The Design And Realization Of Embedded File System Applied In The Wireless Data Acquisition System Based On μC/OS-Ⅱ

In recent years, Campus Smart Card has being become a vital vector in the information communication in campuses, and its application has increased dramatically ranging from E-wallet to Attendance Systems, In Donghua University, the faculties can take the shuttle bus between the campuses by the Campus Smart Card, which helps to check on faculties' work attendance. The purpose of the wireless data acquisition system of the Campus Smart Card is to display the superiority of the wireless communication. After setting the wireless connection between the base station and the embedded card reader terminal, the data acquisition system of the Campus Smart Card can complete the data acquisition automatically, without manual work. The base station is set up in the bus stop. When the school bus enters the bus stop, the base station will connect with the school bus to get data by the polling control method. After the base station has received all the data from the embedded card reader terminal, the data in the card reader terminal will be automatically deleted, at the same time, the base station would put the data into the access database through serial port. However, there are lots of problems in the wireless data acquisition system of Campus Smart Card, for example, the storage space of the system is too small, the system can not be power cut, and the balance of wear and tear of Flash .etc. In this case, we propose to set up an embedded file system which is based onμCOS-II to solve those problems.With the support of the public service system construction project of "211 projects" for our University, the research of the paper has finished the designing of embedded file system which is based onμC/OS-II, and makes the system used in the wireless data acquisition system of the Campus Smart Card.Firstly, the papar introduces the background of the techniques. After analyzing the related techniques, the paper finds out series of problems of the wireless data acquisition system of Campus Smart Card. Then, the paper expresses the design concept of the file system. The paper proposes to use the Hierarchical design method to design the file system, besides; the paper describes the data structure and the algorithm of the key part of the file system. In this case, the paper divides levels of the inner structure of the file system and explains the basic principle of the file system in detail.Secondly, in order to design the structure of the file system and make it applied in practice, the paper works on three places: application programming interface layer, the file management layer and the flash drives layer. Because of those reasons, the FAT and the FDT storage mechanism are improved; besides, the paper proposes to use no fixed positional storage method for the storage mechanism, so as to make it be fit for Flash Memory. At the same time, because of the feature of the embedded hardware, the paper proposes to reduce the wear and tear of flash by equalizing Flash Erase algorithm to.Finally, a two-part test was made for the embedded file system, whose tests are to test the function and the stability of the embedded file system. Test results show that the system runs stable. And the running results indicate that the design of the system is feasible, with a certain amount of practicality, besides that, it is a very good example for other similar systems.The innovation of this paper is introducing the embedded file system and make it applied in wireless data acquisition systems, the paper proposes a detail solution for the problem of flash memory on the balance between wear and tear. In a word, the embedded file system proposal in the paper can solve the problem of data storage in the wireless data acquisition system of Campus Smart Card by lower cost and be much more efficient.