HT45F39 datasheet(46/102 Pages) HOLTEK

46 / 102 page

Rev. 1.10

July 01, 2016

Rev. 1.10

July 01, 2016

HT45F39/HT45F391

Ultrasonic Distance Measurement 8-bit Flash MCU

HT45F39/HT45F391

Ultrasonic Distance Measurement 8-bit Flash MCU

TM Operation

ThekeytounderstandinghowtheTMoperatesistoseeitintermsofafreerunningcounterwhose

valueisthencomparedwiththevalueofpre-programmedinternalcomparators.Whenthefree

runningcounterhasthesamevalueasthepre-programmedcomparator,knownasacomparematch

situation,aTMinterruptsignalwillbegeneratedwhichcanclearthecounterandperhapsalso

changetheconditionoftheTMoutputpin.TheinternalTMcounterisdrivenbyauserselectable

clocksource,whichcanbeaninternalclockoranexternalpin.

TM Clock Source

TheclocksourcewhichdrivesthemaincounterineachTMcanoriginatefromvarioussources.

TheselectionoftherequiredclocksourceisimplementedusingtheTnCK2~TnCK0bitsintheTM

controlregisters.TheclocksourcecanbearatioofthesystemclockfSYSortheexternalTCKnpin.

TheTCKnpinclocksourceisusedtoallowanexternalsignaltodrivetheTMasanexternalclock

sourceorforeventcounting.

TM Interrupts

TheCompactTMshavetwointernalinterrupts,oneforeachoftheinternalcomparatorAor

comparatorP,whichgenerateaTMinterruptwhenacomparematchconditionoccurs.Whena

TMinterruptisgenerateditcanbeusedtoclearthecounterandalsotochangethestateoftheTM

outputpin.

TM External Pins

EachoftheTMshasoneTMinputpin,withthelabelTCKn.TheTMinputpin,isessentiallya

clocksourcefortheTMandisselectedusingtheTnCK2~TnCK0bitsintheTMnC0register.This

externalTMinputpinallowsanexternalclocksourcetodrivetheinternalTM.ThisexternalTM

inputpinissharedwithotherfunctionsbutwillbeconnectedtotheinternalTMifselectedusingthe

TnCK2~TnCK0bits.TheTMinputpincanbechosentohaveeitherarisingorfallingactiveedge.

TheTMseachhaveoneormoreoutputpinswiththelabelTPn.WhentheTMisintheCompare

MatchOutputMode,thesepinscanbecontrolledbytheTMtoswitchtoahighorlowlevelorto

togglewhenacomparematchsituationoccurs.TheexternalTPnoutputpinisalsothepinwherethe

TMgeneratesthePWMoutputwaveform.AstheTMoutputpinsarepin-sharedwithotherfunction,

theTMoutputfunctionmustfirstbesetupusingregisters.Asinglebitinoneoftheregisters

determinesifitsassociatedpinistobeusedasanexternalTMoutputpinorifitistohaveanother

function.

HT45F39 Datasheet(PDF) 46 Page - Holtek Semiconductor Inc