HT45F5Q datasheet(90/114 Pages) HOLTEK

90 / 114 page

Rev. 1.10

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Rev. 1.10

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HT45F5Q

Charger Flash MCU

HT45F5Q

Charger Flash MCU

Interrupt Operation

Whentheconditionsforaninterrupteventoccur,suchasaTMComparatorPorComparatorA

matchorA/Dconversioncompletionetc,therelevantinterruptrequestflagwillbeset.Whether

therequestflagactuallygeneratesaprogramjumptotherelevantinterruptvectorisdeterminedby

theconditionoftheinterruptenablebit.Iftheenablebitissethighthentheprogramwilljumpto

itsrelevantvector;iftheenablebitiszerothenalthoughtheinterruptrequestflagissetanactual

interruptwillnotbegeneratedandtheprogramwillnotjumptotherelevantinterruptvector.The

globalinterruptenablebit,ifclearedtozero,willdisableallinterrupts.

Whenaninterruptisgenerated,theProgramCounter,whichstorestheaddressofthenextinstruction

tobeexecuted,willbetransferredontothestack.TheProgramCounterwillthenbeloadedwitha

newaddresswhichwillbethevalueofthecorrespondinginterruptvector.Themicrocontrollerwill

thenfetchitsnextinstructionfromthisinterruptvector.Theinstructionatthisvectorwillusually

bea“JMP”whichwilljumptoanothersectionofprogramwhichisknownastheinterruptservice

routine.Hereislocatedthecodetocontroltheappropriateinterrupt.Theinterruptserviceroutine

mustbeterminatedwitha“RETI”,whichretrievestheoriginalProgramCounteraddressfrom

thestackandallowsthemicrocontrollertocontinuewithnormalexecutionatthepointwherethe

interruptoccurred.

Thevariousinterruptenablebits,togetherwiththeirassociatedrequestflags,areshowninthe

accompanyingdiagramswiththeirorderofpriority.Someinterruptsourceshavetheirown

individualvectorwhileotherssharethesamemulti-functioninterruptvector.Onceaninterrupt

subroutineisserviced,alltheotherinterruptswillbeblocked,astheglobalinterruptenablebit,

EMIbitwillbeclearedautomatically.Thiswillpreventanyfurtherinterruptnestingfromoccurring.

However,ifotherinterruptrequestsoccurduringthisinterval,althoughtheinterruptwillnotbe

immediatelyserviced,therequestflagwillstillberecorded.

Ifaninterruptrequiresimmediateservicingwhiletheprogramisalreadyinanotherinterruptservice

routine,theEMIbitshouldbesetafterenteringtheroutine,toallowinterruptnesting.Ifthestack

isfull,theinterruptrequestwillnotbeacknowledged,eveniftherelatedinterruptisenabled,until

theStackPointerisdecremented.Ifimmediateserviceisdesired,thestackmustbepreventedfrom

becomingfull.Incaseofsimultaneousrequests,theaccompanyingdiagramshowstheprioritythat

isapplied.Alloftheinterruptrequestflagswhensetwillwake-upthedeviceifitisinSLEEPor

IDLEMode,howevertopreventawake-upfromoccurringthecorrespondingflagshouldbeset

beforethedeviceisinSLEEPorIDLEMode.

HT45F5Q Datasheet(PDF) 90 Page - Holtek Semiconductor Inc