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TUSB564RNQEVM: No Display Port out of EVM

James Pickard
Prodigy 20 points
Part Number: TUSB564RNQEVM
Other Parts Discussed in Thread: HD3SS460, TUSB564

I recieved this evaluation board but I am not able to get Displayport monitor to work. I am using the defaults which I assumed would be ok. Also I have in my design another crossbar hd3ss460 which I also cannot get video out although I am able to see Display information. The source I am using is Dell laptop with Dock that has USB-C port WD19S. Any help with # getting evaluation board to work and #2 getting our design working will be much appreciated.

Regards,

Jim Pickard

Electrical Engineer

  • 0
    TI__Guru*** 139405 points

    Jim

    Do you have a protocol analyzer that can capture the CC log communication between the Dell laptop and the EVM? We want to make sure the PD controller on both ends of the Type-C has entered into the DP Alt Mode first.

    Can you also probe HPD, AUXP, and AUXN? HPD should be 3.3V, AUXP should be around 0.3V, and AUXN should be around 3V when the EVM is connected to the laptop.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 20 points

    Below is CC log from sniffer.

    AUXp = 2.69V

    Auxn = .06V

    HSDC025A Capture 20221215.csv

  • 0 in reply to James Pickard
    TI__Guru*** 139405 points

    Jim

    Can you save the trace in a .tdc format? But at least from the .csv file, it does look like the DP Alt Mode has been negotiated. 

    But the AUXP and AUXN common mode voltage is not correct so the DP link training will not go through the TUSB564 AUX/SBU MUX. The laptop should have 100k pulldown and the DP monitor should have 1M pullup on AUXP, this will give us 0.3V on AUXP. For AUXN, the laptop should have 100k pulldown and the DP monitor should have 1M pulldown, this will give us 3V on AUXN. It looks like the laptop does not have the right pullup/pulldown resistors on AUXP/N.

    Can you try a different laptop or install pullup/pulldown on AUXP/N on the EVM to overcome the 100k in the laptop to get the correct common mode voltage?

    Thanks

    David