【正文】 .................................. 17 本章小結(jié) ................................................................................................................ 17 第 4 章 CPLD 可編程功能實現(xiàn) ........................................................................................... 18 CPLD 介紹及 EDA 設(shè)計流程 ............................................................................... 18 CPLD 簡介 ................................................................................................... 18 EDA 的設(shè)計流程 ......................................................................................... 18 系統(tǒng)頂層原理圖及整體功能介紹 ........................................................................ 21 系統(tǒng)頂層原理圖 .......................................................................................... 22 各模塊功能簡介 .......................................................................................... 22 COUNTER 及 74273B 模塊功能介紹 ....................................................................... 23 Counter 和 74273b 模塊描述 ....................................................................... 23 Counter 和 74273b 原理介紹 ....................................................................... 23 DIV 分頻模塊 ................................................................................................... 24 DIV 分頻原理介紹 ................................................................................. 24 DIV 分頻器 ............................................................................................. 25 ADD_M 模塊 ............................................................................................................. 25 整周期數(shù)計數(shù)原理的方案比較 .................................................................. 25 整周期數(shù)計數(shù)原理的方案實際功能驗證 ................................................... 30 CHENG 模塊 .......................................................................................................... 31 在 QuartusII 軟件平臺中乘法器的使用 .................................................... 31 CHENG 模塊的具體電路及原理 ............................................................... 33 CONVERT_BINARY_BCD 模塊介紹 ......................................................................... 34 BCD 碼介紹 ................................................................................................ 34 二進制轉(zhuǎn) BCD 碼實現(xiàn) ............................................................................... 34 CC 模塊 .................................................................................................................. 37 DISPLAY 模塊功能介紹 ....................................................................................... 38 DISPLAY 模塊中的掃描模塊 ..................................................................... 38 DISPLAY 模塊整體電路 ............................................................................. 39 本章小結(jié) ................................................................................................................ 39 第五章 PCB 制作與數(shù)據(jù)測試 ........................................................................................... 41 PCB 制作 ................................................................................................................ 41 硬件電路原理圖設(shè)計 .................................................................................. 41 PCB 設(shè)計 ...................................................................................................... 42 西南交通大學(xué)本科 畢業(yè)設(shè)計 (論文 ) 第 VIII 頁 實物圖 .......................................................................................................... 43 實物功能測試 ........................................................................................................ 43 測試方法與過程 .......................................................................................... 43 測試數(shù)據(jù)及誤差分析 .................................................................................. 46 結(jié) 論 .............................................................................................................................. 47 致 謝 .............................................................................................................................. 48 參考文獻 .............................................................................................................................. 49 附錄 源程序 ........................................................................................................................ 50 西南交通大學(xué)本科畢業(yè)設(shè)計 (論文 ) 第 1 頁 第 1 章 緒 論 本章為緒論章節(jié)，介紹了 課題 的研究背景以及研究現(xiàn)狀，同時也向大家展示了論文的 研究 內(nèi)容和結(jié)構(gòu)安排。 the phase difference。 the fourth part of the CPLD programmable features to implement, use phase difference measurement distance of algorithms for analysis。 the second part of the overall project analysis and design, to the system requirement analysis, hardware architecture, software functionality, principle made detailed。 關(guān)鍵詞 ： 測距 ； 相位差 ； VHDL 編程 ； CPLD 西南交通大學(xué)本科 畢業(yè)設(shè)計 (論文 ) 第 V 頁 Abstract With the rapid development of modern science and technology, on the location of the application areas, such as a laser rangefinder and ultrasonic distance and so on. One of the characteristics of the ultrasonic distance is: ultrasonic point to strong, energy consumption is slow, medium distances, and ultrasonic distance measurement often used, such as the Finder and level measuring instrument, etc, can be implemented by ultrasound. Use ultrasonic inspection is often pared to quickly, easily, and calculate a simple, easytoachieve realtime control. Common ultrasonic distance principle is the pulse method, using an ultrasonic pulse emitted to receive reflected pulse of and ultrasonic in air speed multiply distance. Implementation features process simple, but accuracy is not enough. Laser distance measurement you can take advantage of the phase, laser range precision p