51单片机读写SD_MMC卡设计报告--本文件介绍了在51平台通过SPI方式读写SD/MMC卡，包括软硬件需求, SD/MMC硬件连接, SPI接口软件模拟，SD/MMC上电初始化，写单块，读单块，写多块，读多块，块擦除，上位串口通讯协议，PC上位软件操作说明等。-51 Single-chip design report card reader SD_MMC This document presents the platform of the 51 way through the SPI rea