目录1绪论..........................................................................................................11.1单片机概述.......................................................................................11.2课题概述...........................................................................................22系统硬件原理及设计.............................................................................32.1核心器件AT89C51介绍..................................................................32.2硬件电路设计.................................................................................52.2.1设计目的......................................................................................52.2.2电路设计原理............................................................................62.2.3总体电路设计............................................................................62.2.4单片机电路设计.........................................................................72.2.5显示电路设计............................................................................72.2.6晶振时间电路设计....................................................................72.2.7控制电路设计............................................................................82.2.8输出电路设计............................................................................83.系统软件设计.........................................................................................9系统软件设计3.1总体流程图.......................................................................................93.2单片机音阶代码实现.....................................................................103.3单片机产生不同频率脉冲信号的原理：.....................................113.4音乐代码实现.................................................................................133.4.1音乐代码库的建立方法...........................................................133.4.2选曲............................................................................................143.4.3歌曲的设计...............................................................................143.5键控子程序................