HT45FH4M
Lithium Battery Backup Power ASSP MCU
EEPROM Data Memory
OneꢀofꢀtheꢀspecialꢀfeaturesꢀinꢀtheꢀdeviceꢀisꢀitsꢀinternalꢀEEPROMꢀDataꢀMemory.ꢀEEPROM,ꢀwhichꢀ
standsꢀforꢀElectricallyꢀErasableꢀProgrammableꢀReadꢀOnlyꢀMemory,ꢀisꢀbyꢀitsꢀnatureꢀaꢀnon-volatileꢀ
formꢀofꢀmemory,ꢀwithꢀdataꢀretentionꢀevenꢀwhenꢀitsꢀpowerꢀsupplyꢀisꢀremoved.ꢀByꢀincorporatingꢀ
thisꢀkindꢀofꢀdataꢀmemory,ꢀaꢀwholeꢀnewꢀhostꢀofꢀapplicationꢀpossibilitiesꢀareꢀmadeꢀavailableꢀtoꢀtheꢀ
designer.ꢀTheꢀavailabilityꢀofꢀEEPROMꢀstorageꢀallowsꢀinformationꢀsuchꢀasꢀproductꢀidentificationꢀ
numbers,ꢀcalibrationꢀvalues,ꢀspecificꢀuserꢀdata,ꢀsystemꢀsetupꢀdataꢀorꢀotherꢀproductꢀinformationꢀtoꢀ
beꢀstoredꢀdirectlyꢀwithinꢀtheꢀproductꢀmicrocontroller.ꢀTheꢀprocessꢀofꢀreadingꢀandꢀwritingꢀdataꢀtoꢀtheꢀ
EEPROMꢀmemoryꢀhasꢀbeenꢀreducedꢀtoꢀaꢀveryꢀtrivialꢀaffair.
EEPROM Data Memory Structure
TheꢀEEPROMꢀDataꢀMemoryꢀcapacityꢀisꢀupꢀtoꢀ64×8ꢀbits.ꢀUnlikeꢀtheꢀProgramꢀMemoryꢀandꢀRAMꢀ
DataꢀMemory,ꢀtheꢀEEPROMꢀDataꢀMemoryꢀisꢀnotꢀdirectlyꢀmappedꢀandꢀisꢀthereforeꢀnotꢀdirectlyꢀ
accessibleꢀinꢀtheꢀsameꢀwayꢀasꢀtheꢀotherꢀtypesꢀofꢀmemory.ꢀReadꢀandꢀWriteꢀoperationsꢀtoꢀtheꢀ
EEPROMꢀareꢀcarriedꢀoutꢀinꢀsingleꢀbyteꢀoperationsꢀusingꢀanꢀaddressꢀandꢀdataꢀregisterꢀinꢀBankꢀ0ꢀandꢀ
aꢀsingleꢀcontrolꢀregisterꢀinꢀBankꢀ1.
EEPROM Registers
ThreeꢀregistersꢀcontrolꢀtheꢀoverallꢀoperationꢀofꢀtheꢀinternalꢀEEPROMꢀDataꢀMemory.ꢀTheseꢀareꢀtheꢀ
addressꢀregister,ꢀEEA,ꢀtheꢀdataꢀregister,ꢀEEDꢀandꢀaꢀsingleꢀcontrolꢀregister,ꢀEEC.ꢀAsꢀbothꢀtheꢀEEAꢀ
andꢀEEDꢀregistersꢀareꢀlocatedꢀinꢀBankꢀ0,ꢀtheyꢀcanꢀbeꢀdirectlyꢀaccessedꢀinꢀtheꢀsameꢀwayꢀasꢀanyꢀotherꢀ
SpecialꢀFunctionꢀRegister.ꢀTheꢀEECꢀregisterꢀhowever,ꢀbeingꢀlocatedꢀinꢀBank1,ꢀcannotꢀbeꢀdirectlyꢀ
addressedꢀdirectlyꢀandꢀcanꢀonlyꢀbeꢀreadꢀfromꢀorꢀwrittenꢀtoꢀindirectlyꢀusingꢀtheꢀMP1ꢀMemoryꢀPointerꢀ
andꢀIndirectꢀAddressingꢀRegister,ꢀIAR1.ꢀBecauseꢀtheꢀEECꢀcontrolꢀregisterꢀisꢀlocatedꢀatꢀaddressꢀ40Hꢀ
inꢀBankꢀ1,ꢀtheꢀMP1ꢀMemoryꢀPointerꢀmustꢀfirstꢀbeꢀsetꢀtoꢀtheꢀvalueꢀ40HꢀandꢀtheꢀBankꢀPointerꢀregister,ꢀ
BP,ꢀsetꢀtoꢀtheꢀvalue,ꢀ01H,ꢀbeforeꢀanyꢀoperationsꢀonꢀtheꢀEECꢀregisterꢀareꢀexecuted.
EEPROM Control Registers List
Bit
Name
7
6
5
4
3
Dꢆ
2
1
D1
0
EEA
EED
EEC
—
D7
—
—
D6
—
Dꢃ
Dꢃ
—
D4
D4
—
Dꢅ
Dꢅ
WR
D0
D0
RD
Dꢆ
D1
WREN
RDEN
EEA Register
Bit
Name
R/W
7
6
5
Dꢃ
R/W
0
4
D4
R/W
0
3
Dꢆ
R/W
0
2
Dꢅ
R/W
0
1
D1
R/W
0
0
D0
R/W
0
—
—
—
—
—
—
POR
Bitꢀ7ꢀ~ꢀ6ꢀ
Bitꢀ5ꢀ~ꢀ0ꢀ
Unimplemented,ꢀreadꢀasꢀ"0"
DataꢀEEPROMꢀaddressꢀ
DataꢀEEPROMꢀaddressꢀbitꢀ5ꢀ~ꢀbitꢀ0
Rev. 1.10
ꢅ7
�anꢀaꢁꢂ 1ꢃꢄ ꢅ01ꢆ
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
