| Speaking of the embedded system, its development difficulty is bigger than the desktop application by far, which is because of the multiplicity of system, the technicality of application, overlapping platform translation and so on.To reduce its development difficulty is always one of the main problems on the study of this domain.Among them, one of the primary causes of the multiplicity of system is the complexity and difficulty of development. The more practical means is to eliminate the platform difference with every effort, which will make the embedded operating system and the application software work in the hypothesized environment which has nothing to do with the virtul platform, as a reslult ,the exploiter can be concentrate on soluting the application question.The majority imbedded typical system for business will tie up the board level support package (Board Support Package, BSP) when it sells, supports from the board level to the application development, which has completely formed the monopoly, and the application sharing has become difficult. Although it could have the better integrated design support service like this, considering of the development of the software and hardware coordination, actually it was unable to make repeat use effectively.After making the analysis of the model BSP and the typical system, it is discovered that, the reason of the limitation of the BSP application is the operating system developer. The merchant always hoped BSP can be in close integration with the upper OS, and didn't take the consideration of its versatility too much. Not only the composition structure, but also the function as well as defines all completely are different, between the different imbedded operating system BSP which support in the identical imbedded operating system of the micro-processor hardware platform, thus one kind imbedded operating system BSP is not supposed to be used in the other. This kind of BSP is one kind of seal special-purpose hardware abstract layer. Therefore, it needs to provide one kind of opening, general hardware abstract layer platform (Current Hardware Abstraction Layer, CHAL) to the imbedded system essence development and the application, make it possible that the development of the imbedded operating system essence in this kind hardware platform is able to support the another kind of hardware platform on the hardware abstract level to carry on.This article discussed Current Hardware Abstraction Layer (CHAL) of Embedded Operating System design technology, and established a platform between the architecture and operation system, which is relatively general and independent .This platform can solve the transplanting problem of Embedded Operating System, simplify and accelerate the development of embedded system software simultaneously.Firstly, based on the full understanding of the mainstream architecture and operation system foundation, it proposed the function model and the stratification structure of CHAL. Secondly, it discussed the CHAL essential technology in detail, including CHAL and OS, the addressing mode, interrupt, DMA technology and so on, explained the CHAL principle of design and the skills by examples.Finally, it introduced the CHAL design procedure and the method, as well as the principle and the method of package of the CHAL in detail, in view of CHAL development of the uCos.The paper forecasts the project significance of CHAL at last, and proposed the next stage research direction which is to build the system Current software development platform in the foundation of CHAL, making it more effectively to realize the coordination design of the software and hardware in embedded system. |
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