• Resolved

TPS65982: Display Port Video bypass from TPS65982+HD3SS460 at USB-C port 1 to USB-C Port 2 TPS65982+HD3SS460

Part Number: TPS65982

Hi,

we are trying to get video through our device from USB-C Port 1 to USB-C Port 2.

Both ports are identical. They contain TPS65982+HD3SS460.

Both ports configured from TPS65982 application customization tool to support Display port (see image).

Video signals connected from Port 1 to Port 2 (after HD3SS460) in next way:

Port 1 / Port 2

LN0 (p) -> LN3 (p)

LN0 (n) -> LN3 (n)

 LN1 (p) -> LN2 (p)

LN1 (n) -> LN2 (n)

 LN2 (p) -> LN1 (p)

LN2 (n) -> LN1 (n)

 LN3 (p) -> LN0 (p)

LN3 (n) -> LN0 (n)

Please help to find out why we can't pass video through our device?

Is something wrong with configuration?

Can we get some support from TI?
We are making device that soon should be in mass production and this issue is completely blocking all future work.

We are using MacBook Pro as video source and LG Ultra Fine monitor.

--

Best Regards,

Sergii

  • hi Sergii,

    Sorry for critical delay, everything you are doing seems correct. Let me further assist you till issue is solved.

    The first step is to make sure the correct MUX ctrl bits on the SS MUX are mapped to the correct 82's GPIO's => go to ‘GPIO event map’ register 0x5c in the config tool. Plug event, AMSEL event, Port Connected CC2 (Cable Orientation Event) need to be mapped correctly in order for the SS MUX to configure the correct signaling. note: also HPD (TX/RX) is GPIO4.

    I attached a couple screenshots in a document to illustrate this. Please let me know the outcome of testing the SSMUX control GPIO config.    

    HD3SS460_GPIO_config.docx

    Thanks

    Jeff

  • In reply to Jeffrey Mueller:

    Hi Jeffrey,
    thanks for the quick answer! Yes, lets make this feature works :)
    I have correct configuration, same as you proposed. Also when i solder wires to Display port connector (istead of USB-C port 2) - i can get video out of MacBook, up to 5K.
    So, looks like MUX is controlled correctly and HDP (TX/RX) set to GPIO 4.
    MacBook is detecting the monitor (it detect that LG UltraFine is connected, but video is absent), and saying that monitor is attached, but MacBook became to be very slow.... I can observe at oscilloscoupe that HPD signal has frequency 3 Hz - I assume that due to that 3Hz MacBook has some issue with perforance.

    When i am connecting external monitor via Display port wires (Samsung 4K) - everything works perfect.
    Any ideas?..
    Best regards,
    Sergii

  • In reply to Sergii Makovetskyi:

    Hi Sergii,

    To confirm and further claify, the connections you are making are the same as the screenshot below (found in the HD3SS460 datashet pg.17 )?

    note: SBU1 and SBU2 are crossed.

    note: this is for pin assignment C and E not pin assignment D

    Thanks

    Jeff

    Jeff

  • In reply to Jeffrey Mueller:

    Hi Jeff,

    why SBU1 and SBU2 are crossed? I think crossing is needed if USB-C cable inserted with 180degree rotation - than we will have polarity event

    Look, i have 2 USB-C MUXes like this:

    Than, I have made connections of 2 ports like that:

    In that case I am able to detect monitor (looks like AUX lines works OK - I could get parameters of the monitor) but i can't get video out. 

    Also i have tried to solder wires directly from Port1_DP to Port2_DP - without MUX1, and situation is the same.

    So, please confirm that I have to connect Lane 0 Source to Lane 3 Sink and so on.

    I also have tried to connect Lanes like that: LN0 to LN0, LN1 to LN1, and so on.. But same result - I can detect Monitor and parameters of it at MacBook, but no video.

    Also, do you know, LG UltraFine monitor, is it works in USB-C mode or only as Thunderbolt 3? I am afraid that it is not working due to that/

  • In reply to Sergii Makovetskyi:

    Hi Sergii,

    I see, thanks for clearing this up. Also thanks for supplying a beautiful diagram of your MUX connections. I will verify your lane connections are correct and also find out about the UltraFine monitor. I will update you in less than 24 hrs.

    Thanks

    Jeff

  • In reply to Sergii Makovetskyi:

    Hi Sergii,

    I attached a word doc to answer your questions. Please let me know if I helped you solve your issue or you have any more questions!

    port to port DP connections.docx

    Thanks

    Jeff

  • In reply to Jeffrey Mueller:

    Hi Jeff,

    thanks a lot! Will try to check it right now.

    Thanks for comment about USB 3.0 P/N swapping. It was done at TI board that we have - EVK TIDA-01243 ;) And than i found that USB 3.0 standard allows to swap P/N  signals (only between the pair RX or TX). I also found it somewhere at TI forum.

    USB 3.0 part works OK in our project.

    I will check video connection and back to you :)

    --

    Best regards,

    Sergii

  • In reply to Sergii Makovetskyi:

    Hi Jeff,
    unfortunately - nothing changed. Video doesn't work.
    MacBook detecting that monitor ids presented and show that everything is ok, but video is absent.
    I have tried to check LG UltraFine monitor and Samsung 4k via usb-c to Display port cable - same results...
    Only 1 monitor was connected at same time.
    Any ideas?
    Do you have any EVK that could pass video from USB-C to another USB-C?

    Best regards,

    Sergii

    p.s. - PD IC configuration file

    PD_PORT1_no_source_TI.zip

  • In reply to Sergii Makovetskyi:

    Hi Sergii,

    Dont worry we will get this working. I attached a word doc with a few suggestions. Please let me know of any updates!

    DP_debug_ideas_QA_e2e.docx

    Thanks

    Jeff

  • In reply to Jeffrey Mueller:

    Hi Jeff,
    thanks for the answers,
    some answers: I have tried to set "F" Pin assignment just for the test. It doesn't work without it too. I am using 2.12 config tool. So, i will try to update and check again. About Display Port signaling - there was also DP 1.3 there, and i've decided to try with "unspecified".
    I will check my USB 3.1 lines again to understand what is wrong.
    I already have communication between the MacBook and Monitor via my board (AUX data is OK, HPD signal available), so i have an issue in latest step - no video :)
    Can you please provide a link to your "82 EVM" ?

    Can you provide a links to schematics of that boards?
    --
    Best regards,
    Sergii