说明：  首先，单片机计算出正弦波所需的ad转换数据，将此数据存入数组，然后将数据放入fifo，单片机只需读fifo，（将fifo设置成循环输出模式）就可得所需波形，另外，控制延时时间，即可控制频率。
(First of all, single-chip microcomputer to calculate the required sine wave ad conversion data, this data into an array, and then the data Add fifo, Singlechip just read fifo, (will be set to cycle fifo output mode) can have waveform requirements, In addition, the control delay time, you can control the frequency.)