實(shí)驗(yàn)十-D-A轉(zhuǎn)換實(shí)驗(yàn)

實(shí)驗(yàn)十D/A轉(zhuǎn)換實(shí)驗(yàn)一.實(shí)驗(yàn)要求利用DAC0832,編制程序產(chǎn)生鋸齒波、三角波、正弦波。三種波輪流顯示，用示波器觀看。二.實(shí)驗(yàn)?zāi)康牧私釪/A轉(zhuǎn)換的基本原理。了解D/A轉(zhuǎn)換芯片0832的性能及編程方法。了解單片機(jī)系統(tǒng)中擴(kuò)展D/A轉(zhuǎn)換的基本方法。三.實(shí)驗(yàn)電路及連線227卩匚||」丁10CS/接SDDOHo用三彼器尿去接融WUI;觀茶見(jiàn)亍逅開(kāi)入三.實(shí)驗(yàn)電路及連線227卩匚||」丁10CS/接SDDOHo用三彼器尿去接融WUI;觀茶見(jiàn)亍逅開(kāi)入I-I-N3g-UREF□LL324；A74L￡14 -~~^<XLC-2-1：D74L5］斗LP13Z4&12：ADIQDI1lout1DI2DI3lout2DHEiMD□15DT1UCCMRJILEUP2C5Vr-f潛口r §MDDij四.實(shí)驗(yàn)說(shuō)明D/A轉(zhuǎn)換是把數(shù)字量轉(zhuǎn)換成模擬量的變換，從本書(shū)D/A電路輸出的是模擬電壓信號(hào)。要實(shí)現(xiàn)實(shí)驗(yàn)要求，比較簡(jiǎn)單的方法是產(chǎn)生三個(gè)波形的表格，然后通過(guò)查表來(lái)實(shí)現(xiàn)波形顯示。產(chǎn)生鋸齒波和三角波的表格只需由數(shù)字量的增減來(lái)控制，同時(shí)要注意三角波要分兩段來(lái)產(chǎn)生。要產(chǎn)生正弦波，較簡(jiǎn)單的手段是造一張正弦數(shù)字量表。即查函數(shù)表得到的值轉(zhuǎn)換成十六進(jìn)制數(shù)填表。這樣做雖然簡(jiǎn)單，但是費(fèi)時(shí)費(fèi)力，沒(méi)有充分發(fā)揮單片機(jī)的能力。利用嵌入式定點(diǎn)、浮點(diǎn)運(yùn)算子程序庫(kù)可方便的完成正弦波的波形表生成工作。有關(guān)子程序庫(kù)的詳細(xì)使用方法請(qǐng)查閱《愛(ài)迪克仿真器51/98/96匯編運(yùn)算子程序庫(kù)使用手冊(cè)》。注意匯編子程序的每個(gè)子程序名應(yīng)為%開(kāi)頭的字符串，匯編程序在匯編時(shí)會(huì)自動(dòng)將子程序鏈入。CALCL51/96禁止用戶對(duì)此改寫(xiě)，否則會(huì)導(dǎo)致調(diào)用出錯(cuò)。D/A轉(zhuǎn)換取值范圍為一個(gè)周期，采樣點(diǎn)越多，精度越高些。本例采用的采樣點(diǎn)為256點(diǎn)/周期。五.實(shí)驗(yàn)框圖程序框圖：

主程序框圖SIN波形￡SIN計(jì)算結(jié)束STACKSSEGMENTSTACK ;堆棧段DW128DUP();注意這里只有128個(gè)字節(jié)STACKSENDSDATASSEGMENT ;數(shù)據(jù)段SHUJUDB67,70,73,76,80,83,86,88,91,94,97,100,102,105,107,109,111,113,115,117DB119,120,122,123,124,125,126,127,127,128,128,128,128,128,127,127,126,125,124,123DB122,120,119,117,115,114,111,109,107,105,102,100,97,94,91,89,86,83,80,77DB73,70,67,64,61,58,55,52,49,46,43,40,37,34,31,29,26,23,21,19DB17,15,13,11,9,8,6,5,4,3,2,1,1,0,0,0,0,0,1,1DB2,3,4,5,6,7,9,11,12,14,16,19,21,23,26,28,31,34,36,39DB42,45,48,51,54,58,61,64DATASENDSCODESSEGMENT;代碼段ASSUMECS:CODES,DS:DATASSTART:MOVAX,DATAS ;初始化MOVDS,AXMOVAX,STACKSMOVSS,AXMOV AH,0MOVDX,0606HMOV AL,BTOC\o"1-5"\h\zOUT DX,ALLP:MOV DX,0602HIN AL,DXAND AL,03HCMP AL,0JZ JUCMP AL,01HJZ SANCMPAL,02HJZSINCE

JZJMPLPJU:MOVDX,0600H ;矩形波MOVAL,0OUTDX,ALP1:CALLPINADDAL,BLOUTDX,ALPUSHDXPUSHAXMOVDX,0602HINAL,DXANDAL,03HCMPAL,00HJNZLPPOPAXPOPDXJMPP1SAN:MOVDX,0600H ;三角波MOVAL,0OUTDX,ALONE:CALLPINADDAL,BLOUTDX,ALPUSHAXPUSHDXMOVDX,0602HINAL,DXANDAL,03HCMPAL,01H

JNZLPPOPDXPOPAXCMPAL,255JNZONETWO:CALLPINSUBAL,BLOUTDX,ALPUSHDXPUSHAXMOVDX,0602HINAL,DXANDAL,3CMPAL,1JNZLPPOPAXPOPDXCMPAL,0JNZTWOJMPONEMOVSI,0；正弦波MOVDX,0600HMOVBX,OFFSETSHUJUA31:MOVAL,[BX+SI]OUTDX,ALPUSHDXPUSHAXMOVDX,0602HINAL,DXANDAL,3CMPAL,2JNZLPSINCE:POPAXPOPDXCALLPINADDSI,BXCMPSI,128JNZA31JMPSINCEPINPROCNEARTOC\o"1-5"\h\zPUSH DXPUSH AXMOV DX,06