HT66F20 datasheet(182/298 Pages) HOLTEK

182 / 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

Comparators

Twoindependentanalogcomparatorsarecontainedwithinthesedevices.Thesefunctionsoffer

flexibilityviatheirregistercontrolledfeaturessuchaspower-down,polarityselect,hysteresisetc.

InsharingtheirpinswithnormalI/OpinsthecomparatorsdonotwastepreciousI/Opinsifthere

functionsareotherwiseunused.

Cn +

Cn -

Cn PO L

Cn OU T

Cn X

Cn SE L

Comparator

Comparator Operation

Thedevicecontainstwocomparatorfunctionswhichareusedtocomparetwoanalogvoltages

andprovideanoutputbasedontheirdifference.Fullcontroloverthetwointernalcomparators

isprovidedviatwocontrolregisters,CP0CandCP1C,oneassignedtoeachcomparator.The

comparatoroutputisrecordedviaabitintheirrespectivecontrolregister,butcanalsobetransferred

outontoasharedI/Opin.Additionalcomparatorfunctionsinclude,outputpolarity,hysteresis

functionsandpowerdowncontrol.

Anypull-highresistorsconnectedtothesharedcomparatorinputpinswillbeautomatically

disconnectedwhenthecomparatorisenabled.Asthecomparatorinputsapproachtheirswitching

level,somespuriousoutputsignalsmaybegeneratedonthecomparatoroutputduetotheslow

risingorfallingnatureoftheinputsignals.Thiscanbeminimisedbyselectingthehysteresis

functionwillapplyasmallamountofpositivefeedbacktothecomparator.Ideallythecomparator

shouldswitchatthepointwherethepositiveandnegativeinputssignalsareatthesamevoltage

level,however,unavoidableinputoffsetsintroducesomeuncertaintieshere.Thehysteresisfunction,

ifenabled,alsoincreasestheswitchingoffsetvalue.

HT66F20 Datasheet(PDF) 182 Page - Holtek Semiconductor Inc