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Visitor II
July 7, 2008
Question

USB bulk transfer rates above 64kbytes/sec

  • July 7, 2008
  • 1 reply
  • 713 views
Posted on July 07, 2008 at 16:48

USB bulk transfer rates above 64kbytes/sec

    This topic has been closed for replies.

    1 reply

    daniel8Author
    Visitor II
    May 17, 2011
    Posted on May 17, 2011 at 09:54

    I've looked through the demos, and none cover this issue.

    I am using the VCOM example as my base, and I am trying to get around 500kb/sec transfer rates. I do not have an UART on the other end (I stripped that out).

    The problem I have is that I do not seem to be able to send more than 64 bytes per frame. I know that with a full speed bus I should be able to get 19 packets per frame, or 64*19= 1.216Mb/sec

    I have tried re-loading my endpoint on EP1_IN_Callback with more data, but that still didnt work. I have a fifo where I load 256bytes at a time for test, and here is my code for my endpoint callback

    void EP1_IN_Callback(void)

    {

    char length;

    char i=1;

    if(fifo.num_free

    //we still have data to write on this endpoint, write it.

    length= read_fifo(&fifo,&us0_tx_buf[0],64);

    UserToPMABufferCopy(&us0_tx_buf[0], ENDP1_TXADDR, length);

    SetEPTxCount(ENDP1,length);

    SetEPTxValid(ENDP1);

    }

    count_in =0;

    }

    But that does not work. Any suggestions on how to get my data rates increased above the 64k? Thanks

    Daniel