03 Data Memory

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1、Section3.DataMemoryHIGHLIGHTS3.1Introduction....................................................................................................................8-23.2DataMemoryOrganization............................................................................................8-23.3DataAlig

2、nment..............................................................................................................8-53.4SoftwareStack...............................................................................................................8-63.5InterfacingProgramandDataMemorySpaces......

3、.......................................................8-63.6RelatedApplicationNotes..............................................................................................8-73.7RevisionHistory...............................................................................................

4、..............8-83DataMemory©2007MicrochipTechnologyInc.AdvanceInformationDS39717A-page3-1PIC24FFamilyReferenceManual3.1INTRODUCTIONAsHarvardarchitecturedevices,PIC24Fmicrocontrollersfeatureseparateprogramanddatamemoryspacesandbusses.ThePIC24Farchitecturealsoallowsthedirectaccessofprogrammemor

5、yfromthedataspaceduringcodeexecution.3.2DATAMEMORYORGANIZATION3.2.1DataAddressSpaceThePIC24Fcorehasa16-bitwidedatamemoryspace,addressableasasinglelinearrange.ThedataspaceisaccessedusingtwoAddressGenerationUnits(AGUs),oneeachforreadandwriteoperations.ThedataspacememorymapisshowninFigure3-1.AllE

6、ffectiveAddresses(EAs)inthedatamemoryspaceare16bitswideandpointtobyteswithinthedataspace.Thisgivesadataspaceaddressrangeof64Kbytesor32Kwords.Thelower32Kbytesofthedatamemoryspace(thatis,whenEA<15>=0)isusedforimplementedmem-oryaddresses,whiletheupperhalf(EA<15>=1)isreservedfortheProgramSpaceVisi

7、bility(PSV)area.FordetailsonPSV,refertoSection4.4“ProgramSpaceVisibilityfromDataSpace”.Note1:Pleaserefertothespecificdevicedatasheetforactualimplementationofdatamemoryinaspecificdevice.2:ShouldanEApointtoalocationoutsideofthephysicallyi