【正文】 channel temperature detections. Temperature value which determines is displayed using the LCD1602 liquidcrystal in directviewing demonstration. This article focuses on system39。該系統(tǒng)利用 AT89C51 單片機采集了各個溫度點的溫度，實現(xiàn)溫度顯示、報警等功能。 糧食是人類生存的必需品，溫度是保存好糧食的先決條件，儲存大量的糧食對穩(wěn)定國民經(jīng)濟的發(fā)展起到至關(guān)重要的作用。糧庫一般較大，測 量 點 會很多 。它以 AT89C51 單片機為主控制芯片，采用數(shù)字溫度傳感器DS18B20 實現(xiàn)多路溫度的檢測，利用 LCD1602 液晶顯示器形象直觀的顯示測出的溫度值。s software and hardware design emphatically on the foundation of determining the design of the program. It describes the system circuit design, the hardware design diagram as well as the function and the characteristic of the chip which is used in the system. This system is simulated through the PROTEUS and KEIL C software. Key Words: Singlechip Microputer DS18B20 Liquidcrystal display Keyboard Warning 東北大學秦皇島分校畢業(yè)設(shè)計（論文） 第 III 頁 目錄 一 緒論 .............................................................................................................................1 背景 ........................................................................................................................................................ 1 設(shè)計的目的和意義 ................................................................................................................................. 1 相關(guān)領(lǐng)域國內(nèi)外技術(shù)和發(fā)展趨勢 ........................................................................................................... 2 二 系統(tǒng)方案設(shè)計 .............................................................................................................4 方案設(shè)計 ................................................................................................................................................ 4 方案論證 ................................................................................................................................................ 5 三 溫度傳感器 .................................................................................................................6 溫度傳感器的選型 ................................................................................................................................. 6 傳感器的選擇原則 .................................................................................................................... 6 溫度傳感器的選擇 .................................................................................................................... 6 溫度上、下限值的設(shè)定原理 ........................................................................................................ 7 四 系統(tǒng)硬件設(shè)計 .............................................................................................................8 系統(tǒng)工作原理綜述 ................................................................................................................................. 8 DS1820 與單片機接口電路 .................................................................................................................... 9 單片機 89C51 為本系統(tǒng)的核心 ................................................................................................10 中央處理器 AT89C51 簡介 ........................................................................................................13 DS18B20 簡介及測溫電路設(shè)計 ..............................................................................................................16 DS18B20 的性能特點 ..............................................................................................................17 DS18B20 的外形和內(nèi)部結(jié)構(gòu) ....................................................................................................17 高速暫存存儲器 .......................................................................................................................21 DS18B20 單總線 (1 一 Wire)的基本原理 .................................................................................22 液晶顯示電路 .........................................................................................................................................29 LCD1602 主要技術(shù)參數(shù) ............................................................................................................29 LCD1602 的引腳說明 ...............................................................................................................30 控制指令說明 ...........................................................................................................................30 按鍵電路 ...............................................................................................................................................31 報警電路 ...............................................................................................................................................33 五 軟件功能及框圖 .......................................................................................................34 主程序 ...................................................................................................................................................34 讀出溫度子程序 ...................................................................................................................................34 溫度轉(zhuǎn)換命令子程序 ............................................................................................................................34 計算溫度子程序 ...................................................................................................................................34 顯示數(shù)據(jù)刷新程序子程序 .....................................................................................................................34 按鍵處理子程序 ....................................................................................................................................34 六 單片機的抗干擾問題 ...............................................................................................40 干擾因素 ...............................................................................................................................................40 硬件抗干擾措施 ..............................