外文翻译--带有只读存储器的单片机集成电路.doc

MicrocontrollerIntegratedCircuitwithReadOnlyMemoryMicrocontrollerintegratedcircuitcomprisesaprocessorcorewhichexchangesdatawithatleastonedataprocessingandstoragedevice.Theintegratedcircuitcomprisesamask-programmedreadonlymemorycontainingagenericprogramsuchasatestprogramwhichcanbeexecutedbythemicrocontroller.Thegeneticprogramincludesabasicfunctionforwritingdataintothedataprogressingorstoragedeviceordevices.Thewritefunctionisusedtoloadadownloadingprogram.Becauseadownloadingprogramisnotpermanentlystoredinthereadonlymemory,themicrocontrollercanbetestedindependentlyoftheapplicationprogram,andremainsstandardwithregardtothetypeofmemorycomponentwithwhichitcanbeusedinasystem.Tobemoreprecise,theinventionconcernsamicrocontrollerintegratedcircuit.AmicrocontrollerisusuallyaVLSI(VeryLargeScaleIntegration)integratedcircuitcontainingallormostofthecomponentsofa"computer".Itsfunctionisnotpredefinedbutdependsontheprogramthatitexecutes.Amicrocontrollernecessarilycomprisesaprocessorcoreincludingacommandsequencer(whichisadevicedistributingvariouscontrolsignalstotheinstructionsofaprogram),anarithmeticandlogicunit(forprocessingthedata)andregisters(whicharespecializedmemoryunits).Theothercomponentsofthe"computer"canbeeitherinternalorexternaltothemicrocontroller,however.Inotherwords,theothercomponentsareintegratedintoeitherthemicrocontrollerorauxiliarycircuits.Theseothercomponentsofthe"computer"aredataprocessingandstoragedevices,forexamplereadonlyorrandomaccessmemorycontainingtheprogramtobeexecuted,clocksandinterfaces(serialorparallel).Asageneralrule,asystembasedonamicrocontrollerthereforecomprisesamicrochipcontainingthemicrocontroller,andapluralityofmicrochipscontainingtheexternaldataprocessingandstoragedeviceswhicharenotintegratedintothemicrocontroller.Amicrocontroller-basedsystemofthiskindcomprises,forexample,oneormoreprintedcircuitboardsonwhichthemicrocontrollerandtheothercomponentsaremounted.Itistheapplicationprogram,I.e.theprogramwhichisexecutedbythemicrocontroller,whichdeterminestheoveralloperationofthemicrocontrollersystem.Eachapplicationprogramisthereforespecifictoaseparateapplication.Inmostcurrentapplicationstheapplicationprogramistoolargetobeheldinthemicrocontrollerandisthereforestoredinamemoryexternaltothemicrocontroller.Thisprogrammemory,whichhasonlytoberead,notwritten,isgenerallyareprogrammablereadonlymemory(REPROM).Aftertheapplicationprogramhasbeenprogrammedinmemoryandthenstartedinordertobeexecutedbythemicrocontroller,themicrocontrollersystemmaynotfunctionasexpected.Inthelastunfavorablesituationthisisaminordysfunctionofthesystemandthemicrocontrollerisstillabletodialogwithateststationviaaserialorparallelinterface.Thisteststationisthenabletodeterminthenatureoftheproblemandindicatespreciselythetypeofcorrection(softwareandphysical)tobeappliedtothesystemforittooperatecorrectly.Unfortunately,mostdysfunctionsofmicrocontroller-basedsystemresultinatotalsystemlock-up,preventinganydialogwithateststation.Itisthenimpossibletodeterminethetypeoffault,i.e.whetheritisaphysicalfault(inthemicrocontrolleritself,inanexternalreadonlymemory,inaperipheraldevice,onabus,etc)orasoftwarefault(i.e.anerrorintheapplicationprogram).Thetroubleshootingtechniqueusuallyemployedinthesecasesoftotallock-upisbasedontheuseofsophisticatedtestdevicesrequiringtheapplicationofprobestothepinsofthevariousintegratedcircuitsofthemicrocontroller-basedsystemundertest.Therearevariousproblemsassociatedwiththeuseofsuchtestdevicesfortroubleshootingamicrocontroller-basedsystem.Theprobesusedinthesetestdevicesareveryfragile,difficulttoapplybecauseofthesmallsizeofthecircuitandtheirclosepacking,andmaynotmakegoodcontactwiththecircuit.Also,becauseoftheirhighcost,thesetestdevicesarenotmassproduced.Consequently,faultymicrocontroller-basedsystemscannotberepairedimmediately,wherevertheyhappentobelocatedatthetime,butmustfirstbereturnedtoaplacewhereatestdeviceisavailable.Troubleshootingamicrocontroller-basedsysteminthiswayistime-consuming,irksomeandcostly.Toavoidtheneedfordirectactiononthemicrocontroller-basedsystemeachtimetheapplicationprogramexecutedbythemicrocontrollerofthesystemischanged,itisstandardpracticetouseadownloadablereadonlymemorytostoretheapplicationprogram,aloadingprogrambeingwrittenintoamask-programmedreadonlymemoryofthemicrocontroller.Themask-programmedreadonlymemoryofthemicrocontrollerisintegratedintothemicrocontrollerandprogrammedonceandforallduringmanufactureofthemicrocontroller.Tochangetheapplicationprogramthemicrocontrollerisresetbyrunningthedownloadingprogram.Thisdownloadingprogramcanthencommunicatewithaworkstationconnectedtothemicrocontrollerbyanappropriatetransmissionline,thisworkstationthenewapplicationprogramtobewrittenintothemicrocontroller.Thedownloadingprogramreceivesthenewapplicationprogramandloadsitintoareadonlymemoryexternaltothemicrocontroller.Althoughthissolutionavoidstheneedfordirectactiononthemicrocontroller-basedsystem(whichwouldentailremovingfromthesystemthereprogrammablereadonlymemoriescontainingtheapplicationprogram,writingintothesememoriesthenewapplicationprogramusinganappropriateprogrammingdeviceandthenreplacingtheminthesystem),itneverthelesshasamajordrawback,namelyspecializationofthemicrocontrollerduringmanufacture.Eachtypeofreprogrammablememoryisassociatedwithadifferentdownloadingprogrambecausetheprogrammingparameters(voltagetobeapplied,durationforwhichthevoltageistobeapplied)varywiththetechnologyemployed.Thedownloadingprogramiswrittenonceandforallintothemask-programmedinternalmemoryofthemicrocontrollerandthelatteristhereforerestrictedtousingmemorycomponentsofthetypeforwhichthisdownloadingprogramwaswritten.Inotherwords,themicrocontrollerisnotastandardcomponentandthisincreasesitscostofmanufacture.Oneobjectoftheinventionistoovercomethesevariousdrawbacksofthepriorart.Tobemoreprecise,anobjectoftheinventionistoprovideamicrocontrollercircuitwhichcanverifyquickly,simply,reliablyandatlowcosttheoperationofasystembasedonthemicrocontroller.Anotherobjectoftheinventionistoprovideamicrocontrollerintegratedcircuitwhichcanaccuratelylocatethedefectivecomponentorcomponentsofasystemusingthemicrocontrollerintheeventofdysfunctionofthesystem.Afurtherobjectoftheinventionistoprovideamicrocontrollerintegratedcircuitwhichavoidstheneedfordirectactiononthemicrocontroller-basedsystemtochangetheapplicationprogram,whilstremainingstandardasregardsthetypeofmemorycomponentwithwhichitcanbeusedinasystem.带有只读存储器的单片机集成电路单片机集成电路包含一个处理器内核，它至少通过一种数据处理或存储设备来交换数据。集成电路包含一个只读掩模程序存储器，其中像测试程序一样的通用程序能被单片机执行。这种通用程序具有将数据写到数据处理和、或存储设备的基本功能。写入功能用于装载程序。因为装载程序并非永久地存储在只读存储器中，所以可对单片机进行测试，而与应用程序无关，并保持系统中能用的存储器元件为标准类型。准确地说，这项发明涉及单片机集成电路。单片机通常是包含一台“计算机”的全部或大部分元件的大规模集成电路，其功能不是预先确定的，而是取决于它执行的程序。一台单片机必然包含一个含有命令时序发生器（即根据程序的指令分配各种控制信号到其他元件的装置）的处理器内核，一个算数逻辑单元（用来处理数据）和寄存器（即特殊的存储单元）。然而，“计算机”的其他单元对单片机而言或是内部的，或是外部的。换言之，其他元件就集成到单片机或辅助电路中。“计算机”的这些其他元件是数据处理或存储装置，例如包含待执行程序的只读或随机存储器、时钟和接口（串行或并行）。基于单片机的系统通常包含一个含有单片机的芯片和许多含有外部数据处理和、或存储器的芯片，这些芯片没有集成在单片机中。例如，这种基于单片机的系统包含一个或多个印刷电路板，上面安装着单片机和其他元件。决定单片机所有操作的是应用程序，即由单片机执行的程序。因此，每个应用程序都是针对特定的应用的。在多数现实应用中，由于应用程序太大，单片机无法存储，因此就存储在单片机的外部存储器中。这种只读处而不能写入的程序存储器通常就是可编程只读存储器。应用程序在写入到存储器中后就开始执行，以便由单片机来执行。单片机系统有可能不会像预期的那样工作。在最不顺的情况下，这只是系统的小故障，单片机仍然能够通过串行或并行口与测试设备对话。测试设备就能够确定问题的性质，并准确的指出校正的类型（软件和硬件），将其应用到系统上，以便正确操作。遗憾的是，基于单片机系统的多数故障导致整个系统死锁，阻止了任何与测试设备的对话。这样就不能确定错误类型时硬件错误（单片机本身，外部只读存储器、外围设备、总线等）还是软件错误（应用程序的错误）。在系统死锁的情