通过4*4矩阵键盘，实现8首曲目的播放以及do、re、mi、fa、so、la、si、do 的琴键功能，这样既能播放音乐也能演奏简单音乐-4* 4 matrix keyboard 8 track player, do, re, mi, fa, so, la, si, do ' keys function, so that can not only play music but also be able to play a simple music