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TPS65981: PD data not correct

Genius 9615 points

Replies: 17

Views: 277

Part Number: TPS65981

Dear all,

one of my AA is facing issues with the TPS65981ABIRTQR.

The device has been configured through the Configuration Tool, mode DFP_D  with +5V at PDO.

The CC pin seems working fine, but the data on the PD bus are not correct.

 

I've attached the project done with the configurator.

Can you please provide me with any hints ?

 

regards,

Domenico

project.zip

  • Hi Domenyko,

    I see a 9V Source and Sink PDO set in the Source capabilities and Sink capabilities registers respectively. Is this intended?
    Additionally, can you check to see if the PD controller is in APP mode by reading the Mode register 0x3 after boot?
    Finally, a PD trace of the failure would help debug the issue.

    Thank you,
    Eric
  • In reply to Eric Beljaars:

    Hi Eric,

    below the ansers to your questions:

    1.      Just 1x PDO source capabilities is enables at 5V , the other sink are disabled.

    2.      PD is in APP mode after boot.

    In the attachment the registers with the devide in debug mode.

    It seems that there aren't any  active contract PDO.

    regards,

    Domenico

    Device 1, port 0 Debug Registers.txt

    Device 1, port 0 Configuration Registers.txt

  • In reply to domenyko:

    Hi Domenyko,

    It seems that the TPS65981 is not detecting a device on the other end of the cable. The TPS65981 will not provide VBUS until a connection has established per the USB Type-C PD spec. What device are you connecting on the other end of the cable?

    Thanks,
    Eric
  • In reply to Eric Beljaars:

    Hi Eric,
    the designer has tried with 2 different cable:
    DP alt mode and HDMI alt mode.

    if you think that the schematic may help, we may continue the conversation by email.
    regards,
    Domenico
  • In reply to domenyko:

    Hi Domenyko,

    Are they attaching anything to the other end of the cable? We will not make a connection unless the correct resistances are presented on the CC line by the connected device. I would suggest ordering a TPS65981EVM and seeing if the issue can be reproduced on that board. In that case, you have a known working platform for debugging.

    Thanks,
    Eric
  • In reply to Eric Beljaars:

    Hi Eric,

    On the other end of the cable there is HDMI/DP monitor of HP.

    The CC lanes are detected in the right way, see registed 0x69, C_CC1 is used for PD protocol and C_CC2 for PP_CABLE:

    Type C State Register (0x69)
      Type C State Register
        CC Pin For PD       C_CC1 is CC pin
        CC1 Pin State       Rd detected (Source only)
        CC2 Pin State       Ra detected (Source only)
        Type C Port State   Reserved

     regards,

    Domenico 

  • In reply to domenyko:

    Hi Domenico,

    I suggest getting a TPS65981EVM and running this same test using the 81EVM. This would let us know if the issue is in the hardware or the configuration. This would also allow us to have a reproducible platform for debugging.

    Thanks,
    Eric
  • In reply to Eric Beljaars:

    Hi Eric,

    The test with EVM were fine. When the cable is connected, the peripheral is recognized and the PD  procedure contract works.  In the board of the cusotmer only the CC orientation is detected.

    I've attached the dump of the registers of both EVM and customer's board.

    Do you have any hint ?

    regards,

    Domenico

    TPS65981_evm_vs_customer_20190314.zip

  • In reply to domenyko:

    Hi Domenyko,

    It looks like the configuration settings on each board is identical (Please confirm).
    If that is the case, I would suggest looking into hardware differences between the TPS65981EVM and the customer board.

    Thanks,
    Eric
  • In reply to Eric Beljaars:

    Hi Eric,

    correct the configuration setting are identical. We have collected some screenshot of the CC1, CC2 and Vbus signals.

    The signals of the customer's board seem to be smoother that the signal of the EVM.

    it seems that the device does not have enough strength to drive the lines. 

    Have you never seen something similar (I've attached the screenshots). 

    I was thinking if wrong capacitors (mounted by mistake) could give these effects.

    regards,

    DomenicoTPS65981EVM_NOX_acq20190315.zip

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