HT66F4530 datasheet(54/224 Pages) HOLTEK

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Rev. 1.00

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HT66F4530/HT66F4540/HT66F4550

A/D Flash MCU with Dual Operational Amplifiers

HT66F4530/HT66F4540/HT66F4550

A/D Flash MCU with Dual Operational Amplifiers

Internal 32kHz Oscillator – LIRC

TheInternal32kHzSystemOscillatorisoneofthelowfrequencyoscillatorchoices,whichis

selectedviaasoftwarecontrolbit,FSS.ItisafullyintegratedRCoscillatorwithatypicalfrequency

of32kHzat5V,requiringnoexternalcomponentsforitsimplementation.Devicetrimmingduring

themanufacturingprocessandtheinclusionofinternalfrequencycompensationcircuitsareused

toensurethattheinfluenceofthepowersupplyvoltage,temperatureandprocessvariationsonthe

oscillationfrequencyareminimised.

Operating Modes and System Clocks

Presentdayapplicationsrequirethattheirmicrocontrollershavehighperformancebutoftenstill

demandthattheyconsumeaslittlepoweraspossible,conflictingrequirementsthatareespecially

trueinbatterypoweredportableapplications.Thefastclocksrequiredforhighperformancewill

bytheirnatureincreasecurrentconsumptionandofcourseviceversa,lowerspeedclocksreduce

currentconsumption.AsHoltekhasprovidedthesedeviceswithbothhighandlowspeedclock

sourcesandthemeanstoswitchbetweenthemdynamically,theusercanoptimisetheoperationof

theirmicrocontrollertoachievethebestperformance/powerratio.

System Clocks

ThesedeviceshavemanydifferentclocksourcesforboththeCPUandperipheralfunction

operation.Byprovidingtheuserwithawiderangeofclockoptionsusingregisterprogramming,a

clocksystemcanbeconfiguredtoobtainmaximumapplicationperformance.

Themainsystemclock,cancomefromahighfrequency,fH,orlowfrequency,fSUB,source,and

isselectedusingtheCKS2~CKS0bitsintheSCCregister.Thehighspeedsystemclockcanbe

sourcedfromanHXTorHIRCoscillator,selectedviaconfiguringtheFHSbitintheSCCregister.

ThelowspeedsystemclocksourcecanbesourcedfromtheinternalclockfSUB.IffSUBisselected

thenitcanbesourcedbyeithertheLXTorLIRCoscillators,selectedviaconfiguringtheFSSbitin

theSCCregister.Theotherchoice,whichisadividedversionofthehighspeedsystemoscillator

hasarangeoffH/2~fH/64.

HT66F4530 Datasheet(PDF) 54 Page - Holtek Semiconductor Inc