通信与电子信息专业英语 课件 Unit 3 Integrated Circuits

Unit3IntegratedCircuits3.1Introduction

3.2PNJunctionandDiode

3.3Transistor

3.4FPGA23.1IntroductionWordsandExpressionsBackgroundsText3WordsandExpressionsmicroelectronic

adj.微电子（学）的microelectronicsandsolid-stateelectronics微电子学与固体电子学miniaturize

vt.使微型化；成为缩影同义词：scaledown,shrinksubstrate n.基底；底物；底层；基层semiconductor n.半导体；半导体装置conductor导体，insulator绝缘体，conductivity电导率WordsandExpressionsIntegratedcircuit(IC),alsocalledmicroelectroniccircuit,microchip,orchip,anassemblyofelectroniccomponents,fabricatedasasingleunit,inwhichminiaturizedactivedevices(e.g.,transistorsanddiodes)andpassivedevices(e.g.,capacitorsandresistors)andtheirinterconnectionsarebuiltuponathinsubstrateofsemiconductormaterial(typicallysilicon).集成电路（IC），也被称为微电子电路、微芯片或芯片，集成了多个电子元件，制造为单个单元，其中微型有源器件（如晶体管和二极管）和无源器件（如电容器和电阻器）及其互连都建立在半导体材料（通常为硅）的薄衬底上。5WordsandExpressionsmicroscopic adj.极小的；微小的；需用显微镜观察的OpticalMicroscope 光学显微镜ElectronMicroscope 电子显微镜STM:ScanningTunnelingMicroscope 扫描隧道显微镜electron

n.电子electron-holepairs

电子空穴对WordsandExpressionsbarrier n.垫垒；障碍；屏障；阻力potentialbarrier 势垒barrierlayer 阻挡层Schottkybarrier 肖特基势垒crystal

n.结晶；晶体；晶振singlecrystal/monocrystal 单晶polycrystal 多晶7WordsandExpressionsShockley’steam(includingJohnBardeenandWalterH.Brattain)foundthat,undertherightcircumstances,electronswouldformabarrieratthesurfaceofcertaincrystals,andtheylearnedtocontroltheflowofelectricitythroughthecrystalbymanipulatingthisbarrier.8WordsandExpressionsvacuumtube 真空管transistor n.晶体管；三极管Controllingelectronflowthroughacrystalallowedtheteamtocreateadevicethatcouldperformcertainelectricaloperations,suchassignalamplification,thatwerepreviouslydonebyvacuumtubes.Theynamedthisdeviceatransistor,fromacombinationofthewordstransferandresistor.9WordsandExpressionsthermostat n.恒温器；温度自动调节器apieceofequipmentthatautomaticallyregulatingthetemperatureinabuilding,machine,orengine.Forexample,atemperaturesensorsendsavaryingsignaltoathermostat,whichcanbeprogrammedtoturnanairconditioner,heater,orovenonandoffoncethesignalhasreachedacertainvalue.WordsandExpressionsbinary adj.二进制的(用0和1记数)；二元的

n.二进制数octal/decimal/hexadecimal 八/十/十六进制Booleanalgebra 布尔代数11WordsandExpressionssynchronize v.使同步desynchronize

去同步(同步破坏)synchronous/asynchronous 同步的/异步的programcounter 程序计数器stackpointer 堆栈指针；堆栈指针寄存器DSP:DigitalSignalProcessor

数字信号处理器DigitalSignalProcessing 数字信号处理技术WordsandExpressionscapture

vt.俘获；捕获；把…输入计算机Wiresharkisafreeandopen-sourcetooltocaptureandanalyzenetworktraffic.ambientnoise

环境噪声；氛围噪音；背景噪音includessoundssuchasrainsounds,oceanwaves,trafficnoise,andelectricalnoisesfromdevicessuchasanairconditioning,refrigerator,icemachine,orfan.WordsandExpressionsdiscernible adj.可辨的；看得清的；辨别得出的digitaleffect 数字特效reconfigurable 可重构的；可重配置的remotecontrol

遥控器；遥控RFIC:RadioFrequencyIC 射频集成电路；射频芯片MMIC:MicrowaveMonolithicIC 微波单片集成电路WordsandExpressionsgalliumarsenide n.砷化镓（Ga-As）compoundsemiconductor 化合物半导体elementsemiconductor 元素半导体

siliconwafer 硅晶圆Unfortunately,GaAsismechanicallymuchlesssoundthansilicon.Itbreakseasily,soGaAswafersareusuallymuchmoreexpensivetobuildthansiliconwafers.15Backgrounds16DigitalSystems:FromLogicGatestoProcessors,/learn/digital-systemsDIYElectronicsProjects,/textbook/experiments/#chpt-7TextOutlineTheConceptandOriginofICBasicTypesofICAnalogvsdigitalcircuitsMicroprocessorcircuitsMemorycircuitsDigitalsignalprocessorsApplication-specificICsRadio-frequencyICs17TheConceptandOriginofICIntegratedcircuitshavetheiroriginintheinventionofthetransistorin1947byWilliamB.ShockleyandhisteamattheAmericanTelephoneandTelegraphCompany’sBellLaboratories.18TheConceptandOriginofICSolid-statedevicesprovedtobemuchsturdier,easiertoworkwith,morereliable,muchsmaller,andlessexpensivethanvacuumtubes.事实证明，固态器件比真空管更坚固、更易用、更可靠、体积更小且成本更低。19TheConceptandOriginofICIn1958JackKilbyofTexasInstruments,Inc.,andRobertNoyceofFairchildSemiconductorCorporationindependentlythoughtofawaytoreducecircuitsizefurther.20Theinventionoftheintegratedcircuitmadetechnologiesoftheinformationagefeasible.BasicTypesofIC：AnalogvsDigitalGenerally,analogcircuitsareconnectedtodevicesthatcollectsignalsfromtheenvironmentorsendsignalsbacktotheenvironment,modifyingthesignalinsomeusefulway—suchasamplifyingitorfilteringitofundesirablenoise.Anothertypicaluseforananalogcircuitistocontrolsomedeviceinresponsetocontinualchangesintheenvironment.21BasicTypesofICThesebasicelements(digitallogiccircuits)arecombinedinthedesignofICsfordigitalcomputersandassociateddevicestoperformthedesiredfunctions.22BasicTypesofIC：AnalogvsDigitalMicroprocessorMicroprocessorsarethemost-complicatedICs.Theyarecomposedofthousandsofindividualdigitalcircuitssynchronizedtoeachother.Eachprocessorhasmanydifferenttypesofregisters.Permanentregistersareusedtostorethepreprogrammedinstructionsrequiredforvariousoperations(suchasadditionandmultiplication).Temporaryregistersstorenumbersthataretobeoperatedonandalsotheresults.23MicroprocessorOtherexamplesofregistersincludetheprogramcounter(alsocalledtheinstructionpointer),whichcontainstheaddressinmemoryofthenextinstruction;thestackpointer(alsocalledthestackregister),whichcontainstheaddressofthelastinstructionputintoanareaofmemorycalledthestack;andthememoryaddressregister,whichcontainstheaddressofwherethedatatobeworkedonislocatedorwherethedatathathasbeenprocessedwillbestored.寄存器的其他例子包括程序计数器（也称为指令指针），存储下一条指令在内存中的地址；堆栈指针（也称为堆栈寄存器），记录放入堆栈的最后一条指令的地址；内存地址寄存器，其中包含要处理的数据所在的地址或已处理的数据将被存储的地址。24MemoryMemoryiscomposedofdensearraysofparallelcircuitsthatusetheirvoltagestatestostoreinformation.存储器由密集的并联电路阵列组成，这些并联电路使用其电压状态来存储信息。25MemoryManufacturerscontinuallystrivetoreducethesizeofmemorycircuits—toincreasecapabilitywithoutincreasingspace.Inaddition,smallercomponentstypicallyuselesspower,operatemoreefficiently,andcostlesstomanufacture.制造商不断努力缩小内存电路的尺寸，以在不增加物理空间的情况下增加存储容量。此外，较小的组件通常使用较少的功率，运行效率更高，制造成本更低。26DSPAdigitalsignalisananalogwaveformthathasbeenconvertedintoaseriesofbinarynumbersforquickmanipulation.Asthenameimplies,adigitalsignalprocessor(DSP)processessignalsdigitally,aspatternsof1sand0s.Forexample,theDSPalgorithminthecircuitmaybeconfiguredtorecognizegapsbetweenspokenwordsasbackgroundnoiseanddigitallyremoveambientnoisefromthewaveform.27DSPDigitalprocessingcanfilteroutbackgroundnoisesofastthatthereisnodiscernibledelayandthesignalappearstobeheardin“realtime.”数字处理可以快速滤除背景噪声，因此没有明显的延迟，信号似乎是“实时”听到的。28ASICAnapplication-specificIC(ASIC)canbeeitheradigitalorananalogcircuit.Asitsnameimplies,anASICisnotreconfigurable;itperformsonlyonespecificfunction.AnASICdoesnotcontainanyabilitytofollowalternateinstructions.29RFICRadio-frequencyICs(RFICs)arewidelyusedinmobilephonesandwirelessdevices.RFICsareanalogcircuitsthatusuallyruninthefrequencyrangeof3kHzto2.4GHz(3,000hertzto2.4billionhertz),andcircuitsoperatingatabout1THz(1trillionhertz)areunderdevelopment.30RFICJustassoundtravelsfasterthroughwaterthanthroughair,electronvelocityisdifferentthrougheachtypeofsemiconductormaterial.正如声音在水中的传播速度比在空气中的传播速度快一样，电子在不同半导体材料中的传播速度也不同。31RFICMMICsusuallyruninthe2-to100-GHzrange,ormicrowavefrequencies,andareusedinradarsystems,insatellitecommunications,andaspoweramplifiersforcellulartelephones.Siliconofferstoomuchresistanceformicrowave-frequencycircuits,andsothecompoundgalliumarsenide(GaAs)isoftenusedforMMICs.323.2PNJunctionandDiodeWordsandExpressionsBackgroundsText33WordsandExpressionsPNJunction PN结diode n.二极管triode 三极管ceramic n.陶瓷；陶瓷制品Aninsulator(suchasceramicordryair)conductselectricityverypoorlybecauseithasfewornofreeelectrons.WordsandExpressions35crystallinesilicon 晶体硅roomtemperature 室温300K(Kelvin)=26.85°C(Celsius)=80.33°F(Fahrenheit)Purecrystallinesilicon,aswithothersemiconductingmaterials,hasaveryhighresistancetoelectricalcurrentatnormalroomtemperature.WordsandExpressions36impurity n.杂质impurity

distribution杂质分布dopant n.掺杂物，掺杂剂

dopantconcentration掺杂浓度implantation n.离子注入；植入Theprocessofintroducingimpuritiesisknownasdopingorimplantation.WordsandExpressionsdoneratom 施主原子；供电子原子acceptoratom 受主原子；接受体原子outershell 外电子层WordsandExpressionshole n.空穴thenamegiventoamissingelectronincertainsolids,especiallysemiconductors.intrinsicsemiconductor 本征半导体extrinsicsemiconductor 非本征半导体Whentheelectricalcharacteristicsaredictatedbyimpurityatoms,thesemiconductorissaidtobeextrinsicsemiconductors.WordsandExpressionsBJT:BipolarJunctionTransistor 双极结型晶体管JFET:JunctionFieldEffectTransistor 结型场效应管rectify vt.整流；精馏；矫正；订正WordsandExpressions40photodiode n.光电二极管photosensor 光敏元件；光传感器photodetector 光检测器；光探测器photocell 光电池；光电管devoid adj.缺乏；完全没有majoritychargecarrier 多数载流子minoritychargecarrier 少数载流子WordsandExpressions41depletionregion 耗尽区Insemiconductorphysics,thedepletionregion,alsocalleddepletionlayer,depletionzone,junctionregionorthespacechargeregion,isaninsulatingregionwithinaconductive,dopedsemiconductormaterialwherethechargecarriershavediffusedaway,orhavebeenforcedawaybyanelectricfield.WordsandExpressionsforward-bias

正向偏压reverse-bias

反向偏压barrierpotential 势垒电压；势垒电位WordsandExpressionsdiffuse

v.扩散，弥漫，渗透；(使光)模糊 adj.弥漫的；扩散的；漫射的migrate v.迁移；转移Diffusionisthemovementofsubstanceunderagradientofconcentration,ormorestrictlyspeaking,chemicalpotential,fromahighconcentrationzonetoalowconcentrationzone,whilemigrationisthemovementofchargedsubstanceundertheactionofanelectricalfield.WordsandExpressions44ANSI:AmericanNationalStandardsInstitute

美国国家标准学会anode n.阳极；正极cathode n.阴极；负极reversesaturationcurrent 反向饱和电流iscausedbydiffusionofminoritycarriersfromtheneutralregionstothedepletionregion.Thiscurrentisalmostindependentofthereversevoltage.WordsandExpressions45qualityfactor 品质因子oridealityfactor,isameasureofhowcloselythediodefollowstheidealdiodeequation.Boltzmannconstant 波尔兹曼常数TheBoltzmannconstantrelatestheaveragerelativekineticenergyofparticlesinagaswiththetemperatureofthegas.reversebreakdownvoltage 反向击穿电压Backgrounds46SemiconductorDevices,/specializations/semiconductor-devicesSemiconductors,/textbook/semiconductors/TextOutlinePNJunctionDiode47PNJunctionAnymaterialcanbeclassifiedasoneofthreetypes:conductor,insulator,orsemiconductor.任何材料都可以归为以下3种类型之一：导体、绝缘体或半导体。48PNJunctionInparticular,thedopedsiliconcanbeusedasaswitch,turningcurrentoffandonasdesired.特别是，掺杂硅可以用作电流开关，根据需要关闭和打开。49PNJunction(Byimplantingacceptoratoms)Theresultingcrystalcontains“holes”initsbondingstructurewhereelectronswouldnormallybelocated.Inessence,suchholescanmovethroughthecrystalconductingpositivecharges.结果是，晶体的键合结构中原本是电子的位置被“空穴”取而代之。本质上，这样的空穴可以在晶体中移动，相当于传输了正电荷。50PNJunctionBycreatingasinglezoneofNmaterialadjacenttoazoneofPmaterial,wewindupwiththePNjunction.ThePNjunctionscanbefoundinavarietyofdevicesincludingBJTsandJFETs.ThemostbasicdevicebuiltfromthePNjunctionisthediode.51DiodeDiodesaredesignedforawidevarietyofusesincludingrectifying,lighting(LEDs)andphotodetection(photodiodes).52DiodeAssumingthecrystalisnotatabsolutezero,thethermalenergyinthesystemwillcausesomeofthefreeelectronsintheNmaterialto“fall”intotheexcessholesoftheadjoiningPmaterial.假设晶体不是绝对零度，系统中的热能将导致N型材料中的一些自由电子“落入”相邻P型材料的空穴中。53DiodeThiswillcreatearegionthatisdevoidofchargecarriers…andthuswerefertoitasadepletionregion.acertainvoltagewillbedroppedacrossthedepletionregioninordertoachievecurrentflow.Thisrequiredpotentialiscalledthebarrierpotentialorforwardvoltagedrop.54DiodeForsilicondevicesthebarrierpotentialisusuallyestimatedataround0.7volts.Forgermaniumdevicesitiscloserto0.3voltswhileLEDsmayexhibitbarrierpotentialsinthevicinityof1.5to3volts,partlydependingonthecolor.对于硅器件，势垒电压通常估计在0.7V左右。对于锗器件，势垒电压接近0.3V，而LED的势垒电压可能在1.5V至3V附近，部分取决于LED的发光颜色。55Diode56Also,ISisnotaconstant.Itincreaseswithtemperature,approximatelydoublingforeach10℃

rise.并且，IS不是常数。它随着温度的升高而增加，每升高10℃，大约会增加一倍。Diode57Theequationdoesnotmodeltheeffectsofbreakdown.VR

isthereversebreakdownvoltage.Notethatthecurrentincreasesrapidlyoncethisreversevoltageisreached.3.3TransistorWordsandExpressionsBackgroundsText58WordsandExpressionsamplify v.放大；增强(声音等)Becausethecontrolled(output)powercanbehigherthanthecontrolling(input)power,atransistorcanamplifyasignal.package vt.封装；将…包装好packagingprocess 封装工艺；封装制程Today,sometransistorsarepackagedindividually,butmanymorearefoundembeddedinintegratedcircuits.WordsandExpressions60extrinsic adj.非本征的；非固有的；外来的extrinsicdiffusion

非本征扩散schematicsymbol 电路符号collector

n.集电极base

n.基极emitter n.发射极WordsandExpressions61regulator n.调节器，调整器，校准器；监管者Bipolartransistorsworkascurrent-controlledcurrentregulators.双极晶体管用作流控电流调节器。IGFET:InsulatedGateField-EffectTransistor 绝缘栅场效应管source

n.源极gate n.栅极 v.门控drain n.漏极WordsandExpressions62channel n.沟道IntheFET,currentflowsalongasemiconductorpathcalledthechannelbetweensourceanddrain.cutoff

n.截止；切断；界限Maximumgate-sourcevoltage“pinchesoff”allcurrentthroughsourceanddrain,thusforcingtheJFETintocutoffmode.WordsandExpressions63dielectric n.电介质；绝缘体amaterialsuchasglassorporcelainwithnegligibleelectricalorthermalconductivitydielectricconstant 介电常数electrostatically 静电；静电地MOSFET:MetalOxideSemiconductorFieldEffectTransistor 金属-氧化物-半导体场效应管WordsandExpressions64enhancement n.提高；增加；增强enhancementtype 增强型；depletiontype 耗尽型CMOS:ComplementaryMOS

互补式金属氧化物半导体Inearly1963FrankWanlassatFairchilddevelopedtheCMOStransistorcircuit,basedonapairofMOStransistors.ThisapproacheventuallyprovedidealforuseinICbecauseofitssimplicityofproductionandverylowpowerdissipation.WordsandExpressions65threshold n.阈值；门槛；界；起始点inversionlayer 反型层ThethresholdvoltageofaMOSFETisusuallydefinedasthegatevoltagewhereaninversionlayerformsattheinterfacebetweentheinsulatinglayer(oxide)andthesubstrate(body)ofthetransistor.Backgrounds66DigitalElectronicsandCircuits,https:///course/digital-electronics-and-circuits-p/CMOSDigitalIntegratedCircuitDesign,/course/cmos-digital-integrated-circuit-design/TextOutlineIntroductionBJTFETJFETIGFET67IntroductionAtransistorisasemiconductordeviceusedtoamplifyorswitchelectronicsignalsandelectricalpower.Therearetwobroadclassificationsoftransistors:bipolar-junctiontransistors(BJT)andfield-effecttransistors(FET).68BJTAbipolartransistorconsistsofathree-layer“sandwich”ofdoped(extrinsic)semiconductormaterials,eitherPNPintheFigure3.9(b)orNPNintheFigure3.9(d).69BJTThefunctionaldifferencebetweenaPNPtransistorandanNPNtransistoristheproperbiasing(polarity)ofthejunctionswhenoperating.PNP晶体管和NPN晶体管之间的功能差异在于工作时的偏置电压极性不同。70BJTGenerallytherearethreedifferentconfigurationsoftransistorsandtheyarecommonbase(CB)configuration,commoncollector(CC)configurationandcommonemitter(CE)configuration.通常晶体管有3种不同的配置，它们是共基极（CB）配置、共集电极（CC）配置和共发射极（CE）配置。71FETAfield-effecttransistorisadeviceutilizingasmallvoltagetocontrolcurrent,includingthejunctionfieldeffecttransistor(JFET)andtheinsulatedgatefieldeffecttransistor(IGFET).Allfieldeffecttransistorsareunipolarratherthanbipolardevices.72FET:JFET73InajunctionfieldeffecttransistororJFET,thecontrolledcurrentpassesfromsourcetodrain,orfromdraintosourceasthecasemaybe.Withnovoltageappliedbetweengateandsource,thechannelisawide-openpathforelectronstoflow.FET:JFET74However,ifavoltageVGSisappliedbetweengateandsourceofsuchpolaritythatitreverse-biasesthePNjunction,theflowbetweensourceanddrainconnectionbecomeslimitedorregulated.然而，如果栅极和源极之间施加反向偏置电压VGS，则源极到漏极之间的电流将受到限制，或者说可以被调节。FET:JFET75ThisbehaviorisduetothedepletionregionofthePNjunctionexpandingundertheinfluenceofareverse-biasvoltage,eventuallyoccupyingtheentirewidthofthechannelifthevoltageisgreatenough.这种行为是由于PN结的耗尽区在反向偏置电压的影响下扩展，如果电压足够大，最终耗尽区会占据沟道的整个宽度。FET:IGFET76

InIGFET,thereisnodirectconnectionbetweenthegateleadandthesemiconductormaterialitself.Rather,thegateleadisinsulatedfromthetransistorbodybyathinbarrier,hencetheterminsulatedgate.ThemostcommontypeofinsulatedgateFETwhichisusedinmanydifferenttypesofelectroniccircuitsiscalledtheMOSFET.FET:IGFET77InadditiontoachoiceofN-channelversusP-channeldesign,MOSFETscomeintwomajortypes:depletionandenhancement.DepletionType-NormallyClosedswitchEnhancementType-NormallyOpenswitchFET:IGFET78Thisinsulatingbarrieractslikethedielectriclayerofacapacitorandallowsgate-sourcevoltagetoinfluencethedepletionregionelectrostaticallyratherthanbydirectconnection.该绝缘屏蔽层的作用类似于电容器的介电层，允许栅极-源极电压以静电方式影响耗尽区，而不是通过直接连接。FET:IGFET79AstheGateterminaliselectricallyisolatedfromthemaincurrentcarryingchannelbetweenthedrainandsource,“Nocurrentflowsintothegate”andtheinputresistanceoftheMOSFETisextremelyhighwayupinthemegaohm(MΩ)region.由于栅极与漏源之间的主载流通道是电隔离的，因此，“没有电流流入栅极”，并且MOSFET的输入电阻高达兆欧姆（MΩ）量级。FET:IGFET80MOSFETsareidealforuseaselectronicswitchesorascommon-sourceamplifiersastheirpowerconsumptionisverysmall.Typicalapplicationsformetal-oxide-semiconductorfieldeffecttransistorsareinmicroprocessors,memories,calculatorsandlogicCMOS(complementaryMOS)gatesetc.3.4FPGAWordsandExpressionsBackgroundsText81WordsandExpressionsnuance n.细微的差别FPGAstandsforfield-programmablegatearray.Atitscore,anFPGAisanarrayofinterconnecteddigitalsubcircuitsthatimplementcommonfunctionswhilealsoofferingveryhighlevelsofflexibility.ButgettingafullpictureofwhatanFPGAisrequiresmorenuance.WordsandExpressions83versatile adj.多功能的；多用途的；多才多艺的VVC:VersatileVideoCoding 多功能视频编码；通用视频编码VRP:VersatileRoutingPlatform 华为通用路由平台sequential

adj.按次序的；顺序的；序列的sequentiallogiccircuit时序逻辑电路combinationallogiccircuit组合逻辑电路WordsandExpressions84approach n.(处理问题、完成任务的)方法Thealternativeisahardware-basedapproach.另一种替代方案是基于硬件的方法。methodology n.方法论；(从事某一活动的)方法，原则improvementmethodology 性能改善方法学modelingmethodology 建模方法学XOR:eXclusiveOR

异或XNORgate/equivalencegate 同或门WordsandExpressions85look-uptable 查找表Lookuptableisactuallyyourcustomizedtruthtablewhicheffectivelydefineshowyourcombinatoriallogicbehaves.flip-flop

触发器Flip-flopisacircuitthatmaintainsastateuntildirectedbyinputtochangethestate.Commontypesofflip-flops:SR,JK,T,D.WordsandExpressionsmultiplexer n.多路复用器demultiplexer 解复用器SRAM:StaticRandomAccessMemory 静态随机存储器86WordsandExpressions87buffer

n.缓冲器；缓存区；缓冲存储器

vt.缓存；缓冲；存储bufferoverflow 缓存溢出buffermanagement

缓冲区管理inverter n.反相器；逆变器；非门HDL:HardwareDescriptionLanguage 硬件描述语言VHDL:Very-High-SpeedICHDL,VerilogHDLWordsandExpressions88synthesis

n.综合；合成；综合体DuringtheFPGAsynthesisprocess,ahighdescriptiondesignoranHDLdesignisconvertedintoagatelevelrepresentationoralogiccomponent.indicator n.标志；指示器；指针Therangeisusuallylimitedtothefull-scaledeflectionoftheindicator.量程通常以指针的满刻度偏转为限。WordsandExpressionsimpedance

n.阻抗measureofthetotaloppositionthatacircuitorapartofacircuitpresentstoelectriccurrent.Impedanceincludesbothresistanceandreactance.proprietary adj.专有的；专利的proprietaryprotocol/publicprotocol 私有协议/公开协议proprietarysoftware/opensourcesoftware

专利软件/开源软件89Backgrounds90HardwareDescriptionLanguagesforFPGADesign,/learn/fpga-hardware-description-languagesTextOutline91IntroFPGAvsMicrocontrollerWhatisaProgrammableGateArray?HowDoYouProgramanFPGAIntro92ThefollowingintroducestheconceptsbehindFPGAsandbrieflydiscusseswhatmakesanFPGAdifferentfromamicrocontrollerindesign,whatlogicgatesare,andhowtoprogramanFPGA.下面介绍FPGA的相关概念，并简要讨论FPGA与微控制器在设计上的区别、什么是逻辑门，以及如何对FPGA进行编程。FPGAvsMicrocontroller93Asmicrocontrollersbecomeincreasinglypowerful,thereislessandlessneedtoconsideralternativesolutionstoourdesignchallenges.SowhenwouldanengineerreachforanFPGAoveramicrocontroller?softwarevshardwareFPGAvsMicrocontrollerAprocessoraccomplishesitstasksbyexecutinginstructionsinasequentialfashion.Thismeansthattheprocessor’soperationsareinherentlyconstrained:thedesiredfunctionalitymustbeadaptedtotheavailableinstructionsand,inmostcases,itisnotpossibletoaccomplishmultipleprocessingtaskssimultaneously.这意味着处理器的操作本身受到限制：所需的功能必须适应可用的指令，并且在大多数情况下，不可能同时完成多个处理任务。94FPGAvsMicrocontrollerThealternativeisahardware-basedapproach.ItwouldbeextremelyconvenientifeverynewdesigncouldbebuiltaroundadigitalICthatimplementstheexactfunctionalityrequiredbythesystem:noneedtowritesoftware,noinstruction-setconstraints,noprocessingdelays,justasingleICthathasinputpins,outputpins,anddigitalcircuitrycorrespondingpreciselytothenecessaryoperations.如果每种新的系统设计都能基于一个数字集成电路来精确实现所需功能，设计者不需要编写软件，没有指令集约束，也没有处理延迟，只需要一个具有输入引脚、输出引脚并能精确完成所需操作的数字集成电路，那将会是非常方便的。95WhatisaProgrammableGateArray?96

AnFPGAisanarrayofcarefullydesignedandinterconnecteddigitalsubcircuitscalledconfigurablelogicblocks(CLBs).CLBsinteractwithoneanotherandwithexternalcircuitryusingamatrixofprogrammableinterconnectsandinput/outputblocks(IOBs).WhatisaProgrammableGateArray?97TheCLBsincludelook-uptables,storageelements(flip-flopsorregisters),andmultiplexersthatallowtheCLBstoperformBoolean,data-storage,andarithmeticoperations.AnI/OblockconsistsofvariouscomponentsthatfacilitatecommunicationbetweentheCLBsandothercomponentsontheboard.Theseincludepull-up/pull-downresistors,buffers,andinverters.TheFPGA’s“program”isstoredinSRAMcellsthatinfluencethefunctionalityoftheCLBsandcontroltheswitchesthatestablishtheconnectionpathways.HowDoYouProgramanFPGA98FPGAsarealwayssupportedbydevelopmentsoftwarethatcarriesoutthecomplicatedprocessofconvertingahardwaredesignintothepr