说明：  本程序为AD977的全部A/D转换的数据采集类型，是采用的SPI数据读取方式来实现的，这样传送过程就不怕错误，十分的有用，是我在应用中的一个典型。
(This procedure for the AD977 all the A/D conversion data acquisition types, is used to read the SPI data mode to achieve, so that the transmission process are not afraid of mistakes, is very useful that I have in a typical application.)