【正文】 display board consists of several independent LED (Light Emitting Diode). The LED dotmatrix display board can display the number or sign, and it is usually used to show time, speed, the state of system etc. This paper introduces a kind of simple 16ｘ 16 LED display screen design process based on MCS51 single chip miniputer . The detail hardware scheme, software flow and assemble language programmer design and so on is followed. The display part can be cascaded to meet the need. The practice proves the design is lowcost and effective. Key words: MCS51； LED； MCU 引言 LED 顯示屏顯示畫面色彩鮮艷，立體感強，靜如油畫，動如電影，廣泛應用于車站、碼頭、機場、商場、醫(yī)院、賓館、銀行、證券市場、建筑市場、拍賣行、工業(yè)企業(yè)管理和其它公共場所。 MCS51 系列單片機簡介 MCS51 系列單片機及其特點 ①可靠性高： 因為芯片是按工業(yè)測控環(huán)境要求設計的，故抗干 擾的能力優(yōu)于 PC 機。 設計一個室內(nèi)用 16ｘ 16 的點陣 LED圖文顯示屏，要求 在目測條件下 LED 顯示屏各點亮度均勻、充足，可顯示圖形和文字， 顯示圖形和文字應穩(wěn)定、清晰無串擾。但是，串行傳輸過程較長，數(shù)據(jù)按順序一位一位地輸出給列驅(qū)動器，只有當一行的各列數(shù)據(jù)都以傳輸?shù)轿恢?，這一行的各列才能并行地進行顯示。 列驅(qū)動電路 列驅(qū)動電路有集成電路 74HC595 構(gòu)成。根據(jù)軟件分層次設計的原理，可以把顯示屏的軟件系統(tǒng)分為兩層 ；第一層是底層的顯示驅(qū)動程序，第二層是上層的系統(tǒng)應用程序。軟件部分需要調(diào)試的主要有顯示屏刷新頻率及顯示效果兩部分。 致謝 本文是在黃金明老師的悉心指導下完成的。s 21 win. Michel Platini, president of European football39。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。t. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters). cause there 。 Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time. 原來，這個世界上，對某個事件能產(chǎn)生化學反應的，除了非做不可的堅決，還有，時間。s Premier League match at Chelsea on Sunday. １７ I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport. For me it39。 五，通過這次畢業(yè)設計，重新復習并進一步學習了 MCS51；熟練掌握了 WORD軟件的使用。 進入中斷 定時器賦初值 讀取行號并增加 1 送新行顯示數(shù)據(jù) 消 隱 切換顯示數(shù)據(jù) 發(fā)送新行號，打開顯示 退出中斷 ８ 圖 5 是系統(tǒng)主程序流程圖。一條行線上要帶動 16列的 LED進行顯示，按每一 LED 器件 20MA 電流計算， 16 個 LED 同時發(fā)光時，需要 320MA 電流，選通三極管 8550 作為驅(qū)動管可滿足要求。P0 口和 P2 口空著，在有必要的時候可以擴展系統(tǒng)的 ROM 和 RAM。當列數(shù)很多時，并列傳輸?shù)姆桨甘遣豢扇〉?。在片外：尋址范圍?64KB；芯片引腳有 48 個或 68 個。 LED 顯示屏顯示畫面色彩鮮艷，立體感強，靜如油畫，動如電影，廣泛應用于車站、碼頭、機場、商場、醫(yī)院、賓館、銀行、證券市場、建筑市場、拍賣行、工業(yè)企業(yè)管理和其它公共場所。 包括 系統(tǒng)具體的硬件設計方案 ,軟件流程圖和部分 匯編語言程序等方面。 p n 結(jié)上未加電壓時構(gòu)成一定的勢壘 ,當加正向偏壓時 ,在外電場作用下 ,p 區(qū)的空穴和 n 區(qū)的電子就向?qū)Ψ綌U散運動 ,構(gòu)成少數(shù)載流子的注入 ,從而在 p n 結(jié)附近產(chǎn)生導帶電子和價帶空穴的復合 ,同時釋放出相對應的能量 hν(h 為普朗克常數(shù) ,ν 為光子頻率 )而發(fā)光。 ②第 2階段 (1978 年 — 1983 年 )，以 MCS51系列為代表，稱 8位單片機。 采用掃描方式進行顯示時，每一行有一個行驅(qū)動器，各行的同名列共用一個驅(qū)動器。圖 1 為顯示屏電路實現(xiàn)的結(jié)構(gòu)框圖。SCLR 信號是移位寄存器清零輸入端，當其為低時移位寄存器的輸出全部為零。 圖 4 顯示驅(qū)動程序流程圖 系統(tǒng)主程序 本文設計的系統(tǒng)軟件能使系統(tǒng)在目測條件下 LED 顯示屏各點亮度均勻、充足，可顯示圖形和文字，顯示圖形和文字應穩(wěn)定、清晰無串擾。 總結(jié)本文的研究工作，主要做了下面幾點較突出的工作： 一、通過查閱大量的相關(guān)資料，詳細了解了 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，明確了研究目標。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。 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。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