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HT66F4530 数据表(PDF) 53 Page - Holtek Semiconductor Inc |
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HT66F4530 数据表(HTML) 53 Page - Holtek Semiconductor Inc |
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53 / 224 page ![]() Rev. 1.00 5� De�e��e� �1� �01� Rev. 1.00 53 De�e��e� �1� �01� HT66F4530/HT66F4540/HT66F4550 A/D Flash MCU with Dual Operational Amplifiers HT66F4530/HT66F4540/HT66F4550 A/D Flash MCU with Dual Operational Amplifiers Internal High Speed RC Oscillator – HIRC TheinternalRCoscillatorisafullyintegratedsystemoscillatorrequiringnoexternalcomponents. TheinternalRCoscillatorhasthreefixedfrequenciesof2MHz,4MHzand8MHz.Devicetrimming duringthemanufacturingprocessandtheinclusionofinternalfrequencycompensationcircuitsare usedtoensurethattheinfluenceofthepowersupplyvoltage,temperatureandprocessvariationson theoscillationfrequencyareminimised.Notethatifthisinternalsystemclockoptionisselected,asit requiresnoexternalpinsforitsoperation,I/OpinsPC0andPC1arefreeforuseasnormalI/Opins. External 32.768kHz Crystal Oscillator – LXT TheExternal32.768kHzCrystalSystemOscillatorisoneofthelowfrequencyoscillatorchoices, whichisselectedviaasoftwarecontrolbit,FSS.Thisclocksourcehasafixedfrequencyof 32.768kHzandrequiresa32.768kHzcrystaltobeconnectedbetweenpinsXT1andXT2.The externalresistorandcapacitorcomponentsconnectedtothe32.768kHzcrystalarenecessaryto provideoscillation.Forapplicationswhereprecisefrequenciesareessential,thesecomponentsmay berequiredtoprovidefrequencycompensationduetodifferentcrystalmanufacturingtolerances. AftertheLXToscillatorisenabledbysettingtheLXTENbitto1,thereisatimedelayassociated withtheLXToscillatorwaitingforittostart-up. However,forsomecrystals,toensureoscillationandaccuratefrequencygeneration,itisnecessary toaddtwosmallvalueexternalcapacitors,C1andC2.TheexactvaluesofC1andC2shouldbe selectedinconsultationwiththecrystalorresonatormanufacturer’sspecification.Theexternal parallelfeedbackresistor,RP,isrequired. Thepin-sharedsoftwarecontrolbitsdetermineiftheXT1/XT2pinsareusedfortheLXToscillator orasI/Oorotherpin-sharedfunctionalpins. • IftheLXToscillatorisnotusedforanyclocksource,theXT1/XT2pinscanbeusedasnormalI/O orotherpin-sharedfunctionalpins. • IftheLXToscillatorisusedforanyclocksource,the32.768kHzcrystalshouldbeconnectedto theXT1/XT2pins. Foroscillatorstabilityandtominimisetheeffectsofnoiseandcrosstalk,itisimportanttoensure thatthecrystalandanyassociatedresistorsandcapacitorsalongwithinterconnectinglinesareall locatedasclosetotheMCUaspossible. Note: 1. RP� C1 and C� a�e �equi�ed. �. Although not shown XT1/XT� pins have a pa�asiti� �apa�itan�e of a�ound 7pF. To inte�nal �i��uits Internal Oscillator Circuit C1 C� XT1 XT� RP 3�.7�8 kHz Inte�nal RC Os�illato� External LXT Oscillator LXT Oscillator C1 and C2 Values Crystal Frequency C1 C2 3�.7�8kHz 10pF 10pF Note: 1. C1 and C� values a�e fo� guidan�e only. �. RP=5M~10MΩ is recommended. 32.768kHz Crystal Recommended Capacitor Values |
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