| SD Card is a flash memory device based on a new generation of semiconductor memory devices, it is widely used in portable devices and can be used as external storage devices for Embedded Systems.The file system offer a group of functions,by using which Embedded Systems can control the file operation of SD card through SPI interface. The function of this system finally realize providing superior file operations function.First,on the base of the detailed analysis of the SD card reader mechanism and features of FAT File System, We provide storage expansion for the MCU with SPI interface to the underlying support. This paper describes the overall structure of the hardware, and introduces its three parts. It then describes in detail the composition and principle of each part, SD card's structure and working principle, introduces the SD card in SPI mode of operation and command response. We chose the ARM32-bit Cortex-M3, and introduce its on-chip resources and focuses on the development board SPI interface. Then we overview the main from the software, FAT operations, SPI operations, file operations and other aspects of concrete implementation of the software design specific elaboration.Then, the paper describes the overall design of the software, FAT16 file system implementations,including the following three aspects:SPI operation, FAT operations, file operations, and these three aspects in details. SPI operation is embedded on the SD card through SPI interface to carry out the operation; FAT operation is FAT table and root directory operations; File operations is based on the SD card on file for the creation of files, delete files, read and write files, and so on.The super terminal is a universal serial interactive software, we can through super terminal and embedded system in interaction, make super terminal becoming embedded system instant "display". We enter commands through the super terminal,matching command and string, and operation results showing in the super terminal. |
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