【正文】 le Read Only Memory）的低電壓，高性能CMOS8位微處理器，俗稱單片機。數(shù)據(jù)保留時間：10年　　低功耗的閑置和掉電模式　　P1口管腳寫入1后，被內(nèi)部上拉為高，可用作輸入，P1口被外部下拉為低電平時，將輸出電流，這是由于內(nèi)部上拉的緣故。 P3口：P3口管腳是8個帶內(nèi)部上拉電阻的雙向I/O口，可接收輸出4個TTL門電流。在平時，ALE端以不變的頻率周期輸出正脈沖信號，此頻率為振蕩器頻率的1/6。在由外部程序存儲器取指期間，每個機器周期兩次/PSEN有效。 由于單片機或CPU的數(shù)據(jù)/地址/控制總線端口都有一定的負載能力，如果負載超過其負載能力，一般應加驅(qū)動器。 晶體振蕩電路MCS51單片機內(nèi)部的振蕩電路是一個高增益反相放大器，引線 XTAL1和XTAL2分別為反向振蕩放大器的輸入及內(nèi)部時鐘工作電路的輸入和來自反向振蕩器的輸出，該反向放大器可以配置為片內(nèi)振蕩器。圖24 復位電路對于數(shù)字顯示電路而言，通常采用LCD顯示或LED顯示。動態(tài)方式顯示時，各數(shù)碼管輪流選通，要使其穩(wěn)定顯示必須采用掃描方式，即在某一時刻只選通一位數(shù)碼管并送出相應的段碼，在另一時刻選通另一數(shù)碼管，并送出相應的段碼，依次規(guī)律循環(huán)，即可以使各位數(shù)碼管顯示將要顯示的字符，雖然這些字符是在不同時刻分別顯示，但由于人眼存在視覺暫留效應，只要每位顯示間隔足夠短就可以給人同時顯示的感覺。系統(tǒng)總電路圖如圖27所示。~，NPN三極管9013做為位控制端的開關(guān)，~，與其相對應的三極管就導通，對應的數(shù)碼管導通顯示。（3）具有豐富的運算符，多達34種。說明：C語言的源文件，可以分割成多個源程序，分別進行編譯，然后連接起來構(gòu)成可知性的目標文件，為開發(fā)大型軟件提供了極大的方便。（8）生成的目標代碼質(zhì)量高，程序執(zhí)行效率高。圖31程序流程圖Proteus ISIS是英國Labcenter公司開發(fā)的電路分析與實物仿真軟件，它可以仿真、分析(SPICE)各種模擬器件和集成電路。它包括標題欄、主菜單、狀態(tài)欄、標準工具欄、繪圖工具欄、對象選擇按鈕、預覽對象方位控制按鈕、仿真進程控制按鈕、預覽窗口、對象選擇器窗口、圖形編輯窗口等十幾個工具，方便了使用者的使用。圖32仿真圖第四章 系統(tǒng)調(diào)試 軟件程序編譯與調(diào)試（1）輸入源程序打開keil軟件，輸入源程序，輸入時應以西文方式輸入字母和符號，且中文注釋前要加分號。在編譯調(diào)試通過以后，生成hex文件以待仿真之用。看一下顯示是否正確，時間運行是否符合運行軌跡。參考文獻[1] 李朝青. 單片機原理及接口技術(shù)（第3版）[M]. 北京：航空航天大學出版社，2006[2] 趙建領(lǐng). 51系列單片機開發(fā)寶典[M]. 北京：電子工業(yè)出版社，2007 [3] 耿永剛，陶國正. 單片機與接口應用技術(shù)[M]. 上海：華東師范大學出版社，2008 [4] 孫惠芹. 單片機項目設(shè)計教程[M]. 北京：電子工業(yè)出版社，2009[5] 楊欣，王玉鳳，劉湘黔. 電子設(shè)計從零開始[M]. 北京：清華大學出版社，2005[6] 余永權(quán). ATMEL89系列單片機應用技術(shù)[M]. 北京：北京航空航天大學出版社，2002附錄附錄1 系統(tǒng)總程序 include typedef unsigned char uint8。sbit d2 = P3^1。= 0xdf。j++。break。P2 = number[a[3]]。 case 5: d2 = 0。 while(1)。i++)。 a[4] = sec/10000%10。ta damagesbased agreement, you should make sure you39。s about how he felt and I would like to speak to him first to find out what his experience was.Uefa has May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. Always feel oneself should go to do something, or write something. Twenty years of life trajectory deeply shallow, suddenly feel something, do it.　　一字開頭的年齡已經(jīng)到了尾聲。t want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already can39。那些曾經(jīng)所謂的非做不可，只是青蔥年華里自己給自己注射的一支強心劑，或者說，是自以為是的精神寄托罷了。ll be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound 690 mph (1,110 kph) in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him pletely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it39。 Have declared the end of the encounter that haven39。s time, your ideas are always special to clear. Want, want, line is clear, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection, or is a selfrighteous spiritual.　　一個人的時候，自己的想法總是特別地清晰。The end of our life, and can meet many things really do?　　而窮盡我們的一生，又能遇到多少事情是真正地非做不可？During my childhood, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional。s 21 win.Michel Platini, president of European football39。Employment tribunals.The (lack of) air up there Watch mCayman Islandsbased Webb, the head of Fifa39。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 you don39。 a[0] = sec%10。 TL1 = 0x67。break。j++。P3=0xff。 case 1: d6 = 0。}void int_init(){ ET1 = 1。sbit d6 = P3^5。uint8 a[6]。主要是編程學的不太成功，在老師的細心指導下，然后再加以修改錯誤，最后完成設(shè)計。如果出現(xiàn)閃爍現(xiàn)象，就要改變一下延時時間，直到合理為止。（4）調(diào)試程序調(diào)試程序時首先要明確程序的具體功能，對程序做認真分析。首先打開已經(jīng)畫好的proteu