摘要本论文主要研究了以嵌入式系统为核心的多协议通信的实现，利用其串口 或 I2C 总线与底层 I/O 节点相连，上层则直接联入 Internet，解决了不同协议 （如 RS232、I2C、TCP/IP）之间的数据通信。 论文介绍了利用 AT89C51 单片机和 RTL8019AS 网卡驱动芯片开发的 RS- 232、I2C 转以太网通信协议的嵌入式以太网通信模块，利用该模块可实现将现 场设备的 RS-232、I2C 通信转换为以太网通信，也可以直接将该模块嵌入单片 机控制设备使用。然后，论文对嵌入式以太网通信模块的硬件电路设计和驱动 程序编写作了详细的介绍，并在不改变以太网 TCP/IP 协议主体结构的基础上， 对 TCP/IP 协议作了精简处理，以满足现场通信的实时性和可靠性要求。最后 论文分析了嵌入式 TCP/IP 协议的总体框架设计、帧的封装过程及数据包的发 送和接收流程。 本课题完成了对嵌入式以太网通信模块的设计，实现了 RS-232、I2C 协议 和以太网通信协议的相互转换功能，并在利用 C 语言模块化的编程思想的基础 上，用单片机实现了嵌入式 TCP/IP 协议的设计。测试结果表明该嵌入式以太 网通信模块具有可靠性高和成本低等特点，能够充分保证不同协议之间通信的 准确性。关键词：TCP/IP 协议栈；嵌入式 Internet；串行通讯；协议转换AbstractThis dissertation mainly research the implementation of a multi-protocol communication with the core of embedded systems, and uses the serial port or the I2C bus connecting the underlying I/O nodes. The upper is directly linked to the Internet，to solve the different protocols(such as RS232, I2C, the TCP/IP) data communications. This dissertation reports the design for an embedded Ethernet module for data exchange among RS-232, I2C and Ethernet communication with a micro-controller AT89C51 and a network card driver chip RTL8019AS. This Ethernet module can be directly used to convert the RS-232 or I2C information mode to Ethernet information mode or be embedded in the equipments controlled by microprocessors. Afterwards, this dissertation introduces the designing of hardware circuit and compiling of corresponding driving program in detail. This design simplified the TCP/IP without changing its main structure to meet the demand for real-time and reliability in field communication. In the end of this dissertation, the general frame for embedded TCP/IP, process of frame packing, and the procedure in sending and receiving data are comprehensively analyzed.In this project, an embedded Ethernet module was designed and the data exchange among RS-232, I2C protocol and Ethernet protocol was fulfilled with this module. At the same time, based on the modular programming method provided by C language, an embedded TCP/IP was realized with MCU. After debugging, it turns out that the designed embedded Ethernet module is of the high reliability and low cost and can be able to fully assurance the accuracy of communication among different protocols.Key words: TCP/IP state; Embedded Internet; Serial Communication; protocol exchange目录摘要.I Abstract.II第 1 章 绪论.- 1 - 1.1 课题背景.- 1 - 1.2 课题目的和意义.- 1 - 1.3 主要研究内容.- 2 - 1.4 本文结构 企鹅 182090931.- 2 - 第 2 章 系统总体架构.- 4 - 2.1 硬件方案.- 4 - 2.2 软件方案.- 5 - 2.2.1 系统模块划分.- 5 - 2.2.2 层次协议模型.- 5 - 2.2.3 TCP/IP 协议栈的实现方案.- 6 - 2.3 开发环境.- 7 - 第 3 章 系统硬件实现.- 8 - 3.1 嵌入式微控制器 AT89C51.- 8 - 3.2 RS-232 模块 .- 8 -3.3 I2C 模块 .- 9 - 3.3.1 I2C 数据传输 .- 9 - 3.3.2 通用 I/O 端口作为 I2C 总线接口.- 9 - 3.4 以太网模块.- 10 - 3.4.1 RTL8019AS 的寄存器介绍.- 10 - 3.4.2 RTL8019AS 的物理连接.- 13 - 第 4 章 系统软件实现.- 1