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畢業(yè)設(shè)計(jì)-基于mcs-51的16x16點(diǎn)陣led電子顯示屏的設(shè)計(jì)-wenkub.com

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【正文】 s not needed. Instead, he plans to deploy his 270squarefoot (25squaremeter) main chute at an altitude of around 5,000 feet (1,524 meters). 19 In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds. Even if everything goes as planned, it won39。t start planning... Those years, those days of do, finally, like youth, will end in our life. 此刻,天空是陰暗的,空氣里有著剛下過(guò)雨之后的清新因子。 At the moment, the sky is dark, the air is fresh factor after just rained. Suddenly thought of blue plaid shirt。想要的,不想要的,界限明確,好像沒(méi)有什么可以撼動(dòng)自己。t remember his appearance. 童年時(shí),覺(jué)得壓歲錢(qián)和新衣服是過(guò)年必備,但是隨著年齡的推進(jìn),會(huì)越來(lái)越發(fā)現(xiàn),那些東西根本就可有可無(wú);初中時(shí),以為要有一場(chǎng)暗戀才意味著真正的成長(zhǎng),但三年過(guò)去后,自己心平氣和的寫(xiě)同學(xué)錄的時(shí)候,突然就發(fā)現(xiàn)是不是真正的成長(zhǎng)了,好像并沒(méi)有那么重要了;然后到了高中,覺(jué)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)句點(diǎn),但畢業(yè)晚會(huì)的時(shí)候最終還是被梗塞在了咽喉,后來(lái)再次站在他曾經(jīng)揮汗如雨的球場(chǎng),看著他投過(guò)籃球的球框時(shí),突然間發(fā)現(xiàn)自己已經(jīng)想不起他的容顏。 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?;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(guò)成了同一天的樣子;或許是追溯過(guò)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(lái),思緒一直很凌亂,在腦海中不斷糾纏。s governing body, has also ordered an immediate investigation into the referee39。s 150th anniversary celebrations and will attend City39。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 it. 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。 ; R3:滾動(dòng)顯示時(shí)控制移動(dòng)速度,單字顯示可控制靜止顯示的時(shí)間。從課題的立項(xiàng)、選題到課題的開(kāi)發(fā)與研究,再到本論文的撰寫(xiě)到定稿的每一步工作都傾注著黃老師的心血和汗水, 同時(shí)得到同學(xué)們相助,并提供了大量的資料 . 在此,對(duì)于老師和同學(xué)們的幫助表示忠心的感謝。 四,在這次畢業(yè)設(shè)計(jì)的過(guò)程中學(xué)會(huì)了 Protel 99se 的基本使用,感到 Protel 99se 對(duì)自動(dòng)化專業(yè)的同學(xué)來(lái)說(shuō)是一門(mén)很有用的課程。 總結(jié)本文的研究工作,主要做了下面幾點(diǎn)較突出的工作: 一、通過(guò)查閱大量的相關(guān)資料,詳細(xì)了解了 LED 的發(fā)光原理和 LED 顯示屏的原理,了解了 LED 的現(xiàn)狀,清楚地了解了 LED 顯示屏與其它顯示屏 相比較有那些 優(yōu)點(diǎn),明確了研究目標(biāo)。 這個(gè)方案設(shè)計(jì)的 16x 16 的點(diǎn)陣 LED圖文顯示屏,電路簡(jiǎn)單,成本較低,且較容易擴(kuò)展成更大的顯示屏;顯示屏各點(diǎn)亮度均勻、充足;顯示圖形或文字穩(wěn)定、清晰無(wú)串?dāng)_;可用靜止、移入 移出等多種顯示方式顯示圖形或文字。顯示屏刷新率由定時(shí)器 T0的溢出率和單片機(jī)的晶振頻率決定,表 給出了實(shí)驗(yàn)調(diào)試時(shí)采用的頻率及其對(duì)應(yīng)的定時(shí)器 T0 初值。 單元顯示屏可以接收來(lái)自控制器(主控制電路板)或上一級(jí)顯示單元模塊傳輸下來(lái)的數(shù)據(jù)信息和命令信息,并可將這些數(shù)據(jù)信息和命令信息不經(jīng)任何變化地再傳送到下一級(jí)顯示模塊單元中,因此顯示板可擴(kuò)展至更多的顯示單元,用于顯示更多的顯示內(nèi)容。 圖 4 顯示驅(qū)動(dòng)程序流程圖 系統(tǒng)主程序 本文設(shè)計(jì)的系統(tǒng)軟件能使系統(tǒng)在目測(cè)條件下 LED 顯示屏各點(diǎn)亮度均勻、充足,可顯示圖形和文字,顯示圖形和文字應(yīng)穩(wěn)定、清晰無(wú)串?dāng)_。 顯示驅(qū)動(dòng)程序 顯示驅(qū)動(dòng)程序在進(jìn)入中斷后首先要對(duì)定時(shí)器 T0 重新賦初值,以保證顯示屏刷新率的穩(wěn)定, 1/16 掃描顯示屏的刷新率(幀 頻)計(jì)算公式如下: 刷頻率(幀頻) =1/16 T0 溢出率 =1/16 f/12( 65536t) 其中 f位晶振頻率, t 為定時(shí)器 T0初值(工作在 16 位定時(shí)器模式)。顯示驅(qū)動(dòng)程序負(fù)責(zé)向屏體送顯示數(shù)據(jù),并負(fù)責(zé)產(chǎn)生行掃描信號(hào)和其他控制信號(hào),配合完成 LED 顯示屏的掃描顯示工作。 QB 1 16 Vcc QC 2 15 QA QD 3 14 SI QE 4 13 G QF 5 12 RCK QG 6 11 SCK QH 7 10 SCLR GND 8 9 QH 圖 3. 74HC595 外形及引腳 行驅(qū)動(dòng)器 單片機(jī) P1口低 4位輸出的行號(hào)經(jīng) 4/16線譯碼器 74LS154譯碼后生成 16條行選通信號(hào)線,再經(jīng)過(guò)驅(qū)動(dòng)器驅(qū)動(dòng)對(duì)應(yīng)的行線。SCLR 信號(hào)是移位寄存器清零輸入端,當(dāng)其為低時(shí)移位寄存器的輸出全部為零。引腳SCK 是移位寄存器的移位時(shí)鐘脈沖,在其上升沿發(fā)生移位,并將 SI的下一個(gè)數(shù)據(jù) 打入最低位。它具有一個(gè) 8 位串入并出的移位寄存器和一個(gè) 8 位輸出鎖存器的結(jié)構(gòu),而且移位寄存器和輸出鎖存器的控制是各自獨(dú)立的,可以實(shí)現(xiàn)在顯示本行列數(shù)據(jù)的同時(shí),傳送下一行的列數(shù)據(jù),既達(dá)到重疊處理的目的。P1口低 4 位與行驅(qū)動(dòng)器相連,送出行選信號(hào); ~ 口則用來(lái)發(fā)送控制信號(hào)。圖 1 為顯示屏電路實(shí)現(xiàn)的結(jié)構(gòu)框圖。為了達(dá)到重疊處理的目的,列數(shù)據(jù)的顯示就需要具有所存功能。這樣,對(duì)于一行的顯示過(guò)程就可以分解成列數(shù)據(jù)準(zhǔn)備(傳輸)和列數(shù)據(jù)顯示兩部分。顯然,采用并行方式時(shí),從控制電路到列驅(qū)動(dòng)器的線路數(shù)量大,相應(yīng)的硬件數(shù)目多。 采用掃描方式進(jìn)行顯示時(shí),每一行有一個(gè)行驅(qū)動(dòng)器,各行的同名列共用一個(gè)驅(qū)動(dòng)器。因此在實(shí)際應(yīng)用中的顯示屏幾乎都不采用這種設(shè)計(jì),而采用另外一種稱為動(dòng)態(tài)掃描的顯示方法。圖形或文字顯
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