HT45F12 datasheet(36/104 Pages) HOLTEK

36 / 104 page

Rev. 0.00

3�

�e�te��e� �� 01�

Rev. 0.00

�e�te��e� �� 01�

HT45F12

8-Bit Flash MCU with Op Amps & Comparators

HT45F12

8-Bit Flash MCU with Op Amps & Comparators

Operating Modes and System Clocks

Presentdayapplicationsrequirethattheirmicrocontrollershavehighperformancebutoftenstill

demandthattheyconsumeaslittlepoweraspossible,conflictingrequirementsthatareespecially

trueinbatterypoweredportableapplications.Thefastclocksrequiredforhighperformancewill

bytheirnatureincreasecurrentconsumptionandofcoursevice-versa,lowerspeedclocksreduce

currentconsumption.AsHoltekhasprovidedthedevicewithbothhighandlowspeedclocksources

andthemeanstoswitchbetweenthemdynamically,theusercanoptimisetheoperationoftheir

microcontrollertoachievethebestperformance/powerratio.

System Clocks

ThedevicehasmanydifferentclocksourcesforboththeCPUandperipheralfunctionoperation.

Byprovidingtheuserwithawiderangeofclockoptionsusingconfigurationoptionsandregister

programming,aclocksystemcanbeconfiguredtoobtainmaximumapplicationperformance.

Themainsystemclock,cancomefromeitherahighfrequency,fH,orlowfrequency,fL,source,

andisselectedusingtheHLCLKbitandLCKS2~LCKS0bitsintheSYSMODregister.Thehigh

speedsystemclockcanbesourcedfromeitheranHXT,ERC,ECorHIRCoscillator,selectedviaa

configurationoption.ThelowspeedsystemclocksourcecanbesourcedfrominternalclockLIRC.

Theotherchoice,whichisadividedversionofthehighspeedsystemoscillatorhasarangeof

fH/2~fH/64.

System Operation Modes

Therearesixdifferentmodesofoperationforthemicrocontroller,eachonewithitsown

specialcharacteristicsandwhichcanbechosenaccordingtothespecificperformanceand

powerrequirementsoftheapplication.Therearetwomodesallowingnormaloperationofthe

microcontroller,theNORMALModeandSLOWMode.Theremainingfourmodes,theSLEEP0,

SLEEP1,IDLE0andIDLE1ModeareusedwhenthemicrocontrollerCPUisswitchedoffto

conservepower.

HT45F12 Datasheet(PDF) 36 Page - Holtek Semiconductor Inc