使用低功耗低成本技术的时钟设计

Typicalembeddedcontrolapplicationsplacedemands

suchaslowpowerconsumption,smallsize,lowcost

andreducedcomponentcountontothemicrocontroller.

Thisapplicationnoteimplementsa24-hourdigital

clock,alarmand99minute59secondcountdown

timer,yetoperatesontwo“AA”batteries.The

PIC16C54Aisperfectforthisapplication,duetoit’s

smallsize,highcurrentI/OswithdirectLEDdrive,low

cost,fastinstructionthroughputandlowfrequency/cur-

rentoperation.AN615ClockDesignUsingLowPower/CostTechniquesClocksystemAuthor:JohnDayA32.768kHzcrystalwaschosenfortheclockduetoSr.,FieldApplicationEngineer,Bostonthelowpowerandcostrequirementsofthisdesign.Thefourinternalphasesofthisinputclockcreateaninter-INTRODUCTIONnalinstructioncycle.Therefore,theinstructiontimeis