4 Replies Latest reply on May 19, 2017 7:47 PM by userc_38564

    gpiftousb  data error



        I use fpga to generate pseudo-random code and use FX3 to transfer to the pc,when I use the "control center" to view the data,I find when I send a fixed data,and  the control center shows the rignt data,but when I send the pseudo-random code,it shows error code,why?Is it because my clock is too big?I use 50Mhz clk,and I use the example of "cyfxgpiftousb".In addition ,I find when I reset fpga and send the same pseudo-random code,the control center shows different data with the first time? Why?





        • 1. Re: gpiftousb  data error

          What is the error shown by control center?  Is it error code 997? If so, this corresponds to a timeout in the Xferdata call. This may mean that your device/FX3 may not have any data buffer ready to be send to the host. Please make sure that there is atleast one buffer ready. You can check if you have any buffer by making the DMA channel as manual and check for PROD event in the DMA callback. If you do not get any PROD event, this means that there are no data buffers ready. When you see this behaviour, what is the size of the data transmitted from the FPGA, and what is your DMA buffer size? You can try by making the DMA buffer size small (i.e.1024). When you retry, then it may happen that this time the buffer got full (partially full + the current transfer), and you will get the data along-with the data you were supposed to receive in the previous transfer. 

          • 2. Re: gpiftousb  data error



            Thanks for your reply. You may not understand me ,now  I have transfered the data to the pc,but the data in the "control center" is not the same with what I have sent,because I know the correct data . there  is no error 997,I use fpga send cycling data ,so I use the example "cyfxgpiftousb" ,when I send the fixed data ,it is same with the data I sent ,but when I send the data with clock ,it shows different data .


                      If you don not understand me,I attaches them .





            • 3. Re: gpiftousb  data error

              Can it be that the buffer has a data from different time and you may have probed it at a different time? We can analyze this better, by follow. 


              Instead of a random data, please generate counting data(incremental) from the FPGA. 


              From the control center, please record what data you get. Please in_transfer from the control center multiple times and attach the data recieved everytime.

              • 4. Re: gpiftousb  data error

                ok,thank you very much,Nishant  ,I solved ,