2 Replies Latest reply on Oct 10, 2011 4:11 AM by hyun-chul.shin

    DMA buffer size

    hyun-chul.shin

      Dear forum members,

         

       

         

      I experimented bulk transfer speed with DMA buffer 32KB and 16 burst endpoint, and I got a speed 262MB/s.

         

       

         

      What is the relation between DMA buffer size and burst size?

         

       

         

      Is there any delay at buffer changing time? If not, I think CyUSB driver can't manipulate DMA machanism efficiently.

         

       

         

      Best Regards,

         

      HC

        • 1. Re: DMA buffer size
          ananda_26

          Hi,

             

          I didn't quite understand your question with regards to the buffer changing and DMA manipulation of CyUSB.sys.

             

          Which buffer changing are you talking about? on the host side or device side?

             

          Regards,

             

          Anand

          • 2. Re: DMA buffer size
            hyun-chul.shin

            Hi Anand,

               

            I changed device side buffer size up to 48KByte.

               

            and buffer size seems to be set up to 64K-1 byte. Right?

               

            Another question, If an CRC error occured at bulk transfer, do the firmware and PC driver handle this error automatically?

               

            Regards,

               

            HC