4 Replies Latest reply on Sep 5, 2011 7:11 AM by userc_42837

    USB 3 bulk transfer bandwidth and diagnostic output on the serial port

    userc_42837

      Hi, can anybody tell me what is the maximum continuous transfer bandwidth measured so far (using the cypress provided reference designs) using continuous bulk device to host transfers on a standard equipped USB 3 enabled windows 7 host (in terms of MBytes/s) ? Which design has been used? 

         

      Is there any way to enable OS/usb stack diagnostic output on the FX3 serial port ? As I saw there are quite a lot of things which are done transparent to the user. It would be helpful for debuging and troubleshooting reasons to output as much diagnostic as possible on the serial port.

         

      Thanks in advance, Joel

        • 1. Re: USB 3 bulk transfer bandwidth and diagnostic output on the serial port
          userc_38471

          We've seen upto 110MB/s. One customer has seen upto 120MB/s, You might want to look at http://www.cypress.com/?app=forum&id=167&rID=53351 for the corresponding modifications.

             

          When you say OS/USB stack messages are you talking about the Cypress driver for Windows or the FX3 API stack?

             

          Regards,

             

          Anand

          • 2. Re: USB 3 bulk transfer bandwidth and diagnostic output on the serial port
            userc_42837

                                 I was thinking about the embedded USB stuff (embedded USB driver,...)

               

            Looking at your programming manual there is a lot of things which your embedded framework is doing before passing the control to our application task. It would be nice if there is a way of outputting some messages which are allowing us to understand if something went wrong or everything was ok.

               

            Joel

               

                         

               
            • 3. Re: USB 3 bulk transfer bandwidth and diagnostic output on the serial port
              userc_42837

              By the way... I'm happy to know that you've seen 120 MBytes/s of transfer rate... unfortunately me, and considering some comments in this forum also other peoples, are not able to reproduce this figures using the cypress provided reference designs.

                 

              With which reference design you measured 120 MBytes/s ?

                 

              Please give me a host application and a fx3 firmware able to demonstrate 120 MByte/s on a Device to Host communication (bulk Out endpoint). 

                 

               

                 

              In the past I worked with the FX2 and I had no problem on reaching 43 Mbytes/s on bulk out endpoints but with all the Cypress provided reference designs for FX3 I get performances which are well below this figure (the board is enumerated as a SS device).

                 

               

                 

              Please, help would be appreciated.

                 

               

                 

              Regards, Joel

              • 4. Re: USB 3 bulk transfer bandwidth and diagnostic output on the serial port
                userc_42837

                I'm even wondering if it is possible to have more than 25..30 MB/s with the FX3 as long as we use  DMA_TYPE_MANUAL_OUT transfers from cpu to usb...

                   

                (I modified the streamer in order to have bulk out transfers of 4MB in order to reduce the thread call frequency on the host but it doesn’t change anything... always 26 MB/s of speed, I also modified the source of the Bulk Source Sink Application in order to avoid the CPU copying the pattern into the dma buffers)

                   

                Joel