單片機(jī)試題及答案（SINGLECHIPEXAMINATIONQUESTIONSANDANSWERS）AFILLINTHEBLANKS1POINTSPERMINUTE,20POINTS1MONOLITHICMICROCOMPUTERCONSISTSOFCPU,MEMORYANDTHREEPARTS2,INTHEMCS51SYSTEM,WHENTHESIGNALISVALID,ITMEANSTHATTHESIGNALISSENTOUTSTABLYFROMTHEP0PORT3,ACCESSTO8031PIECESOFEXTERNALDATAMEMORYUSINGTHEADDRESSINGMODE4,ACCUMULATORA80H,EXECUTEINSTRUCTIONADDA,83H,CARRYBITSC5,INSTRUCTIONLCALL37B0H,THEFIRSTADDRESSIN2000H,THECOMPLETIONOFTHEOPERATIONISINTOTHESTACK,SENTTOPC6,MCS51INTERRUPTSOURCE,2INTERRUPTPRIORITY,PRIORITYBYTHESOFTWARETOFILLINTHESPECIALFUNCTIONREGISTERIPTOCHOOSE7,ASSEMBLYLANGUAGEANDTWOBASICINSTRUCTIONSIN8,ADDRESSINGMODE,USINGAASINDEXREGISTERS,ORTOREGISTER9,INTERRUPTREQUESTSIGNALTRIGGERANDTRIGGERTWOTRIGGERMODES10,USETHESERIALPORTEXTENDEDPARALLELPORT,SERIALINTERFACEMODESHOULDBE11,74LS273ISUSUALLYUSEDASASIMPLEINTERFACEEXTENSION,WHILE74LS244ISOFTENUSEDASASIMPLEINTERFACEEXTENSION12,MCS51PARALLELI/OPORTINFORMATIONANDTWOKINDSOFREADINGMETHOD,READMODIFYWRITEOPERATIONISFORPARALLELI/OPORTOFTHELATCH13,THREEIMPORTANTINDEXESOFA/DCONVERTERARE,ANDSUMUPTWO,CHOOSEAQUESTIONCHOOSEACORRECTANSWERFROMTHEALTERNATIVEANSWER,ANDWRITETHECODEINPARENTHESES1POINTSFOREACHQUESTION,10POINTS1THELANGUAGETHATCOMPUTERSCANRECOGNIZEISAASSEMBLYLANGUAGEBNATURALLANGUAGECMACHINELANGUAGECHIGHLEVELLANGUAGE2WHENTHEMCS51CHIPISUSEDTOEXPANDMEMORYCHIPS,THE4I/OPORTSAREUSEDASDATABUSESAP0ANDP2MOUTHBP0MOUTHCP2ANDP3MOUTHDP2MOUTH3,ATLEASTONEOFTHEINTERRUPTSERVICEPROGRAMATRANSFERINSTRUCTIONBTRANSFERINSTRUCTIONCADDITIONINSTRUCTIONDINTERRUPTRETURNINSTRUCTION4THESIGNALTHATDOESNOTWORKWHENACCESSINGEXTERNALMEMORYISABAAALE5,THEFOLLOWINGINSTRUCTIONS,READONLYTHEINSTRUCTIONSOFTHEPINISAMOVP1,ABORLP1,0FHCMOVCC,P15DDJNZP1,LAB6,THEUSEOFTIMERT1,THEREARESEVERALMODESOFWORKA1SPECIESB,2SPECIESC,3SPECIESD,4SPECIES7,IFMCS51INTERRUPTSOURCESAREPROGRAMMEDASTHESAMELEVEL,WHENTHEYSIMULTANEOUSLYAPPLYINTERRUPTS,CPUFIRSTRESPONDSABCT1DT08,WHENTHEMCS51RESPONSEISINTERRUPTED,WHICHOFTHEFOLLOWINGCONDITIONSISNOTNECESSARYTHECURRENTINSTRUCTIONISEXECUTEDB,INTERRUPTISOPENC,NOPEERORADVANCEDINTERRUPTSERVICED,ANDMUSTHAVERETIINSTRUCTION9,IFTHE8255PORTAISSETTOMODE2,THEPORTBISSETTOACANONLYBE0BOR2CEXCEPTFORMODE2,ANDANYOTHERWAYCANDANYWAY10,WHENTHEMCS51MULTIMACHINECOMMUNICATION,SERIALINTERFACEMODESHOULDBEAMODE0BMODE1CMODE2DMODE0ORMODE2FOURREADORWRITEPROGRAMS15POINTS1WRITEAPROGRAMTOTRANSFERTHEDATAFROMTHE100UNITSOFTHE1000HUNITTOTHEBEGINNINGOFTHE2000H8POINTS2SETR020H,R125H,20H80H,21H90H,22HA0H,25HA0H,26H6FH,27HAFTERTHEFOLLOWINGPROGRAMISEXECUTED,WHATISTHERESULT20H21H22H23HCYR0R1CLRCMOVR2，3環(huán)MOVA，R0ADDCA，R1MOVR0，一INCR0公司R1DJNZR2，環(huán)JNC下MOVR0，01H否則，下一步DECR0否則，五、MCS51單片機(jī)外擴(kuò)展一片2716存儲(chǔ)器，畫出系統(tǒng)電路原理圖，寫出地址分布。（15分）六、MCS51單片機(jī)P1端口上，經(jīng)驅(qū)動(dòng)器接有只發(fā)光二極管FOSC8，6MHZ，試編寫程序，使這8只發(fā)光管每隔2秒循環(huán)發(fā)光。（20分）單片微機(jī)原理及應(yīng)用一卷參考答案一、填空題（每空1分，共20分）1、I/O2、低83415位地址、寄存器間接、2003H，37B06、5個(gè)，IP7、符號(hào)指令和偽指令8、PC或DPTR9、電平和脈沖10、方式011、輸出輸入12、讀引腳和讀鎖存器13、轉(zhuǎn)換速度、分辨率和轉(zhuǎn)換精度。二、選擇題（從備選答案中選擇一個(gè)正確答案，并將代號(hào)寫在括號(hào)內(nèi)。每題1。分，共10分）1，C2，B3，D4，C5，C6，C7，B8，C9，A10，C三、簡答題（每題5分，共20分）1、MCS51單片機(jī)內(nèi)部包括哪些主要邏輯功能部件答MCS51單片機(jī)主要由下列部件組成1個(gè)8位CPU；1個(gè)片內(nèi)振蕩器及時(shí)鐘電路；4KBROM程序存儲(chǔ)器，256BRAM；21個(gè)特殊功能寄存器；2個(gè)16位定時(shí)/計(jì)數(shù)器；4個(gè)8位并行I/O口及1個(gè)可編程全雙工串行接口；可尋址64KB的外部程序存儲(chǔ)器空間；可尋址64KB的外部數(shù)據(jù)存儲(chǔ)器空間；5個(gè)中斷源、兩個(gè)優(yōu)先級(jí)中斷嵌套中斷結(jié)構(gòu)。2、MCS51單片機(jī)內(nèi)部有幾個(gè)定時(shí)/計(jì)數(shù)器它們由哪些寄存器組成答MCS51單片機(jī)內(nèi)部有兩個(gè)16位可編程的定時(shí)/計(jì)數(shù)器，簡稱定時(shí)器0（T0）和定時(shí)器1（T1）。它們分別由方式寄存器TMOD、控制寄存器TCON和數(shù)據(jù)寄存器TH0、TL0，TH1、TL1組成。3、單片機(jī)對(duì)中斷優(yōu)先級(jí)的處理原則是什么答（1）低優(yōu)先級(jí)中斷源可被高優(yōu)先級(jí)中斷源所中斷，而高優(yōu)先級(jí)中斷源不能被任何中斷源所中斷；（2）一種中斷源（不管是高優(yōu)先級(jí)還是低優(yōu)先級(jí)）一旦得到響應(yīng)，與它同級(jí)的中斷源不能再中斷它。當(dāng)同時(shí)收到幾個(gè)同一優(yōu)先級(jí)的中斷時(shí)，響應(yīng)哪一個(gè)中斷源取決于內(nèi)部查詢順序。其優(yōu)先級(jí)排列如下中斷源同級(jí)內(nèi)的中斷優(yōu)先級(jí)0最高外部中斷定時(shí)器/計(jì)數(shù)器0溢出中斷外部中斷1定時(shí)器/計(jì)數(shù)器1溢出中斷串行口中斷最低4、設(shè)MCS51單片機(jī)的FOSC12MHZ，要求用T0定時(shí)150US，分別采用定時(shí)方式0，定時(shí)方式1和方式2時(shí)的定時(shí)初值。采用方式0定時(shí)的初值為FBH，50H采用方式1定時(shí)的初值為FFH，6AH采用方式2定時(shí)的初值為6AH四、閱讀或編寫程序1、編寫一程序?qū)崿F(xiàn)將1000H單元開始的100個(gè)單元的數(shù)據(jù)轉(zhuǎn)移到2000H開始的單元中。（8分）程序如下ORG0000HMOVDPTR，1000H；給源數(shù)據(jù)塊地址指針DPTR賦初值MOVP2，20H；給目的數(shù)據(jù)塊地址指針P2和R0賦初值MOVR0，00H環(huán)MOVX指令，指令MOVXR0，一INCDPTRINCR0CJNER0，64H，環(huán)否則，2、設(shè)R020H，R125H20H90H80H,21H,22HA0H,25HA0H,26H6FH,27H,AFTERTHEFOLLOWINGPROGRAMISEXECUTED,WHATISTHERESULT7POINTS20H21H20H00H22H23H17H01HCYA128H17HR023HR1CLRCMOVR2,3ONERINGMOV,R0ADDCAR1MOVR0,ACOMPANYR0COMPANYR1DJNZR2,RINGAJNCMOVR0,01HSJMPDOLLARSNEXTMONTH,R0SJMPDOLLARSFIVE,MCS51SINGLECHIPMICROCOMPUTERTOEXPANDAPIECEOF2716MEMORY,DRAWTHESYSTEMCIRCUITSCHEMATICDIAGRAM,WRITEADDRESSDISTRIBUTION15POINTSTHEADDRESSRANGEOFPROGRAMMEMORYIS0000H07FFH,0800H0FFFH,1000H17FFHSIX,MCS51SINGLECHIPP1PORT,THEDRIVERCONNECTEDWITH8LIGHTEMITTINGDIODES,FOSC6MHZ,TRYTOWRITEPROCEDURES,SOTHATTHE8LIGHTEMITTINGDIODESEVERY2SECONDSCYCLEOFLIGHT20POINTSMOVTMOD,10MOVJAN,OD8HMOVTL1,0E0HSETBTR1MOV,80HAG1MOVP1,AMOVR7,100AG2JBCTF1,AG3SJMPAG2AG3MOVJANUARY,OD8HMOVTL1,0E0HDJNZR7,AG2RRASJMPAG1BONE,ONE,FILLINTHEBLANKS1POINTSPERMINUTE,20POINTS1THESYSTEMBUSOFTHECOMPUTERHASADDRESSBUS,CONTROLBUSAND2USUALLY,THEPCSP,ONTHEPOWERONRESETOFTHESINGLECHIPMICROCOMPUTER,WHILETHEWORKINGREGISTERDEFAULTSTOGROUPONE,ANDTHEADDRESSRANGEOFTHEREGISTERISFROMTHEOPCODEADDRESSIS1000H3,JZE,E20H,ANDTHEDESTINATIONADDRESSOFITIS4,ASSEMBLYLANGUAGECANUSEPSEUDOINSTRUCTIONS,THEYARENOTREALINSTRUCTIONS,BUTONLYFORSOMEKINDOFCONTROL5,ASSUMETHECONTENTSOFTHEACCUMULATOR30HA,EXECUTEINSTRUCTIONS1000HMOVCAA,PCAFTERTHAT,THECONTENTSOFTHEPROGRAMMEMORYUNITARESENTTOTHEACCUMULATORA6,MCS51SINGLECHIPMICROCOMPUTERACCESSTOEXTERNALMEMORY,THEUSEOFSIGNALLATCHFROMTHEMOUTHOFTHELOW8BITADDRESSSIGNAL7,MCS51MICROCONTROLLER8031HASABITTIMER/COUNTER,CANBESETTOWORKINAWAY8,MCS51SINGLECHIPMICROCOMPUTERHASAINTERRUPTSOURCE,CANBEDIVIDEDINTOINTERRUPTPRIORITYPOWERUPRESET,INTERRUPTSOURCEINTERRUPTLEVELISTHEHIGHEST9,USETHESERIALPORTEXTENDEDPARALLELPORT,SERIALINTERFACEMODESHOULDBE10THETWOMOSTIMPORTANTINDEXESOFSEMICONDUCTORMEMORYARESUM11IFTHEOUTPUTVOLTAGEOFA8BITD/ACONVERTERIS5V,THERESOLUTIONOFTHED/ACONVERTERISASFOLLOWS12,WHENWRITINGTHE8255ACONTROLWORD,YOUNEEDTOSETA1ANDA0ASTWO,CHOOSEAQUESTIONCHOOSEACORRECTANSWERFROMTHEALTERNATIVEANSWER,ANDWRITETHECODEINPARENTHESESEACHITEMIS1POINTS,ATOTALOF10POINTS1INCPU,SOMEOFTHECHARACTERISTICREGISTERSTHATREFLECTTHESTATEOFTHEPROGRAMORREFLECTTHERESULTSOFTHEOPERATIONARE1PSWPCBCDSP2,TOVISITTHEMCS51CHIPRAMTRANSFERINSTRUCTIONOPCODEMNEMONICINSTRUCTIONITIS1MOVMOVXBCDABOVEISMOVC3THEJUMPRANGEOFINSTRUCTIONALMPIS1256B1KBBCD64KB2KB4,TOENABLEMCS51TORESPONDTOTHETIMERT1INTERRUPT,THESERIALINTERFACEINTERRUPT,ITSINTERRUPTALLOWSREGISTERIECONTENTSHOULDBE198H84HBCD22H42H5INTERRUPTREQUESTSIGNALSISSUEDBYEACHINTERRUPTSOURCEARERECORDEDINTHEMCS51SYSTEM1IEIPBCDSCONTCON6,CPUADDRESSINGPERIPHERALSPORTADDRESSTWOWAYS,ONEISTHEUNIFIEDADDRESSING,ANDTHEOTHERISAHYBRIDADDRESSINGBDYNAMICADDRESSINGCINDEPENDENTADDRESSINGDINDEXEDADDRESSING7INTHEFOLLOWINGFOURNARRATIVES,ONEOFTHEMISTAKESISATHEADDRESSSPACEOF16ADDRESSLINESISUPTO1MBBTHESTORAGEUNITOFTHEMEMORYISBYTEADDRESSABLECTHEREGISTERUSEDTOSTOREADDRESSINCPUISCALLEDADDRESSREGISTERDONLYADDRESSINFORMATIONCANBETRANSMITTEDOVERTHEADDRESSBUS8,WHENMCS51EXPANDSA8255,ITNEEDSTOOCCUPYPORTADDRESSA1B2C3D49,WHENTHEMCS51PORTISUSEDTOEXTENDTHEPARALLELI/OPORT,THESERIALPORTSHOULDBESELECTEDAMODE0BMODE1CMODE2DMODE310,AMEMORYCHIPISA8KB4/CHIP,THENTHEROOTOFITSADDRESSLINEISA11ROOTSB,12ROOTSC,13ROOTSD,14ROOTSFOURREADORWRITEPROGRAMS15POINTS1READTHEFOLLOWINGPARAGRAPHSANDANSWERTHEQUESTIONS1WHATKINDOFOPERATIONDOESTHEPROGRAMPERFORM2,THEKNOWNINITIALVALUE60H23H,61H61H,ANDAFTERTHEPROGRAM62HCLRCMOVA,9AHSUBBA,60HADDA,61HDAAMOV62H,A2WRITEAPROGRAMTOCLEARALLTHE7000H70FFHUNITSINTHEOUTOFDATEDATAMEMORY8POINTSFIVE,MCS51MICROCONTROLLEREXPANSIONOFAPIECEOF8255,DRAWTHESYSTEMCIRCUITSCHEMATICS,WRITEADDRESSDISTRIBUTION15POINTSSIX,MCS51MICROCONTROLLERP1PORT,THEDRIVERCONNECTEDWITH8LIGHTEMITTINGDIODES,FOSC6MHZ,TRYTOWRITEPROCEDURES,SOTHATTHE8LIGHTEMITTINGDIODESEVERY2SECONDSCYCLEOFLIGHT20POINTS“SINGLECHIPMICROCOMPUTERPRINCIPLEANDAPPLICATION“EXAMINATIONPAPERBREFERENCEANSWERSFIRST,FILLINTHEBLANKS1POINTSPERMINUTE,20POINTS1,DATABUS2,PC0000H,SP07H0000H07H3,1022H4,ASSEMBLYPROCESSFORSOMEKINDOFCONTROL5,1031H6,ALE,P07,216,FOUR,8,5,2EXTERNALINTERRUPT09,MODE010,STORAGECAPACITYANDSTORAGESPEED11,5/25500196V12,11TWO,CHOOSEAQUESTIONCHOOSEACORRECTANSWERFROMTHEALTERNATIVEANSWER,ANDWRITETHECODEINPARENTHESES1POINTSFOREACHQUESTION,10POINTS1,B2,B3,C4,A5,B6,C7,A8,D9,A10,CTHREE,QUESTIONSANDANSWERS5POINTS,20POINTSEACH1WHATISTHERELATIONSHIPBETWEENTHECLOCKCYCLEANDTHEOSCILLATIONPERIODOFMCS51MICROCONTROLLERHOWTODIVIDETHETIMESEQUENCEOFAMACHINECYCLEANSWERCLOCKCYCLEISTHEMOSTBASICUNITOFTIMEOFSCMTHEMACHINECYCLEISTHETIMEREQUIREDTOCOMPLETEASPECIFIEDOPERATIONAMACHINECYCLEIS6CLOCKCYCLES,ATOTALOF12OSCILLATIONPERIODICITY,INTURNEXPRESSEDASS1P1,S1P2,S6P1,S6P22WHATARETHESIMILARITIESANDDIFFERENCESBETWEENTHEFOURPARALLELI/OPORTSWITHINMCS51WHATISTHEFUNCTIONATHEMCS51MICROCONTROLLERHASFOUR8BITBIDIRECTIONALPARALLELI/OPORTS,EACHOFWHICHCONSISTSOFALATCH,ANOUTPUTDRIVERANDANINPUTBUFFERBUTTHEFOURFUNCTIONSOFTHEPORTARENOTALLTHESAME,THEP0PORTCANBEUSEDASAGENERALI/OPORT,BUTALSOCANBEUSEDASADDRESS/DATABUSP1PORTISAQUASIBIDIRECTIONALPARALLELPORT,ASAGENERALPARALLELI/OPORTTOUSEINADDITIONTOP2CANBEUSEDASAUNIVERSALI/OUSE,CANALSOACCESSTHEEXTERNALMEMORYINCPUHIGHEIGHTADDRESSLINESP3ISAMULTIFUNCTIONALPORTINADDITIONTOAQUASIBIDIRECTIONALI/OFUNCTION,BUTALSOHASSECONDFUNCTIONS3BRIEFLYDESCRIBETHEINTERRUPTRESPONSEPROCESSOFMCS51SINGLECHIPMICROCOMPUTERANSWERCPUSEQUENTIALLYSAMPLESEACHINTERRUPTSOURCEDURINGEACHS5P2OFTHEMACHINECYCLE,ANDCHECKSTHEINTERRUPTFLAGINTHEORDEROFPRIORITYINTHENEXTMACHINECYCLES6INTERVAL,SUCHASTHEQUERYTOANINTERRUPTFLAGIS1,THEINTERRUPTWILLBEPROCESSEDBYPRIORITYINTHENEXTMACHINECYCLES1,ANDTHEINTERRUPTSYSTEMWILLAUTOMATICALLYSENDTHECORRESPONDINGINTERRUPTVECTORADDRESSTOTHEPCTHROUGHTHEHARDWARE,SOASTOENTERTHECORRESPONDINGINTERRUPTSERVICEPROGRAMONCETHEINTERRUPT,CPUFIRSTSETTHECORRESPONDINGINTERRUPTPRIORITYTRIGGER“,ANDTHENBYTHEHARDWAREIMPLEMENTATIONOFALONGCALLINSTRUCTION,THECURRENTPCVALUEINTOTHESTACK,INORDERTOPROTECTTHEENTRANCEADDRESSBREAKPOINT,ANDTHENTHERESPECTIVEINTERRUPTSERVICEINTOPC,ANDTHENFROMTHECPUINTERRUPTSERVICEPROGRAMSTARTSTOEXECUTEFORSOMEINTERRUPTSOURCES,CPUAUTOMATICALLYCLEARSTHEINTERRUPTFLAGAFTERTHERESPONSEISINTERRUPTEDWHATISTHEFUNCTIONOFTHESAMPLEANDHOLDCIRCUITIN4ANDA/DCONVERSIONINTERFACEWHATARETHEPRECONDITIONSFOROMITTINGTHESAMPLEANDHOLDCIRCUITANSWERTHEFUNCTIONOFTHESAMPLEANDHOLDCIRCUITINTHEA/DCONVERSIONINTERFACEISTOCONVERTATIMEEDGESIGNALINTOATIMEDISCRETESIGNAL,AN