【正文】 intelligent tester. This design,based on STC89C51 microcontroller and MQ3 alcohol concentration sensor. System sensor output 4 ~ 20mA standard signal through AD0832 core A / D converter circuit, after conditioning, data processing by the MCU, the final alcohol concentration value from the LCD display. This paper describes the data acquisition subsystem, data processing and data display subsystem and alarm circuit design methods and processes. System requirements for the sampling sites exceeding the alcohol concentration diode reminder alarm circuit monitors. Meanwhile, the operator specific alarm point for the upper limit set by MCU programming. Alcohol tester will bring a driving signal prior to a safe Key words:Alcohol concentration sensor (MQ3)。 A / D converter。Hardware design 桂林電子科技大學(xué)畢業(yè)設(shè)計（論文）報告紙 目 錄 引言 ......................................................... 1 1. 緒論 ..................................................... 2 酒精濃度檢測儀開發(fā) 背景 .............................................................................................. 2 酒精濃度檢測儀的發(fā)展 .................................................................................................. 2 酒精濃度檢測儀設(shè)計內(nèi)容 .............................................................................................. 2 2. 方案器件簡介 .............................................. 3 MCU 選擇的簡介 ............................................................................................................. 3 數(shù)模轉(zhuǎn)換器的簡介 .......................................................................................................... 5 時鐘芯片的簡介 .............................................................................................................. 7 液晶顯示器的簡介 .......................................................................................................... 8 3 總體 方案設(shè)計 .............................................. 9 STC89C52 單片機 ............................................................................................................ 9 ADC0832 數(shù)模轉(zhuǎn)換 ....................................................................................................... 10 AT24C02 存儲器 ............................................................................................................ 10 LCD1602 液晶顯示 ........................................................................................................ 10 編譯軟件介紹 ................................................................................................................ 12 4 硬件設(shè)計 ................................................. 13 最小系統(tǒng)的實現(xiàn) ............................................................................................................ 13 數(shù)據(jù)采集設(shè)計 ................................................................................................................ 15 A/D 轉(zhuǎn)換設(shè)計 ................................................................................................................. 16 按鍵設(shè)計 ........................................................................................................................ 16 外圍擴充存儲器電路 .................................................................................................... 17 時鐘芯片電路 ................................................................................................................ 18 LCD1602 液晶顯示設(shè)計 ................................................................................................ 19 報警設(shè)計 ........................................................................................................................ 20 電源電路設(shè)計 ................................................................................................................ 21 5. 軟件設(shè)計 ................................................ 22 編譯語言的選擇 ............................................................................................................ 22 主程序模塊 .................................................................................................................... 22 A/D 轉(zhuǎn)換模塊 ................................................................................................................. 23 按鍵輸入模塊 ................................................................................................................ 23 桂林電子科技大學(xué)畢業(yè)設(shè)計（論文）報告紙 時鐘模塊 ........................................................................................................................ 24 液晶顯示輸出模塊 ........................................................................................................ 25 外圍存儲模塊 ................................................................................................................ 27 6. 系統(tǒng)調(diào)試 ................................................. 28 系統(tǒng) 硬件調(diào)試 ................................................................................................................ 28 .......................................................................................................... 28 .................................................................................................................. 28 系統(tǒng)軟件調(diào)試 ................................................................................................................ 28 系統(tǒng)整體調(diào)試 ................................................................................................................ 29 7. 結(jié)束語 .................................................. 29 謝 辭 ...................................................... 30 參考文獻(xiàn) .................................................... 31 附 錄 ...................................................... 32 附錄一 硬件設(shè)計仿真圖 ..................................................................................................... 32 附錄二 硬件設(shè)計原理圖和 PCB 圖 ..................................................................................... 33 附錄三 檢測程序 ..............................................