标签: 串行io

PIC16CXXXmicrocontrollersfromMicrochipTechnology,Inc.,high-performance,EPROM-based8-bitmicrocon-trollers.Someofthemembersofthisseries(likethePIC16C71andPIC16C84)donothaveanon-chiphard-wareasynchronousserialport.ThisapplicationnotedescribestheinterruptdrivensoftwareimplementationofAsynchronousSerialI/O(HalfDuplexRS-232Communi-cations)usingPIC16CXXXmicrocontrollers.Thesemicrocontrollerscanoperateatveryhighspeedswithaminimumof250nscycletime(withinputclockfrequencyof16MHz).TotesttheRS-232routines,asimpleDigitalVoltmeter(DVM)/AnalogDataAcquisitionSystemhasbeenimplementedusingaPIC16C71,inwhich,uponreceptionofacommandfromhost(IBMPC-AT),an8-bitvalueoftheselectedA/Dchannelistransmittedbacktothehost.MSoftwareImplementationofAsynchronousSerialI/OAN555TransmissionofabyteisperformedbycallingtheAuthor:AmarPalacherlaPutCharfunctionandthedatabyteintheTxRegisMicrochipTechnologytransmittedout.Beforecallingthisfunction(PutChar),CodeUpdate:ScottFinkthedatamustbeloadedintoTxRegandensuretheMicrochipTechnologyInc.serialportisfree.Theserialportisfreewhenboththe_txmtP……