| This paper is about to design an embedded system based on the32-bit ARM processorCortex-M3, to achieve the goal of extending the functions of the on-board wireless videoserver. Compared with the ARM9system, this system acts a role as the hypogynouscomputer section. And the ARM9system is used for video data acquisition, processing,transmission and system control. The Cortex-M3system works in coordination with thesuperordination machine DM368system, and fulfill the task of external equipment inputdata acquisition and processing and also the control of the output device.The development and the future application of embedded system at home and abroadis analyzed in this paper. The analysis is about the characteristics and composition ofembedded systems, the embedded processors and embedded operating systems. Acomparision of the advantage and disadvantage and the application of the mainstreamembedded operating system is given in this part, and the embedded real-time operatingsystem μC/OS-Ⅱ, which is used in the design of this paper, is refered in detail. The taskscheduling mechanism, the synchronization and communication mechanism between thetasks and the interruption mechanism as well as the clock of μC/OS-Ⅱ is given adiscussion. What's more, the ARM Cortex-M3based MCU LM3S1538used in the systemdesign is mainly presented, including the NVIC(Nested Vectored Interrupt Controlle),MPU(Memory Protection Unit) and the timer. Under comprehensive consideration ofperipheral control of the on-board wireless video server system,this paper proposed adesign scheme which uses Cortex-M3as the peripheral control chip, and the μC/OS-Ⅱas the operating system, it discussed the function of the system modules, as well as the chipselecting. The paper gives a hardware design of the system, and also discussed grafting onLM3S1538of the μ C/OS-Ⅱ operating system. The design of the system control software,and the software instruction as well as the communication between the main task and thesub tasks are all indicated in detail.There is also a declare of software design of the threemodules: the GPS module, the infrared module, the network keyboard module, includingthe design of the interrupt service routines, the data analytical procedures and the communication procedures with the main task of each module. Finally, it is the proving ofthe design in the on-board wireless video server, there is a show of the actual result of thedesign. |
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