HT67F488 datasheet(28/171 Pages) HOLTEK

28 / 171 page

Rev. 1.60

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HT67F488/HT67F489

TinyPowerTM A/D Flash MCU with LCD & EEPROM

Special Function Register Description

MostoftheSpecialFunctionRegisterdetailswillbedescribedintherelevantfunctionalsections,

howeverseveralregistersrequireaseparatedescriptioninthissection.

Indirect Addressing Register – IAR0, IAR1, IAR2

TheIndirectAddressingRegisters,IAR0,IAR1andIAR2,althoughhavingtheirlocationsinnormal

RAMregisterspace,donotactuallyphysicallyexistasnormalregisters.Themethodofindirect

addressingforRAMdatamanipulationusestheseIndirectAddressingRegistersandMemory

Pointers,incontrasttodirectmemoryaddressing,wheretheactualmemoryaddressisspecified.

ActionsontheIAR0,IAR1andIAR2registerswillresultinnoactualreadorwriteoperationto

theseregistersbutrathertothememorylocationspecifiedbytheircorrespondingMemoryPointers,

MP0,MP1L/MP1HorMP2L/MP2H.Actingasapair,IAR0andMP0cantogetheraccessdata

onlyfromSector0whiletheIAR1registertogetherwithMP1L/MP1HregisterpairandIAR2

registertogetherwithMP2L/MP2HregisterpaircanaccessdatafromanyDataMemorysector.As

theIndirectAddressingRegistersarenotphysicallyimplemented,readingtheIndirectAddressing

Registersindirectlywillreturnaresultof“00H”andwritingtotheregistersindirectlywillresultin

nooperation.

Memory Pointers – MP0, MP1L, MP1H, MP2L, MP2H

FiveMemoryPointers,knownasMP0,MP1L,MP1H,MP2LandMP2H,areprovided.These

MemoryPointersarephysicallyimplementedintheDataMemoryandcanbemanipulatedinthe

samewayasnormalregistersprovidingaconvenientwaywithwhichtoaddressandtrackdata.

WhenanyoperationtotherelevantIndirectAddressingRegistersiscarriedout,theactualaddress

thatthemicrocontrollerisdirectedtoistheaddressspecifiedbytherelatedMemoryPointer.MP0,

togetherwithIndirectAddressingRegister,IAR0,areusedtoaccessdatafromSector0,while

MP1L/MP1HtogetherwithIAR1andMP2L/MP2HtogetherwithIAR2areusedtoaccessdata

fromalldatasectorsaccordingtothecorrespondingMP1HorMP2Hregister.DirectAddressingcan

beusedinalldatasectorsusingthecorrespondinginstructionwhichcanaddressallavailabledata

memoryspace.

ThefollowingexampleshowshowtoclearasectoroffourDataMemorylocationsalreadydefined

aslocationsadres1toadres4.

HT67F488 датащи(PDF) 28 Page - Holtek Semiconductor Inc