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DS90UB953-Q1: Part of the image received over FPD link has noise

Stefan Koncar
Genius 3050 points
Part Number: DS90UB953-Q1

Hi,

We have following setup:

HDMI input is 1920x1080, 60 fps and this video is converted to RGB888, 1920x1080, 60 fps, 4 lane CSI2 output. This video is sent to TDA2p chip via coax cable, but part of the image has noise, like on image below:

Can you help us to solve this problem? On receive side (TDA2p) CRC error is detected? UB953 is configured in non-synchronous mode with external clock. UB953 has 25 MHz external clock, but two other chips in the chain have 27 MHz input. Could this produce this kind of problems? Any other suggestions?

Best Regards,

Stefan.

  • 0
    TI__Genius 10475 points
    Stefan,
    Please provide more information about what you are seeing. It is important to meet the datasheet guidelines on the PCB insertion loss, return loss and good layout practices are followed to ensure good margin in the system. Also make sure the power supply ripple and clock jitter are below the threshold. You can refer to the datasheet for additional details.
  • 0 in reply to Palaniappan Manickam
    Genius 3050 points

    Hi,

    You can download schematics for serializer here: 

    This is schematic of deserializer:

    Do you need some other information?

    Regards,

    Stefan.

  • 0 in reply to Palaniappan Manickam
    Genius 3050 points
    Hi,

    One more update - this problem occurs only when using 4 lanes on UB953. If I use 2 lanes everything is OK, but I need 4 lanes in order to transfer FULL HD video at 60 fps. UB953 is also tested in test pattern mode and everything is OK, it seems that problem arises at UB953 CSI input lanes. Do you have some suggestions how to debug this problem?

    Best Regards,
    Stefan.
  • 0 in reply to Palaniappan Manickam
    Genius 3050 points
    Hi,

    This issues is resolved. We had 25 MHz external oscillator and because of that FPD link rate was 2 Gbps.

    I switched to Internal AON Clock (50 MHz) - 4 Gbps line rate mode. We will put external 50 MHz oscillator in new HW revision.

    Best Regards,

    Stefan.