HT66F20 datasheet(143/298 Pages) HOLTEK

143 / 298 page

Rev. 1.90

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Rev. 1.90

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HT66F20/HT66F30/HT66F40/HT66F50/HT66F60

HT66FU30/HT66FU40/HT66FU50/HT66FU60

Enhanced A/D Flash Type 8-Bit MCU with EEPROM

HT66F20/HT66F30/HT66F40/HT66F50/HT66F60

HT66FU30/HT66FU40/HT66FU50/HT66FU60

Enhanced A/D Flash Type 8-Bit MCU with EEPROM

Capture Input Mode

ToselectthismodebitsTnM1andTnM0intheTMnC1registershouldbesetto01respectively.

Thismodeenablesexternalsignalstocaptureandstorethepresentvalueoftheinternalcounter

andcanthereforebeusedforapplicationssuchaspulsewidthmeasurements.Theexternalsignalis

suppliedontheTPn_0orTPn_1pin,whoseactiveedgecanbeeitherarisingedge,afallingedgeor

bothrisingandfallingedges;theactiveedgetransitiontypeisselectedusingtheTnIO1andTnIO0

bitsintheTMnC1register.ThecounterisstartedwhentheTnONbitchangesfromlowtohigh

whichisinitiatedusingtheapplicationprogram.

WhentherequirededgetransitionappearsontheTPn_0orTPn_1pinthepresentvalueinthe

counterwillbelatchedintotheCCRAregistersandaTMinterruptgenerated.Irrespectiveofwhat

eventsoccurontheTPn_0orTPn_1pinthecounterwillcontinuetofreerununtiltheTnONbit

changesfromhightolow.WhenaCCRPcomparematchoccursthecounterwillresetbacktozero;

inthiswaytheCCRPvaluecanbeusedtocontrolthemaximumcountervalue.WhenaCCRP

comparematchoccursfromComparatorP,aTMinterruptwillalsobegenerated.Countingthe

numberofoverflowinterruptsignalsfromtheCCRPcanbeausefulmethodinmeasuringlong

pulsewidths.TheTnIO1andTnIO0bitscanselecttheactivetriggeredgeontheTPn_0orTPn_1

pintobearisingedge,fallingedgeorbothedgetypes.IftheTnIO1andTnIO0bitsarebothset

high,thennocaptureoperationwilltakeplaceirrespectiveofwhathappensontheTPn_0orTPn_1

pin,howeveritmustbenotedthatthecounterwillcontinuetorun.

AstheTPn_0orTPn_1pinispinsharedwithotherfunctions,caremustbetakeniftheTMisinthe

InputCaptureMode.Thisisbecauseifthepinissetupasanoutput,thenanytransitionsonthispin

maycauseaninputcaptureoperationtobeexecuted.TheTnCCLRandTnDPXbitsarenotusedin

thisMode.

HT66F20 Datasheet(PDF) 143 Page - Holtek Semiconductor Inc