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时间: 2019-12-24 21:20
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ManyapplicationsrequiredrivingLEDsalongwithaninterfacetoakeypad.ImplementingsuchdesignsusuallyinvolvesusingupsignificantamountsoftheprocessorsI/Olines.Thisapplicationnotedescribesamethodwhichusesonly16I/OpinsofaPIC16C5Xmicrocontrollertosamplea4x4keypadmatrix,anddirectlydrivefour7-segmentLEDs(Figure1).AN529MultiplexingLEDDriveanda4x4KeypadSamplingdriveoftheLEDsispossible,becauseofthehighsinkAuthor:StanD’SouzaandsourcecapabilitiesofPIC16C5Xmicrocontroller,MicrochipTechnologyInc.thuseliminatingtheuseofanexternaldrivetransistor,andresultsinareductioninbothcostandcomplexityofINTRODUCTIONtheoverallcircuit.TypicallyapplicationshavingLEDsa……
标签: 4x4键盘
