Embedded Real-time Operating System ¦Ìc / Os-ii Arm In Applied Research

With the development of computer technology, communication technology and the in-depth application of the Internet, more and more embedded systems are running around us. Real-time digital processing, functions interlinked with network, intellectual software and better-extended ability have nearly become the mutual need of modern real-time measuring and monitoring systems. And because of the increasing complexity of the embedded systems, the embedded operating system has become the most important part of the embedded system. In all kinds of embedded operating systems, μC/OS-Ⅱ has the advantage of clear structure and open source, so it has been widely used in embedded system based on monitoring system and PDA. Combined the embedded real-time operating system with the modularized hardware design, a digital platform that can be used repeatedly will be formed, such a platform can not only increase the developing efficiency and reduce the cost, but also optimize the resource of software and hardware step by step and enhance its performance by researching this platform for a long term so as to meet the increasingly complicated application need.Embedded operating system is the center of embedded system. This paper proposes an embedded real-time operating system by hardware expansion and software development based on ARM7TDMI, using μC/OS-Ⅱ as its kernel.First, the author describes the status, the development and some important conceptions of Embedded Operating System. The birth,the development and features of μC/OS-Ⅱ are described in this paper, and the system architecture, communication method and scheduler are also introduced. Although μC/OS-Ⅱ can be used for various single chips.It has been used widely in many domains. But it can only support 64 ready tasks of fixed priorities. It is not sufficient for new complicated real time systems. The following is what is creative in this paper: This paperintroduces a new method to extend it' s ready task number. The new method uses the data structure of priority queue, thus to make it support more ready tasks and set it' s task scheduling more flexible.The author also discussed the applying field of the ARM chip, the advantage of the ARM instruction set, the ARM7TDMI structure, the registers in the ARM ,the uC/OS-II transplanting procedures to the ARM.Secondly, because u C/OS-II is just a kernel, only providing the base function of management, it has to expand the performance of kernel for realizing an integrated and utilitarian embedded real-time system. This paper expands the hardware and develops the software based on transplanting. This paper succeeds in designing file system, UART communication,the system message queue and the net parts connected.At last, this paper designs some simple programs to'test the performance of the system. At the end of the paper, several features of the embedded real-time operating system, some programming rules and some development methods are concluded.