3 Replies Latest reply on Oct 20, 2011 9:43 AM by userc_44417

    Bulk-Mode Burstsize and dma-buffers in FX3





      I´ve experienced problems with burstsize > 8 when setting up a bulk endoint at the fx3.


      Using code like:




              endPointConfig.enable = 1;


              endPointConfig.epType = CY_U3P_USB_EP_BULK;


              endPointConfig.burstLen = 16;


              endPointConfig.streams = 0;




              /* Configure the Endpoint */


              apiRetStatus = CyU3PSetEpConfig(CY_FX_EP_PRODUCER,&endPointConfig);


              if (apiRetStatus != CY_U3P_SUCCESS)




                  /* Error Handling */


                  CyU3PDebugPrint (4, "USB Set Endpoint config failed, Error Code = %d\n",apiRetStatus);



          Throws an error 64 when calling CyU3PSetEpConfig.   
          Using endPointConfig.burstLen = 16 seems to work.   
          Is the burstlength in fx3 limited to 8 ?   
          Another question is the relation between dma-buffersize an burstlength.   
          It seems to work when i do a cpu to endpoint dma with a buffer-size of 16*1024 to a endpoint with a burstsize of 8.   
          Ist that ok ?   
          E.g. does that mean there is no fixed relationship between endpoint burstlength and dma-buffersize within the fx3 device ?   
          best regards