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Original question:

TPS65988: Problems with applying Patch Bundle (I2C, SPI Less)

TPS65988: TPS65988 only negotiates PDO at initial plug-in

Tobias Johansson
Prodigy 50 points
Part Number: TPS65988

Hello. Since i could not get the patch-loading/-programming to work - see related question - I had do resort to writing to the registers directly, thanks to the Raw View in Application Customization Tool (v. 6.1.3)

This has led to a somewhat correct configuration.

  • We have 2 PDO's (5V and 15V).
  • PassMark USB PD Tester PM125

If I set the USB PD tester to by default request the 5V PDO, I get 5V on the port.

If I set the USB PD tester to by default request the 15V PDO, I get 15V on the port.

However, I can not get the negotiation to switch PDO after this "initial negotiation" to work.

Have tried the exact same configuration (except for a couple of GPIO pins that differ) in the TPS65988EVM - where the negotiation is working "back and forth" between the two available PDOs.

Could you please help me by pointing me in the right direction or review my project-file for any clear mistakes.
USB_5V_15V.pjt

Thank you.

  • 0
    TI__Mastermind 34736 points

    Hi Tobias,

    Can you capture a PD log when switching the sink PDOs? It might be a PM125 limit with not being able to send new sink cap when switching sink PDOs. 

    Thanks and Regards,

    Raymond Lin

  • 0 in reply to Raymond Lin
    Prodigy 50 points

    Hi. Absolutely.

    Switching from (default) 15V/3A PDO to 5V/3A PDO:

    Switching from (default) 5V/3A PDO to 15V/3A PDO:

    As you can see, no negotiation happens between the Sink/Source - no change in voltage. But the CC lines "must" be fine as the negotitation/Source Capabilities on initial plug-in works just fine (as seen in the earlier PD-logs and the fact that the correct PDO's are listed in the PM125).

    However, when trying the same thing on the TPS65988EVM, I get:
    (Default) 5V/3A to 15V/3A:

    And back to 5V/3A (including the negotiation for 15V/3A still in the log):

    This is what leads me to believe that the PM125 "should" be able to send sink cap.

    Any ideas?

    Thanks,

    Tobias

  • +1 in reply to Tobias Johansson
    Prodigy 50 points

    Hello again, I manages to solve the specific issue.

    The issue was with me writing the data the wrong way to the PD 3.0 Configuration Register (0x42) (i.e. [0x00, 0x00, 0x04, 0x1A] instead of [0x1A, 0x04, 0x00, 0x00]).

    However, the configuration only works for one port. The port it does not work for tries to use the GPIO #13 (SWD DATA) for toggling between 5 and 15 V from a variable DCDC output, but "it never goes high/3V3. Are there any limitations to using GPIO #13 for this? I believe it is what is used in the EVM default configuration.

    GPIO #14 is used for the other port (in the same way) and works as intended with the current configuration.

    Thanks!

    // Tobias

  • 0 in reply to Tobias Johansson
    TI__Mastermind 37855 points

    Hi Tobias,

    There should not be any limitations with GPIO 13. It should work the same as GPIO 14 but for th eother port.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    Prodigy 50 points

    Hi again, thank you for your time.

    After patching with jumper wires/reconfiguring to GPIO15 instead of 13 - the "Port 0 Source PDO 1 Negotiated" goes high as expected and wanted functionality is achieved.

    However, as a last question - since I've tried the "old configuration" (see images in lmy last reply) with GPIO13 on multiple manufactured units (even checked soldering/resoldered GPIO13/Pin 41), with no success. You are sure that for the TPS65988 there are nothing "special" needed to set GPIO13 as output/be used as described above - since it is labeled as "SWD DATA" etc?

  • 0 in reply to Tobias Johansson
    TI__Mastermind 37855 points

    Hi Tobias,

    I was able to talk with the engineer that supports the GUI and he said that the (SWD DATA) should not be there. The datasheet also makes no reference of that pin being SWD DATA.

    That pin should function as a normal GPIO, but let me see if I can replicate your issue on my end with a 65988EVM.

    If you have the even working with GPIO15, I recommend continuing to use that GPIO.

    Thanks and Regards,

    Chris.