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DS90UB954-Q1: MIPI CSI signal quality test issue

Zongtao Wang
Prodigy 140 points
Part Number: DS90UB954-Q1

Hello Experts:

my use case : camera video input to 954 , transistor to CSI to SOC .I  test  CSI signal quality ,but  two lane part of item occur failed .My question is if there are any register that we can set to optimization the signal quality?

thank you ~

report.html.pdf

  • 0
    TI__Guru** 103215 points

    Hello,

    These two failing items have no register control for correction inside the DS90UB954-Q1. For the test 1.3.11, the failing limit is 375ps, and the measurement is exactly 375ps, so I suspect if you were to run this test several times you would actually see that passing intermittently and it is likely that adding the probes to actually perform this test are providing some extra capacitance and slowing down the rise time ever so slightly. You may be able to improve the results just by using a different probe. 

    For test 1.5.4, the skew is controlled by the layout (length matching between differential pairs). Can you check what the routing distance is for the data lane vs. the clock lane in your design?

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    Prodigy 140 points

    hello Casey:

    thank for your reply.

    the past test result is base decrease the camera resolution ratio. the below test result is by camera normally output .please help to check if can improve by set the register.

    report.htmlreport.html

  • 0 in reply to Casey McCrea
    Prodigy 140 points

    hello Casey:

    thank for your reply.

    the past test result is base decrease the camera resolution ratio. the below test result is by camera normally output .please help to check if can improve by set the register.

    2656.report.html2656.report.html

  • 0 in reply to Zongtao Wang
    TI__Guru** 103215 points

    Zongtao,

    I'm not sure what you are requesting here. Also in the reports I can't see any pictures loading. The 954 CSI-2 output is configured from the factory to meet the MIPI DPHY CTS, so if you are seeing failures we should focus on the layout or the CTS probing solution to resolve compliance failures. I would not recommend any manual adjustment of the 954 CSI-2 TX settings since making changes would be very unpredictable (doesn't match how we validated the part), and could lead to other unexpected failures. Would you like us to review your schematic/layout for 954?

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    Prodigy 140 points

    hello Casey:
    sorry , it is the compliance test report, the layout and sch we had send the TI local FAE ,we want to search more way  for the issue.

    3733.report.html.pdfreport1.html.pdf

  • 0 in reply to Zongtao Wang
    TI__Guru** 103215 points

    Hello Zongtao,

    From just the report it is difficult for me to recommend anything to you. I think what would be best is if you would like feedback, I would need to see your setup and or the schematic/layout. All I can tell from the report is that many items are failing, but there is no way for me to tell why without information about your setup

    Best Regards,

    Casey