HT67F488 datasheet(140/171 Pages) HOLTEK

140 / 171 page

Rev. 1.60

140

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HT67F488/HT67F489

TinyPowerTM A/D Flash MCU with LCD & EEPROM

UART Interrupt

SeveralindividualUARTconditionscangenerateaUARTinterrupt.Whentheseconditionsexist,

alowpulsewillbegeneratedtogettheattentionofthemicrocontroller.Theseconditionsarea

transmitterdataregisterempty,transmitteridle,receiverdataavailable,receiveroverrun,address

detectandanRXpinwake-up.Toallowtheprogramtobranchtotherespectiveinterruptvector

addresses,theglobalinterruptenablebit,EMI,andUARTinterruptenablebit,UARE,mustfirst

beset.Whentheinterruptisenabled,thestackisnotfullandanyoftheseconditionsarecreated,

asubroutinecalltotheUARTInterruptvectorwilltakeplace.Whentheinterruptisserviced,the

UARTInterruptflag,UARF,willbeautomaticallycleared.TheEMIbitwillalsobeautomatically

clearedtodisableotherinterrupts.However,theUSRregisterflagswillbeclearedautomatically

whencertainactionsaretakenbytheUART,thedetailsofwhicharegivenintheUARTsection.

Time Base Interrupt

ThefunctionoftheTimeBaseInterruptsistoprovideregulartimesignalintheformofaninternal

interrupt.Theyarecontrolledbytheoverflowsignalsfromtheirrespectivetimerfunctions.When

thesehappenstheirrespectiveinterruptrequestflags,TB0ForTB1Fwillbeset.Toallowthe

programtobranchtotheirrespectiveinterruptvectoraddresses,theglobalinterruptenablebit,

EMIandTimeBaseenablebits,TB0EorTB1E,andassociatedMulti-functioninterruptenablebit,

mustfirstbeset.Whentheinterruptisenabled,thestackisnotfullandtheTimeBaseoverflows,a

subroutinecalltotheMulti-functionInterruptvectorwilltakeplace.WhentheTimeBaseInterrupt

isserviced,theEMIbitwillbeautomaticallyclearedtodisableotherinterrupts,howeveronlythe

Multi-functioninterruptrequestflagwillbealsoautomaticallycleared.AstheTB0ForTB1Fflag

willnotbeautomaticallycleared,ithastobeclearedbytheapplicationprogram.

ThepurposeoftheTimeBaseInterruptistoprovideaninterruptsignalatfixedtimeperiods.Their

clocksourcesoriginatefromtheinternalclocksourcefTB.ThisfTBinputclockpassesthrougha

divider,thedivisionratioofwhichisselectedbyprogrammingtheappropriatebitsintheTBC

registertoobtainlongerinterruptperiodswhosevalueranges.TheclocksourcethatgeneratesfTB,

whichinturncontrolstheTimeBaseinterruptperiod,canoriginatefromseveraldifferentsources,

asshownintheSystemOperatingModesection.

HT67F488 Datasheet(PDF) 140 Page - Holtek Semiconductor Inc