HT67F488 datasheet(142/171 Pages) HOLTEK

142 / 171 page

Rev. 1.60

14�

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HT67F488/HT67F489

TinyPowerTM A/D Flash MCU with LCD & EEPROM

LVD Interrupt

TheLowVoltageDetectorInterruptiscontainedwithintheMulti-functionInterrupt.AnLVD

InterruptrequestwilltakeplacewhentheLVDInterruptrequestflag,LVF,isset,whichoccurs

whentheLowVoltageDetectorfunctiondetectsalowpowersupplyvoltage.Toallowtheprogram

tobranchtoitsrespectiveinterruptvectoraddress,theglobalinterruptenablebit,EMI,LowVoltage

Interruptenablebit,LVE,andassociatedMulti-functioninterruptenablebit,mustfirstbeset.When

theinterruptisenabled,thestackisnotfullandalowvoltageconditionoccurs,asubroutinecallto

theMulti-functionInterruptvectorwilltakeplace.WhentheLowVoltageInterruptisserviced,the

EMIbitwillbeautomaticallyclearedtodisableotherinterrupts,howeveronlytheMulti-function

interruptrequestflagwillbealsoautomaticallycleared.AstheLVFflagwillnotbeautomatically

cleared,ithastobeclearedbytheapplicationprogram.

TM Interrupts

TheCompactandPeriodicTypeTMshavetwointerruptseach.AlloftheTMinterruptsare

containedwithintheMulti-functionInterrupts.ForeachoftheCompactandPeriodicTypeTMs

therearetwointerruptrequestflagsTnPFandTnAFandtwoenablebitsTnPEandTnAE.ATM

interruptrequestwilltakeplacewhenanyoftheTMrequestflagsareset,asituationwhichoccurs

whenaTMcomparatorPorAmatchsituationhappens.

Toallowtheprogramtobranchtoitsrespectiveinterruptvectoraddress,theglobalinterruptenable

bit,EMI,respectiveTMInterruptenablebit,andrelevantMulti-functionInterruptenablebit,MFnE,

mustfirstbeset.Whentheinterruptisenabled,thestackisnotfullandaTMcomparatormatch

situationoccurs,asubroutinecalltotherelevantMulti-functionInterruptvectorlocationswilltake

place.WhentheTMinterruptisserviced,theEMIbitwillbeautomaticallyclearedtodisableother

interrupts,howeveronlytherelatedMFnFflagwillbeautomaticallycleared.AstheTMinterrupt

requestflagswillnotbeautomaticallycleared,theyhavetobeclearedbytheapplicationprogram.

Interrupt Wake-up Function

Eachoftheinterruptfunctionshasthecapabilityofwakingupthemicrocontrollerwheninthe

SLEEPorIDLEMode.Awake-upisgeneratedwhenaninterruptrequestflagchangesfromlowto

highandisindependentofwhethertheinterruptisenabledornot.Therefore,eventhoughthedevice

isintheSLEEPorIDLEModeanditssystemoscillatorstopped,situationssuchasexternaledge

transitionsontheexternalinterruptpins,alowpowersupplyvoltageorcomparatorinputchange

maycausetheirrespectiveinterruptflagtobesethighandconsequentlygenerateaninterrupt.Care

mustthereforebetakenifspuriouswake-upsituationsaretobeavoided.Ifaninterruptwake-up

functionistobedisabledthenthecorrespondinginterruptrequestflagshouldbesethighbeforethe

deviceenterstheSLEEPorIDLEMode.Theinterruptenablebitshavenoeffectontheinterrupt

wake-upfunction.

HT67F488 Datasheet(PDF) 142 Page - Holtek Semiconductor Inc