My data follow like this. 1.PC send data to FX3 2.FX3 write data to FPGA 3.FPGA processing data then give FX3 readable flag 4.FX3 read data from FPGA 5.PC read data from FX3 The problem comes when FPGA processing too later, Step 3 is not finished but PC is going to read from FX3. When step 4 is finished but FX3 not send ERDY TP to PC so my program stuck in read function. In USB2.0 the data follow is right. PC could read processed data from FPGA. But USB3.0 is not work well. Thank you everyone!