【正文】 輸入，并在 LCD 液晶顯示屏 上顯示相對應(yīng)的通道值。s antiracism taskforce, is in London for the Football Association39。 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 jump When 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。t agree with the disciplinary action your employer has taken against you ? your employer dismisses you and you think that you have been dismissed unfairly. For more information about dismissal and unfair dismissal, see Dismissal. You can make a claim to an employment tribunal, even if you haven39。 單片機為 8 位處理器，當(dāng)輸入電壓為 時，輸出數(shù)據(jù)值為 255（ FFH） ，決定了該電壓表的最大分辨率（精度）只能達到 。共陰極數(shù)碼管顯示 04 DB 6DH,7DH,07H,7FH,6FH。送段碼給 P0 口 MOV A,R3 MOV P2,A。顯示位數(shù)賦初值，用到 3 位數(shù)碼管 MOV R3,0FDH。變換十分位調(diào)整值 5 送 B DIV AB 淮安信息職業(yè)技術(shù)學(xué)院畢業(yè)論文 22 MOV LED2,A。等待轉(zhuǎn)換結(jié)束 SETB OE。存放三個數(shù)碼管的段碼 ADC EQU 35H。 淮安信息職業(yè)技術(shù)學(xué)院畢業(yè)論文 18 圖 643 LED與單片機接口間的設(shè)計 第七章 總體電路 19 第七章 總體 電路 總體 電路 經(jīng)過以上的設(shè)計過程，可設(shè)計出 基于單片機的 簡易數(shù)字直流電壓 表硬件電路原理圖如圖 711 所示。 ⑶ LED 譯碼方式 第六章 硬件電路設(shè)計 17 譯碼方式是指由顯示字符轉(zhuǎn)換得到對應(yīng)的字段碼的方式，對于 LED 數(shù)碼管顯示器，通常的譯碼方式有硬件譯碼和軟件譯碼方式兩種。 LED 由于結(jié)構(gòu)簡單、價格便宜、與單片機接口方便等優(yōu)點而得到廣泛應(yīng)用。 OE： 數(shù)據(jù)輸出允許信號，輸入，高電平有效。 2）具有轉(zhuǎn)換起停控制端。用戶也可以采用外部時鐘。 XTAL2： 震蕩器反相放大器的輸出端。 PSEN： 程序儲存允許輸出是外部程序存儲器的讀選通信號，當(dāng) AT89C51由外部程序存儲器讀取指令時，每個機器周期兩次 PSEN 有效，即輸出兩個脈沖。 RST： 復(fù)位輸入。對端口寫 “1”，通過內(nèi)部的電阻把端口拉到高電平，此時，可作為輸入口。當(dāng) “1”被寫入 P0 口時，每個管腳都能夠作為高阻抗輸入端。1288 位內(nèi)部 RAM AT89C51 單片機為很多嵌入式控制系統(tǒng)提供了一種靈活性高且價廉的方案。 圖 611 電壓范圍粗測電路 為了粗略地得到被測量的電壓范圍我們采用多組比較器的方式，通過階梯式比較的方法確定輸入電壓的范圍。 2. 逐次逼近式 A/D 轉(zhuǎn)換器。 淮安信息職業(yè)技術(shù)學(xué)院畢業(yè)論文 6 第四章 總體設(shè)計 系統(tǒng)設(shè)計 主要分為兩部分：硬件電路及軟件程序。 (4)測量速度快 :采樣速度一般每秒種為幾十次到上萬次，甚至可達百萬次。如音樂集成單片機，看似簡單的功能，微縮在純電子 芯片 中（有別于 磁帶機 的原理），就需要復(fù)雜的類似于計算機的原理。采用單片機控制使得儀器儀表數(shù)字化、智能化、微型化，且功能比起采用 電子或 數(shù)字電路 更加強大。 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。 由于單片機在工業(yè)控制領(lǐng)域的廣泛應(yīng)用，單片機由芯片內(nèi)僅有 CPU 的專用 處理器 發(fā)展而來 ?？梢妼頂?shù)字電壓表必將取代模擬電壓表。數(shù)字式電壓表首先將模擬量經(jīng)模數(shù)（ A/D）轉(zhuǎn)換器變成數(shù)字量，然后用電子計數(shù)器計數(shù)，并以十進制數(shù)字顯示被測電壓值。該設(shè)計主要由三個模塊組成： A/D 轉(zhuǎn)換模塊，數(shù)據(jù)處理模塊及顯示模塊。 關(guān)鍵詞 ： 【單片機】 【數(shù)字電壓表】 【 A/D 轉(zhuǎn)換】 【 AT89C51】 【 ADC0809】 目錄 II 目 錄 第一章 緒論 .................................................................................................................. 3 第二章 設(shè)計背景 ......................................................................................................... 4 單片機 .............................................................................................................. 4 單片機的簡介 ....................................................................................... 4 單片機的應(yīng)用領(lǐng)域 ............................................................................... 4 數(shù)字電 壓表 ...................................................................................................... 4 數(shù)字電壓表的特點 ............................................................................... 4 第三章 設(shè)計目的與功能要求 ..................................................................................... 5 設(shè)計目的 .......................................................................................................... 5 功能要求 .......................................................................................................... 5 第四章 總體設(shè)計 ......................................................................................................... 6 系統(tǒng)設(shè)計 ............................................................................................