Design And Implementation Of Sd Card Reading And Writting System Based On The Mcf51jm128

This paper puts forward a scheme to resolve the problem that embedded system can not save mass data. The scheme is achieved mainly based on ColdFire microcontrollers,the realization of the SPI mode of SD card reader of the underlying design,and can save the data into SD card in the file format of FAT 16, so as to achieve the purpose of the embedded system memory.The system includes hardware design and software design.In the aspect of hardware design, it implements the minimal hardware system for reading and writing the SD card. Freescale MCF51JM128 is used as the microcontroller of the system.The basis of this microcontroller. This paper design and implementation of the power management modules, crystal oscillator circuit module, USB interface module, serial interface module, SD card interface module, BDM debugging module reset circuit module. Kingston SD memory card with a volume capacity of 2G is used in this system. The SD card communicates with the microprocessor through the SD expansion slot in MCF51JM128.In the aspect of software, it implements hardware system initialization, based reading and writing SD card in SPI method, creating file in SD card in the file format of FAT 16 and saving data into SD card in the basis of SPI.Through PC-HyperTerminal can directly communicate with the SD card for later analysis of data is a convenience.Result proves that, this system has achieved the base reading and writing function and strong manipulation. Beside, it implements file creating, saving and reading functions through virtual serial ports. File saved in the SD card can be directly read by PC. This scheme provides an effective way to solve the embeded system memory bottleneck problem, and achieves the goal of extending embeded system memory.