实现FPGA和PC机之间的通信。PC机发送的数据可以通过FPGA显示在数码管上；FPGA通过按键发送的数据可以显示在PC机的串口调试助手上。-Communication between the FPGA and the PC. PC sends the data can be displayed through the FPGA digital tube FPGA through the button to send the data can be displayed on a PC seri