avr教程 avr architecture

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1、ArchitectureCoreandPeripheralsAtmelMCUTraining-ASIA2004December2004TheAVRCOREHarvardarchitectureSeparatememoriesandbusesforprogramanddata32x8-bitgeneralpurposeworkingregistersLargeAccumulatorSingleclockcycleaccesstime3registerpairactas16-bitdatapointersSingle-cycleArith

2、meticLogicUnit(ALU)operation16-bitStackPointer22-bitProgramCounter2XPointerYPointerZPointerR0R1R2R26R27R28R29R30R31XHXLYLYHZLZH32x8-bitGeneralPurposeRegisters328-bitAccumulatorRegistersAllhavedirectaccesstoALU3registerpairactas16-bitdatapointersInstructionsetsupportfora

3、utoincrement,decrementanddisplacementofpointersEnablingefficientaddresscalculations.ZPointersuitedforlookuptablesandindirectjumpDirectaddressofupto64K3SingleCycleInstructionExecutionRegisterFileALURegisteroperationstakeONEclockpulseontheEXTERNALclockinput4MemoryOverview

4、andInterconnectionGeneralpurposeregistersmanagealldatatransferDirectProgrammemoryaccessDirectSRAMaccessEEPROMaccessviaIOregistersEEAR,EEDR,EECRSecureProgrammemoryandEEPROMaccessTimedsequenceProgramMemoryRegisterFileI/ORegistersEEPROMSRAM5ProgramMemoryandDataPointersStac

5、kPointer+ThreeDatapointersOneortwopointers+SPiscommonfor8-bitPointerreloadingisminimizedCodeefficientmemorytomemorycopySeparatestacksforreturnaddressesandlocalvariablesPointerhandlingsimilartoC-languageAutoIncrement/DecrementIndirectwithDisplacementEfficientforaccessing

6、arraysandstructsEfficientwhenplacinglocalvariablesonSoftwareStackCSourcecodeunsignedchar*var1,*var2;*var1++=*--var2;AssemblycodeLDR16,-XSTZ+,R166AVR-DesignedforCProgrammingArchitectureandinstructionsetco-designedwithIARSystemsCompilerdevelopmentprojectinitiatedbeforearc

7、hitectureandinstructionsetfrozenCompilerexperts’adviceimplementedinhardwarePotentialHLLbottlenecksidentifiedandremovedThedesignprocessresultedinInstructionsetsupportfor16-bitarithmeticoperations32workingregisterswhicheliminatemovetoandfromSRAMSingleCycleexecution7ASmall

8、CFunction/*Returnthemaximumvalueofatableof16integers*/intmax(int*array){chara;intmaximum=-32768;for(a=0;a<16;a