Research And Design Of Embedded TCP/IP Protocol Stack Based On SOPC

With the advent of 21st century which is the era of network and information, internet has penetrated into people's life in all aspects. At the same time the rise of embedded internet devices represents internet development has entered a new time. There is no doubt that this will bring tremendous opportunities for the development of embedded market. Meanwhile the increasing network connectivity, network infrastructure and architecture have increased the demand of having more content to provide these. And it also requires lower economic costs, greater bandwidth to meet the growing demand of increasing network connection. Embedded systems are defined by the IEEE as the control of the monitor or auxiliary equipment installed machinery and plant operation. As an important part in computer field, embedded system is famous for its compact structure, low power consumption, reliable performance and low-cost. So it has not only become hotspot for research, but also been widely used in everyday's production and life, especially suited for monitoring with higher real-time requirements. Because of the urgency of information interaction, it is a trend for embedded system to get access to the internet.Embedded system requires network protocol to get access to the internet, the standard TCP / IP protocol has a large amount of code for embedded systems, taking up a lot of resources, largely limits the functions of embedded systems. In this regard, this paper does some simplification on the standard TCP / IP after analyzing it, so that it can achieve the most basic functions and network protocols for embedded systems, that is embedded TCP / IP protocol stack. The application of embedded TCP / IP protocol stack depends on application environment of the embedded system, the system provides different protocol modules according to specific application needs. In order to save memory capacity, adapt to the diversity of embedded applications and reduce difficult of the development process. In the open source network protocol, LwIP, which is the TCP / IP protocol stack of an implementation, is a lightweight network protocol that can be run with or without the support of the operating system. LwIP stack mainly concerns how to reduce memory usage and code size. To simplify the processing and memory requirements, lwIP had reduced API——some of the data need not be copied any more. LwIP generally requires very little RAM and ROM, so LwIP protocol stack is very suitable for low-end embedded systems.Combined with the development of embedded systems, in order to achieve expansion of the network function and reduce costs, this paper summarizes the characteristics of embedded Internet network technology and proposes an embedded TCP / IP protocol stack, which uses SOPC system as the hardware platform and QuartusⅡas the software platform, to achieve QuartusⅡLwIP network interface expansion. QuartusⅡis a Programmable System on Chip design software developed by Altera. SOPC software is the basic of SOPC design, its input can be many pattern, such as: schematic, VHDL, Verilog HDL, and AHDL (Altera Hardware Description Language) and other design input forms. It has its own Synthesizer and simulator, so it can complete the design process from design input to the complete hardware configuration of PLD. The integrated environment of QuartusⅡincludes system-level design, embedded software development, programmable logic device design, verification and simulation tools. Meanwhile, the embedded SOPC Builder system development tool provides a platform for building blocks of system-level definition. SOPC Builder NiosⅡbased on embedded soft core processor. Designers can generate, compile and simulate the soft core processor by the develop tools. And then the data can be downloaded to the programmable logic device to do the real-time verification and assessment.After understanding the analysis of embedded systems and embedded TCP / IP protocol stack, this paper expands the SOPC-based embedded TCP / IP protocol stack design. The main purpose of this process is to simplify the standard TCP / IP protocol, introduce TCP / IP protocol stack into the SOPC embedded system and connect the embedded system to the network. So the network function can be achieved in order to meet the network requirements of embedded devices. Specific to the Internet network through the understanding and awareness. Focus on the research and analysis of the open source lightweight embedded TCP / IP protocol stack LwIP, this paper makes some in-depth analysis of the embedded network protocol architecture and designs the TCP / IP protocol stack in the ARP protocol, TCP protocol, UDP protocol, IP protocol, ICMP protocols and other related interfaces model after understanding the network——internet. Using NiosⅡkernel-based embedded systems, this paper, which combines working mechanism and principles of embedded systems, builds a SOPC system by SOPC Builder development tool. And then this paper designs and integrates the embedded systems, using QuartusⅡembedded real time operating system. Finally, the LwIP transplantation and test are done by using embedded operating system and Internet is connected successfully in embedded operating system.Due to the limited time and my ability, there still exists some inadequacies that needs to research in the future. For example, most of the IP Core just finishes the necessary functions so that takes up too many resources. In the future, customized IP Core can be used according to the characteristics of the system. Thus the system resources can be saved and the design can also be more specific. This paper only concerns the real-time TCP / IP protocol within the embedded system, it doesn't concern the effects of the application on the internet. This packet is transmitted over the network without any guarantee of the quality, it is difficult to meet the needs of embedded system for network. Therefore, future researches should focus on how to improve the transmission of data packets in real time on internet, in order to ensure data transmission quality.This paper solves the problem successfully that embedded system cannot adequately meet the demand of real-time network application due to limited resources. Then by analyzing the test results of embedded TCP/IP network component, this paper provides some advices of improvement in the future. Through this research project I have understood embedded applications in-depth. Also by simplifying the standard TCP / IP protocol and in-depth study the transplantation of the open source LwIP, I have a deeper understanding of the network communication protocol. These experiences make me achieve a good foundation for my study and work in the future.