The Design And Realization Of General Bootloader In ARM Embedded Operating System

With the prevalence and development of portable facilities, embedded system has been a focus of attention. Recent trends have seen a push towards the need for developing embedded systems, able to run with the underlying help of an operating system, which should be advanced and reliable, such as embedded Linux, WINDOWS CE, etc. Bootloader is a part of an embedded system. It is a section of codes executing before kernel image and is responsible for reloading the kernel image. It also can support specific hardware modules to implement specific functions.Accordingly the development of the embedded systems leads to the popularity of microprocessors. The ARM architecture has established itself as one of the leading microprocessors in today's embedded and portable market. Nowadays most of the semiconductor foundries produce the microprocessors based on ARM architecture. Its simple design founded in RISC principles yet balanced by CISC influence leads to low cost/power cores which offer high performance.This work examines the challenges facing the design and implementation of a bootloader based on PXA255, which uses Intel Xscale core. Intel Xscale core is compatible with ARM V5TE, so it is typical. The OS is embedded Linux. The achievements of this work not only includes the basic function of bootloader, but also considers it as a basis for more complex and sophisticated systems, which means it supports two modes of bootloader and it adds the support for some hardware modules to provide some convenience for other developers. These hardware modules include serial, USB, NOR FLASH etc.The thesis also expands the realized bootloader: after clarifing the common features of ARM embedded system, it introduces how to port the bootloader to other ARM embedded systems. The"general-purpose"is just limited to theories.