摘要随着信息技术的快速进展，以太网嵌入式设备的应用越来越广泛。为了让以太网各设备之间能公平有效地共享通信媒介，对以太网 MAC 层数据处理系统的讨论显得尤为重要。为此,本文首先分析了以太网及其相关协议的基本内涵,解剖了以太网MAC 层通信机制、帧的特性与格式、PHY 接口协议、ARP 协议以及 I2C协议。同时通过对 FPGA 芯片的了解，确定了基于 88E1111 芯片和XC3S400FPGA 芯片相结合的系统设计方案，支持 1000Base-T 标准以太网的接入,完成了系统的硬件电路设计。系统设计中，88E1111 完成 PHY 层数据的处理，FPGA 则完成 MAC 层数据的处理,主要包含接收 MAC 数据帧的校验和解封、待发送数据帧的封装、MAC 地址滤波、IP 数据包的提取、ARP 地址映射等，是系统的核心.在 FPGA 设计中,遵循自上而下的设计思想，对顶层模块以及 PHY 接口、MAC 核心处理、用户配置、用户数据各功能子模块依次进行设计。关键词：以太网 MAC 层 FPGAABSTRACTWith the rapid development of IT，the embedded devices of accessing to Ethernet are used more and more widely。In order to make each device enjoy a fair and effective shared communications medium， it is particularly important to research the data processing system of the Ethernet MAC layer。To this end，it is firstly done to analyze the basic connotation of Ethernet and the related agreements,and to dissect the communication mechanisms of the Ethernet MAC layer，the characteristics and format of the frame ，the PHY interface protocol,the ARP protocol，I2C protocol in the paper。According to the characteristics and working principle of the FPGA chip ，the system design, which supports the accessing of the 1000Base—T Ethernet,is determined based on the combination of the 88E1111 PHY chip and XC3S400-4fg456C FPGA chip of Xilinx 。 Then the hardware circuit design is accomplished by the Cadence development tool 。In this system, 88E1111 and FPGA respectively completes the data processing of PHY layer and the data pro...
