最简单的单片机程序，可以在此之上进行实验开发，里面包括单片机键盘扫描和串口打印程序，可以在此之上进行其他程序的编写，非常方便，所有代码带有详细注解-The simplest single-chip process, can experiment on the development, which include single-chip serial keyboard scanning and printing process, can carry out other procedures on