嵌入式系统课程论文

rehabilitation training, because at that time the city has not specifically for deaf children of professional rehabilitation agencies, she will accept rehabilitation training must go to Suzhou, due to her age is too small must take care of their parents, her mother had to resign to Suzhou to take care of her, thus to their family brought two problems, one is the economic pressure, second, children are in the most need caring parents feel Term age and father separated, unable to feel the happy family to grow. In order to avoid more and more families appear this kind of circumstance, actively coordinating the city FIMITIC established rehabilitation center, operation center for the XX membership received rehabilitation training of special children and parents brought great convenience, to enable them to the nearest and handy to get high-quality rehabilitation services, Huimin policy of the Communist Party of China has been fully reflected.Regular organization of the fast forward, three special children into society. Due to the special childrens own disability, they rarely and social contact, we hope that in their rehabilitation training can have more opportunities to integrate into society, by the municipal CDPF coordination has been relevant departments of the strong support, promote the special children into social work: one is the municipal CDPF and City Bureau of education in training children rehabilitation assessment, 2015 years 3 hearing-impaired children get a rehabilitation of the good results, enter the ordinary kindergarten and primary school; the second is the city library volunteer monthly to center on childrens stories, playing games and other entertainment activities, into a Step broaden their way of thinking; the third is under the support of the City Board of education, the center will and Yanshan Mountain kindergarten cooperation, fusion education project weekly by the special education teacher lead 1-2 hearing-impaired children into Yanshan Mountain kindergarten accept half a day of kindergarten education, let children with special filling feeling kindergarten learning atmosphere, for their future access to kindergarten and primary school lay a solid foundation., handicap love, care for children with special. Caring for children with special needs to let them with healthy children as happy growth but also our work direction: one is actively contact the society from all walks of life of the difficulties children with special care and support this year in coordination with the city FIMITIC, Ningbo Bank Co., Ltd. XX branch president assistant Zhao Yi for a row represents dandelion love fund to in the center received rehabilitation training of Xu Yang and Xu Miao brother and sister to send two of the loving enterprises special care; the second is actively contact the love team and community volunteers to the children in the center to all kinds of theatrical performances and interactive games, let them enjoy the happiness in the activities, and further enrich the Their spiritual and cultural life.Five, increase the propaganda of rehabilitation services, and further enhance the sense of rehabilitation. In the suburbs especially in rural areas, to disabled南京信息工程大学 嵌入式系统设计 题目：嵌入式Linux操作系统的开发与应用 姓名： 学号： 院系：电子与信息工程学院 专业：电子信息工程 指导老师：二0一二年五月二十日office.children are in need of early detection, early intervention. Early rehabilitation concept is relatively weak, is generally believed that developing children behind with the growth of the age will continue to improve, to increase the propaganda of rehabilitation policy and the concept of rehabilitation is crucial. For this center to increase efforts to promote the relentless efforts: is to assist the city FIMITIC in national ear care day national helping the disabled day during major festivals held special rehabilitation knowledge lectures, rehabilitation policy and rehabilitation concept and a series of publicity activities; the second is on a monthly basis to carry out parent training and rehabilitation guidance Into the family and other rehabilitation services. Two regulations promulgated in party power for a long time and under the condition of governing the country according to law, implement the full strictness of strategic deployment, implementation by Board Trustee administering the party and strengthen the inner-party supervision of major initiatives. Two rules match, the guidelines adhere to the positive advocacy, LiDE, party members and cadres to visible, reach the high standards; Around discipline cracked the requirements of the regulations, set out a negative list, and focus on State control, which gives the party organizations and party members out of the bottom line. The following, mainly from four to two party rule interpretation: first part of both necessity and process of legislative changes within the party; part two interpretation of legislative changes within the party principles of part two of regulation within the party after the third major change and several key issues need part on how well the two implementation of inner-party regulations. A, the guidelines and the regulations of the need for revision and revision process of Central Committee of CPC party members and leading cadres honesty in politics a number of amendments to the guidelines and the Chinese Communist Party disciplinary regulations classified as 2015 1 the focus of strengthening the construction of partys laws and regulations. Two party rule revisions last year, centralized the party wisdom, gather consensus, learn from historical experience, respect for wisdom, reflecting the unity of inheritance and innovation; Follow the correct direction and seize the limited objectives, uphold the partys leadership, people, centered on solving problems. New standards and regulations, as amended, and reflects the partys 18 and 18 in the third, four in the plenary session, reflects the experience of studying and implementing the XI series of important speech, General Secretary, reflects the partys 18 since the comprehensive practice of strictly administering the party. (A) the need to amend the two regulations in the party of the code was in 1997 the CPC party members and leading cadres honesty in politics a number of standards (for trial implementation) revised on the basis of which, published in January 2010, on strengthening the construction of leading cadres play an important role. But with the deepening of the party controls the party, strictly administering the party, has been unable to fully adapt to the needs. A is content had fan, 8 a ban, and 52 a no to remember, and also to practice line; II is gel refining positive advocate insufficient, ban sex terms too much, no reflected self-discipline of嵌入式Linux操作系统的开发与应用电子与信息工程学院 南京 210044摘要：Linux是一个功能强大而稳定的操作系统，它可以运行在X86 PC，Sun Sparc，Digtial Alpha,680x0,PowerPC及MIPS等多种平台上，可见，Linux是目前支持硬件平台最多的操作系统。Linux最大的特点在于它是开放源代码的，它遵循公共版权许可证（GPL），秉承“自由的思想，开放的源码”的原则。本文主要介绍了嵌入式Linux操作系统的特点，开发流程及应用。关键词：嵌入式系统，嵌入式Linux，特点，开发流程，应用0 引言嵌入式系统是将计算机硬件和软件结合起来构成的一个专门的装置，这个装置可以完成一些特定的功能和任务。嵌入式系统已经有了40多年的发展历史，并且是以硬件和软件交替双螺旋式发展的。嵌入式系统采用“量体裁衣”的方式把所需的功能嵌入到各种应用系统中。嵌入式操作系统是一种支持嵌入式系统应用的操作系统软件，它是嵌入系统极为重要的组成部分。嵌入式操作系统具有能够有效管理越来越复杂的系统资源，能够把硬件虚拟化，能够提供库函数、驱动程序及工具集等特点。常见的嵌入式操作系统有：VxWorks、QNX、Nucleus Embedded、ThreadX、uC/OS-、Linux等等。1嵌入式系统的基本概况1.1 嵌入式系统的概念嵌入式系统的一般定义是：以应用为中心，以计算机技术为基础，软件、硬件可裁减，功能、可靠性、成本、体积、功耗严格要求的专用计算机系统。另外，根据不同的分类标准，嵌入式系统有不同的分类方法，根据嵌入式系统的复杂程度，可以分为简单嵌入式系统和复杂嵌入式系统。1.2 嵌入式系统的组成 从组成上看，嵌入式系统可分为嵌入式硬件系统和嵌入式软件系统两大部分，如图1所示。图1 嵌入式系统组成嵌入式硬件系统主要由嵌入式处理器及相关支撑硬件和外围电路等组成。其中，嵌入式处理器在嵌入式硬件系统中处于核心地位，按照功能和用途划分，它可以进一步细分为以下几种类型：嵌入式微控制器、嵌入式微处理器和嵌入式数字信号处理器。嵌入式软件系统通常可划分为嵌入式操作系统和应用软件两部分。在一些复杂的系统中，为了简化应用开发，还提供了一个中间层（嵌入式中间件层）。在早期的嵌入式系统中，系统的复杂性较低，这时的嵌入式系统通常不使用操作系统，而是由应用程序控制和管理硬件。2 嵌入式Linux操作系统2.1 Linux的历史最初的Linux的代码是1991年由芬兰的大学生Linus Torvalds写的。他将Linux的原始代码放在Internet上，让人们自由下载。1993年底到1994年初，Linux 1.0终于诞生了，他已经是一个功能完备的操作系统，而且内核写得紧凑、高效，可以充分发挥硬件的性能。Linux的生命力来自于它的开源思想，自Linus公开Linux代码以来，世界各地的程序员和软件爱好者不断地对Linux系统进行修改和加强。在开源运动的带动下，数不胜数的应用软件出现在Linux系统之上，大大加强了Linux系统的使用能力。2.2 Linux操作系统的特点第一，Linux系统是层次结构且内核完全开放。Linux是由很多体积小且性能高的微内核系统组成。在内核代码完全开放的前提下，不同领域和不同层次的用户可以根据自己的应用需要方便地对内核进行改造，低成本地设计和开发出满足自己需要的嵌入式系统。第二，强大的网络支持功能。Linux诞生于因特网时代并具有Unix的特性，保证了它支持所有标准因特网协议，并且可以利用Linux的网络协议栈将其开发成为嵌入式的TCP/IP网络协议栈。 此外，Linux还支持ext2、fat16、fat32、romfs等文件系统，为开发嵌入式系统应用打下了很好的基础。第三，Linux具备一整套工具链，容易自行建立嵌入式系统的开发环境和交叉运行环境，可以跨越嵌入式系统开发中仿真工具的障碍。Linux也符合IEEE POSIX.1标准，使应用程序具有较好的可移植性。使用嵌入式Linux，一旦软硬件能够支持正常的串口功能，即使不用仿真器，也可以很好地进行开发和调试工作，从而节省一笔不小的开发费用。嵌入式Linux为开发者提供了一套完整的工具链（tool chain）。它利用GNU的gcc做编译器，用gdb、kgdb、xgdb做调试工具，能够很方便地实现从操作系统到应用软件各个级别的调试。第四，Linux具有广泛的硬件支持特性。无论是RISC还是CISC、32位还是64位等各种处理器，Linux都能运行。Linux通常使用的微处理器是Intel X86芯片家族，但它同样能运行于Motorola公司的68K系列CPU和IBM、Apple、Motorola公司的PowerPC CPU以及Intel公司的StrongARM CPU等处理器。Linux支持各种主流硬件设备和最新硬件技术，甚至可以在没有存储管理单元（MMU）的处理器上运行。这意味着嵌入式Linux将具有更广泛的应用前景。2.3 嵌入式Linux系统的开发流程嵌入式系统的开发与通常PC机上的软件开发有很大的区别，原有的PC机的软件开发过程从编写程序、编译和运行等过程全在同一个PC机平台上完成；嵌入式开发的程序编写和编译还在PC机上完成，但编译产生的结果要在嵌入式目标平台上运行。通常将这种在主机上开发编译，在目标平台上调试运行的开发模式称为交叉开发。运行在主机上的编译器（如GCC）编译程序产生目标机上运行的可执行程序的编译过程称为交易编译。嵌入式系统采用这种交叉开发、交叉编译的开发模式主要是因为嵌入式系统是种专用的计算机系统，采用量体裁衣、量身定制的方法制造，它的这种特点使其与通用PC机的开发与使用特点有很大的不同。图2是一个嵌入式交叉开发环境的示意图。图2 嵌入式开发环境示意图如图2所示，一个嵌入式系统的开发环境一般包括嵌入式目标板、开发用的宿主PC机和硬件调试器，他们之间通过串口、JTAG或BDM等调试接口和网络等接口互相连接。其中，嵌入式软件系统运行于嵌入式目标板上，这些软件所对应的程序开发和编译在宿主机上运行，程序的调试则由宿主机通过硬件调试器控制目标机执行相应的操作实现。在运行嵌入式Linux的系统时，硬件调试器只在Bootloader程序开发以及Linux内核移植时有可能需要使用。应用程序的开发通常是Linux操作系统在嵌入式目标机上运行起来之后进行。此时，更多的是在宿主机上使用GDB通过网络与目标板通信，进行程序的调试。也就是硬件调试器多在底层软件开发调试时使用，对于应用程序的开发调试通常使用其他手段。嵌入式Linux操作系统开发的第一步就是在宿主机上建立交叉开发所需的交叉编译环境。交叉编译环境的建立主要是在宿主机上安装交叉编译工具Cross-gcc。Cross-gcc工具链通常是使用别人已经编译好的交叉编译的GCC工具链。在交叉编译环境建立好之后，就可以在宿主机上利用交叉编译环境构造一个嵌入式Linux系统。Linux操作系统是由Linux内核和应用程序两大部分组成。Linux内核的开发主要是根据实际的需要进行内核裁剪和配置，然后用交叉编译器编译生成内核的二进制文件映像。对于许多自行设计的嵌入式系统，内核的开发还包括根据实际的硬件系统进行内核和外设驱动程序的移植开发。应用程序通常都放在Linux的根文件系统中。根文件系统主要存放了嵌入式的配置文件、设备文件、应用程序、动态链接库以及其他一些相关的程序和文件。通常最初的根文件系统只是一个基本的根文件系统，只包含了一些必要的系统支撑程序。在宿主机PC机上完成嵌入式Linux软件系统的构建之后，就在嵌入式硬件系统上测试、运行构造好的嵌入式Linux软件系统。其中，测试工作需要在宿主机上通过远程终端操控嵌入式开发板完成。通常在嵌入式开发板上存在一个内核的引导加载程序，它用于硬件的初始化，给用户提供一个操作界面，将嵌入式Linux加载到内存中运行。除此之外，它对于嵌入式Linux系统的开发调试也起到很大的作用。一个基本的嵌入式Linux系统在目标板上运行起来之后，就要进行程序移植开发和调试。3 嵌入式Linux操作系统的应用由于Linux具有对各种设备的广泛支持性，因此，能方便地应用在机顶盒、IA设备、PDA、掌上电脑、WAP手机、寻呼机、车载盒以及工业控制等智能信息产品中。3.1 嵌入式工业控制网络的实现方案基于嵌入式Linux的工控系统以嵌入式微处理器为核心来运行嵌入式Linux操作系统。应用程序可通过网络进行更新，并可通过键盘进行人机对话，数据可通过LCD现场显示，重要数据可用文件形式保存在Flash等闪存存储器中；数据和报警信息可通过串口向上位机传输，也可以通过以太网向工业以太网或Internet发布，用户还可通过网络实现远程监控和远程维护。更为关键的是，可充分利用Internet上已有的软件和协议（如：ftp，http等应用程序）迅速搭建前台数据采集系统，以实现测控系统和后台管理系统的通讯。这种方式的优点有：(1)不需要专用的通信线路即可用现成的Internet网络将数据传送到任何地方；(2)不仅能够传递数据信号，也可以传递音频和图像信号；(3)由于目前的Internet协议是现成和公开的，因此，利用大到几十兆的Microsoft IE浏览器，或小到只有600KB的Mosaic浏览器都可以对网络数据进行读取。4 结束语嵌入式技术是计算机技术、半导体技术和微电子技术等多种先进技术的融合。在所谓的后PC时代，随着计算机和通信技术的飞速发展，互联网的迅速普及和3C融合的加速，嵌入式技术成为新世纪最有生命力的技术之一，得到了飞速发展和广泛应用。它通过在各个行业的具体应用渗透到社会生活的各个角落。从日常用品到工业生产、军事国防、医疗卫生、科学教育乃至商业服务等方方面面。而在嵌入式系统的应用中，Linux嵌入式操作系统所具有的技术优势和独特的开发模式给业界以新异，我相信，它能成为Internet时代嵌入式操作系统中的最强音。作为电子信息工程专业的学生，学好嵌入式系统，对我们将来找工作会有很大的优势。参考文献：1郑灵翔.嵌入式Linux系统设计.北京：北京航空航天大学出版社. 2陈文智.嵌入式系统开发原理与实践M.北京：清华大学出版社. 3张斌，高波.Linux网络编程M.北京：清华大学出版社. 4马洪连 丁男等.嵌入式系统设计教程.北京：电子工业出版社. 5刘琰.Linux嵌入式系统开发平台选型探讨J.单片机与嵌入式系统应用，2004（7）.