Research On Embedded System Hardware Abstraction Layer And Application In Development Process

As the core of embedded system, embedded operating system has the ability to make full use of previously investment, lower the development difficulty, and shorten the development lifecycle, so it is widely spread in many design area. In this paper we elaborate on portability in embedded operating systems, focusing in the hardware abstraction layer proposed by Microsoft in Windows NT. Our work is based on the college project "Visual Vehicle Information Management System".This article summarizes research on embedded system Hardware Abstraction Layer (HAL).First of all; we study the architecture of embedded system, emphasize the importance of embedded operating system in improving system reliability, reusability and portability. We present an analysis of embedded system OS portability requirements that the embedded application ask for, and suggested that the embedded system OS design should obey three rules: hierarchy, modular and object oriented. Secondly, we investigate the definition, structure, function and detail form of HAL. Based on these works, we present an object-oriented embedded system hardware abstraction layer-EHAL and give a set of consistent interface standards of HAL API. This framework shows how HAL shield the detail operation of hardware to the OS. With the initialization function listed, we migrate the target board SHARP LH7A400 the universal Bootloader U-BOOT; with the function that the HAL provide the hardware dependent device driver, we reconstruct part of the embedded Linux system driver. Test results show that the HAL solution greatly improved the portability and reliability of Linux.