HT66F007 datasheet(35/131 Pages) HOLTEK

35 / 131 page

Rev. 1.41

April 11, 2017

Rev. 1.41

April 11, 2017

HT66F007/HT66F008

Cost-Effective A/D Flash MCU with EEPROM

HT66F007/HT66F008

Cost-Effective A/D Flash MCU with EEPROM

Operating Modes and System Clocks

Presentdayapplicationsrequirethattheirmicrocontrollershavehighperformancebutoftenstill

demandthattheyconsumeaslittlepoweraspossible,conflictingrequirementsthatareespecially

trueinbatterypoweredportableapplications.Thefastclocksrequiredforhighperformancewill

bytheirnatureincreasecurrentconsumptionandofcoursevice-versa,lowerspeedclocksreduce

currentconsumption.AsHoltekhasprovidedthesedeviceswithbothhighandlowspeedclock

sourcesandthemeanstoswitchbetweenthemdynamically,theusercanoptimisetheoperationof

theirmicrocontrollertoachievethebestperformance/powerratio.

System Clocks

ThedeviceshavemanydifferentclocksourcesforboththeCPUandperipheralfunctionoperation.

Byprovidingtheuserwithawiderangeofclockoptionsusingconfigurationoptionsandregister

programming,aclocksystemcanbeconfiguredtoobtainmaximumapplicationperformance.

Themainsystemclock,cancomefromeitherahighfrequency,fH,oralowfrequency,fL,andis

selectedusingtheHLCLKbitandCKS2~CKS0bitsintheSMODregister.Thehighspeedsystem

clockcanbesourcedfromeitheranHXTorHIRCoscillator,selectedviaaconfigurationoption.

ThelowspeedsystemclocksourcecanbesourcedfromtheinternalclockfL.IffLisselectedthen

itcanbesourcedfromtheLIRCoscillator.Theotherchoice,whichisadividedversionofthehigh

speedsystemoscillatorhasarangeoffH/2~fH/64.

Therearetwoadditionalinternalclocksfortheperipheralcircuits,thesubstituteclock,fSUB,and

theTimeBaseclock,fTBC.EachoftheseinternalclocksissourcedbytheLIRCoscillator.ThefSUB

clockisusedtoprovideasubstituteclockforthemicrocontrollerjustafterawake-uphasoccurred

toenablefasterwake-uptimes.

HT66F007 Datasheet(PDF) 35 Page - Holtek Semiconductor Inc