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Original question:

TUSB8020B: Communication problem with Kingston drive.

TUSB8020B: Communication problem with Kingston drive.

Russ Chen
Prodigy 165 points

Part Number: TUSB8020B

Hi,

We've tried the command.

https://e2e.ti.com/support/interface/f/138/p/910863/3380685#3380685

And seemed like it did not resolve the problem.

Is there any other way to release compliance mode?

Thanks.

  • 0
    TI__Guru 60870 points

    Russ,

    It seems like the issue is not the hub port entering compliance mdoe, can you provide any USB debug logs from the failed connection?  What OS is being used?

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 165 points

    Hi, JMMN,

    Good day and thanks.

    I'm asking our software engineer to help to provide the data.

    Further confirm, if we're using I2C to set the mode, what should we do on the pin SMBUSz/SS_DN2 (Pin.22)?

    Pull low?

    Enclosed is final schematic of our product for your reference.

    Thanks.

    RussIEI_TUSB8020BI_Schematic_Review_20200728.pdf

  • 0 in reply to Russ Chen
    TI__Guru 60870 points

    Hi Russ,

    SMBUSz should be high in I2C mode or it can be left unconnected.  I was reviewing the history on this issue and I saw that LeCroy usb traces were provided in the past.  Is it possible to provide those in the case where dsportEcr is set on the TUSB8020B, but the problem still occurs?  I would like to confirm the failure mechanism.

    I also saw the notes on the OS in use from earlier.

    Thanks,

    JMMN

  • 0 in reply to JMMN
    TI__Guru 60870 points

    Also, schematic looks good, but the USB_VBUS signal is a status input to the hub that should only be high when an active upstream connection is connected to the hub.  Connecting this signal directly to a power rail can cause interoperability issues.

    Is this issue seen with any other USB drives?  I have ordered that specific USB drive model for lab testing.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 165 points

    Hi, JMMN,

    Good day.

    The HUB is integrated inside our system, and downstream port 2 is connected to a serial port and remain ON all the time.

    That means hub should be awake all the time, that's the reason we connect USB_VBUS to system power.

    From out testing, Kingston one is the only storage that has this kind of issue.

    Thanks.

    Russ

  • 0 in reply to Russ Chen
    TI__Guru 60870 points

    Hi Russ,

    I bought several of the exact Kingston model shown here:  https://www.kingston.com/us/usb-flash-drives/datatraveler-g4-usb-flash-drive

    Can you confirm this is the model with the issue?  I have tested this and several other Kingston brands and not been able to duplicate the issue.  From previous testing, you were able to duplicate the issue on a Windows 10 platform correct?  The Kingston drive is not configured as a boot drive, correct?  Is there any additional debug information that you con provide?  Perhaps using the USBMON tool?

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 165 points

    Hi, JMMN,

    Good day.

    Apologize for the late reply and update.

    We don't know why, but seems like the problem was solved. There's no recognize symptom on our product with the Kingston drive.

    Our software engineer did try the register setting for TUSB8020, but nothing changes (From the system log).

    After that, somehow, the Kingston drive is good for testing on any other units which is not set the register.

    Just curious, will the setting on Kingston one been changed when we set the register on TUSB8020?

    Anyway, the problem is solved, and we're sending the USB drive back to our customer for verification.

    Thank you very much for your support during the period.

    Sincerely,

    Russ 

  • 0 in reply to Russ Chen
    TI__Guru 60870 points

    Hi Russ,

    I am glad the problem is resolved, but I am not sure how it happened.  Changing the dsportecr bit in the TUSB8020B only prevents that specific hub's downstream porta from entering compliance mode unless specifically enabled to do so through as USB command.  It cannot change the behavior of the Kingston drive.

    Let me know if you need additional support.

    Regards,

    JMMN