流传的用SPI驱动SD卡的程序基本都是针对没有FIFO的SPI接口的，这样做程序比较通用；但是如果处理器的SPI接口有FIFO的话，那么FIFO的性能就浪费了。其实把程序稍加改动，就可以大幅度提高SD卡的读取速度-Compared to general procedure is in sending a continuous and successive spread with the SPI driver SD card program is the basic for no FIFO SPI