基于AT89C51單片機的16x16LED點陣顯示的課程設(shè)計

PAGE單片機課程設(shè)計16×16LED點陣顯示16×16LED點陣顯示的設(shè)計【摘要】本設(shè)計使用AT89C51系列高速單片機作為主控制模塊，利用簡單的外圍電路來驅(qū)動64×16的點陣LED顯示屏。利用AT89C51系列高速單片機本身強大的功能，可以很方便的實現(xiàn)單片機與PC機間的數(shù)據(jù)傳輸及存儲，并能利用軟件方便的進行顯示內(nèi)容的多樣變化，另一方面點陣顯示屏廣泛的應(yīng)用于醫(yī)院、機場、銀行等公共場所，所以本設(shè)計具有很強的現(xiàn)實應(yīng)用性。本LED顯示屏能夠以動態(tài)掃描的方式同時顯示4個16×16點陣漢字，并能通過上位機軟件修改顯示內(nèi)容和顯示效果等等。把字符內(nèi)碼存儲在空閑的單片機程序存儲器空間，使本LED顯示系統(tǒng)能掉電存儲1024個字符。設(shè)計中采用了SPI接口的GB2312標(biāo)準(zhǔn)字庫，支持所有的國標(biāo)字符和ASC=2\*ROMANII標(biāo)準(zhǔn)字符的顯示。因為采用串行傳輸方式，使本系統(tǒng)的可擴展性得到提升，便于多個顯示單元的級聯(lián)。本文從LED的顯示原理入手，詳細(xì)闡述了LED動態(tài)顯示的過程，以及硬件電路的設(shè)計、計算和軟件的算法?！娟P(guān)鍵詞】LED動態(tài)顯示AT89C51點陣漢子顯示仿真引言LED顯示屏是一種通過控制半導(dǎo)體發(fā)光二極管的顯示方式，用來顯示文字、圖形、圖像、動畫、行情、視頻、錄像信號等各種信息的顯示屏幕。圖文顯示屏可與計算機同步顯示漢字、英文文本和圖形；視頻顯示屏采用微型計算機進行控制，圖文、圖像并茂，以實時、同步、清晰的信息傳播方式播放各種信息，還可顯示二維、三維動畫、錄像、電視、VCD節(jié)目以及現(xiàn)場實況。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(yīng)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。它的優(yōu)點：亮度高、工作電壓低、功耗小、微型化、易與集成電路匹配、驅(qū)動簡單、壽命長、耐沖擊、性能穩(wěn)定。當(dāng)今社會在飛速發(fā)展無疑能源、健康、空間的利用，成了人們著重關(guān)注的對象。而在這個信息傳遞極速的社會，LED的出現(xiàn)給人們帶來了希望之光。LED的特色之處一是節(jié)能（直接功耗，間接耗能），二是基本無電離輻射，三提高空間利用率。而這些特色又恰好解決了上述的三種問題。然而LED點陣顯示屏的特點不僅僅于此LED點陣顯示屏用的是數(shù)碼管，而數(shù)碼管具有實用,便宜等優(yōu)點。做出來的LED點陣顯示很耐用。LED點陣顯示屏之所以受到廣泛重視而得到迅速發(fā)展，是與LED顯示屏本身所具有的優(yōu)點分不開的。LED點陣顯示屏的發(fā)展前景極為廣闊，目前正朝著更高亮度、更高耐氣候性、更高的發(fā)光密度、更高的發(fā)光均勻性，可靠性、全色化方向發(fā)展。本文要求設(shè)計一個能顯示16X16點陣圖文LED顯示屏，要求能顯示圖文或文字，顯示圖文或文字應(yīng)穩(wěn)定、清晰，圖文或文字顯示，以卷簾形式向上下左右滾動顯示?？傮w設(shè)計：拉高。如果微處理器在外部執(zhí)行狀態(tài)ALE禁止，置位無效。

/PSEN：外部程序存儲器的選通信號。在由外部程序存儲器取指期間，每個機器周期兩次/PSEN有效。但在訪問外部數(shù)據(jù)存儲器時，這兩次有效的/PSEN信號將不出現(xiàn)。

/EA/VPP：當(dāng)/EA保持低電平時，則在此期間外部程序存儲器（0000H-FFFFH），不管是否有內(nèi)部程序存儲器。注意加密方式1時，/EA將內(nèi)部鎖定為RESET；當(dāng)/EA端保持高電平時，此間內(nèi)部程序存儲器。在FLASH編程期間，此引腳也用于施加12V編程電源（VPP）。

XTAL1：反向振蕩放大器的輸入及內(nèi)部時鐘工作電路的輸入。

XTAL2：來自反向振蕩器的輸出16×16LED點陣顯示制作以UCDOS中文宋體字庫為例，每一個字由16行16列的點陣組成顯示。即國家標(biāo)準(zhǔn)漢字庫中的每一個字均由256點陣來表示。我們可以把每一個點理解為一個像素，而把每一個字的字形理解為一幅圖像。事實上這個漢字屏不僅可以顯示漢字，也可以顯示在256像素范圍內(nèi)的任何圖形。這里我們以“高”字說明，如下圖所示：圖為字模提取軟件提取16*16LED漢字顯示代碼用8位的AT89C51單片機控制，由于單片機的總線為8位，一個字需要拆分為2個部分。一般把它拆分為上部和下部，上部由8×16點陣組成，下部也由8×16點陣組成。在本例中單片機首先顯示的是左上角的第一列的上半部分，即第0列的p00—p07口。方向為p00到p07,顯示漢字“魏”時,p02點亮,由上往下排列,為p0.0滅，p0.1滅,p0.2滅,p0.3滅,p0.4滅,p0.5亮,p0.6滅,p0.7滅。即二進制00000100，轉(zhuǎn)換為16進制為04h。上半部第一列完成后，繼續(xù)掃描下半部的第一列，為了接線的方便，我們?nèi)栽O(shè)計成由上往下掃描，即從p27向p20方向掃描，從上圖可以看到，這一列全部為不亮，即為00000000，16進制則為00h。然后單片機轉(zhuǎn)向上半部第二列，仍為p01點亮，為00000100，即16進制04h.這一列完成后繼續(xù)進行下半部分的掃描，p20點亮，為二進制00000010，即16進制02h.依照這個方法，繼續(xù)進行下面的掃描，一共掃描32個8位，可以得出漢字“魏”的掃描代碼為：DB40H,06H,84H,F8H,FEH,11H,24H,11H,24H,FFH,FCH,39H,24H,55H,44H,91H,FCH,11H,40H,FEH,60H,24H,A0H,44H,A8H,28H,22H,11H,22H,2AH,1EH,44H

由這個原理可以看出，無論顯示何種字體或圖像，都可以用這個方法來分析出它的掃描代碼從而顯示在屏幕上。不過現(xiàn)在有很多現(xiàn)成的漢字字模生成軟件，就不必自己去畫表格算代碼了。用4個8×8LED點陣構(gòu)成16×16LED點陣Proteus中只有5×7和8×8等LED點陣，并沒有16×16LED點陣，而在實際應(yīng)用中，要良好地顯示一個漢字，則至少需要16×16點陣。下面我們就首先介紹使用8×8點陣構(gòu)建16×16點陣的方法，并構(gòu)建一塊16×16LED點陣，用于本例的顯示任務(wù)。首先，從Proteus7.1的元件庫中找到“MATRIX-8X8-RED”元器件，并將四塊該元器件放入Proteus文檔區(qū)編輯窗口中。此時需要注意,如果該元器件保持初始的位置（沒有轉(zhuǎn)動方向），我們要首先將其左轉(zhuǎn)90°，使其水平放置，那么此時它的左面8個引腳是其行線，右邊8個引腳是其列線（當(dāng)然，如果你是將右轉(zhuǎn)，則右邊8個引腳是行線）。然后我們將四個元器件對應(yīng)的行線和列線分別進行連接，使每一條行線引腳接一行16個LED，列線也相同。并注意要將行線和列線引出一定長度的引腳，以便下面我們使用。連接好的16×16點陣如圖1所示。圖1點陣模塊組合成如上圖的16×16點陣只是第一步，這樣分開的數(shù)塊并不能達到好的顯示效果,下面我們要將其進一步組合。組合實際上很簡單，首先選中如上圖中右側(cè)的兩塊8×8點陣，然后拖動并使其與左側(cè)的兩塊相并攏，如圖2所示。圖1點陣模塊組合可以看到原來的連線已經(jīng)自動隱藏了，至于線上的交點，我們不要去動。然后，我們再來最后一步，選中下側(cè)的兩塊點陣，并拖動使其與上側(cè)的兩塊并攏,最后的效果如圖3所示。看到,原來雜亂的連線現(xiàn)在已經(jīng)幾乎全部隱藏了，一塊16×16的LED點陣做成了。需要注意，做成的LED點陣的行線為左側(cè)的16個引腳，下側(cè)的16個引腳為其列線，而且其行線為高電平有效，列線為低電平有效。然后，我們將其保存，以便以后使用。二、實驗電路及連線電路主要由單片機和一些外部設(shè)備連接而成，利用4個8*8LED顯示組裝成16*16LED顯示，2個R*8排電阻，一個74HC154組成。該顯示器采用AT89C51單片機作為控制器，12MHz晶振，其中P0口作為字符數(shù)據(jù)輸出口，P2口作為顯示器掃描輸出口，第31管腳（EA）接電源。電路包括單片機、電源電路、時鐘電路、復(fù)位電路、驅(qū)動電路和LED點陣電路等。本設(shè)計的核心是利用單片機讀取顯示字型碼，通過驅(qū)動電路對16×16LED點陣進行動態(tài)掃描，以實現(xiàn)漢字的滾動顯示?？傠娐愤B線圖如下所示：軟件設(shè)計本軟件要求實現(xiàn)如下要求：漢字要穩(wěn)定、明亮并且文字要以一定速度上升滾動顯示。顯示屏軟件模塊：初始化程序、主程序、多字滾動、顯示程序、掃描程序。顯示程序的主要功能是向屏體提供顯示數(shù)據(jù)，并產(chǎn)生各種控制信號，使屏幕按設(shè)計的要求顯示。軟件設(shè)計中，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(yīng)用程序。顯示驅(qū)動程序負(fù)責(zé)向屏體送顯示數(shù)據(jù)，并負(fù)責(zé)產(chǎn)生行掃描信號和其他控制信號，配合完成LED顯示屏的掃描顯示工作。顯示驅(qū)動器程序由定時器T0中斷程序?qū)崿F(xiàn)。系統(tǒng)應(yīng)用程序完成系統(tǒng)環(huán)境設(shè)置（初始化）、顯示效果處理等工作，由主程序來實現(xiàn)。顯示驅(qū)動程序顯示驅(qū)動程序在進入中斷后首先要對定時器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）計算公式如下：刷頻率（幀頻）=1/16×T0溢=1/16×f/12（65536-t）其中f位晶振頻率，t為定時器T0初值（工作在16位定時器模式）。然后顯示驅(qū)動程序查詢當(dāng)前燃亮的行號，從顯示緩存區(qū)內(nèi)讀取下一行的顯示數(shù)據(jù)，并通過串口發(fā)送給移位寄存器。為消除在切換行顯示數(shù)據(jù)的時候產(chǎn)生拖尾現(xiàn)象，驅(qū)動程序先要關(guān)閉顯示屏，即消隱，等顯示數(shù)據(jù)打入輸出鎖存器并鎖存，然后再輸出新的行號，重新打開顯示。圖六為顯示驅(qū)動程序（顯示屏掃描函數(shù)）流程圖進入中斷進入中斷消消隱定時器賦初值切換顯示數(shù)據(jù)讀取行號并增加切換顯示數(shù)據(jù)讀取行號并增加1發(fā)送新行號，打開顯示送新行顯示數(shù)據(jù)發(fā)送新行號，打開顯示送新行顯示數(shù)據(jù)退出中斷退出中斷系統(tǒng)主程序本設(shè)計的系統(tǒng)軟件能使系統(tǒng)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(yīng)穩(wěn)定、清晰無串?dāng)_。圖形或文字顯示有靜止、移入移出等顯示方式。系統(tǒng)主程序開始以后，首先是對系統(tǒng)環(huán)境初始化，包括設(shè)置串口、定時器、中斷和端口；然后以“卷簾出”效果顯示圖形，停留約幾秒；接著向上滾動顯示“”這幾個漢字及一個圖形，然后以“卷簾入”效果隱去圖形。由于單片機沒有停機指令，所以可以設(shè)置系統(tǒng)程序不斷的循環(huán)執(zhí)行上述顯示效果。單元顯示屏可以接收來自控制器（主控制電路板）或上一級顯示單元模塊傳輸下來的數(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顯示模塊單元中，因此顯示板可擴展至更多的顯示單元，用于顯示更多的顯示內(nèi)容。如果想改變些事內(nèi)容，先用字模產(chǎn)生字代碼，將用這段代碼覆蓋原來的代碼，即可顯示你想要的內(nèi)容。系統(tǒng)主程序流程圖：開始開始系統(tǒng)初始化系統(tǒng)初始化““卷簾出”顯示效果““上滾屏”顯示效果““卷簾入”顯示效果程序編寫如下：ORG000HJMPMIANORG030HMIAN:MOVP3,#00MOVP1,#0FFHMOVP0,#00MOVP2,#00CALLDELAYMOVR5,#2MOVA,#40MOVB,#32MULABMOV22H,AMOV23H,BMOVDPTR,#TABLE1MOVR0,DPLMOVR1,DPHMOV20H,DPLMOV21H,DPHLOOP:MOVR7,#5L1:MOVR6,#16MOVR4,#00MOVDPL,R0MOVDPH,R1L16:MOVA,R4MOVP1,AINCR4CLRAMOVCA,@A+DPTRMOVP0,AINCDPTRCLRAMOVCA,@A+DPTRMOVP2,AINCDPTRCALLDELAYMOVP0,#00MOVP2,#00DJNZR6,L16DJNZR7,L1MOVR0,DPLMOVR1,DPHMOVA,R0ADDA,R5MOVR0,AJNCDPINCR1DP:MOVA,20HADDA,22HMOVA,DPHSUBBA,21HCJNEA,23H,LOOPCLRCMOVA,DPLSUBBA,20HCJNEA,22H,LOOPJMPMIANDELAY:MOVR2,#2D1:MOVR3,#248DJNZR3,$DJNZR2,D1RETTABLE1:XI:DB004H,000H,0C4H,0FFH,044H,040H,044H,050HDB044H,048H,0FCH,047H,044H,040H,044H,040HDB044H,040H,0FCH,047H,044H,048H,044H,048HDB044H,040H,0E6H,0FFH,044H,000H,000H,000HBEI:DB000H,020H,020H,060H,020H,020H,020H,010HDB020H,010H,0FFH,07FH,000H,000H,000H,000HDB0FFH,03FH,020H,040H,010H,040H,008H,040HDB00CH,040H,000H,040H,000H,070H,000H,000HMIN:DB000H,000H,0FEH,0FFH,022H,041H,022H,021HDB022H,011H,022H,001H,0E2H,003H,022H,00DHDB022H,011H,022H,021H,022H,041H,03FH,041HDB082H,081H,000H,081H,000H,0E0H,000H,000HZU:DB010H,040H,010H,030H,0F1H,00FH,092H,040HDB096H,080H,090H,07FH,010H,004H,020H,086HDB090H,045H,06FH,034H,0C8H,00FH,048H,034HDB06CH,044H,048H,0C6H,000H,044H,000H,000HDA:DB020H,000H,020H,040H,020H,040H,020H,020HDB020H,010H,020H,00CH,0A0H,003H,07FH,000HDB0A0H,001H,020H,006H,020H,008H,020H,010HDB020H,020H,030H,060H,020H,020H,000H,000HXUE:DB040H,004H,030H,004H,011H,004H,096H,004HDB090H,004H,090H,044H,091H,084H,096H,07EHDB090H,006H,090H,005H,098H,004H,014H,004HDB013H,004H,050H,006H,030H,004H,000H,000HDIAN:DB000H,000H,0F8H,007H,048H,002H,048H,002HDB048H,002H,048H,002H,0FFH,03FH,048H,042HDB048H,042H,048H,042H,048H,042H,0FCH,047HDB008H,040H,000H,070H,000H,000H,000H,000HQI:DB040H,000H,020H,000H,058H,000H,047H,000HDB054H,000H,054H,000H,054H,000H,054H,000HDB054H,000H,054H,000H,0D4H,01FH,014H,020HDB006H,040H,004H,080H,000H,070H,000H,000HGONG:DB000H,020H,004H,020H,004H,020H,004H,020HDB004H,020H,004H,020H,004H,020H,0FCH,03FHDB004H,020H,004H,020H,004H,020H,004H,020HDB004H,020H,004H,020H,000H,020H,000H,000HCHENG:DB024H,008H,024H,006H,0A4H,001H,0FEH,0FFHDB0A3H,000H,022H,041H,020H,041H,07EH,049HDB042H,049H,042H,049H,042H,07FH,042H,049HDB042H,049H,07EH,069H,000H,041H,000H,000HXUE:DB040H,004H,030H,004H,011H,004H,096H,004HDB090H,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