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HT66F4530 数据表(PDF) 49 Page - Holtek Semiconductor Inc |
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HT66F4530 数据表(HTML) 49 Page - Holtek Semiconductor Inc |
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49 / 224 page ![]() Rev. 1.00 48 De�e��e� �1� �01� Rev. 1.00 49 De�e��e� �1� �01� HT66F4530/HT66F4540/HT66F4550 A/D Flash MCU with Dual Operational Amplifiers HT66F4530/HT66F4540/HT66F4550 A/D Flash MCU with Dual Operational Amplifiers Reading Data from the EEPROM ToreaddatafromtheEEPROM,thereadenablebit,RDEN,intheEECregistermustfirstbeset hightoenablethereadfunction.TheEEPROMaddressofthedatatobereadmustthenbeplaced intheEEAregister.IftheRDbitintheEECregisterisnowsethigh,areadcyclewillbeinitiated. SettingtheRDbithighwillnotinitiateareadoperationiftheRDENbithasnotbeenset.When thereadcycleterminates,theRDbitwillbeautomaticallyclearedtozero,afterwhichthedatacan bereadfromtheEEDregister.ThedatawillremainintheEEDregisteruntilanotherreadorwrite operationisexecuted.TheapplicationprogramcanpolltheRDbittodeterminewhenthedatais validforreading. Writing Data to the EEPROM TheEEPROMaddressofthedatatobewrittenmustfirstbeplacedintheEEAregisterandthedata placedintheEEDregister.TowritedatatotheEEPROM,thewriteenablebit,WREN,intheEEC registermustfirstbesethightoenablethewritefunction.Afterthis,theWRbitintheEECregister mustbeimmediatelysethightoinitiateawritecycle.Thesetwoinstructionsmustbeexecuted consecutively.TheglobalinterruptbitEMIshouldalsofirstbeclearedbeforeimplementingany writeoperations,andthensetagainafterthewritecyclehasstarted.NotethatsettingtheWRbit highwillnotinitiateawritecycleiftheWRENbithasnotbeenset.AstheEEPROMwritecycleis controlledusinganinternaltimerwhoseoperationisasynchronoustomicrocontrollersystemclock, acertaintimewillelapsebeforethedatawillhavebeenwrittenintotheEEPROM.Detectingwhen thewritecyclehasfinishedcanbeimplementedeitherbypollingtheWRbitintheEECregisteror byusingtheEEPROMinterrupt.Whenthewritecycleterminates,theWRbitwillbeautomatically clearedtozerobythemicrocontroller,informingtheuserthatthedatahasbeenwrittentothe EEPROM.TheapplicationprogramcanthereforepolltheWRbittodeterminewhenthewritecycle hasended. Write Protection Protectionagainstinadvertentwriteoperationisprovidedinseveralways.Afterthesedevices arepowered-ontheWriteEnablebitinthecontrolregisterwillbeclearedpreventinganywrite operations.Alsoatpower-ontheMemoryPointerhighbyteregister,MP1HorMP2H,willbereset tozero,whichmeansthatDataMemorySector0willbeselected.AstheEEPROMcontrolregister islocatedinSector1,thisaddsafurthermeasureofprotectionagainstspuriouswriteoperations. Duringnormalprogramoperation,ensuringthattheWriteEnablebitinthecontrolregisteris clearedwillsafeguardagainstincorrectwriteoperations. EEPROM Interrupt TheEEPROMwriteinterruptisgeneratedwhenanEEPROMwritecyclehasended.TheEEPROM interruptmustfirstbeenabledbysettingtheDEEbitintherelevantinterruptregister.Whenan EEPROMwritecycleends,theDEFrequestflagwillbeset.Iftheglobal,EEPROMinterruptsare enabledandthestackisnotfull,ajumptotheassociatedEEPROMInterruptvectorwilltakeplace. Whentheinterruptisserviced,theEEPROMInterruptflag,DEF,willbeautomaticallycleared.The EMIbitwillalsobeautomaticallyclearedtodisableotherinterrupts.Moredetailscanbeobtained intheInterruptsection. |
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