電氣工程及其自動(dòng)化專業(yè)外文文獻(xiàn)英文文獻(xiàn)外文翻譯方面

1、外文原文（復(fù)印件）A:FundamentalsofSingle-chipMicrocomputerThesingle-chipmicrocomputeristhecuIminationofboththedevelopmentofthedigitalcomputerandtheintegratedcircuitarguablythetowmostsignificantinventionsofthe20thcentury[1].Thesetowtypesofarchitecturearefoundinsingle-chipmicrocomputer.Someemploythesplitprogram/datamemoryoftheHarvardarchitecture,shownin-5A,othersfollowthephilosophy,widelyadaptedforgeneral-purposecomputersandmicroprocessors,ofmakingnologicaldistinctionbetweenprogramanddatamemoryasinthePrincetonarchitecture,shownin-5A.Ingeneraltermsasingle-chipmicrocomputerischaracterizedbytheincorporationofalltheunitsofacomputerintoasingledevice,asshowninFig3-5A-3.-5A-1AHarvardtype-5A.AconventionalPrincetoncomputerFig3-5A-3.PrincipalfeaturesofamicrocomputerReadonlymemory(ROM).roMisusuallyforthepermanent,non-volatilestorageofanapplicationsprogram.Manymicrocomputersandmicrocontrollersareintendedforhigh-volumeapplicationsandhencetheeconomicalmanufactureofthedevicesrequiresthatthecontentsoftheprogrammemorybecommittedpermanentlyduringthemanufactureofchips.Clearly,thisimpliesarigorousapproachtoROMcodedevelopmentsincechangescannotbemadeaftermanufacture.Thisdevelopmentprocessmayinvolveemulationusingasophisticateddevelopmentsystemwithahardwareemulationcapabilityaswellastheuseofpowerfulsoftwaretools.SomemanufacturersprovideadditionalROMoptionsbyincludingintheirrangedeviceswith(orintendedforusewith)userprogrammablememory.Thesimplestoftheseisusuallydevicewhichcanoperateinamicroprocessormodebyusingsomeoftheinput/outputlinesasanaddressanddatabusforaccessingexternalmemory.ThistypeofdevicecanbehavefunctionallyasthesinglechipmicrocomputerfromwhichitisderivedalbeitwithrestrictedI/Oandamodifiedexternalcircuit.TheuseoftheseROMlessdevicesiscommoneveninproductioncircuitswherethevolumedoesnotjustifythedevelopmentcostsofcustomon-chipROM[2];therecanstillbeasignificantsavinginI/Oandotherchipscomparedtoa

conventionalmicroprocessorbasedcircuit.MoreexactreplacementforROMdevicescanbeobtainedintheformofvariantswith'piggy-back'EPROM(ErasableprogrammableROM)socketsordeviceswithEPROMinsteadofROM。ThesedevicesarenaturallymoreexpensivethanequivalentROMdevice,butdoprovidecompletecircuitequivalents.EPROMbaseddevicesarealsoextremelyattractiveforlow-volumeapplicationswheretheyprovidetheadvantagesofasingle-chipdevice,intermsofon-chipI/O,etc.,withtheconvenienceofflexibleuserprogrammability.Randomaccessmemory(RAM).ramisforthestorageofworkingvariablesanddatausedduringprogramexecution.Thesizeofthismemoryvarieswithdevicetypebutithasthesamecharacteristicwidth(4,8,16bitsetc.)astheprocessor,Specialfunctionregisters,suchasstackpointerortimerregisterareoftenlogicallyincorporatedintotheRAMarea.ItisalsocommoninHarardtypemicrocomputerstotreattheRAMareaasacollectionofregister;itisunnecessarytomakedistinctionbetweenRAMandprocessorregisterasisdoneinthecaseofamicroprocessorsystemsinceRAMandregistersarenotusuallyphysicallyseparatedinamicrocomputer.Centralprocessingunit(CPU)gecpuismuchlikethatofanymicroprocessor.Manyapplicationsofmicrocomputersandmicrocontrollersinvolvethehandlingofbinary-codeddecimal(BCD)data(fornumericaldisplays,forexample),henceitiscommontofindthattheCPUiswe11adaptedtohandlingthistypeofdata.Itisalsocommontofindgoodfacilitiesfortesting,settingandresettingindividualbitsofmemoryorI/Osincemanycontrollerapplicationsinvolvetheturningonandoffofsingleoutputlinesorthereadingthesingleline.Theselinesarereadilyinterfacedtotwo-statedevicessuchasswitches,thermostats,solid-staterelays,valves,motor,etc.varyParallelinput/output.parallelinputandoutputschemessomewhatindifferentmicrocomputer;inmostamechanismisprovidedtoatleastallowsomeflexibilityofchoosingwhichpinsareoutputsandwhichareinputs.Thismayapplytoallorsomeoftheports.SomeI/Olinesaresuitablefordirectinterfacingto,forexample,fluorescentdisplays,orcanvaryprovidesufficientcurrenttomakeinterfacingothercomponentsstraightforward.SomedevicesallowanI/Oporttobeconfiguredasasystembustoallowoff-chipmemoryandI/Oexpansion.Thisfacilityispotentiallyusefulasaproductrangedevelops,sincesuccessiveenhancementsmaybecometoobigforon-chipmemoryanditisundesirablenottobuildontheexistingsoftwarebase.Serialinput/outputSerialcommunicationwithterminaldevicesis

Serialinput/outputSerialcommunicationwithterminaldevicesiscommonmeansofprovidingalinkusingasmallnumberoflines.Thissortofcommunicationcanalsobeexploitedforinterfacingspecialfunctionchipsorlinkingseveralmicrocomputerstogether.Boththecommonasynchronoussynchronouscommunicationschemesrequireprotocolsthatprovideframing(startandstop)information.ThiscanbeimplementedasahardwarefacilityorU(S)ART(Universal(synchronous)asynchronousreceiver/1ransmitter)relievingtheprocessor(andtheapplicationsprogrammer)ofthislow-level,time-consuming,detail.tismerelynecessarytoselectedabaud-rateandpossiblyotheroptions(numberofstopbits,parity,etc.)andload(orreadfrom)theserialtransmitter(orreceiver)buffer.Serializationofthedataintheappropriateformatisthenhandledbythehardwarecircuit.Timing/cOUnterfacilities.Manyapplicationofsingle-chipmicrocomputersrequireaccurateevaluationofelapsedrealtime.Thiscanbedeterminedbycarefulassessmentoftheexecutiontimeofeachbranchinaprogrambutthisrapidlybecomesinefficientforallbutsimplestprograms.Thepreferredapproachistousetimercircuitthatcanindependentlycountprecisetimeincrementsandgenerateaninterruptafterapresettimehaselapsed.Thistypeoftimerisusuallyarrangedtobereloadablewiththerequiredcount.Thetimerthendecrementsthisvalueproducinganinterruptorsettingaflagwhenthecounterreacheszero.Bettertimersthenhavetheabilitytoautomaticallyreloadtheinitialcountvalue.Thisrelievestheprogrammeroftheresponsibilityofreloadingthecounterandassessingelapsedtimebeforethetimerrestarted,whichotherwisewoundbe necessary ifcontinuouspreciselytimedinte rru ptswererequired(asin aclock,fo rexample).Sometimesassociated wit h timerisaneventcounter. WiththisfacilitythereisusuallyaspecialinputTimingcomponents.ThTimingcomponents.Theclockcircuitryofmostmicrocomputersrequiresonlysimpletimingcomponents.Ifmaximumperformanceisrequired,acrystalmustbeusedtoensurethemaximumclockfrequencyisapproachedbutnotexceeded.Manyclockcircuitsalsoworkwitharesistorandcapacitoraslow-costtimingcomponentsorcanbedrivenfromanexternalsource.Thislatterarrangementisusefulisexternalsynchronizationofthemicrocomputerisrequired.WORDSANDTERMSculmination門.頂點(diǎn)spiltadj.分離的volatilen.易變的commitv保證albeitconj.雖然customadj.定制的variantadj.不同的piggy-backadj.背負(fù)式的socketn.插座B:PLC[1]PLCs(programmablelogicalcontroller)faceevermorecomplexchallengesthesedays.Whereoncetheyquietlyreplacedrelaysandgaveanoccasionalreporttoacorporatemainframe,theyarenowgroupedintocells,givennewjobandnewlanguages,andareforcedtocompeteagainstagrowingarrayofcontrolproducts.Forthisyear'sannualPLCtechnologyupdate,wequeriedPLCmakersonthesetopicsandmore.ProgramminglanguagesHigherlevelPLCprogramminglanguageshavebeenaroundforsometime,butlatelytheirpopularityhasmushrooming."AsRaymondLeveille,vicepresident&generalmanager,SiemensEnergy&Automation.inc;Programmablecontrolsarebeingusedformoreandmoresophisticatedoperations,languagesotherthanladderlogicbecomemorepractical,efficient,andpowerful.Forexample,it'sverydifficulttowriteatrigonometricfunctionusingladderlogic."LanguagesgainingacceptanceincludeBoolean,controlsystemflowcharting,andsuchfunctionchartlanguagesasGraphcetanditsvariation.Andthere'sincreasinginterestinlanguageslikeCandBASIC.PLCsinprocesscontrolThusfar,PLCshavenotbeenusedextensivelyforcontinuousprocesscontrol.Willthiscontinue"ThefeelingthatI'vegotten,"saysKenJannotta,manger,productplanning,seriesOneandSeriesSixproduct,atGEFanucNorthAmerica,'isthatPLCswillbeusedintheprocessindustrybutnotnecessarilyforprocesscontrol."Severalvendors-obviouslybettingthattheoppositewillhappen-haveintroducedPLCsoptimizedforprocessapplication.RichRyan,manger,commercialmarketing,Allen-bradleyProgrammableControlsDiv.,citesPLCs'sincreasingusesuchindustriesasfood,chemicals,andpetroleum.Ryanfeelstherearetwotypesofapplicationsinwhichthey'reappropriate."one,"hesays,"iswherethesizeoftheprocesscontrolsystemthat'sbeingautomateddoesn'tjustifyDCS[distributedcontrolsystem].Withthestartingpricetagsofchoseproductsbeingrelativelyhigh,aprogrammablecontrollermakessenseforsmall,lowloopcountapplication.Thesecondiswhereyouhavetointegratetheloopcloselywiththesequentiallogical.Batchcontrollersareprimeexample,wherethesequenceandmaintainingtheprocessvariableareintertwinedsocloselythatthebenefitsofhavingaprogrammablecontrollertodothesequentiallogicaloutweighssomeofthedisadvantagesofnothavingadistributedcontrolsystem."BillBarkovitz,presidentofTriconex,predictsthat"allfuturecontrollersthatcomeoutintheprocesscontrolsystembusinesswillembracealotofmorePLCtechnologyandalotmorePLCfunctionalitythantheyeverdidbefore."CommunicationsandMAPCommunicationsarevitaltoanindividualautomationcellandtobeautomatedfactoryasawhole.We'veheardalotaboutMAPinthelastfewyears,andalotofcompanieshavejumpedonthebandwagon.[2]Many,however,weredisappointedwhenafully-definedandcompletedMAPspecificationdidn'tappearimmediately.SaysLarryKomarek:"Rightnow,MAPisstillamovingtargetforthemanufacturers,aspecificationthatisnotfinal.Presently,forexample.peopleareintroducingproductstomeetthe.productswillbeobsoletewhenthenewstandardforisintroduced."Becauseofthis,manyPLCvendorsareholdingoffonfullMAPimplementations.Omron,forexample,hasanongoingMAP-compatibilityprogram;[3]butFrankNewburn,vicepresidentofOmron'sIndustrialDivision,reportsthatbecauseofthelackofafirmdefinition,Omron'sPLCsdon'tyettalktoMAP.Sinceit'sunlikelythatanindividualPLCwouldtalktobroadMAPanyway,makersareconcentratingonproprietarynetworks.AccordingtoSalProvanzano,usersfearthatiftheydogetonboardandvendorswithdrawfromMAP,they'llbetheonesleftholdingacommunicationsstructurethat'snotsupported.UniversalI/OWhilethereareconcernsaboutthelackofcompatiblecommunicationsbetweenPLCsfromdifferentvendors,theconnectionattheotherend-theI/O-isevenmorefragmented.Withrareexceptions,I/Oisstillproprietary.YettherearethosewhofeelthatI/Owilleventuallybecomemoreuniversal.GEFanucishopingtodothatwithitsGeniussmartI/Oline.TheindependentI/Omakersarepullinginthesamedirection.ManysaythatI/Oissuchahigh-valueitemthatPLCmakerswillalwayswanttokeepitproprietary.AsKenJannotta,says:"TheI/Oisgoingtobeadisproportionateamountofthehardwaresale.CertainlyeachPLCvendorisgoingtotrytoprotectthat."Forthatreason,hesays,PLCmakerswon'tbeginsellinguniversalI/Osystemfromothervendor."ifwestartsellingthatkindofproduct,"saysjannotta,"whatdowemanufacture"WithmoreintelligentI/Oappearing,SalProvanzanofeelsthiswillleadtomoredifferentiationamongI/Ofromdifferentmakers."WheretheI/Obecomesextremelyintelligentandbecomespartofthesystem,"hesays,"itreallyishardtodefinewhichistheI/OandwhichisCPU.ItreallyCPU,ifyouwill,isequallyintegratedintothesystemastheI/O."ConnectingPLCI/OtoPCsWhiledifferentPLCsprobablywillcontinuetouseproprietaryI/O,severalvendorsmakeitpossibletoconnectstheirI/OtoIBMPC-compatibleequipment.Alle-bradeley,Could,andCincinnatiMilacronalreadyhave,andrumorhasitthatGEisplanningsomethingalongthesesamelines.[4]Bi11Ketelhut,manageofproductplanningatGEFanucNorthAmerica,seesthissortofthingasalternativetouniversalI/O."Ithinkthetrend,insteadoftowarduniversalI/O,wi11bemultiplehostinterface,"hesays.JodieGlore,directorofmarking,SquareDAutomationProducts,ViewsitasanotherindicationthatPLCsare,andhavebeenforsometime,industrialcomputers.PLCsVSPCsIftheIBM7552,theActionInstrumentsBC22,andothercomputersareappearingonthefactoryfloor,won'tthismeannewcompetitionforPLCsRichRyan:"Therearesomecontrolfunctionsthatarebetterjobsforcomputers.Programmablecontrollershavebeenforcedtofitintothoseapplications."Yet,themajorityofvendorswesurveyeddon'tlikethe"PCinvasion"willposeaproblemforthem.MostsaidthatPLCsandPCsareenoughapartinarchitecturethattheywillusuallydothecontrol.Theydon'tfeelthatPCswilltakejobsfromPLCsjustbecausePLCI/OmodulescannowbeconnectedtoPCs;theybelievethissimplymeansthatPLCsandPCswillbeabletosharethesamedata."Thereareinherentarchitecturaldifferencesbetweenageneralpurposecomputer,"saysRichRyan,"andaprogrammablecontroller.Therearehardwareconstructsbuiltintoalmosteverymanufacture'sprogrammablecontrollertodaythatcustomizethehardwareto ru n ladderlogicandtosolvemachinecode."Onefundamentaldifferencehe c itesiscalledstateofthemachine.Ryan:"Whenyoushutthemachine off, orinterruptthecycle,oryoujumptoanotherspotinthecycle,programmablecontrollersinherentlyrememberthestateofthemachine:whatthetimerswere,whatthecounterswere,whatthestatesofallthelatcheswere.Computersdon'tinherentlydothat."WORDSANDTERMSbetv.確信optimizedn.優(yōu)化程序corporateadj.共同的mushroom▼.迅速發(fā)展trigonometricfunction三角函數(shù)vendor門.廠商tagn.標(biāo)簽smartadj.智能型的compatibleadj.兼容的2、外文資料翻譯譯文單片機(jī)基礎(chǔ)單片機(jī)是電腦和集成電路發(fā)展的巔峰，有據(jù)可查的是他們也是20世紀(jì)最有意義的兩大發(fā)明。這兩種特性在單片機(jī)中得到了充分的體現(xiàn)。一些廠家用這兩種特性區(qū)分程序內(nèi)存和數(shù)據(jù)內(nèi)存在硬件中的特性，如圖3-5A-1，依據(jù)同樣的原理廣泛的適用于一般目的的電腦和微電腦，一些廠家在程序內(nèi)存和數(shù)據(jù)內(nèi)存之間不區(qū)分的像Princeton特性，展示如圖3-5A-2.只讀存貯器（ROM）.ROM是通常的永久性的，非應(yīng)用程序的易失性存儲(chǔ)器。不少微機(jī)和單片機(jī)用于大批量應(yīng)用，因此，經(jīng)濟(jì)的設(shè)備制造要求的程序存儲(chǔ)器的內(nèi)容是在制造期間永久性的刻錄在芯片中，這意味著嚴(yán)謹(jǐn)?shù)姆椒?，因?yàn)樾薷腞OM代碼不能制造之后發(fā)展。這一發(fā)展過程可能涉及仿真,使用硬件仿真功能以及強(qiáng)大的軟件工具使用先進(jìn)的開發(fā)系統(tǒng)。一些制造商在其提供的設(shè)備包括的范圍（或擬使用）用戶可編程內(nèi)存.其中最簡單的通常是設(shè)備能夠運(yùn)行于微處理器模式通過使用一些輸入/輸出作為地址線額外的ROM選項(xiàng)和數(shù)據(jù)總線訪問外部內(nèi)存.這種類型的設(shè)備可以表現(xiàn)為單芯片微型計(jì)算機(jī)盡管有限制的I/O和外部修改這些設(shè)備的電路.小內(nèi)存裝置的應(yīng)用是非常普遍的在永久性內(nèi)存的制造中[2];但仍然可以在我節(jié)省大量成本I/O和其它芯片相比，傳統(tǒng)的基于微處理器電路.更準(zhǔn)確的ROM設(shè)備更換，可在與'形式變種背馱式'EPROM（可擦除可編程只讀存儲(chǔ)器）插座或存儲(chǔ)器，而不是ROM器件。這些器件自然價(jià)格比同等ROM設(shè)備貴，但不提供完整的等效電路.EPROM的設(shè)備也非常有吸引力對于低容量應(yīng)用中，他們提供的單芯片器件的優(yōu)勢，在以下方面的板載I/O等，在靈活的用戶可編程帶來的便利。隨機(jī)存取存儲(chǔ)器（RAM）。RAM用于變量和工作在程序使用該存儲(chǔ)器的執(zhí)行.隨數(shù)據(jù)存儲(chǔ)設(shè)備的大小不同類型而有所不同，但具有相同的特征寬度（4,8,16比特等）作為處理器。特殊功能寄存器，如棧指針或定時(shí)器寄存器，往往邏輯納入內(nèi)存區(qū)域.它也在型微電腦的硬件中做集中內(nèi)存，它是不必要的區(qū)分內(nèi)存和處理器之間的區(qū)別在通常不物理上分開的微機(jī)中。中央處理單元（CPU）。CPU是很象微型電子計(jì)算機(jī)和微控制器的任何微電腦.許多微電腦和微控制器涉及到二進(jìn)制編碼（十進(jìn)制處理（BCD）的數(shù)據(jù)為例）數(shù)字顯示，因而，常?？梢园l(fā)現(xiàn)該CPU是很適合處理這種類型的數(shù)據(jù)。對設(shè)施良好與否進(jìn)行的測試，設(shè)置和重置單個(gè)位的內(nèi)存或I/O控制器的應(yīng)用程序，也是常見的因?yàn)樵S多涉及打開和關(guān)閉的單輸出線或在單線.這些線很容易連接到二進(jìn)制的設(shè)備，如開關(guān)，恒溫器，固態(tài)繼電器，閥門，電機(jī)等并行輸入/輸出.并行輸入和輸出的計(jì)劃有所不同，在不同的微機(jī)，在大多數(shù)設(shè)立一個(gè)機(jī)制，至少選擇讓其中一些引腳輸出，一些引腳輸如是非常靈活的。這可能適用于所有或端口.有些I/O線直接連接到適當(dāng)?shù)脑O(shè)備，例如，熒光顯示器，也可以提供足夠的電流，使接口和其他設(shè)備直接相連.一些設(shè)備允許一個(gè)I/O端口,其他組件將作為系統(tǒng)總線配置為允許片外存儲(chǔ)器和I/O擴(kuò)展。這個(gè)設(shè)施是潛在有用的一個(gè)產(chǎn)品系列的發(fā)展，因?yàn)檫B續(xù)增強(qiáng)可能成為太上存儲(chǔ)器，這是不可取的，不是建立在現(xiàn)有的軟件基礎(chǔ)上的。串行輸入/輸出。串行通信是指與終端設(shè)備的鏈接使用少量的通訊線.這種通訊也可利用特殊的接口連接功能芯片使幾個(gè)微型機(jī)連在一起。雙方共同異步同步通信方案要求的規(guī)則提供成幀（啟動(dòng)和停止）的信息。這可以作為一個(gè)硬件設(shè)施或U（擰）藝術(shù)（通用執(zhí)行（同步）異步接收器/發(fā)送器）減輕處理器（和應(yīng)用程序）的這種低層次的確費(fèi)時(shí).它也只需要選擇一個(gè)波特率及其他可能的選擇（停止位，奇偶校驗(yàn)等）和負(fù)載號碼（或讀?。?，串行發(fā)送器（或接收）的緩沖器.進(jìn)行適當(dāng)?shù)母袷降臄?shù)據(jù)串行處理，然后由硬件電路完成。定時(shí)/計(jì)數(shù)器設(shè)施。許多應(yīng)用的單片機(jī)需要對過去的真實(shí)時(shí)間準(zhǔn)確的評價(jià)。這可以由每個(gè)程序中的執(zhí)行時(shí)間分支認(rèn)真評估，但除最簡單的程序外，他的工作效率不高。首選方法是使用計(jì)時(shí)器電路，能獨(dú)立計(jì)算精確的時(shí)間增量，并生成一個(gè)預(yù)設(shè)的時(shí)間后中斷的時(shí)間。這種類型的定時(shí)器通常在所要求的數(shù)量可重載中應(yīng)用。計(jì)時(shí)器然后減少此值產(chǎn)生中斷或設(shè)置標(biāo)記時(shí)，計(jì)數(shù)器到達(dá)零.更好的計(jì)時(shí)器有自動(dòng)加載初始值的功能。這將緩解重新加載計(jì)數(shù)器和評估所用的時(shí)間，計(jì)時(shí)器重新啟動(dòng)之前這是必要的。有時(shí)候與定時(shí)器相關(guān)的是一個(gè)事件計(jì)數(shù)器。這個(gè)設(shè)備通常有一個(gè)特殊的輸入引腳，可直接驅(qū)動(dòng)計(jì)數(shù)器。定時(shí)元件。大多數(shù)微型計(jì)算機(jī)時(shí)鐘電路只需要簡單的計(jì)時(shí)元件.如果要求最高性能，必須使用晶體以確保最大時(shí)鐘頻率接近，但不會(huì)超出。許多時(shí)鐘電路，還具有電阻和低電容工作成本定時(shí)元件，也可以從外部源驅(qū)動(dòng)。這后一種安排是有用的在微機(jī)外部同步是必需的時(shí)候。B:PLC[1]今天的PLC（可編程邏輯控制器）將面對日益復(fù)雜的挑戰(zhàn)。一旦他們悄悄地取代繼電器，偶爾向主機(jī)報(bào)告，如果他們將他們比作細(xì)胞，賦予新的工作和新