实现了对SD卡的SPI方式下读写操作，已经测试了，可以直接用-The realization of the SD card to read and write SPI operation mode has been tested, can be directly used

单片机读写sd卡程序。工作于spi模式之下。-SCM reader sd card procedures. Working in spi mode below.

8051 (AT89S52) Assembler Source for reading FAT16-Filesystem from SD-card. It can handle up to 8 concurrent files. Writing to FAT16 is planned but not implemented yet. Also SPI Bit-Banging for addressing SD-Card is included and an small app for servi