DA转换，和12864输出。每一位发送间隔在200us左右，包含三种波形sine tri和 squ，留有较多函数可做拓展使用，已通过调试和仿真，课设使用byJ_ksd(DA conversion, and 12864 output. Each sending interval is about 200us, containing three kinds of waveforms sine tri and squ, leaving more functions to expand, and has