基于μC/OS-Ⅱ的嵌入式网络协议栈的研究

【作者】 张莉；

【导师】 蔡征宇；

【作者基本信息】 南京理工大学 ， 通信与信息系统， 2007， 硕士

【摘要】 随着计算机技术的发展，嵌入式系统已经广泛应用于国防、工业、交通、能源、信息技术以及日常生活等各个领域，并成为近年来新兴的研究热点，网络化是主要趋势之一。在实际应用中，嵌入式系统的网络化，根据自身的不同特点和需要，采用不同的方案。LwIP是开源的TCP／IP协议栈，LwIP实现的重点是在保持TCP／IP协议栈主要功能的基础上减少对RAM的占用，这使LwIP协议栈适合在嵌入式系统中使用。μC／OS-Ⅱ是堪称最著名的实时开源操作系统，但毕竟只是一个实时的任务调度及通信内核，缺少对外围设备和接口的支持，如没有文件系统、网络协议、图形界面。因此选择采用μC／OS-Ⅱ与免费的TCP／IP协议栈LwIP相结合的方法实现嵌入式系统的网络化功能。本文首先介绍了嵌入式系统的发展趋势和ARM7微处理器。其次分析了嵌入式实时操作系统μC／OS-Ⅱ的系统内核，并针对在使用实时内核时，优先级反转是实时系统中出现最多的问题，分析了μC／OS-Ⅱ中的优先级反转问题和给出了解决方案。然后详细阐述了μC／OS-Ⅱ在S3C44BOX上的移植过程。再次分析了LwIP协议栈的实现和LwIP在μC／OS-Ⅱ系统上的移植过程。最后阐述了网络芯片RTL8019AS的驱动程序的详细开发过程。通过以上工作，实现了嵌入式系统的网络连接。更多还原

【Abstract】 With the development of computer, embedded system has been used in national defense, industry, traffic control, energy sources, information technology and civil living, and become a researching focus with one of the hot trends is making it networking.In the practical applications, making embedded system networking should choose different projects based on their characteristics and needs. LwIP is an open source TCP/IP stack whose design emphasis is to use as little RAM as possible while maintaining most functions of TCP/IP stack. So LwIP stack is very appropriate in the embedded system application.μC/OS-Ⅱis a famous open source RTOS,but it only consists of real time task schedule and communication kernel, lacking support to peripheral equipment and interface,such as file system, network protocol, and graphic interface. So I choose to transplant the open source TCP/IP stack--LwIP toμC/OS-Ⅱsystem and realize network connection in embedded system.In this paper, firstly the development of embedded system and ARM7 are introduced。Secondly, the kernel of embedded RTOSμC/OS-Ⅱis analyzed and when using real-time system, priority inversion which affects the real-time performance of the system occurs often, so priority inversion problem inμC/OS-Ⅱand the mechanism to avoid it are analyzed. Thirdly, the process of how to transplantμC/OS-Ⅱto the S3C44BOX platform is primary expatiated on. And then, the implement of LwIP stack and how to transplant LwIP stack toμC/OS-Ⅱsystem are primary expatiated on. At last, the process of how to design the network driver of RTL8019AS is also primary expatiated on. By the work above, embedded system realizes network connection.更多还原