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USB 3.0 Device Enumerated as USB 2.0

USB 3.0 Device Enumerated as USB 2.0

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How to debug when a USB 3.0 device is not enumerated as USB 3.0 but as USB 2.0?

Check Hardware:

  1. The clock provided to FX3 should satisfy the specifications given in Table 4 of FX3 datasheet.
  2. The noise on power supplies AVDD, U3TX_VDDQ, and U3RX_VDDQ should be below 20 mV and  on VDD should be below 100 mV.
  3. USB 3.0 traces on the board should follow the specifications given in AN70707.
  4. Use standard certified USB cables.


Check Firmware:

  1. Use the same firmware on FX3 DVK and check for the issue. This helps determine whether the issue is related to hardware or firmware.
  2. Check whether SuperSpeed connection is enabled in the CyFx3BootUsbConnect ( CyBool_t connect, CyBool_t ssEnable ) API.
  3. Disable LPM in the firmware and check for the issue.
  4. Check with multiple Host controllers and OS.



Version: *A

Translation - Japanese: USB 2.0として挙げられるUSB 3.0デバイス - KBA204163 - Community Translated (JA)