Research On Key Technology And System Implementation Of Handheld Terminal Based On ARM

In recent years, embedded systems have developed very quickly; multi-functional handheld embedded graphical terminal devices have been highly concerned and researched. In addition, because handheld terminal devices usually run in mobile environments, traditional mechanical hard disk hardly meet the needs in certain aspects, whereas the Flash memory is suitable for its resistance to shock, high integration, low power, and etc. However, the Flash memory, due to its own characteristics and the defects of its file systems based on Flash in wear leveling algorithms, usually causes the decreasing of storage capacity with the passing of time, and thus eventually may play a bad effect on the whole system.The subject does deep research on the key technologies for handheld terminal devices, and ultimately constructs a widely used and stable platform for secondary development. This paper selects the best open-source operating system Linux, which however does not have a graphical interface. The graphic architecture of embedded mostly adopts QT/Qtopia, the model of which yet does not have a good scalability. In this thesis, the X Window graphic architecture of desktop Linux and GTK graphic library are transplanted to the embedded Linux of handheld terminal devices, and UBIFS in the system is improved.The main contents include the following:①Select the appropriate hardware development platform, design and build of the RS232 conversion circuit, and integrate the RFID module into the hardware development platform via the RS232 port.②Transplant U-boot, Linux kernel, LCD device driver and network chip device driver into the above mentioned hardware development platform, build the root file system and develop the program development related to RFID.③Do research on the embedded Linux and the graphics architecture of desktop Linux, and transplant the X Window and GTK into the embedded Linux successfully.④Improve the wear leveling algorithm of the UBI file system, propose a dynamic wear leveling algorithm based on temperature (also referred to as written frequency of logic block) and age (also referred to as erase count of physical block), which makes the Flash memory get a better balancing than before, wholly extends the life of flash, and improves the stability of the system. Finally, the experiment proves that the Linux and the graphic architecture of X Window can be transplanted successfully into the handheld terminal devices. In addition, through the contrastive analysis of data obatained from experiments, UBI file system gets an improvement in the aspect of wear leveling on flash memory.