几个常用的接口实验的程序代码，用Verilog HDL语言编写的，包括七段数码管、拨码开关、蜂鸣器、矩阵键盘、串口、I2C、跑马灯等。-Some commonly used experimental procedures for the interface code, using Verilog HDL language, including Seven-Segment LED, DIP switch, buzzer, matrix k