利用蜂鸣器播放音乐. 这是刚学51单片机时制作的一个小程序，稍作修改便可作为一个简易的音乐播放器使用。,The use of buzzers to play music. This is just when the production of single-chip microcomputer 51 places a small program, with some slight modifications it can be used as a simple music player to u

调试51单片机的简易程序————键盘扫面(A simple program for debugging 51 singlechip -- Keyboard sweep surface)