说明：  基于Proteus的51系列单片机设计与仿真,设置有九个按钮，每个按钮对应不同频率的音符，分别是do,re,me,fa,so,la,si和报文音
(Based on Proteus 51 Series single-chip design and simulation, set nine buttons, each button corresponding to different frequencies of the notes, respectively, is do, re, me, fa, so, la, si and reported Wenyin)