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Original question:

TPS65981: Application Customization Tool 4.03 Display Port Capabilities (Register 0x51) Doesn't allow for both Display Port...

TPS65981: Different behavior with 3.18 Configuration GUI and 4.03 Configuration GUI

David McCoy
Prodigy 155 points
Part Number: TPS65981

Hello,

I am using a TPS65981 in a data DFP and power sink configuration (5V @  1A and anywhere between 9V - 20V @ 3A). The chip is also connected to the external HD3SS460RHRT mux for USB3.0 and/or DisplayPort.

Problem

Currently the design does not support the following

  • Flipping the cable
  • DisplayPort doesn't work with version 4.03
  • USB Doesn't work with version 4.03

The only thing, I think, of note within the 01.12.08 firmware release notes is number 4 on the bug fixes 'Fixed DPSourceSink Bit Status when the port is configured UFPD or DFPD on the Type C Connection' but I don't see how it can cause such a difference on the design.

Notes

Using the Application Customization I noticed different results with different versions of the configuration tool.

Here are the behaviors I've seen with Version 3.18 and Version 4.03

3.18

  • Device is powered @ 20V
  • USB Devices Work
  • DisplayPort Does not go into DisplayPort Alternate Mode
  • Works when cable is flipped

4.03

  • Device is powered @ 20V
  • USB Device Does Not Work
  • TPS65981 Does not go into DisplayPort Alternate Mode
  • Does not work when cable is flipped

When I switched the max voltage to 15V instead of 20V

3.18

  • Device is powered @ 15V
  • USB Devices Work
  • DisplayPort Does go into DisplayPort Alternate Mode (DisplayPort isn't working but that may be an unrelated problem)
  • Does not work when cable is flipped

4.03

  • Device is powered @ 15V
  • USB Device Does Not Work
  • TPS65981 Does not go into DisplayPort Alternate Mode
  • Does not work when cable is flipped

It seems as though I'm getting better results with the 3.18. Perhaps I'm doing something wrong.

I've attached a PDF of the relevant schematic pages, I followed the TPS65981EVM but I flipped the AMSEL and MX_CTL0_EN signals but I was able to fix them and add internal pull-up/pull-down resistors in the configuration tool. The schematic pages doesn't show this but R157, R158, R161 and R162 are unpopulated.

I've attached my configuration projects for both version of the configuration tool 3.18 and 4.03

I've also purchased a TotalPhase USB Power Delivery Analyzer and have captured logs of the 15V for both versions of the configuration. If you would like to view the logs you can get the tool Total Phase Data Center and open the logs

2019.2.5 TPS6598 Issue.zip

  • 0
    TI__Mastermind 36756 points
    Hi David,

    GUI version 4.03 has a feature where you can "Import settings from Project" This would ensure your settings are the same between GUI4.03 and GUI3.18. Please follow the following steps:
    1. Open GUI 4.03 and select Project --> New Project
    2. Select any TPS65981 project to start
    3. Select Project --> Import Settings from Project
    4. Navigate to your 3.18 project file and select it

    Once this process is complete, I would suspect the same behavior with the latest tool. No change to device behvario was made betweem GUI releases.

    If this answers your question, PLEASE select "This resolved my issue"

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    Prodigy 155 points
    Eric,

    Thanks for getting back to me. I think I saw you mention this in another post and so that is how I created the 4.03 project by importing my settings from 3.18 project. That's a really helpful feature.

    Dave
  • 0 in reply to David McCoy
    TI__Mastermind 36756 points
    Hi David,

    Do you have an EVM available for testing? I have not seeng this behavior on my EVM using either GUI.

    Thanks,
    Eric
  • 0 in reply to Eric Beljaars
    Prodigy 155 points

    Eric,

    Unfortunately, I don't have the EVM available. I'll go get that and see if I can do an apples to apples comparison. Thanks for checking out the different versions GUI tools of the board.

    Dave

  • 0 in reply to David McCoy
    TI__Mastermind 36756 points
    Thanks, Dave.
    I'm looking forward to your updates.

    Eric
  • 0 in reply to Eric Beljaars
    Prodigy 155 points

    Eric,

    I haven't received the EVM yet but I did figure something out. We designed a carrier board for the NVIDIA TX2. The system behaves like a laptop, where the USB-C hub will power the carrier board and allow the user to use USB-3 and Displayport. Most of the time our carrier board is not connected to any external power, so all the power is supplied by the USB-C hub. specifically, the incoming power is routed through the PP_HV internal path of the TPS65981. The PP_5V0 is configured as an output if we are in that rare case where we have external power and want to attach an un-powered USB-C Hub.

    For the NVIDIA TX2 there cannot be voltages on some pins before the TX2 module turns on. When the module is turned on, it will assert a 'power enable' signal which I use to enable all the other regulators on the board. This includes the 5V regulator.

    This is where, I think, a problem is. There is a condition in which the cable can be connected but the PP_CABLE is left unpowered. For some reason the 3.18 configuration tool will somehow make this work while the 4.03 does not.

    I've setup the board to be powered by an external wall wart which supplies power to the TPS65981. Now the 4.03 works better (the SS_EN, AMSEL make sense) but still doesn't work when the cable is flipped. This might be due to the fact that I was running the chip out of spec.

    The problem is not resolved yet but hopefully this info can help others who sees similar issues.

    Dave

  • 0 in reply to David McCoy
    TI__Mastermind 36756 points
    Hi David,

    From your description above it sounds like you've narrowed it down to a PP_Cable or VCONN issue?
    If that's the case, I would suggest checking your setting for VCONN in the System Configuration Register (0x28).

    Thanks,
    Eric