目录1引言.......................................................................................................61.1目的和意义..................................................................................61.2本系统主要研究内容..................................................................62.总体方案论证与设计...........................................................................72.1主控模块的选型和论证...............................................................72.2显示模块的选型和论证...............................................................72.3按键模块的选型和论证...............................................................72.4功率放大模块的选型和论证.......................................................82.5系统整体设计概述.......................................................................83.系统硬件电路设计.............................................................................103.1主控模块....................................................................................103.1.1STC89C52单片机主要特性.............................................103.1.2STC89C52单片机的中断系统.........................................143.1.3单片机最小系统设计......................................................143.2数码管模块设计.........................................................................153.2.1数码管原理介绍..............................................................153.2.2数码管电路设计..............................................................163.3矩阵键盘模块设计.....................................................................183.4功率放大模块设计.....................................................................193.4.1LM386内部原理...............................................................203.4.2LM386使用注意事项......................................................2134.系统软件设计......................................................................................234.1系统软件总体设计.....................................................................234.2定时器产生音乐信号原理.........................................................244.3程序设计原理.