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.帶有只讀存儲(chǔ)器的單片機(jī)集成電路單片機(jī)集成電路包含一個(gè)處理器內(nèi)核，它至少通過(guò)一種數(shù)據(jù)處理或存儲(chǔ)設(shè)備來(lái)交換數(shù)據(jù)。集成電路包含一個(gè)只讀掩模程序存儲(chǔ)器，其中像測(cè)試程序一樣的通用程序能被單片機(jī)執(zhí)行。這種通用程序具有將數(shù)據(jù)寫(xiě)到數(shù)據(jù)處理和、或存儲(chǔ)設(shè)備的基本功能。寫(xiě)入功能用于裝載程序。因?yàn)檠b載程序并非永久地存儲(chǔ)在只讀存儲(chǔ)器中，所以可對(duì)單片機(jī)進(jìn)行測(cè)試，而與應(yīng)用程序無(wú)關(guān)，并保持系統(tǒng)中能用的存儲(chǔ)器元件為標(biāo)準(zhǔn)類型