【作者】 邓超；

【导师】 康晓涛；

【作者基本信息】 吉林大学 ， 信号与信息处理， 2005， 硕士

【副题名】基于INTEL PXA255处理器的嵌入式系统

【摘要】 嵌入式系统作为一个新兴的技术发展方向,已经越来越受到人们的关注。由于其体积小、性能强、功耗低、可靠性高以及适应面广等优点,已经广泛应用于工业控制、军事国防、网络通信、消费电子等多个领域。 本课题就是在以上背景下,开发的一款带有CAN总线的嵌入式工控触摸屏系统基本软硬件平台。可在此平台上按照功能要求进行进一步的开发,设计出某项针对具体功能应用的产品。本文在最后设计了本系统的一个具体应用方案——工业锅炉水位控制系统。 本文通过对嵌入式系统进行研究和分析,选定了相应的处理器以及操作系统,并分析比较了当今国内外比较有影响的几种现场总线,选择CAN总线作为系统的一个扩展总线,并对CAN协议及其原理进行了研究,采取了部分改进措施。然后根据要求以及所选定的嵌入式处理器设计了相应的硬件平台方案。在嵌入式操作系统方面,与其他常见的操作系统相比较后选定了嵌入式Linux作为本系统的操作系统,编译、裁剪之后成功移植到开发板上,同时编写了CAN BUS在LINUX下的驱动程序,然后进行了调试、编译和加载工作。硬件设计方面,使用CADENCE软件绘制了电路的原理图及PCB图,制板焊件后调试成功,嵌入式Linux系统成功加载到开发板上,系统能够稳定运行。最后对系统进行分析、总结,找出系统的不足之处,在以后的改版工作中进行解决,并对系统进一步的开发工作进行了展望。更多还原

【Abstract】 1. Significance of studyWith intelligent, networked development, embedded technology is launched in an all-round way, and has already become the common developing direction of the communication and consumption products at present, at the same time; embedded system has got more and more attention. Embedded system has been applied in industrial control, military, communication, electronics and so on, because it has the character of small size, high performance, low cost, high reliability and high applicability.There is the world’s largest household appliances market in the world in our country, so these information household appliances products have enormous markets. At the same time, there must be keen competition in it, if you want to win in this competition, you must master key technology and put out one’s own products in time. Many small and medium enterprises who buy the scheme not only need spend a lot of money on it, but also can’t master the key technology, so they will find it difficult to develop their own products and can’t be in the forefront of information industry. So, we can find out, it is the best way for enterprises to develop their own development board, which can save the funds and get the technological guarantee. As following: Save product’s development funds, easy to control the cost of products; Raise the technological content of the products, get the preponderance in the competition; Will not be eliminated by the cruel competition; Can make one’s own rule, make the industry standard; Understand one’s own development board, can transplant the system. So, the intention of this topic is designing the basic software and hardwareplatform of embedded industry control touch-screen system equipped with CAN bus, we can develop some kind of product by adding to corresponding function block on this platform.2. Universal Project of the embedded systemAfter analyzing the system, need of function and conveniences of extend, we adopt Intel XScale PXA255 as the system’s CPU, 64MB Samsung SDRAM as the system’s memorizer. At the same time, we expand the corresponding function blockby the need of system. We compare synthetically several usual FIELD BUS and choose CAN BUS as the system’s extend interface, because one mainly applied direction of the project is industrial control.In addition, we have adopted embedded Linux as the operating system, because it not only avoids the licence expenses, save the cost, but also it has very high stability and strong network function. At the same time, embedded Linux has abundant developing instruments and a large number of files, it is clear that the application of embedded Linux will be more and more extensive.3. The hardware realization of the embedded systemThe principle of the hardware design is that both guaranteeing system can normal run, and meets the need of the system for small size, high performance, low cost, high reliability and high applicability. So according to this principle, when we design the principle chart and PCB, we both consider the rationality of system design, and pay attention to the influence of PCB on the consumption, the dependability and size of the system.In the power designing, we adopt two high performances depressurization DC-DC switch regulator MAX1821 for system’s power, one of which is 3.3v for board, the other one is 1.33v for CPU’s core. The reliable and steady power is the key to the whole system’s success. Adopt MAX811 for the system’s reset circuit, the whole power system is made up.We have adopted the memory of the large capacity (64MB Samsung SDRAM, 32MB Intel flash) for extending the system’s function and accelerating the system’s processing.We use two of PXA255’s serial interface for our project, one is full function interface, the other is Bluetooth one. Every UART (Universal Asynchronous Receiver Transmitter) is connected to the I/O port by Maxim MAX3244ECAI RS-232. BT UART is connected to a standard 9-pin RS-232 interface. FF UART is connected to another port with JTAG (Joint Test Action Group), the board communicates with pc by this port.4. The software realization of the embedded systemThe embedded Linux is adopted as the project’s operating system, which includes as following:1. Building cross-compile environment with cygwin on pc, adopt Linux2.4.19 as system’s core;2. According to system’s scheme, compile and download blob (boot loader object);更多还原