【正文】 究一種基于射頻識別（Radio Frequence Identification：RFID）技術的門禁系統(tǒng)。摘要為了適應信息時代的需要，保證建筑內(nèi)部的安全性，滿足用戶當時的各種需求，門禁系統(tǒng)應運而生。門禁系統(tǒng)集電腦技術、電子技術、機械技術、磁電技術和射頻識別技術于一體，使卡與鎖之間實現(xiàn)完整“對話” 功能，以智能卡來控制門鎖的開啟，開創(chuàng)了門禁管理的新概念，它不僅給管理者提供了更安全、更快捷、更自動化的管理模式，而且也給使用者帶來了極大的方便。（1）研究了基于射頻識別技術的門禁系統(tǒng)的總體設計，設計了射頻 IC 讀卡器的電路原理圖，給出了 PCB 板。當沒有卡進入讀卡能量范圍時，系統(tǒng)顯示時鐘，當有卡進入時則讀卡內(nèi)數(shù)據(jù)并將卡號信息顯示在液晶顯示器上。（3）針對設備組網(wǎng)應用要求，門禁終端通信采用 RS485 總線，同時結合門禁讀卡器研究了 RS485 的網(wǎng)絡拓撲結構，通過 RS485 接口與 PC 機組成通信網(wǎng)絡系統(tǒng)。（4）設計單片機的包看門狗、液晶顯示、數(shù)據(jù)存儲和實時時鐘等在內(nèi)的外圍模塊電路，采用串口設計如 SPI、I 2C 等，從而節(jié)約了單片機的 I/O 接口。（5）根據(jù)射頻識別門禁系統(tǒng)總體設計要求，采用模塊化軟件設計方法，根據(jù) MF RC500 的特性，系統(tǒng)地對 MF RC500 芯片的操作流程進行研究，設計主程序的流程圖和各個模塊子程序，使用 C51 語言開發(fā)了讀寫器的底層控制軟件，并完成程序的調(diào)試，證明結果滿足設計要求。將射頻識別應用到門禁系統(tǒng)，具有廣泛的應用前景，本文基于這一思想設計了小型門禁系統(tǒng)的底層模塊，同時還有待于進一步研究擴展，比如利用 Inter 接入取代 RS485 聯(lián)網(wǎng)方式，擴大系統(tǒng)的規(guī)模。s I / O interface. Access Control System Design at the same time bining the access control circuit, pleted the equipment selection.（5） To meet the Radio Frequency Identification Access Control System design requirements ,we design by modular software method. According to the characteristics of MF RC500 and the systematic research on the operation of MF RC500 chip process, design the flow chart of the main program modules subroutine, use C51language development the bottom of the reader control software, and pleted the debugging process that results meet the design requirements.RFID with convenient and efficient bees the focus of attention of the industry, and China is being an RFID tag production of the most promising production base. Applicated Radio frequency identification to the Access Control System, has broad application prospects. Based on this thinking, this paper gives out the realization of the specific design, but also to be further study on the expansion, such as the use of Inter access to replace RS485 interconnection, expanding the size of the system.Keywods： Access Control System； Radio Frequency Identification； MF RC500； Proximity Coupling Device； Serial Communication.目錄摘要 ................................................................................................................................IABSTRACT ..................................................................................................................II第 1 章 緒論 .................................................................................................................1 課題背景及意義 ..................................................................................................1 國內(nèi)外研究發(fā)展現(xiàn)狀 ........................................................................................2 本文主要研究內(nèi)容 ..............................................................................................3第 2 章 門禁系統(tǒng)的技術基礎 ......................................................................................5 射頻識別技術 ......................................................................................................5 射頻識別技術原理 ...................................................................................5 RFID 天線 ................................................................................................6 射頻識別系統(tǒng)的典型結構 .......................................................................8 RFID 同其它自動識別技術的比較 .........................................................9 門禁系統(tǒng)結構原理 ..........................................................................................10 密碼技術 .........................................................................................................12第 3 章 基于射頻識別的門禁系統(tǒng)總體設計 ............................................................16 系統(tǒng)總體方案設計 ..........................................................................................16 系統(tǒng)設計的基本要求 .................................................................................16 系統(tǒng)方案 .....................................................................................................17 系統(tǒng)硬件模塊分析 ..........................................................................................17 射頻讀寫模塊分析 .....................................................................................17 其他部分硬件分析 .....................................................................................18 射頻讀寫模塊設計 ..........................................................................................19 直接匹配天線 ..................................................................................................20 EMC 電路 ....................................................................................................20 接收電路 .....................................................................................................20 直接匹配天線的天線匹配電路 .................................................................21 RS485 通訊模塊 ..............................................................................................25 RS485 接口 .............................................................................................26 RS485 網(wǎng)絡拓撲結構 .............................................................................27 外圍接口電路 ..................................................................................................29 看門狗電路 .............................................................................................29 液晶模塊 .................................................................................................313. 7 數(shù)據(jù)存儲的硬件設計 ...................................................................................353. 7. 1 數(shù)據(jù)存儲器的接口 .................................................................................363. 7. 2 I2C 總線協(xié)議 ..........................................................................................36 實時時鐘的硬件設計 ....................................................................................373. 8. 1 實時時鐘的接口 .....................................................................................373. 8. 2 時鐘數(shù)據(jù)傳輸?shù)目刂?.............................................................................383. 8. 3