【正文】 ssion distance measurement function. Simple digital voltage measuring circuit from the A / D conversion, data processing, display control and so on. Key words: SCM AT89C51 A / D converter ADC0809 data processing 目錄 i 目 錄 第一章 引言 ................................................................................................................... 1 引言 ................................................................................................................... 1 課題研究的現(xiàn)狀和發(fā)展趨勢 ........................................................................... 1 智能儀表目前發(fā)展?fàn)顩r ................................................................................... 2 第二章 設(shè)計(jì)任務(wù)及可行性分析 ................................................................................... 5 系統(tǒng)設(shè)計(jì)要求 ................................................................................................... 5 系統(tǒng)設(shè)計(jì)思路 ................................................................................................... 5 總體結(jié)構(gòu) ........................................................................................................... 6 數(shù)字電流表的組成 ................................................................................... 6 電路設(shè)計(jì) ................................................................................................... 6 10 倍放大器電路 .......................................................................................... 7 A/D 轉(zhuǎn)換電路 ............................................................................................... 7 電橋輸入電路 ........................................................................................... 8 測量電路 ................................................................................................... 9 第三章 元器件的選擇 ................................................................................................. 11 單片機(jī)的選擇 ................................................................................................. 11 A/D 轉(zhuǎn)換器的選擇 ......................................................................................... 12 LED 顯示電路的選擇 .................................................................................... 13 所需元器件清單 ............................................................................................. 14 第四章 數(shù)字式電流表的硬件設(shè)計(jì) ............................................................................. 15 硬件電路設(shè)計(jì)概述 ......................................................................................... 15 主要元器件的介紹 ......................................................................................... 15 單片機(jī) AT89S51..................................................................................... 15 主要性能參數(shù) ......................................................................................... 16 AT89S51 的引腳 ......................................................................................... 16 A/D 轉(zhuǎn)換芯片 ADC0809 ........................................................................... 22 ADC0809 內(nèi)部邏輯結(jié)構(gòu) ........................................................................... 22 ii 目錄 ADC0809 的引腳 ....................................................................................... 23 ADC0809 的工作原理 ............................................................................... 24 4 位一體 7 段 LED 數(shù)碼管 ........................................................................ 24 控制電路模塊 ................................................................................................. 25 總電路 ..................................................................................................... 25 AT89S51 的復(fù)位電路和時(shí)鐘電路 ............................................................. 26 A/D 轉(zhuǎn)換電路 ............................................................................................. 27 顯示電路 ................................................................................................. 28 第五章 數(shù)字式電流表的軟件設(shè)計(jì) ............................................................................. 29 系統(tǒng)程序設(shè)計(jì)總方案 ..................................................................................... 29 系統(tǒng)子程序設(shè)計(jì) ............................................................................................. 29 初始化程序 ............................................................................................. 29 A/D 轉(zhuǎn)換子程序 ......................................................................................... 30 顯示子程序 ............................................................................................. 30 系統(tǒng)程序代碼 ................................................................................................. 31 第六章 數(shù)字式電流表的調(diào)試 ..................................................................................... 35 軟件調(diào)試 ......................................................................................................... 35 顯示結(jié)果及誤差分析 ..................................................................................... 35 顯示結(jié)果 ................................................................................................. 35 誤差分析 ................................................................................................. 38 第七章 結(jié) 論 ............................................................................................................... 39 致謝 ......................................................................................................................... 41 參考文獻(xiàn) ......................................................................................................................... 43 第一章 引言 1 第一章 引言 引言 傳統(tǒng)的指針式刻度電流表功能單一，精度低，容易引起視差和視覺疲勞，因而不能滿足數(shù)字化時(shí)代的需求。采用單片機(jī)的數(shù)字電流表，將連續(xù)的模擬量如直流電壓轉(zhuǎn)化成不連續(xù)的離散的數(shù)字形式并加以顯示，從而精度高、抗干擾能力強(qiáng)，可擴(kuò)展性