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Rev. 1.71 94 April 11, 2017 Rev. 1.71 95 April 11, 2017

HT66F002/HT66F0025/HT66F003/HT66F004

Cost-Effective A/D Flash MCU with EEPROM

HT66F002/HT66F0025/HT66F003/HT66F004

Cost-Effective A/D Flash MCU with EEPROM

Capture Input Mode

ToselectthismodebitsPTnM1andPTnM0inthePTMnC1registershouldbesetto01respectively.

Thismodeenablesexternalsignalstocaptureandstorethepresentvalueoftheinternalcounter

andcanthereforebeusedforapplicationssuchaspulsewidthmeasurements.Theexternalsignal

issuppliedonthePTPnIorPTCKnpin,selectedbythePTnCKSbitinthePTMnC1register.The

inputpinactiveedgecanbeeitherarisingedge,afallingedgeorbothrisingandfallingedges;the

activeedgetransitiontypeisselectedusingthePTnIO1andPTnIO0bitsinthePTMnC1register.

ThecounterisstartedwhenthePTnONbitchangesfromlowtohighwhichisinitiatedusingthe

applicationprogram.

WhentherequirededgetransitionappearsonthePTPnIorPTCKnpinthepresentvalueinthe

counterwillbelatchedintotheCCRAregisterandaTMinterruptgenerated.Irrespectiveofwhat

eventsoccuronthePTPnIorPTCKnpinthecounterwillcontinuetofreerununtilthePTnONbit

changesfromhightolow.WhenaCCRPcomparematchoccursthecounterwillresetbacktozero;

inthiswaytheCCRPvaluecanbeusedtocontrolthemaximumcountervalue.WhenaCCRP

comparematchoccursfromComparatorP,aTMinterruptwillalsobegenerated.Countingthe

numberofoverowinterruptsignalsfromtheCCRPcanbeausefulmethodinmeasuringlongpulse

widths.ThePTnIO1andPTnIO0bitscanselecttheactivetriggeredgeonthePTPnIorPTCKnpin

tobearisingedge,fallingedgeorbothedgetypes.IfthePTnIO1andPTnIO0bitsarebothsethigh,

thennocaptureoperationwilltakeplaceirrespectiveofwhathappensonthePTPnIorPTCKnpin,

howeveritmustbenotedthatthecounterwillcontinuetorun.

AsthePTPnIorPTCKnpinispinsharedwithotherfunctions,caremustbetakenifthePTMisin

theCaptureInputMode.Thisisbecauseifthepinissetupasanoutput,thenanytransitionsonthis

pinmaycauseaninputcaptureoperationtobeexecuted.ThePTnCCLR,PTnOCandPTnPOLbits

arenotusedinthisMode.

Holtek HT66F002 User Manual

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