Holtek HT66F30 - EEPROM Data Memory; EEPROM Data Memory Str�Ct�Re; EEPROM Registers

Rev. 2.50 44 June 22, 2017 Rev. 2.50 45 June 22, 2017
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
EEPROM Data Memory
ThedevicecontainsanareaofinternalEEPROMDataMemory.EEPROM,whichstandsfor
ElectricallyErasableProgrammableReadOnlyMemory,isbyitsnatureanon-volatileform
ofre-programmablememory,withdataretentionevenwhenitspowersupplyisremoved.By
incorporatingthiskindofdatamemory,awholenewhostofapplicationpossibilitiesaremade
availabletothedesigner.TheavailabilityofEEPROMstorageallowsinformationsuchasproduct
identificationnumbers,calibrationvalues,specificuserdata,systemsetupdataorotherproduct
informationtobestoreddirectlywithintheproductmicrocontroller.Theprocessofreadingand
writingdatatotheEEPROMmemoryhasbeenreducedtoaverytrivialaffair.
EEPROM Data Memory Structure
TheEEPROMDataMemorycapacityvariesfrom32×8to256×8bits,accordingtothedevice
selected.UnliketheProgramMemoryandRAMDataMemory,theEEPROMDataMemoryisnot
directlymappedintomemoryspaceandisthereforenotdirectlyaddressableinthesamewayasthe
othertypesofmemory.ReadandWriteoperationstotheEEPROMarecarriedoutinsinglebyte
operationsusinganaddressanddataregisterinBank0andasinglecontrolregisterinBank1.
Device Capacity Address
HT66F20 32×8
00H~1FH
HT66F30 64×8 00H~3FH
HT66F40
128×8 00H~7FH
HT66F50/HT66F60 256×8 00H~FFH
EEPROM Registers
ThreeregisterscontroltheoveralloperationoftheinternalEEPROMDataMemory.Thesearethe
addressregister,EEA,thedataregister,EEDandasinglecontrolregister,EEC.AsboththeEEA
andEEDregistersarelocatedinBank0,theycanbedirectlyaccessedinthesamewasasanyother
SpecialFunctionRegister.TheEECregisterhowever,beinglocatedinBank1,cannotbedirectly
addresseddirectlyandcanonlybereadfromorwrittentoindirectlyusingtheMP1MemoryPointer
andIndirectAddressingRegister,IAR1.BecausetheEECcontrolregisterislocatedataddress40H
inBank1,theMP1MemoryPointermustrstbesettothevalue40HandtheBankPointerregister,
BP,settothevalue,01H,beforeanyoperationsontheEECregisterareexecuted.