HT67F488 datasheet(75/171 Pages) HOLTEK

75 / 171 page

Rev. 1.60

�ove��e� �� 016

HT67F488/HT67F489

TinyPowerTM A/D Flash MCU with LCD & EEPROM

Timer/Counter Mode

Toselectthismode,bitsTnM1andTnM0intheTMnC1registershouldallbesetto11respectively.

TheTimer/CounterModeoperatesinanidenticalwaytotheCompareMatchOutputMode

generatingthesameinterruptflags.TheexceptionisthatintheTimer/CounterModetheTMoutput

pinisnotused.ThereforetheabovedescriptionandTimingDiagramsfortheCompareMatch

OutputModecanbeusedtounderstanditsfunction.AstheTMoutputpinisnotusedinthismode,

thepincanbeusedasanormalI/Opinorotherpin-sharedfunction.

PWM Output Mode

Toselectthismode,bitsTnM1andTnM0intheTMnC1registershouldbesetto10respectively

andalsotheTnIO1andTnIO0bitsshouldbesetto10respectively.ThePWMfunctionwithin

theTMisusefulforapplicationswhichrequirefunctionssuchasmotorcontrol,heatingcontrol,

illuminationcontroletc.Byprovidingasignaloffixedfrequencybutofvaryingdutycycleonthe

TMoutputpin,asquarewaveACwaveformcanbegeneratedwithvaryingequivalentDCRMS

values.

AsboththeperiodanddutycycleofthePWMwaveformcanbecontrolled,thechoiceofgenerated

waveformisextremelyflexible.InthePWMOutputMode,theTnCCLRbithasnoeffectasthe

PWMperiod.BothoftheCCRPandCCRAregistersareusedtogeneratethePWMwaveform,one

registerisusedtocleartheinternalcounterandthuscontrolthePWMwaveformfrequency,while

theotheroneisusedtocontrolthedutycycle.ThePWMwaveformfrequencyanddutycyclecan

thereforebecontrolledbythevaluesintheCCRAandCCRPregisters.

Aninterruptflag,oneforeachoftheCCRAandCCRP,willbegeneratedwhenacomparematch

occursfromeitherComparatorAorComparatorP.TheTnOCbitintheTMnC1registerisusedto

selecttherequiredpolarityofthePWMwaveformwhilethetwoTnIO1andTnIO0bitsareusedto

enablethePWMoutputortoforcetheTMoutputpintoafixedhighorlowlevel.TheTnPOLbitis

usedtoreversethepolarityofthePWMoutputwaveform.

• 10-bit PTM, PWM Output Mode

CCRP

1~1023

Pe�iod

1~10�3

10�4

Duty

CCRA

IffSYS=8MHz,TMclocksourceselectfSYS/4,CCRP=512andCCRA=128,

ThePTMPWMoutputfrequency=(fSYS/4)/512=fSYS/2048=3.90625kHz,duty=128/512=25%.

IftheDutyvaluedefinedbytheCCRAregisterisequaltoorgreaterthanthePeriodvalue,thenthe

PWMoutputdutyis100%.

HT67F488 데이터시트(PDF) 75 Page - Holtek Semiconductor Inc