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Rev. 1.50 114 August 28, 2017 Rev. 1.50 115 August 28, 2017

HT66F0175/HT66F0185

A/D Flash MCU with EEPROM

HT66F0175/HT66F0185

A/D Flash MCU with EEPROM

Capture Input Mode

ToselectthismodebitsTnM1andTnM0intheTMnC1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TPnorTCKnpin,selectedbytheTnCAPTSbitintheTMnC1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TnIO1andTnIO0bitsintheTMnC1register.Thecounter

isstartedwhentheTnONbitchangesfromlowtohighwhichisinitiatedusingtheapplication

program.

WhentherequirededgetransitionappearsontheTPnorTCKnpinthepresentvalueinthecounter

willbelatchedintotheCCRAregistersandaTMninterruptgenerated.Irrespectiveofwhatevents

occurontheTPnorTCKnpinthecounterwillcontinuetofreerununtiltheTnON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TMn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TnIO1

andTnIO0bitscanselecttheactivetriggeredgeontheTPnorTCKnpintobearisingedge,falling

edgeorbothedgetypes.IftheTnIO1andTnIO0bitsarebothsethigh,thennocaptureoperation

willtakeplaceirrespectiveofwhathappensontheTPnorTCKnpin,howeveritmustbenotedthat

thecounterwillcontinuetorun.

AstheTPnorTCKnpinispinsharedwithotherfunctions,caremustbetakeniftheTMnisinthe

InputCapture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TnCCLR,TnOCandTnPOLbitsarenot

usedinthisMode.

Holtek HT66F0175 User Manual

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