Design And Implementation Of An Embedded System Experimental Platform

An embedded system is any computer that is a component in a larger system and that relies on its own microprocessor. This thesis presents a design of an embedded platform, which is designed for the reseach in Embedded System, and for the hand-held PC products also. DragonBall EZ microprocessor is chosen as the central processor. 4M bytes flash and 4M bytes DRAM are set on the platform. According to the hardware design, uClinux is chosen as the operating system and microwindows as the graphical user interface, which provides APIs to the programer. This thesis introduces how to build the gcc cross-compiler for m68k platforms. Then the steps to build an entironment with the functions such as program monitor, files transfer and flash burning are discussed. This thesis analyses the kernel of uClinux, which is different from the standard Linux kernel. According to the MMU-less embedded microprocessors, uClinux kernel removes the parts correspond to the virtual memory management, creating a small and efficient kernel image. Also, the thesis provides methods of porting uClinux to the DragonBall EZ platform: to change the codes related to the platform architectures in order to make the operating system boot smoothly. As some extended work, JFFS, a flash based journaling file system, is added to the uClinux system, and drivers for some special character devices, buttons, are written. This thesis analyses the infrastructure of microwindows system in details. The whole system is designed in three levels, with the device drivers on the lowest, the graphical engines on the middle, and the APIs on the upper level. It makes the microwindows easy to port to many platforms. The methods of porting microwindows to the DragonBall EZ platform are discussed: change the configurations to use m68k cross-complier, and change some codes related to memory management to make the system suit for uClinux. At the end of the thesis, an application of the platform is presented: the sample of a ebook. The ebook includes an application written with the APIs provided bymicrowindows. Many functions such as pageup,pagedown are implemented.