【正文】 利用 LM324 的比較作用將輸入信號(hào)與參考電壓進(jìn)行比較，到大于時(shí) LM324 輸出端為高電平，否則為低電平。設(shè)計(jì)中在輸入端串聯(lián)了一片 74LS04 的六非門芯片，提高輸入的驅(qū)動(dòng)能力，以便于單片機(jī)處理。如果長期在高轉(zhuǎn)速下運(yùn)作，對(duì)汽車發(fā)動(dòng)機(jī)的壽命將大打折扣。同時(shí)電機(jī)運(yùn)作，將控制汽車油路的電磁閥逐漸閉合，使供油減小，發(fā)動(dòng)機(jī)轉(zhuǎn)速降低，直至電磁閥完全閉合，停止供油。再啟動(dòng)定時(shí)器計(jì)時(shí)，如此循環(huán)。最后將所得的值賦給數(shù)碼管顯示。 程序流程圖 開 始定 時(shí) 器 、 外 部 中 斷及 參 數(shù) 初 始 化F l a g _ s = 1調(diào) 用 S m o o t h （ ）F l a g _ s = 0調(diào) 用 顯 示 函 數(shù)否是轉(zhuǎn) 速 值 大 于 設(shè)定 值電 機(jī) 運(yùn) 作指 示 燈 亮電 機(jī) 停 止指 示 燈 滅否是 圖 主程序流程圖 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 10 定 時(shí) 器 0中斷 開 始COUNT++TH0=0TL0=0退 出 圖 定時(shí)器 0 中斷函數(shù)流程圖 外 部 中 斷 0開 始F l a g = 1S t a t i c u n s i g n e d c h a r m = 0T [ M ] = T H 0 * 2 5 6 + T L 0 + 6 5 5 3 6 * C O U N TT H 0 = 0T L 0 = 0C O U N T = 0m + +m = 5m = 0F l a g _ s = 1F l a g = 1T H 0 = 0T L 0 = 0T r 0 = 1是否退 出是否 圖 外部中斷函數(shù)流程圖 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 11 5 系統(tǒng) 仿真與調(diào)試 Proteus 軟件介紹 系統(tǒng)采用 Proteus 軟件 來進(jìn)行程序的仿真，這款軟件 是英國 Labcenter electronics 公司出版的 EDA工具軟件 。它是目前最好的仿真單片 機(jī)及外圍器件的工具。 仿真圖建立 系統(tǒng)采用 Proteus 軟件進(jìn)行仿真，利用軟件自帶的仿真模塊建立系統(tǒng)的仿真圖。 圖 主控芯片仿真 由于汽車上常用的轉(zhuǎn)速傳感器為霍爾式，集成的傳感器其輸出的信號(hào)為脈沖信號(hào)。圖 為濾波轉(zhuǎn) 換電路。 圖 系統(tǒng)的顯示器件 當(dāng)系統(tǒng)檢測完后得到轉(zhuǎn)速大于我所設(shè)定的值時(shí)，控制執(zhí)行機(jī)構(gòu)運(yùn)作同時(shí)指示燈將會(huì)點(diǎn)亮。在仿真中我選用直流電機(jī)作為執(zhí)行機(jī)構(gòu)。 圖 仿真圖（一） 當(dāng)調(diào)節(jié)信號(hào)發(fā)生器改變輸入的頻 率值時(shí)，單片機(jī)通過對(duì)其進(jìn)行計(jì)數(shù)并運(yùn)算處理，在數(shù)碼管上面對(duì)應(yīng)的顯示當(dāng)前值。仿真結(jié)果正確。基本滿足設(shè)計(jì)要求。此時(shí)輸入頻率為 140HZ，輸出為 8450r/min，其和理論 140*60=8400r/min有一定誤差，在設(shè)計(jì)要求范圍內(nèi)。 sbit MO=P3^3。 //第一次中斷標(biāo)志 bit Flag_s。 sbit RW=P2^6。 uchar COUNT。 uchar W[5]={1,2,3,4,5}。 unsigned int Smooth(void)。 void write_cmd(uchar cmd)。 void LCD_Init()。 void Write_Datas(uchar address,uchar Wdata)。 uchar msg2[14]= r/min 。 Flag=0。 COUNT=0。 Init()。 EA=1。 for(i=0。i++) { write_data(msg1[i])。 for(i=0。i++) { write_data(msg2[i])。 Flag_s=0。 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 26 MO=1。 MO=0。 } } void delay(uint N)//延時(shí) N毫秒子程序 { uint x,y。x0。y0。 } void write_cmd(uchar cmd)//寫指令子程序 { RS=0。 P1=cmd。 E=1。 E=0。 RW=0。 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 27 delay(1)。 delay(1)。 } void LCD_init() { E=0。//5*7 點(diǎn)陣字符 write_cmd(0x0c)。//AC 自動(dòng)增一，畫面不動(dòng) write_cmd(0x01)。//設(shè)置 DDRAM 地址 } void Write_Datas(uchar address,uchar Wdata) { write_cmd(0x80+address)。//寫數(shù)據(jù) } void LCD_Disp(uint d) { unsigned char dd[4],i。 dd[1]=d%1000/100。 dd[3]=d%10。i4。 } } 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 28 // //名稱：定時(shí)器，中斷初始化 //功能：定時(shí)器 0采用 16 位，中斷下降沿觸發(fā) // void Init(void) { TMOD=0x01。 ET0=1。 } // //名稱：濾波函數(shù) //功能：加權(quán)濾波，權(quán)值 1,2,3,4,5 // unsigned int Smooth(void) { uchar i。 float sum。 sum=0。i5。 } sum=sum/15。 dat=(int)avg。 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 29 return dat。 T[m]=TH0*256+TL0+65536*COUNT。 TL0=0。 m++。 Flag_s=1。 TH0=0。 TR0=1。 TH0=0。 } g an employment tribunal clai Employment tribunals sort out disagreements between employers and employees. You may need to make a claim to an employment tribunal if: ? you don39。t appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. If you are worried about how the time limits apply to you, take advice from one of the anisations listed under Further help. Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation. Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the anisations listed under Further help. If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your pensation if you win the case. This is known as a damagesbased agreement. In England and Wales, your solicitor can39。re clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by , click on nearest CAB. For more information about making a claim to an employment tribunal, see Employment tribunals. The (lack of) air up there Watch mCayman Islandsbased Webb, the head of Fifa39。s 150th anniversary celebrations and will 發(fā)動(dòng)機(jī)轉(zhuǎn)速 電控系統(tǒng)程序設(shè)計(jì)及仿真 31 attend City39。s about how he felt and I would like to speak to him first to find out what his experience was. Uefa has opened disciplinary proceedings against CSKA for the racist behaviour of their fans during City39。s governing body, has also ordered an immediate investigation into the referee39。s plaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day?；蛟S是愧疚于自己似乎把轉(zhuǎn)瞬即逝的很多個(gè)不同的日子過成了同一天的樣子；或許是追溯過去，對(duì)自己那些近乎偏執(zhí)的怪異信念的醒悟，這些天以來，思緒一直很凌亂，在腦海中不斷糾纏。二十年的人生軌跡深深淺淺，突然就感覺到有些事情，非做不可了。 Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isn39。 Then in high school, think don39。t remember his appearance. 童年時(shí)，覺得壓歲錢和新衣服是過年必備， 但是隨著年齡的推進(jìn)，會(huì)越來越發(fā)現(xiàn)，那些東西根本就可有可無；初中時(shí)，以為要有一場暗戀才意味著真正的成長，但三年過去后，自己心平氣和的寫同學(xué)錄的時(shí)候，突然就發(fā)現(xiàn)是不是真正的成長了，好像并沒有那么重要了；然后到了高中，覺得非要吐露出自己的心聲才能為高中生涯里的懵懂情愫劃上一個(gè)