标签: pic18c601

ThePIC18C601andPIC18C801aretheveryfirstmembersofMicrochip’sPIC18familythatareROM-lessmicrocontrollers—thatis,theyhavenoon-chipprogrammemory.BothoffertheenhancedPIC18architecture,alongwiththeabilitytousedifferenttypesandsizesofexternalprogrammemorytoexactlyfitanyapplication.Inadditiontostandard1.5Kbytesofgen-eralpurposeRAM,thePIC18C601canaddressupto256Kbytesofexternalprogrammemory,whilethePIC18C801canaddressupto2Mbytesofexternalprogrammemory.Withthisamountofavailableaddressablespace,thePIC18C601/801devicesbecomeidealcandidatesformorecomplexapplica-tions(e.g.TCP/IPstacks),developedwithhighlevelprogramminglanguages,suchas‘C’.AN778ImplementingtheExternalMemoryInterfaceonPIC18C601/801MCUsGiventhenumberandtypesofmemoriesavailableAuthor:GaurangKavaiyatoday,findingandinterfacingmemorytotheMicrochipTechnologyInc.PIC18C601/801devicespotentiallybecomesachal-lengingtask.ThisapplicationnotedescribesthePIC18C601/801externalmemory……

ThePIC18C601andPIC18C801microcontrollersarethefirstmembersofMicrochip’sPIC18familywithnoon-chipprogrammemory.TheyofferthePIC18archi-tecture,withtheabilitytousedifferenttypesandsizesofexternalprogrammemory(upto2Mbyte)toexactlyfitmostapplications.Inmodernembeddedapplications,wherefeaturesandfunctionalityareconstantlyevolving,FLASHmemoryisanidealchoiceforexternalprogrammemory.Fieldupgradabilityisalmostalwaysdesirableinthesesys-tems,too.MostcommonlyavailableFLASHdevices,however,disablereadaccesswhilebeingprogrammedorerased.Theyalsorequirespecialcommandsequencesforprogramming,andhavelongereraseandwritetimesthanreadtimes.Asaresult,systemsusingFLASHtechnologyrequireeitherasecondmem-orydevice,oramicrocontrollerwithbuilt-inmemoryspace,inordertoimplementfieldreprogrammability.PIC18C601/801controllersdothisbyallowingpartofon-chipdatamemorytobereconfiguredasprogrammemory.MAN819ImplementingBootloaderFirmwareforthePIC18C601/801ROMlessMicrocontrollersThisapplicationnotediscussesthegeneraldesignAuthors:GaurangKavaiyaandNileshRajbhartirequirementsforbootloaderfirmwareinaROMlessMicrochipTechnologyInc.controllersystem.Toillustratethekeypoints,afully-featuredreferencedesign,withaninterfacetoexternalhostsoft……

ThePIC18C601/801partsyouhavereceivedconformfunctionallytotheDeviceDataSheet(DS39541A),exceptfortheanomaliesdescribedbelow.AlltheproblemslistedherewillbeaddressedinfuturerevisionsofthePIC18C601/801silicon.MPIC18C601/801PIC18C601/801Rev.C0Silicon/DataSheetErrataThePIC18C601/801partsyouhavereceivedconform3.Module:InterruptsfunctionallytotheDeviceDataSheet(DS39541A),exceptfortheanomaliesdescribedbelow.Highpriorityinterruptsmaybecomeimproperlyenabled,whilelowpriorityinterruptsbecomeAlltheproblemslistedherewillbeaddressedinfutureimproperlydisabledatthesametime.ThismayrevisionsofthePIC18C601/801silicon.occurwhenlowpriorityinterruptsareinan1.Modu……

ThePIC18C601/801partsyouhavereceivedconformfunctionallytotheDeviceDataSheet(DS39541A),exceptfortheanomaliesdescribedbelow.AlltheproblemslistedherewillbeaddressedinfuturerevisionsofthePIC18C601/801silicon.MPIC18C601/801PIC18C601/801Rev.B1Silicon/DataSheetErrataThePIC18C601/801partsyouhavereceivedconform3.Module:Core(DCCharacteristics)functionallytotheDeviceDataSheet(DS39541A),exceptfortheanomaliesdescribedbelow.ThespecificationforthedevicePower-downCurrent(parameterD020)haschanged.ThenewAlltheproblemslistedherewillbeaddressedinfuturemaximumvalueis50Aat85°C.revisionsofthePIC18C601/801silicon.Thisnewvalueappliestobothstandardand1.Module:……