單片機(jī)系統(tǒng)-畢業(yè)論文外文翻譯

1、1外文原文外文原文Microcomputersystemronicsystemsareusedfhinginfmationinthemostgeneralsensethisinfmationmaybetelephoneconversationinstrumentreadacompanysaccountsbutineachcasethesamemaintypeofoperationareinvolved:theprocessingstag

2、etransmissionofinfmation.inconventionalelectronicdesigntheseoperationsarecombinedatthefunctionlevelfexampleacounterwhetherelectronicmechanicalstesthecurrentincrementsitbyoneasrequired.Asystemsuchasanelectronicclockwhiche

3、mployscountershasitsstageprocessingcapabilitiesspreadthroughoutthesystembecauseeachcounterisabletosteprocessnumbers.Presentdaymicroprocessbasedsystemsdepartfromthisconventionalapproachbyseparatingthethreefunctionsofproce

4、ssingstagetransmissionintodifferentsectionofthesystem.ThispartitioningintothreemainfunctionswasdevisedbyVonNeumannduringthe1940swasnotconceivedespeciallyfmicrocomputers.Almosteverycomputerevermadehasbeendesignedwiththiss

5、tructuredespitetheenmousrangeintheirphysicalfmstheyhaveallbeenofessentiallythesamebasicdesign.Inamicroprocessbasedsystemtheprocessingwillbeperfmedinthemicroprocessitself.Thestagewillbebymeansofmemycircuitsthecommunicatio

6、nofinfmationintooutofthesystemwillbebymeansofspecialinputoutput(IO)circuits.Itwouldbeimpossibletoidentifyaparticularpieceofhardwarewhichperfmedthecountinginamicroprocessbasedclockbecausethetimewouldbestedinthememyincreme

7、ntedatregularintervalsbutthemicroprocess.Howeverthesoftwarewhichdefinedthesystemsbehaviwouldcontainsectionsthatperfmedascounters.Theapparentlyratherabstractapproachtothearchitectureofthemicroprocessitsassociatedcircuitsa

8、llowsittobeveryflexibleinusesincethesystemisdefinedalmostentirelysoftware.Thedesignprocessislargelyoneofsoftwareengineeringthesimilarproblemsofconstructionmaintenancewhichoccurinconventionalengineeringareencounteredwhenp

9、roducingsoftware.Thefigure1.1illustrateshowthesethreesectionswithinamicrocomputerareconnectedintermsofthecommunicationofinfmationwithinthemachine.Thesystemiscontrolledbythemicroprocesswhichsupervisesthetransferofinfmatio

10、nbetweenitselfthememyinputoutputsections.Theexternalconnectionsrelatetotherest(thatisthe3flowofinfmationtofrommemyinputoutputdevices.Someinputoutputdevicesaregeneralpurposetypeswhileothersaredesignedfcontrollingspecialha

11、rdwaresuchasdiscdrivescontrollinginfmationtransmissiontoothercomputers.MosttypesofIOdevicesareprogrammabletosomeextentallowingdifferentmodesofoperationwhilesomeactuallycontainspecialpurposemicroprocessstopermitquitecompl

12、exoperationstobecarriedoutwithoutdirectlyinvolvingthemainmicroprocess.Themicroprocessmemyinputoutputcircuitmayallbecontainedonthesameintegratedcircuitprovidedthattheapplicationdoesnotrequiretoomuchprogramdatastage.Thisis

13、usuallythecaseinlowcostapplicationsuchasthecontrollersusedinmicrowaveovensautomaticwashingmachines.Theuseofsinglepackageallowsconsiderablecostsavingstoemadewhenarticlesaremanufacturedinlargequantities.Astechnologydevelop

14、smemepowerfulprocessslargerlargeramountsofmemyarebeingincpatedintosinglechipmicrocomputerswithresultingsavinginassemblycostsinthefinalproducts.Fthefeseeablefuturehoweveritwillcontinuetobenecessarytointerconnectanumberofi

15、ntegratedcircuitstomakeamicrocomputerwheneverlargeramountsofstageinputoutputarerequired.Anothermajengineeringapplicationofmicrocomputersisinprocesscontrol.Herethepresenceofthemicrocomputerisusuallymeapparenttotheuserbeca

16、useprovisionisnmallymadefprogrammingthemicrocomputerftheparticularapplication.Inprocesscontrolapplicationsthebenefitsiffittingtheentiresystemontosinglechipareusuallyoutweighedbythehighdesigncostinvolvedbecausethisstifequ

17、ipmentisproducedinsmallerquantities.Meoverprocesscontrollersareusuallymecomplicatedsothatitismedifficulttomakethemassingleintegratedcircuits.Twoapproachesarepossiblethecontrollercanbeimplementedasageneralpurposemicrocomp

18、uterratherlikeamerobustversionifahobbycomputerasapackagedsystemsignedfreplacingcontrollersbasedonoldertechnologiessuchaselectromagicrelays.Inthefmercasethesystemwouldprobablybeprogrammedinconventionalprogramminglanguages

19、suchastheonesto9beintroducedlaterwhileintheothercaseaspecialpurposelanguagemightbeusedfexampleonewhichallowedthefunctionofthecontrollertobedescribedintermsofrelayinterconnections.IneithercaseprogramscanbestedinRAMwhichal

20、lowsthemtobealteredtosuitchangesinapplicationbutthismakestheoverallsystemvulnerabletolossifpowerunlessbatteriesareusedtoensurecontinuityofsupply.AlternativelyprogramscanbestedinROMinwhichcasetheyvirtuallybecomepartofthee