【文章內(nèi)容簡(jiǎn)介】 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。圖35 溫度采集電路繼電器通常應(yīng)用于自動(dòng)化的控制電路中，它實(shí)際上是用小電流去控制大電流運(yùn)作的一種“自動(dòng)開關(guān)”，本設(shè)計(jì)中，繼電器開關(guān)電路外接+12V電源，另一端接接空調(diào)控制開關(guān)，繼電器主要的作用就是驅(qū)動(dòng)空調(diào)制冷。繼電器開關(guān)電路圖如圖36。圖36繼電器開關(guān)電路 溫度傳感器DS18B20簡(jiǎn)介XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX[7]。工作原理：如圖37溫度的變化會(huì)影響晶振的振蕩頻率，但是溫度系數(shù)越小，受到的影響也就越小。XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。斜率累加器比較計(jì)數(shù)器1等于0計(jì)數(shù)器2等于0預(yù)置低溫系數(shù)晶振高溫系數(shù)晶振溫度寄存器預(yù)置加1LSB置位/清除停止圖37 DS18B20測(cè)量溫度原理圖內(nèi)部結(jié)構(gòu)：DS18B20的內(nèi)部結(jié)構(gòu)（如圖38）主要由配置寄存器，溫度傳感器，非揮發(fā)的溫度報(bào)警觸發(fā)器TH和TL以及64位光刻ROM這四部分組成。DS18B20的管腳排列如圖39所示。存儲(chǔ)器和控制高速緩存存儲(chǔ)溫度靈敏原件低溫觸發(fā)器高溫觸發(fā)器配置寄存器8位CRC生成64位ROM和單線接口電源檢測(cè)圖38 DS18B20的內(nèi)部結(jié)構(gòu)圖39 DS18B20的外形圖DS18B20引腳的功能描述：GND為地信號(hào)。DQ為數(shù)據(jù)輸入/輸出引腳。當(dāng)在寄生電源下，也可以向器件提供電源。VDD為可選擇的VDD引腳。當(dāng)在寄生電源下，此引腳必須接地。 溫度采集接口設(shè)計(jì)XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。 報(bào)警電路設(shè)計(jì)本設(shè)計(jì)采用的是有源蜂鳴器。當(dāng)系統(tǒng)上電后，電流通過(guò)限流電阻驅(qū)動(dòng)三極管放大蜂鳴器，根據(jù)軟件流程蜂鳴器報(bào)警。如下圖310的報(bào)警電路。圖310 報(bào)警電路 顯示電路設(shè)計(jì)XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。、。如圖311顯示電路[9]。圖311 顯示電路 鍵盤電路設(shè)計(jì)XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。當(dāng)運(yùn)行在模式三時(shí)，系統(tǒng)可以通過(guò)加鍵（ADD）和減鍵（SUB）對(duì)之前的溫度上翻查詢和下翻查詢[11]。圖312 按鍵電路 本章小結(jié)本章主要的任務(wù)就是對(duì)硬件電路的設(shè)計(jì)，并且對(duì)設(shè)計(jì)所需要的各個(gè)電路分別作了獨(dú)立的分析，其中對(duì)溫度傳感器DS18B20作了詳細(xì)的分析，包括DS18B20的外形圖、工作原理、內(nèi)部結(jié)構(gòu)，以便更好的理解使用DS18B20。同時(shí)也畫出了各個(gè)電路的電路圖，電路圖是在protel中畫出的，在畫圖的的過(guò)程中，進(jìn)一步掌握和鞏固了對(duì)protel的使用。掌握了硬件后，對(duì)下一步的軟件編程作好了鋪墊。4 軟件設(shè)計(jì)本程序設(shè)計(jì)主要有四部分，分別是主程序，時(shí)間控制程序，溫度報(bào)警程序和顯示程序。主程序開始初始化變量DS18B20采集溫度初始化定時(shí)器溫度是否過(guò)高蜂鳴器報(bào)警繼電器開關(guān)執(zhí)行溫度值數(shù)據(jù)類型變化各個(gè)值轉(zhuǎn)換成LED顯示N定時(shí)時(shí)間是否到結(jié)束YYN