PIC16基本振荡器设计

Theoscillatorcircuitisoneofthemostoverlooked

areasofmicroprocessorcircuitdesign.Components

areusuallyselectedbasedonthemanufacturers

tables.Ifthecircuitstartsupandworks,fine,noothe

thoughtneedbegiventoit,right?Wrong.Manycondi

tionscannegativelyaffecttheperformanceofyou

design.Highertemperaturesandlowersupplyvoltages

canlowertheloopgainintheoscillatorcircuit,causing

poor,slow,ornostart-up.Coldertemperaturesand

highersupplyvoltagescanincreasetheloopgaino

theoscillatorcircuit,causingthecrystaltobeover

driven,andpotentiallydamaged;orthecircuitcanbe

forcedtoanotherharmonicandthrowoffthetiming,o

ceasefunctioningaltogether.Itisalsopossibleto

wastepowerthroughtheimproperselectionofcompo

nentsorClockmodes.MFACT001BasicPIC16/17OscillatorDesignFIGURE1:TYPICALPIERCEPARALLELAuthor:DanMatthewsRESONANTOSCILLATORMicrochipTechnologyInc.CIRCUITGainofinverter/amplifierisbasedonselectedClockmode.TheoscillatorcircuitisoneofthemostoverlookedClockModes:areasofmicroprocessorcircuitdesign.Components