通过开发板上的8 个按键控制发光二极管led1~led8 显示。通过这个实验，进 一步掌握case 语句的编程方法及FPGA I/O 口的输出控制。-Eight button control panel through the development of light-emitting diode led1 ~ led8. Through this experiment, and further understand the case statement programming and FP