Secure Digital Card及其与AT89C51SND1C的接口设计

针对单片机本身存储容量有限且急需扩展外存的问题,采用SD卡作为解决外存扩展的方案.为了利用微处理器实现读写SD卡的功能,依据串行外设接口协议SPI协议和SD卡的串行外设模式,研究了单片机的SPI接口与SD卡进行通信的问题,简要介绍了SD卡及其SPI接口特点,给出了单片机AT89C51SND1C与SD卡的接口电路图,分析了SD卡的文件系统结构,并给出了其软件实现流程图,解决了嵌入式系统中大容量存取的问题.

Interface design between secure digital card and single chip microcomputer

In view of the question that single chip microcomputer has limited storage capacity and the extemal memory needs to be expanded urgently, secure digital card is used to solve the external storage expansion. In order to make use of microcontroller to read or write secure digital card, according to synchronous peripheral interface protocol and secure digital card synchronous peripheral interface mode, the communication between synchronous peripheral interface of single chip microcomputer and secure digital card is studied. In this paper, the feature of secure digital card and its SPI protocol character and its file system structure are introduced, the interface between AT89C51SNDC and secure digital card as well as the program flows chart are given finally. As a result, the large storage capacity problem of embedded system is resolved.