【正文】 t: the paycheck, the benefits, the incentives and the rewards were mine alone. Not much of a purpose in being selfserving, is there? While I was a student, I felt I was leading a purposeful life. Learning new things, broadening my horizons, expanding my life experiences all gave my life a zip and drive that I had not felt since being in survival mode when my kids were small. After graduating college I felt oddly deflated… but by then, China was on my horizon. 。ve been here I have been tasked with nothing more challenging than learning my students39。s own path. He urges the reader to find rectitude and lead a moral life. He professes that, only by being self reliant, as opposed to relying on the government and being dictated to by society, can one begin leading a decent and purposeful life. He avers that such a life is the only life worth living. I agree with him. This essay was written during a time of social upheaval in America, and it is rather odd that Emerson authored it, as he was a part of the upper crust of society at the time. It just so happened that he looked around him, at the indolence and the wantonness of the people in his circle。s lost, I believe, are the interesting setups and pauses that illuminate the Chinese art of storytelling. Much of the plot is still there. It is the flavor that was sacrificed. The American edition uses the framework of the Empress Dowager in her senior years reminiscing at the beginning and the end of each episode, hinting at what39。s Poly Theater. Their show, titled Ulan Muqir on the Grassland, depicted the history and development of the art troupe. Being from the region allowed me to embrace the culture of Inner Mongolia and being a member of the troupe showed me where I belonged, Nasun, the art troupe39。t have a formal stage. The audience just sat on the grass. Usually, the performances became a big party with local people joining in. For him, the rewarding part about touring isn39。s Shaanxi province pass through a stop on the ancient Silk Road, Gansu39。通過這次畢業(yè)設(shè)計我對單片機又有了更深的了解，發(fā)現(xiàn)我們的很多機械產(chǎn)物都和單片機有著息息相關(guān)的聯(lián)系。 現(xiàn)代人類生活中所用的幾乎每件電子和機械產(chǎn)品中都會集成有單片機 。主回路控制執(zhí)行程序的任務(wù)是初始化數(shù)據(jù)存儲單元，確 定電機工作參數(shù) Nmin／ Nmax， 并將其換算成“有效過零脈沖”的個數(shù)；確定中斷優(yōu)先 級、開中斷，為了保證正弦波的完整，工頻過零同步中斷 INT0確定為高一級的中斷 源。 DS18B20芯片功能命令表 基于單片機的智能電風(fēng)扇控制系統(tǒng) 10 主要程序如下： MAIN: ；初始化 LCALL RST_DS18B20 LCALL GET_TEMPER MOV A,20H MOV C,08H RRC A MOV C,09H RRC A MOV C,10H RRC A MOV C,11H RRC A MOV 20H,A LCALL DISPLAY AJMPMAIN RST_DS18B20: SETB P3. 7 NOP CLR P3. 7 MOV R1, 3 RST1:MOV R0, 110 DJNZ R0, $ DJNZ R1,RST1 SETB P3. 7 NOP NOP MOV R0, 25H RST2:JNB P3. 7,RST3 基于單片機的智能電風(fēng)扇控制系統(tǒng) 11 DJNZ R0,RST2 LJMP RST4 RST3: SETB FLAG LJMP RST5 RST4:CLR FLAG LJMP RST7 RST5:MOV R0, 115 RST6:DJNZ R0, $ RST7: SETB P3. 7 RET WR_DS18B20: ；寫數(shù)據(jù)子程序 MOV R2, 8 CLR C WR1: CLR P3. 7 MOV R3, 6 DJNZ R3, $ RRC A MOV P3. 7,C MOV R3, 25 DJNZ R3, $ SETB P3. 7 NOP DJNZ R2,WR1 SETB P3. 7 RET RD_DS18B20: ；讀數(shù)據(jù)子程序 MOV R4, 2 MOV R1, 20H READ1: 基于單片機的智能電風(fēng)扇控制系統(tǒng) 12 MOV R2, 8 READ2: CLR C SETB P3. 7 NOP NOP CLR P3. 7 NOP NOP NOP SETB P3. 7 MOV R3, 9 READ3: DJNZ R3,READ3 MOV C, P3. 7 MOV R3, 23 READ4: DJNZ R3,READ4 RRC A DJNZ R2,READ2 MOV R1,A INC R1 DJNZ R4,READ1 RET 基于單片機的智能電風(fēng)扇控制系統(tǒng) 13 電機調(diào)速與控制模塊程序流程 程序設(shè)計原理 采用雙向可控硅過零觸發(fā)方式，由單片機控制雙向可控硅的通斷，通過改變每個控制周期內(nèi)可控硅導(dǎo)通和關(guān)斷交流完整全波信號的個數(shù)來調(diào)節(jié)負(fù)載功率，進而達到調(diào)速的目的。與單片機通過接插件連接，可以用于系統(tǒng)的控制和輸出，其原理圖如圖所示： HD7279A 鍵盤和顯示器控制模塊電路原理圖 第三章 系統(tǒng)軟件設(shè)計 數(shù)字溫度傳感器模塊程序設(shè)計 本系統(tǒng)的運行程序采用匯編語言編寫，采用模塊化設(shè)計，整體程序由主程序和子程序構(gòu)成。 U 為 可 控 硅 在 一 個 電 源 周 期 全 導(dǎo) 通 時所 對 應(yīng) 的 電 壓 有效值 ,V。 電機控制模塊硬件設(shè)計 電路中采用了過零雙向可控硅型光耦 MOC3041,集光電隔離、過零檢測、過零觸發(fā)等功能于一身 ,避免了輸 入輸出通道同時控制雙向可控硅觸發(fā)的缺陷 ,簡化了輸出通道隔離 2驅(qū)動電路的結(jié)構(gòu)。在額定電 壓、額定功率下，以最高轉(zhuǎn)速運轉(zhuǎn)時，要求風(fēng)葉最大圓周上的線速度不大于2150m/min。 2DS18B20溫度計原理圖 DS18B20的溫度處理方法 DS18B20直接將測量溫度值轉(zhuǎn)化為數(shù)字量提交給單片機，工作時必須嚴(yán)格遵守 單總線器件的工作時序。 溫度傳感器模塊組成 本模塊以 DS18B20作為溫度傳感器， AT89C51作為處理器，配以溫度顯示作為溫度控制輸出單元。整個系統(tǒng)結(jié)構(gòu)緊湊，抗干擾能力強，性價比高。 當(dāng)溫度每升高 2℃則電風(fēng)扇風(fēng)速自動上升一個檔位。 本設(shè)計中的智能電風(fēng)扇控制系統(tǒng)，是指將電風(fēng)扇的電機轉(zhuǎn)速作為被控制量，由單片機分析采集到的數(shù)字溫度信號，在通過可控硅對風(fēng)扇電機進行風(fēng)速控制，從而達到無須人為控制便可自動調(diào)整風(fēng)力大小的效果。s living standard, household appliances products tend to automation, intelligent, environmental protection and development of human nature, we can design a kind of intelligent electric fan control system to solve these problems. MCS51 single chip microputer as the core, through the temperature sensor to the environment temperature data collect