说明：  通过指定的串口操作,就可以实现正常的播放,上下曲操作,音量调节等等.通过这次设计,也详细了解了MP3的编码格式,了解学习不能停留在书本上面,因为技术是日益更新
(The specified serial port operation, can achieve normal playback, up and down operation, volume control and so on. Through this design, but also a detailed understanding of the MP3 encoding format, learn not to stay on the books, because the technology is increasingly updated)