HT67F488 datasheet(79/171 Pages) HOLTEK

79 / 171 page

Rev. 1.60

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HT67F488/HT67F489

TinyPowerTM A/D Flash MCU with LCD & EEPROM

Capture Input Mode

ToselectthismodebitsTnM1andTnM0intheTMnC1registershouldbesetto01respectively.

Thismodeenablesexternalsignalstocaptureandstorethepresentvalueoftheinternalcounter

andcanthereforebeusedforapplicationssuchaspulsewidthmeasurements.Theexternalsignalis

suppliedontheTPn_0,TPn_1orTCKnpin,selectedbytheTnCAPTSbitintheTMnC0register.

Theinputpinactiveedgecanbeeitherarisingedge,afallingedgeorbothrisingandfallingedges;

theactiveedgetransitiontypeisselectedusingtheTnIO1andTnIO0bitsintheTMnC1register.

ThecounterisstartedwhentheTnONbitchangesfromlowtohighwhichisinitiatedusingthe

applicationprogram.

WhentherequirededgetransitionappearsontheTPn_0,TPn_1orTCKnpinthepresentvaluein

thecounterwillbelatchedintotheCCRAregisterandaTMinterruptgenerated.Irrespectiveof

whateventsoccurontheTPn_0,TPn_1orTCKnpinthecounterwillcontinuetofreerununtilthe

TnONbitchangesfromhightolow.WhenaCCRPcomparematchoccursthecounterwillreset

backtozero;inthiswaytheCCRPvaluecanbeusedtocontrolthemaximumcountervalue.When

aCCRPcomparematchoccursfromComparatorP,aTMinterruptwillalsobegenerated.Counting

thenumberofoverflowinterruptsignalsfromtheCCRPcanbeausefulmethodinmeasuringlong

pulsewidths.TheTnIO1andTnIO0bitscanselecttheactivetriggeredgeontheTPn_0,TPn_1

orTCKnpintobearisingedge,fallingedgeorbothedgetypes.IftheTnIO1andTnIO0bitsare

bothsethigh,thennocaptureoperationwilltakeplaceirrespectiveofwhathappensontheTPn_0,

TPn_1orTCKnpin,howeveritmustbenotedthatthecounterwillcontinuetorun.

AstheTPn_0,TPn_1orTCKnpinispinsharedwithotherfunctions,caremustbetakeniftheTMn

isintheCaptureInputMode.Thisisbecauseifthepinissetupasanoutput,thenanytransitionson

thispinmaycauseaninputcaptureoperationtobeexecuted.TheTnCCLR,TnOCandTnPOLbits

arenotusedinthisMode.

HT67F488 датащи(PDF) 79 Page - Holtek Semiconductor Inc