Regards,

    Solomon