HT67F370 datasheet(49/225 Pages) HOLTEK

49 / 225 page

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HT67F370

TinyPowerTM A/D Flash MCU with LCD & EEPROM

HT67F370

TinyPowerTM A/D Flash MCU with LCD & EEPROM

Programming Considerations

CaremustbetakenthatdataisnotinadvertentlywrittentotheEEPROM.Protectioncanbe

enhancedbyensuringthattheWriteEnablebitisnormallyclearedtozerowhennotwriting.Also

theMemoryPointerhighbyteregister,MP1HorMP2H,couldbenormallyclearedtozeroasthis

wouldinhibitaccesstoSector1wheretheEEPROMcontrolregisterexists.Althoughcertainlynot

necessary,considerationmightbegivenintheapplicationprogramtothecheckingofthevalidityof

newwritedatabyasimplereadbackprocess.

WhenwritingdatatheWRbitmustbesethighimmediatelyaftertheWRENbithasbeensethigh,

toensurethewritecycleexecutescorrectly.TheglobalinterruptbitEMIshouldalsobecleared

beforeawritecycleisexecutedandthenre-enabledafterthewritecyclestarts.Notethatthedevice

shouldnotentertheIDLEorSLEEPmodeuntiltheEEPROMreadorwriteoperationistotally

complete.Otherwise,theEEPROMreadorwriteoperationwillfail.

Programming Examples

• Reading data from the EEPROM – polling method

MOV A,EEPROM_ADRES;userdefinedaddress

MOV EEA,A

MOV A,040H;setupmemorypointerMP1L

MOV MP1L,A;MP1LpointstoEECregister

MOV A,01H;setupmemorypointerMP1H

MOV MP1H,A

SET IAR1.1;setRDENbit,enablereadoperations

SET IAR1.0;startReadCycle-setRDbit

BACK:

SZ IAR1.0;checkforreadcycleend

JMP BACK

CLR IAR1 ;disableEEPROMread/write

CLR MP1H

MOV A,EED;movereaddatatoregister

MOV READ_DATA,A

• Writing Data to the EEPROM – polling method

MOV A,EEPROM_ADRES;userdefinedaddress

MOV EEA,A

MOV A,EEPROM_DATA;userdefineddata

MOV EED,A

MOV A,040H;setupmemorypointerMP1L

MOV MP1L,A;MP1LpointstoEECregister

MOV A,01H;setupmemorypointerMP1H

MOV MP1H,A

CLR EMI

SET IAR1.3;setWRENbit,enablewriteoperations

SET IAR1.2;startWriteCycle-setWRbit–executedimmediately

;aftersetWRENbit

SET EMI

BACK:

SZ IAR1.2;checkforwritecycleend

JMP BACK

CLR IAR1 ;disableEEPROMread/write

CLR MP1H

HT67F370 Datasheet(PDF) 49 Page - Holtek Semiconductor Inc

HT67F370 Datasheet(HTML) 49 Page - Holtek Semiconductor Inc

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