SPI接口AD转换器代码 本代码实现了对串行（SPI）接口的软件模拟 这是在一个项目中要用到SPI接口的器件，调试成功，可以在WAVE下编译通过，可以直接调用 SPI接口AD转换器代码 2002/3/9 design by elven-SPI AD converter code of the source implementation of the serial (SPI) interface software simulation This is a project that will be used SPI interface devices, debug successful, the compiler through WAVE, and can directly call SPI AD converter code 2002/3/9 by design's Eleven