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)integratedcircuitcontainingallormostofthecomponentsofacomputer.Itsfunctionisnotpredefinedbutdependsontheprogramthatitexecutes.Amicrocontrollernecessarilycomprisesaprocessorcoreincludingacommandsequencer(whichisadevicedistributingvariouscontrolsignalstotheinstructionsofaprogram),anarithmeticandlogicunit(forprocessingthedata)andregisters(whicharespecializedmemoryunits).Theothercomponentsofthecomputercanbeeitherinternalorexternaltothemicrocontroller,however.Inotherwords,theothercomponentsareintegratedintoeitherthemicrocontrollerorauxiliarycircuits.Theseothercomponentsofthecomputeraredataprocessingandstoragedevices,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