1 Reply Latest reply on Jan 7, 2015 1:33 AM by kumr

    Initial handshake and speed detection

    robert.beauchaine

      Does anyone have a good reference on the entire handshake process for an FX3 device?  We're trying to track down enumeration issues - frequent failures to detect a device, and a USB 3.0 interface that always fails to enumerate as USB 3.0 and falls back to 2.1.  The USB event log used in the USBBulkSourceSink image shows the following, but I need a better understanding of the exact sequence of events that occur between "attempted again" and "disabled".  I have protocol analyzer traces of the sequence, but still lack a deeper understanding of what is happening and why.

         

       

         

          

         

                     

                                                                                                                                                                  

      0x51

       

      /* Indicates that a USB 3.0 connection is being attempted again. */

      0x42

       

      /* Indicates that the USB High-Speed handshake has been completed. */

      0x12

       

      /* Indicates that USB 3.0 Rx Termination has been detected. */

      0x10

       

      /* Indicates that the USB 3.0 link has been disabled. */

       

        • 1. Re: Initial handshake and speed detection
          kumr

          The enumeration process would that the device tries SuperSpeed enumeration 3 times and then falls back to USB 2.0. The failures you see could be because of a bad cable, impedance mismatch on the trace, bad power supply etc. As a first step, make sure that your board is designed according to the guidelines in AN70707 (http://www.cypress.com/?rID=53203).

             

           

             

          And if you can take a bus trace with a hardware analyser like a LeCroy or a Beagle or an Ellisys, please do so and attach it here (or mail it over to Tech Support).