HT45F3W datasheet(131/167 Pages) HOLTEK

131 / 167 page

Rev. 1.50

130

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Rev. 1.50

131

De�e��e� 01� �01�

HT45F3W

R-Type Blood Pressure Meter Flash MCU

HT45F3W

R-Type Blood Pressure Meter Flash MCU

Charge Pump Interrupt

ThechargepumpInterrupt,iscontainedwithintheMulti-functionInterrupt.Toallowtheprogram

tobranchtotheirrespectiveinterruptvectoraddresses,theglobalinterruptenablebit,EMI,multi-

functionenablebit,MFnEandchargepumpinterruptenablebit,CHPE,mustfirstbeset.Whenthe

interruptisenabled,thestackisnotfullandtheinputvoltageofchargepumpisgreaterthan3.8V,a

subroutinecalltotherespectiveMulti-functionInterruptvector,willtakeplace.Whentheinterrupt

isserviced,theEMIbitwillbeautomaticallyclearedtodisableotherinterrupts,howeveronlythe

Multi-functioninterruptrequestflagwillbealsoautomaticallycleared.

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.

Programming Considerations

Bydisablingtherelevantinterruptenablebits,arequestedinterruptcanbepreventedfrombeing

serviced,however,onceaninterruptrequestflagisset,itwillremaininthisconditioninthe

interruptregisteruntilthecorrespondinginterruptisservicedoruntiltherequestflagisclearedby

theapplicationprogram.

WhereacertaininterruptiscontainedwithinaMulti-functioninterrupt,thenwhentheinterrupt

serviceroutineisexecuted,asonlytheMulti-functioninterruptrequestflags,MFnF,willbe

automaticallycleared,theindividualrequestflagforthefunctionneedstobeclearedbythe

applicationprogram.

Itisrecommendedthatprogramsdonotusethe“CALL”instructionwithintheinterruptservice

subroutine.Interruptsoftenoccurinanunpredictablemannerorneedtobeservicedimmediately.

Ifonlyonestackisleftandtheinterruptisnotwellcontrolled,theoriginalcontrolsequencewillbe

damagedonceaCALLsubroutineisexecutedintheinterruptsubroutine.

EveryinterrupthasthecapabilityofwakingupthemicrocontrollerwhenitisinSLEEPorIDLE

Mode,thewakeupbeinggeneratedwhentheinterruptrequestflagchangesfromlowtohigh.Ifitis

requiredtopreventacertaininterruptfromwakingupthemicrocontrollerthenitsrespectiverequest

flagshouldbefirstsethighbeforeenterSLEEPorIDLEMode.

AsonlytheProgramCounterispushedontothestack,thenwhentheinterruptisserviced,ifthe

contentsoftheaccumulator,statusregisterorotherregistersarealteredbytheinterruptservice

program,theircontentsshouldbesavedtothememoryatthebeginningoftheinterruptservice

routine.

Toreturnfromaninterruptsubroutine,eitheraRETorRETIinstructionmaybeexecuted.TheRETI

instructioninadditiontoexecutingareturntothemainprogramalsoautomaticallysetstheEMI

bithightoallowfurtherinterrupts.TheRETinstructionhoweveronlyexecutesareturntothemain

programleavingtheEMIbitinitspresentzerostateandthereforedisablingtheexecutionoffurther

interrupts.

HT45F3W Datasheet(PDF) 131 Page - Holtek Semiconductor Inc

HT45F3W Datasheet(HTML) 131 Page - Holtek Semiconductor Inc

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