SD卡文件读写测试程序，用于SD卡文件的读写-SD card file read and write test procedures for the SD card read and write files

SD卡上的Tini-FatFs0.07，测试了将SD卡上的txt类型文件内容通过串口输出, 测试读文件速度大约在1M BYTEs/s。-Tini, SD card-FatFs0.07 test txt type file on the SD card through the serial port output, test reading a file speed around 1M BYTEs/s.