3 Replies Latest reply on Jul 26, 2011 5:31 AM by anand.srinivasan.asokan

    Slow Data transmission due to control transfers

    ashley.grealish

      I am attermpting to loop the sending of a 11 byte data packet to an FX2 development board. The firmware appear to be set up correctly and I ave measure that the processing of this data packet on the firmware side takes 30us. However the PC is taking 5ms between loops.

         

      I have captures some timings from the PC using USBlizer and it looks like the device is reconfiguring itself between transmissions.

         

      Here is the output from the USBlizer software:

         

      http://www.appliedrelaytesting.com/other/WriteDataExport.html

         

      The data packet I am sending is "A0 01 67 00 05 03 12 34 56 78 50", as you can see after sending the packet the USB hub tries to get descriptor which takes 899 us.

         

      Any ideas about how to fix this?

         

       

         

      Thank you in advance.