Holtek HT66F30 - Page 221

Rev. 2.50 220 June 22, 2017 Rev. 2.50 221 June 22, 2017
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
A/D Converter Interrupt
TheA/DConverterInterruptiscontrolledbytheterminationofanA/Dconversionprocess.AnA/D
ConverterInterruptrequestwilltakeplacewhentheA/DConverterInterruptrequestag,ADF,is
set,whichoccurswhentheA/Dconversionprocessnishes.Toallowtheprogramtobranchtoits
respectiveinterruptvectoraddress,theglobalinterruptenablebit,EMI,andA/DInterruptenablebit,
ADE,mustrstbeset.Whentheinterruptisenabled,thestackisnotfullandtheA/Dconversion
processhasended,asubroutinecalltotheA/DConverterInterruptvector,willtakeplace.Whenthe
interruptisserviced,theA/DConverterInterruptag,ADF,willbeautomaticallycleared.TheEMI
bitwillalsobeautomaticallyclearedtodisableotherinterrupts.
Time Base Interrupt
ThefunctionoftheTimeBaseInterruptsistoprovideregulartimesignalintheformofaninternal
interrupt.Theyarecontrolledbytheoverowsignalsfromtheirrespectivetimerfunctions.When
thesehappenstheirrespectiveinterruptrequestflags,TB0ForTB1Fwillbeset.Toallowthe
programtobranchtotheirrespectiveinterruptvectoraddresses,theglobalinterruptenablebit,EMI
andTimeBaseenablebits,TB0EorTB1E,mustrstbeset.Whentheinterruptisenabled,thestack
isnotfullandtheTimeBaseoverows,asubroutinecalltotheirrespectivevectorlocationswill
takeplace.Whentheinterruptisserviced,therespectiveinterruptrequestag,TB0ForTB1F,will
beautomaticallyresetandtheEMIbitwillbeclearedtodisableotherinterrupts.
ThepurposeoftheTimeBaseInterruptistoprovideaninterruptsignalatxedtimeperiods.Their
clocksourcesoriginatefromtheinternalclocksourcef
TB
.Thisf
TB
inputclockpassesthrougha
divider,thedivisionratioofwhichisselectedbyprogrammingtheappropriatebitsintheTBC
registertoobtainlongerinterruptperiodswhosevalueranges.Theclocksourcethatgeneratesf
TB
,
whichinturncontrolstheTimeBaseinterruptperiod,canoriginatefromseveraldifferentsources,
asshownintheSystemOperatingModesection.