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TUSB1002EVM: Mass storage not detected when insert TUSB1002EVM in between PCIe daughter card based Host and Mass storage stick

Part Number: TUSB1002EVM
Other Parts Discussed in Thread: TUSB1002

Hi,

I have the TUSB1002 EVM evaluation board to test how TUSB1002 works. I have tested it with following setup.

A)  PC (PCIe Type A Port)  ---------  Mass storage stick (Sandisk pendrive).

B)  PC (Thunderbolt Type C Port)  ---------  USB3.1 Type A to Type B Cable  -------------  TUSB1002 EVM   ---------- Mass storage stick (Sandisk pendrive).

C)  PC (PCIe Type C Port)  ---------  USB3.1 Type A to Type B Cable  -------------  TUSB1002 EVM   ---------- Mass storage stick (Sandisk pendrive).

For setup A :

Mass storage device detected successfully on PC.

For setup B :

Mass storage device detected successfully on PC.

For setup C:

Mass storage device not detected.

I have tested same behavior with different PC and found issue with TUSB1002 re-driver with PCIe based USB3 Host controller port.

Best Regards,

Trupesh Vasoya

  • Hi,
    On above setup, I forgot to mention one thing. I have used Type C OTG cable to connect PCIe Type C Host with TUSB1002 EVM Type B port. Please find below setup.

    A) PC (PCIe Type A Port) --------- Mass storage stick (Sandisk pendrive).

    B) PC (Thunderbolt Type C Port) --------- Type C OTG cable --------- USB3.1 Type A to Type B Cable ------------- TUSB1002 EVM ---------- Mass storage stick (Sandisk pendrive).

    C) PC (PCIe Type C Port) --------- Type C OTG cable --------- USB3.1 Type A to Type B Cable ------------- TUSB1002 EVM ---------- Mass storage stick (Sandisk pendrive).

    Best Regards,
    Trupesh Vasoya
  • Hello Trupesh,

        I think you have a misconception, on the PC side you can't have a PCIe port, there is no way that connection would work, these must be USB ports, meanwhile the Thunderbolt port I am assuming that it is a thunderbolt 3. Please let me know whether you are using the same EQ settings in all three cases, that may be the issue because the TUSB1002 has been designed to be placed and configured in one port, this means that for a different port you may need to change the EQ settings.

    Regards,

    Diego.

  • Hi Diego,

    Thanks for the quick reply.

    First of all, let me clear setup environment. I havePCIe based card with USB3.1 port, plugged into PC's PCIe port. please find attached image for that card. When I connect pendrive directly on that USB port then it is working fine, but when I used EVM module in between Host and pendrive then Mass storage device not detected. As you suggested, I have tried different EQ setting but still result is same.

    Waiting for your positive response.

    Best Regards,

    Trupesh Vasoya

  • Hello Trupesh,

    What Is the configuration you've tried on the EVM?. It may be a configuration issue only.

    Regards,
    Diego.
  • Hi Diego,

    We have tried all combination of configuration setting and found same results. The issue is only with USB Host available with PCIe card, for other USB port it is working fine. 

    Let me know if you require any other information from my side.

    Best Regards,

    Trupesh Vasoya

  • Trupesh,

    Then the issue is most likely to be caused by an incompatibility on the RX detection circuitry. We've solved this issue by placing >256uF AC capacitors on the RX pair of the TUSB1002. This workaround is also contemplated by an ECN in the USB3.1 specification.

    Regards,
    Diego.
  • Hi Diego,

    Thanks for the reply. By placing >256uF AC capacitors on the RX pair of the TUSB1002, the issue almost resolved. Thanks you so much for your kind help.

    As a suggestion, Is there any way to add this info in reference documents for re-driver usage. Because we have developed our board with TI re-driver with the help of reference documents of re-driver and right now do not have any way to place capacitor on RX pair.

    Thanks & Regards,
    Trupesh Vasoya

  • Thanks for the suggestion Trupesh, I agree with you that this change has to be done.

    Regards,

    Diego.