这是一个arm7 spi 读写sd卡的源代码，里面添加上fatfs的文件系统， 方便学习文件系统 你要好好调试彩能够学习到文件系统的关键-This is a arm7 spi, speaking, reading and writing the sd card source code, add the fatfs inside the file system, convenient learning file system to take debugging color can learn to