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1、1、外文原文（复印件）A:FundamentaIsofSingle-chipMicrocomputerof bothThesing1e-chipmicrocomputeristheculminationthedevelopmentofthedigitaicomputerandtheintegratedcircuitarguab1ythetowmostsignificantinventionsofthe20thcentury1LThesetowtypesofarchitectorearefoundinsingIe-chipmicrocomputer.Someemp1oythesplitprogr
2、am/datamemoryoftheHarvardarchitecture,showninFig.3-5A-1,othersfollowthephiIosophy,widelyadaptedforgeneral-purposecomputersandmicroprocessors,ofmakingnologicaldistinctionbetweenprogramanddatamemoryasinthePrincetonarchitecture,showninFig.3-5A-2.Ingeneraltermsasing1e-chipmicrocomputerischaracterizedbyt
3、heincorporationofalltheunitsofacomputerintoasingledevice,asshowninFig3-5A-3.ProgramInput&AHarvardtypeFig.3-5A-2.AconventionalPrincetoncomputerExternalSystemTimer/TimingSerialI/OResetROMInterruptsPrarallelCPUPowerFig3-5A-3.PrincipalfeaturesofamicrocomputerReadOnIymemory(ROM).ROMisusuallyforthepermane
4、nt,non-vo1ati1estorageofanapplicationsprogram.Manymicrocomputersandmicrocontrollersareintendedforhigh-vo1umeapplicationsandhencetheeconomicalmanufactureofthedevicesrequiresthatthecontentsoftheprogrammemorybecommittedpermanent1yduringthemanufactureofchips.Clearly,thisimpliesarigorousapproachtoROMcode
5、deveIopmentsincechangescannotbemadeaftermanufacture.ThisdeveIopmentprocessmayinvo1veemuIationusingasophiSticateddevelopmentsystemwithahardwareemuIationcapabiIityaswellastheuseofpowerfulsoftwaretools.Somemanufacturersprovideadditiona1ROMoptionsbyincludingintheirrangedeviceswith(orintendedforusewith)u
6、serprogrammab1ememory.Thesimplestoftheseisusuallydevicewhichcanoperateinamicroprocessormodebyusingsomeoftheinput/outputlinesasanaddressanddatabusforaccessingexternalmemory.Thistypeofdevicecanbehavefunctiona11yasthesinglechipmicrocomputerfromwhichitisderivedalbeitwithrestrictedI/Oandamodifiedexternal
7、circuit.TheuseoftheseROMlessdevicesiscommoneveninproductioncircuitswherethevolumedoesnot justify the development costs can still be a significant sav i ng to a conventional microprocessor replacement for ROM devices can be with ,p i ggy-back, EPROM(Erasable devices with EPROM instead of ROM 。expens
8、i ve than equivalent ROM device, but do circuit equ i va 1 ents. EPROM based devices are attract i ve for 1ow-voIume app1i cat ions where advantages of a s ing 1e-chip device, in terms etc. , with the conven i ence of flexible userof custom on-chip ROM2;there in I/O and other chips compared based ci
9、rcuit. More exact obtained in the form of variants programmab1e ROM ) sockets orThese devices are natural 1y more provide compIete also extreme 1y they provide the of on-chip I/O, programmability.Randomaccessmemory(RAM).RAMisforthestorageofworkingvariab1esanddatausedduringprogramexecution.Thesizeoft
10、hismemoryvarieswithdevicetypebutithasthesamecharacter!Sticwidth(4,8,16bitsetc.)astheprocessor,Specia1functionregisters,suchasstackpointerortimerregisterareoftenlogicallyincorporatedintotheRAMarea.11isalsocommoninHarardtypemicrocomputerstotreattheRAMareaasacollectionofregister;itisunnecessarytomakedi
11、stinctionbetweenRAMandprocessorregisterasisdoneinthecaseofamicroprocessorsystemsinceRAMandregistersarenotusual1yphysicallyseparatedinamicrocomputer.Centralprocessingunit(CPU).TheCPUismuchlikethatofanymicroprocessor.Manyapp1icationsofmicrocomputersandmicrocontrollersinvolvethehand1ingofbinary-codedde
12、cimal(BCD)data(fornumericaldisplays,forexample),henceitiscommontofindthattheCPUiswelladaptedtohand1ingthistypeofdata.11isalsocommontofindgoodfacilitiesfortesting,settingandresettingindividualbitsofmemoryorI/OsincemanycontrolIerapp1icationsinvolvetheturningonandoffofsingleoutputlinesorthereadingthesi
13、ngleline.Theselinesarereadi1yinterfacedtotwo-statedevicessuchasswitches,thermostats,solid-staterelays,valves,motor,etc.ParaII6Iinpuatuatpuat.Paral1elinputandoutputschemesvarysomewhatindifferentmicrocomputer;inmostamechanismisprovidedtoatleastallowsomeflexibilityofchoosingwhichpinsareoutputsandwhicha
14、reinputs.Thismayapp1ytoallorsomeoftheports.SomeI/Olinesaresuitab1efordirectinterfacingto,forexamp1e,fIuorescentdisplays,orcanprovidesufficientcurrenttomakeinterfacingothercomponentsstraightforward.SomedevicesallowanI/Oporttobeconfiguredasasystembustoallowoff-chipmemoryandI/Oexpansion.Thisfacilityisp
15、otentiallyusefulasaproductrangedevelops,sincesuccessiveenhancementsmaybecometoobigforon-chipmemoryanditisundesirablenottobuildontheexistingsoftwarebase.SiaIinpiltOUtPUt.Serialcommunicationwithterminaldevicesiscommonmeansofprovidingalinkusingasma11numberoflines.ThissortofcommunicationcanalsobeexpIoit
16、edforinterfacingspecialfunctionchipsorlinkingseveralmiCrocomputerstogether.Boththecommonasynchronoussynchronouscommunicationschemesrequireprotocolsthatprovideframing(startandstop)information.Thiscanbeimp1ementedasahardwarefacilityorU(三)ART(Universal(synchronous)asynchronousreceiver/transmitter)relie
17、vingtheprocessor(andtheapp1icationsprogrammer)ofthis1ow-1eve1,time-consuming,detailtismere1ynecessarytoselectedabaud-rateandpossiblyotheroptions(numberofstopbits,parity,etc.)andload(orreadfrom)theserialtransmi11er(orreceiver)buffer.Serializationofthedataintheappropriateformatisthenhandledbythehardwa
18、recircuit.Timing/counterfaciIiies.Manyapplicationofsingle-chipmicrocomputersrequireaccurateevaluationofelapsedrealtime.Thiscanbedeterminedbycarefu1assessmentoftheexecutiontimeofeachbranchinaprogrambutthisrapidlybecomesinefficientforal1butsimplestprograms.Thepreferredapproachistousetimercircuitthatca
19、nindependentlycountprecisetimeincrementsandgenerateaninterruptafterapresettimehaselapsed.Thistypeoftimerisusual1yarrangedtobereloadablewiththerequiredcount.Thetimerthendecrementsthisvalueproducinganinterruptorsettingaflagwhenthecounterreacheszero.Bettertimersthenhavetheabilitytoautomatical1yreloadth
20、einitialcountvalue.Thisrelievestheprogrammeroftheresponsibi1ityofreloadingthecounterandassessingelapsedtimebeforethetimerrestarted,whichotherwisewoundbenecessaryifcontinuousprecise1ytimedinterruptswererequired(asinaclock,forexample).Sometimesassociatedwithtimerisaneventcounter.Withthisfacilitytherei
21、susuallyaspecialinputpin,thatcandrivethecounterdirectly.Timingcomponnats.TheclockcircuitryofmostmiCrocomputersrequiresonlysimpletimingcomponents.Ifmaximumperformanceisrequired,acrystalmustbeusedtoensurethemaximumclockfrequencyisapproachedbutnotexceeded.Manyclockcircuitsalsoworkwitharesistorandcapaci
22、toraslow-costtimingcomponentsorcanbedrivenfromanexternalsource.ThislatterarrangementisusefulisexternalSynchronizationofthemicrocomputerisrequired.WORDSANDTERMSculminationn.顶点spiltadj.分离日勺volatilen.易变Bz-Jcommitv.保证albeitconj.虽然customadj.定制的Jvariantadj.不一样日勺piggy-backadj.背负式日勺socketn.插座B:PLC1PLCs(prog
23、rammab1elogicalcontroller)faceevermorecomplexchaiIengesthesedays.Whereoncetheyquietlyreplacedrelaysandgaveanoccasionalreporttoacorporatemainframe,theyarenowgroupedintocells,givennewjobandnew1anguages,andareforcedtocompeteagainstagrowingarrayofcontrolproducts.Forthisyear,sannualPLCtechnologyupdate,we
24、queriedPLCmakersonthesetopicsandmore.ProgrammingIanguagesHigherlevelPLCprogramminglanguageshavebeenaroundforsometime,butlatelytheirpopu1arityhasmushrooming.AsRaymondLeveilie,vicepresident&generalmanager,SiemensEnergy&Automation.inc;Programmablecontro1sarebeingusedformoreandmoresophisticatedoperation
25、s,languagesotherthanladderlogicbecomemorepractical,efficient,andpowerful.Forexamp1e,itsverydifficulttowriteatrigonometricfunctionusingladderlogic.z,LanguagesgainingacceptanceincludeBoolean,controlsystemfIowcharting,andsuchfunctionchartlanguagesasGraphcetanditsvariation.Andthere,sincreasinginterestin
26、1anguageslikeCandBASIC.PLCsinprocesscontrolThusfar,PLCshavenotbeenusedextensivelyforcontinuousprocesscontrol.Willthiscontinue?”ThefeelingthatI,vegotten,saysKenJannotta,manger,productp1anning,seriesOneandSeriesSixproduct,atGEFanucNorthAmerica,isthatPLCswillbeusedintheprocessindustrybutnotnecessariIyf
27、orprocesscontro1.Severalvendors-obvious1ybettingthattheoppositewillhappen-haveintroducedPLCsoptimizedforprocessapp1ication.RichRyan,manger,commercia1marketing,Allen-bradleyProgrammableControlsDiv.,citesPLCs,sincreasingusesuchindustriesasfood,chemicals,andpetroleum.Ryanfeelstherearetwotypesofapp1icat
28、ionsinwhichthey,reappropriate.one,hesays,zziswherethesizeoftheprocesscontrolsystemthatysbeingautomateddoesn,tjustifyDCSdistributedcontrolcontrolsystem.system.With the starting pricetags of chose products beingrelat ively high, a programmab1econtrol Ier makes sense for smal1,1ow loop count app1icat i
29、on . Thesecond i s where you have tointegrate the loop closely withthesequent ial logical . Batchcontrol Iers are prime example , wherethe sequence and maintainingthe process variab1e are intertwinedsoclosely that the benefitsof having a programmab1e control 1 ertodo the sequent ial logicaloutweighs
30、 some of the d i sadvantagesofnot hav i ng a di stri butedBillBarkovitz,presidentofTriconex,predictsthatallfuturecontrolIersthatcomeoutintheprocesscontrolsystembusinesswillembracealotofmorePLCtechnologyandalotmorePLCfunctionalitythantheyeverdidbefore.CommunicationsandMAPCommunicationsarevitaltoanind
31、ividualautomationcellandtobeautomatedfactoryasawhole.We,veheardalotaboutMAPinthelastfewyears,andalotofcompanieshavejumpedonthebandwagon.2Many,however,werediSappointedwhenafully-definedandcompletedMAPspecificationdidn,tappeariminediate1y.SaysLarryKomarek:Rightnow,MAPisstillamovingtargetforthemanufact
32、urers,aspecificationthatisnotfinal.Present1y,forexamp1e.peopleareintroducingproductstomeettheMAP2.1standard.Yet2.1-basedproductswillbeobsoletewhenthenewstandardforMAP3.Oisintroduced.Becauseofthis,manyPLCvendorsareholdingoffonfullMAPimplementations.Omron,forexample,hasanongoingMAP-Compatibilityprogra
33、m;3butFrankNewburn,vicepresidentof0mron,sIndustrialDivision,reportsthatbecauseofthelackofafirmdefinition,Omron,sPLCsdon,tyettalktoMAP.Sinceit,sunlikelythatanindividua1PLCwouldtalktobroadMAPanyway,makersareconcentratingonproprietarynetworks.AccordingtoSalProvanzano,usersfearthatiftheydogetonboardandv
34、endorswithdrawfromMAP,they,11betheonesleftholdingaCommunicationsstructurethat,snotsupported.UniversalI/OWhilethereareconcernsaboutthelackofcompatib1ecommunicationsbetweenPLCsfromdifferentvendors,theconnectionattheotherend-theI/O-isevenmorefragmented.Withrareexceptions,I/Oisstillproprietary.Yettherea
35、rethosewhofeelthatI/Owilleventual1ybecomemoreuniversal.GEFanucishopingtodothatwithitsGeniussmartI/Oline.TheindependentI/Omakersarepullinginthesamedirection.ManysaythatI/Oissuchahigh-valueitemthatPLCmakerswillalwayswanttokeepitproprietary.AsKenJannotta,says:TheI/Oisgoingtobeadisproportionateamountoft
36、hehardwaresale.CertainlyeachPLCvendorisgoingtotrytoprotectthat.Forthatreason,hesays,PLCmakerswon,tbeginsellinguniversalI/Osystemfromothervendor.ifwestartsellingthatkindofproduct,“saysjannotta,zzwhatdowemanufacture?WithmoreintelligentI/Oappearing,SalProvanzanofeelsthiswillleadtomoredifferentiationamo
37、ngI/Ofromdifferentmakers.“WheretheI/Obecomesextrerne1yinte11igentandbecomespartofthesystem,hesays,“itreal1yishardtodefinewhichistheI/OandwhichisCPU.11real1yCPU,ifyouwill,isequal1yintegratedintothesystemastheI/O.ConnectingPLCI/OtoPCsWhiledifferentPLCsprobab1ywillcontinuetouseproprietaryI/O,severalven
38、dorsmakeitpossibletoconnect5theirI/OtoIBMPC-compatib1eequipment.Alle-brade1ey,Could,andCincinnatiMilacronalreadyhave,andrumorhasitthatGEisp1anningsomethingalongthesesamelines.4Bi11Ketelhut,manageofproductplanningatGEFanucNorthAmerica,seesthissortofthingasalternativetouniversalI/O.z/1thinkthetrend,in
39、steadoftowarduniversa1I/O,willbemultiplehostinterface,hesays.JodieGlore,directorofmarking,SquareDAutomationProducts,ViewsitasanotherindicationthatPLCsare,andhavebeenforsometime,industria1computers.PLCsVSPCsIftheIBM7552,theActionInstrumentsBC22,andothercomputersareappearingonthefactoryfloor,won,tthis
40、meannewcompetitionforPLCs?RichRyan:Therearesomecontrolfunctionsthatarebetterjobsforcomputers.ProgrammablecontrolIershavebeenforcedtofitintothoseapp1ications.Yet,themajorityofvendorswesurveyeddon,tlikethePCinvasionwillposeaproblemforthem.MostsaidthatPLCsandPCsareenoughapartinarchitecturethattheywillu
41、suallydothecontrol.Theydon,tfeelthatPCswilltakejobsfromPLCsjustbecausePLCI/OmodulescannowbeconnectedtoPCs;theybelievethissimplymeansthatPLCsandPCswillbeabletosharethesamedata.“Thereareinherentarchitecturaldifferencesbetweenageneralpurposecomputer,saysRichRyan,“andaprogrammab1econtrolIer.Therearehard
42、wareconstructsbuiltintoalmosteverymanufacture,sprogrammab1econtrolIertodaythatcustomizethehardwaretorunladderlogicandtosolvemachinecode,z,Onefundamentaldifferencehecitesiscalledstateofthemachine.Ryan:zzWhenyoushutthemachineoff,orinterruptthecycle,oryoujumptoanotherspotinthecycle,programmab1econtrolI
43、ersinherent1yrememberthestateofthemachine:whatthetimerswere,whatthecounterswere,whatthestatesofallthelatcheswere.Computersdon,tinherent!ydothat.WORDSANDTERMSbetv.确信optimizedn.优化程序corporateadj.共同0mushroomv.迅速发展trigonometricfunction三角函数vendorn.厂商tagn.标签smartadj.智能型0compatibleadj.兼容02、外文资料翻译译文单片机基础单片机是
44、电脑和集成电路发展日勺巅峰，有据可查日勺是他们也是20世纪最故意义日勺两大发明。这两种特性在单片机中得到了充足的体现。某些厂家用这两种特性辨别程序内存和数据内存在硬件中日勺特性，如图3-5A-1,根据同样的原理广泛日勺合用于一般目日勺日勺电脑和微电脑，某些厂家在程序内存和数据内存之间不辨别时像PrineCton特性，展示如图3-5A-2.只读存贮器（ROM）.RoM是一般B永久性B,非应用程序B易失性存储器。不少微机和单片机用于大批量应用，因此，经济的设备制造规定的程序存储器的内容是在制造期间永久性的刻录在芯片中，这意味着严谨的措施，由于修改ROM代码不能制造之后发展。这一发展过程也许波及仿真
45、，使用硬件仿真功能以及强大的软件工具使用先进的开发系统。某些制造商在其提供的设备包括aJ范围（或拟使用）顾客可编程内存.其中最简朴B一般是设备可以运行于微处理器模式通过使用某些输入/输出作为地址线额外日勺ROM选项和数据总线访问外部内存.这种类型的设备可以体现为单芯片微型计算机尽管有限制HI/0和外部修改这些设备的电路.小内存装置0应用是非常普遍0在永久性内存0制造中2;但仍然可以在我节省大量成本I/O和其他芯片相比，老式的基于微处理器电路.更精确0ROM设备更换，可在与形式变种背驮式EPROM（可擦除可编程只读存储器）插座或存储器，而不是RoM器件。这些器件自然价格比同等ROM设备贵，但不提
46、供完整的等效电路.EPROM的设备也非常有吸引力对于低容量应用中，他们提供B单芯片器件日勺优势，在如下方面B板载I/0等，在灵活的顾客可编程带来0便利。随机存取存储器（RAM）oRAM用于变量和工作在程序使用该存储器日勺执行.随数据存储设备0大小不一样类型而有所不一样，但具有相似日勺特性宽度（4,8,16比特等）作为处理器。特殊功能寄存器，如栈指针或定期器寄存器，往往逻辑纳入内存区域.它也在型微电脑的硬件中做集中内存，它是不必要0辨别内存和处理器之间B区别在一般不物理上分开日勺微机中。中央处理单元（CPU）oCPU是很象微型电子计算机和微控制器的任何微电脑.许多微电脑和微控制器波及到二进制编码
47、（十进制处理（BCD）0数据为例）数字显示，因而，常常可以发现该CPU是很适合处理这种类型0数据。对设施良好与否进行的测试，设置和重置单个位的J内存或I/0控制器日勺应用程序，也是常见0由于许多波及打开和关闭0单输出线或在单线.这些线很轻易连接到二进制B设备，如开关，恒温器，固态继电器，阀门，电机等并行输入/输出.并行输入和输出B计划有所不一样，在不一样的微机，在大多数设置一种机制，至少选择让其中某些引脚输出，某些引脚输如是非常灵活的。这也许合用于所有或端口.有些I/O线直接连接到合适日勺设备，例如，荧光显示屏，也可以提供足够B电流，使接口和其他设备直接相连.某些设备容许一种I/O端口,其他组
48、件将作为系统总线配置为容许片外存储器和I/O扩展。这个设施是潜在有用的一种产品系列日勺发展，由于持续增强也许成为太上存储器，这是不可取B,不是建立在既有日勺软件基础上日勺。串行输入/输出。串行通信是指与终端设备的链接使用少许的通讯线.这种通讯也可运用特殊日勺接口连接功能芯片使几种微型机连在一起。双方共同异步同步通信方案规定日勺规则提供成帧（启动和停止）日勺信息。这可以作为一种硬件设施或U（拧）艺术（通用执行（同步）异步接受器/发送器）减轻处理器（和应用程序）日勺这种低层次确实费时.它也只需要选择一种波特率及其他也许日勺选择（停止位，奇偶校验等）和负载号码（或读取），串行发送器（或接受）的缓冲器.进行合适的格式的数据串行处理，然后由硬件电路完毕。定期/计数器设施。许多应用B单片机需要对过去的真实时间精确的评价。这可以由每个程序中的执行时间分支认真评估，但除最简朴的程序外，他B工作效率不高。首选措施是使用计时器电路，能独立计算精确B时间增量，并生成一种预设的时间后中断B时间。这种类型的定期器一般在所规定的J数量可重载中应用。计时器然后减少此值产生中断或设置标识时，计数器抵达零.更好0计时器有自动加载初始
