BS85B12-3/BS85C20-3/BS85C20-5
Touch Key Flash MCU with LCD/LED Driver
EEPROM Data Memory
TheꢀdevicesꢀcontainꢀanꢀareaꢀofꢀinternalꢀEEPROMꢀDataꢀMemory.ꢀEEPROM,ꢀwhichꢀstandsꢀforꢀ
ElectricallyꢀErasableꢀProgrammableꢀReadꢀOnlyꢀMemory,ꢀisꢀbyꢀitsꢀnatureꢀaꢀnon-volatileꢀformꢀ
ofꢀre-programmableꢀmemory,ꢀwithꢀdataꢀretentionꢀevenꢀwhenꢀitsꢀpowerꢀsupplyꢀisꢀremoved.ꢀByꢀ
incorporatingꢀthisꢀkindꢀofꢀdataꢀmemory,ꢀaꢀwholeꢀnewꢀhostꢀofꢀapplicationꢀpossibilitiesꢀareꢀmadeꢀ
availableꢀtoꢀtheꢀdesigner.ꢀTheꢀavailabilityꢀofꢀEEPROMꢀstorageꢀallowsꢀinformationꢀsuchꢀasꢀproductꢀ
identificationꢀnumbers,ꢀcalibrationꢀvalues,ꢀspecificꢀuserꢀdata,ꢀsystemꢀsetupꢀdataꢀorꢀotherꢀproductꢀ
informationꢀtoꢀbeꢀstoredꢀdirectlyꢀwithinꢀtheꢀproductꢀmicrocontroller.ꢀTheꢀprocessꢀofꢀreadingꢀandꢀ
writingꢀdataꢀtoꢀtheꢀEEPROMꢀmemoryꢀhasꢀbeenꢀreducedꢀtoꢀaꢀveryꢀtrivialꢀaffair.
EEPROM Data Memory Structure
TheꢀEEPROMꢀDataꢀMemoryꢀcapacityꢀisꢀ64 8ꢀorꢀ128 8ꢀbitsꢀforꢀthisꢀseriesꢀofꢀdevices.ꢀUnlikeꢀtheꢀ
×
×
ProgramꢀMemoryꢀandꢀRAMꢀDataꢀMemory,ꢀtheꢀEEPROMꢀDataꢀMemoryꢀisꢀnotꢀdirectlyꢀmappedꢀ
intoꢀmemoryꢀspaceꢀandꢀisꢀthereforeꢀnotꢀdirectlyꢀaddressableꢀinꢀtheꢀsameꢀwayꢀasꢀtheꢀotherꢀtypesꢀofꢀ
memory.ꢀReadꢀandꢀWriteꢀoperationsꢀtoꢀtheꢀEEPROMꢀareꢀcarriedꢀoutꢀinꢀsingleꢀbyteꢀoperationsꢀusingꢀ
anꢀaddressꢀandꢀdataꢀregisterꢀinꢀBankꢀ0ꢀandꢀaꢀsingleꢀcontrolꢀregisterꢀinꢀBankꢀ1.
Device
Capacity
Address
BS85B12-3
64×8
00H ~ 3FH
BS85C20-3
/BS85C20-5
128×8
00H ~ 7FH
EEPROM Registers
ThreeꢀregistersꢀcontrolꢀtheꢀoverallꢀoperationꢀofꢀtheꢀinternalꢀEEPROMꢀDataꢀMemory.ꢀTheseꢀareꢀtheꢀ
addressꢀregister,ꢀEEA,ꢀtheꢀdataꢀregister,ꢀEEDꢀandꢀaꢀsingleꢀcontrolꢀregister,ꢀEEC.ꢀAsꢀbothꢀtheꢀEEAꢀ
andꢀEEDꢀregistersꢀareꢀlocatedꢀinꢀBankꢀ0,ꢀtheyꢀcanꢀbeꢀdirectlyꢀaccessedꢀinꢀtheꢀsameꢀwasꢀasꢀanyꢀotherꢀ
SpecialꢀFunctionꢀRegister.ꢀTheꢀEECꢀregisterꢀhowever,ꢀbeingꢀlocatedꢀinꢀBank1,ꢀcannotꢀbeꢀaddressedꢀ
directlyꢀandꢀcanꢀonlyꢀbeꢀreadꢀfromꢀorꢀwrittenꢀtoꢀindirectlyꢀusingꢀtheꢀMP1ꢀMemoryꢀPointerꢀandꢀ
IndirectꢀAddressingꢀRegister,ꢀIAR1.ꢀBecauseꢀtheꢀEECꢀcontrolꢀregisterꢀisꢀlocatedꢀatꢀaddressꢀ40Hꢀinꢀ
Bankꢀ1,ꢀtheꢀMP1ꢀMemoryꢀPointerꢀmustꢀfirstꢀbeꢀsetꢀtoꢀtheꢀvalueꢀ40HꢀandꢀtheꢀBankꢀPointerꢀregister,ꢀ
BP,ꢀsetꢀtoꢀtheꢀvalue,ꢀ01H,ꢀbeforeꢀanyꢀoperationsꢀonꢀtheꢀEECꢀregisterꢀareꢀexecuted.
EEPROM Register List
•ꢀ BS85B12-3
Bit
Name
7
6
5
4
3
D3
2
1
D1
0
EE�
EED
EEC
—
D7
—
—
D6
—
D5
D5
—
D4
D4
—
D2
D2
WR
D0
D0
RD
D3
D1
WREN
RDEN
•ꢀ BS85C20-3/BS85C20-5
Bit
Name
7
6
5
4
3
D3
2
1
D1
0
EE�
EED
EEC
—
D7
—
D6
D6
—
D5
D5
—
D4
D4
—
D2
D2
WR
D0
D0
RD
D3
D1
WREN
RDEN
Rev. 1.20
38
�ꢀꢁꢀst 10ꢂ 2012
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
