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 external 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.