Holtek HT66F002 - EEPROM Data Memory; EEPROM Data Memory Structure

Rev. 1.71 32 April 11, 2017 Rev. 1.71 33 April 11, 2017
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
STATUS Register
Bit 7 6 5 4 3 2 1 0
Name — — TO PDF OV Z AC C
R/W — — R R R/W R/W R/W R/W
POR — — 0 0 × × × ×
"×" unknown
B
it7~6 Unimplemented,readas"0"
Bit5 TO:WatchdogTime-Outag
0:Afterpoweruporexecutingthe"CLRWDT"or"HALT"instruction
1:Awatchdogtime-outoccurred.
Bit4 PDF:Powerdownag
0:Afterpoweruporexecutingthe"CLRWDT"instruction
1:Byexecutingthe"HALT"instruction
Bit3 OV:Overowag
0:nooverow
1:anoperationresultsinacarryintothehighest-orderbitbutnotacarryoutofthehighest-
orderbitorviceversa.
B
it2 Z:Zeroag
0:Theresultofanarithmeticorlogicaloperationisnotzero
1:Theresultofanarithmeticorlogicaloperationiszero
Bit1 AC:Auxiliaryag
0:noauxiliarycarry
1:anoperationresultsinacarryoutofthelownibblesinaddition,ornoborrowfromthehigh
nibbleintothelownibbleinsubtraction
Bit0 C:Carryag
0:nocarry-out
1:anoperationresultsinacarryduringanadditionoperationorifaborrowdoesnottakeplace
duringasubtractionoperation
Cisalsoaffectedbyarotatethroughcarryinstruction.
EEPROM Data Memory
Thesedevicescontain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
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identicationnumbers,
calibrationvalues,specic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is32×8bitsforthisseriesofdevices.UnliketheProgram
MemoryandRAMDataMemory,theEEPROMDataMemoryisnotdirectlymappedandis
thereforenotdirectlyaccessible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twoaddressregistersand
onedataregisterinBank0andasinglecontrolregisterinBank1.