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DS90UB954-Q1EVM: unable to understand the reported resolution

omar chakroun
Prodigy 225 points
Part Number: DS90UB954-Q1EVM
Other Parts Discussed in Thread: ALP, DS90UB949-Q1, DS90UB940-Q1

Hi all,

we are trying to interconnect multiple system in order to feed the ti953 with an RGB stream coming from HDMI to CSI-2 converter.

the chain contains; HDMI/CSi-2 converter -> TI953 -> TI954 -> CSi2to HDMI Converter.

we configured the scripts under alp in order to pass RGB888 and we are wondering if it is the same thing as the default RGB that is natively supported by HDMI 1.4?

we see that the TI954 report resolution but we are not sure if it is correct or no; we are using 1920*1080 @ 60fps as input in standard RGB.

can you provide us with a script that reads the data from the ti953 input connector (the one on which is supposed to connect the daughter card) on RGB and get it serialized and sent to the ti954? so we can compare to ours maybe we are missing something.

thank you in advance.

  • 0
    TI__Guru** 103215 points
    Omar,

    1920x1080x60 with 24bpp (RGB888) will likely be too much bandwidth for 953. It can support 3.2Gbps CSI-2 total, but for this resolution and color depth the CSI-2 data should be higher than this (assuming typical blanking).

    The easier path for supporting this would be:

    HDMI -> DS90UB949-Q1 -> DS90UB940-Q1 -> CSI2 to HDMI Converter

    949 and 940 can support this resolution and color depth in dual link mode and there would be no need for the HDMI to CSI-2 converter.

    Best Regards,
    Casey
  • 0 in reply to Casey McCrea
    Prodigy 225 points
    hi Casey,

    we managed to see a good resolution report even with our HDMI to CSi-2 converter and we see that the reported resolution on the TI954 is changing when we change the HDMI input resolution.
    according to our calculation it should not be an issue for the total bandwidth, we are around 3.07gbps. we tested also on YUV422 on 8bpc and the Ti954 reports a good resolution. Another question is is there any ability to check for transmission errors?

    thanks,
    omar
  • 0 in reply to omar chakroun
    TI__Guru** 103215 points
    Omar,

    What is the problem? Are you not getting video feed all the way through the chain? There are forward channel error registers and CSI error registers that can be read on both 953 and 954. I would suggest reading back the CSI_RX_STS on the 954 to start.

    3.07Gbps seems low for 1080p60 RGB888. That would leave only 3% blanking headroom to the active video. What is the pixel clock frequency for the HDMI input?

    Best Regards,
    Casey
  • 0 in reply to Casey McCrea
    Prodigy 225 points

    Hi Casey,

    the issue is that we are getting a good reporting up to the TI954 but the last step is not functionning (that's a component from another provider). we changed to YUV422 and it seems ok for the TI components at least. we checked that particular register and it is reporting checksum error (0x4). please find attached all the register that we read when we initiate the script and that report some errors.

    thank you again,

    omar

  • 0 in reply to omar chakroun
    TI__Guru** 103215 points
    Hey Omar,

    It looks like there are some CSI errors, they could be originating at the 953 input (you can check the CSI error registers on the 953 to verify). Can you please verify proper operation by using CSI PATGEN from the 954 first to ensure it is working correctly? In the ALP install folder there is an example PATGEN script for 1080p30 RGB888: 954_patgen_RGB888_colorbar_1920x1080p30.py

    C:\Program Files (x86)\Texas Instruments\Analog LaunchPAD v1.57.0010\PreDefScripts\DS90UB954

    It can be modified for 60fps by changing the line period if needed. Give that a try first to verify the 954->Converter link. If that works correctly, then please use PATGEN on the 953 in order to verify the 953-954-Converter link. If that also works, then I believe the problem is with the first link between the Converter->953.

    Best Regards,
    Casey