1 Reply Latest reply on Mar 8, 2016 9:46 PM by dhritimank_56

    USB 2.0 on the FX3 Super Speed Explorer Kit SlaveFIFOSync code


      I am working with a FX3 Super Speed Explorer Kit in Linux and I am using the SlaveFIFOSync in APP note AN65974. I was able to get the USB 3 running at about 2Gbps, but USB 2.0 is only 30Mbps (bits NOT bytes). I notice that the burst length in the code is not 16 for the "case CY_U3P_HIGH_SPEED:", but rather it is set to 1. I tried to change it to 16, 8, 4, and 2 and they all will not allow the image to load on the board. I don't know if I am even looking in the right place to speed up the USB 2.0, but I figured it was a good place to start. I need to get the USB 2.0 to run at the ~480Mbps rate. Does anyone have any experience with the USB 2.0 side of the SlaveFIFOSync code?



        • 1. Re: USB 2.0 on the FX3 Super Speed Explorer Kit SlaveFIFOSync code



          Burst Length is a parameter defined in the USB 3.0 Specification and is not applicable for USB 2.0. This is the reason why changing the burst length to 2,4,6,8 won't work. It should always remain 1.


          As far as the throughput is concerned, indeed 30Mbps(~4 MBps) is very less. It should be like 20-30 MBps. But since the USB endpoints are bulk, it will depend on the USB bus condition also, whether there are some ISOC devices connected which will have higher priority and will decrease the Bulk throughput.