FIFO Mode, Direct Mode, and Packet Handler Operation for EZRadioPro

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1、AN537FIFOMODE,DIRECTMODE,ANDPACKETHANDLEROPERATIONFOREZRADIOPRO1.IntroductionThisapplicationnotediscussesthedifferencesbetweenFIFOmodeandDirectmodeofoperationoftheEZRadioPROfamilyofchips.AdetaileddiscussionoftheoperationoftheautomaticPacketHandler(PH)isalsoprovided.DetailsofoperationinbothT

2、XmodeandRXmodeareprovided.ThepurposeofthisapplicationnoteistoexpandupontheinformationavailableinthedatasheetsforEZRadioPROdevices.ThisapplicationnotedoesnotdiscussRawDatamode(asmayberequiredbylegacysystemswithnon-standardpacketstructures).Pleasereferto“AN463:RawDataModewithEZRadioPRO”formorei

3、nformationonsuchapplications.ThroughoutthisdocumentreferencewillbemadetothegeneralpacketstructureasshowninFigure1.PreambleDataCRCSyncWordTXHeaderPacketLength1-255Bytes1-4Bytes0or2Bytes0-4Bytes0or1ByteFigure1.GeneralPacketStructure2.FIFOModeInFIFOmode,thetransmitandreceivedataisstoredinintegra

4、tedFIFOregistermemoryforlatertransmissionorretrievalviatheSPIinterface.Directreal-timeoutputoftheRXDATAonaphysicaloutputpinmayadditionallybeobtainedbyconfiguringaGPIOpinappropriately,butitisnotrequired.TheFIFOsareaccessedviaSPIRegister7Fhandaremostefficientlyaccessedwithburstread/writeoperati

5、on.2.1.FIFOModeinTXInTXFIFOmode,theTXDATAtobetransmittedisnotappliedtoaphysicalinputpin,butinsteadisprogrammed(bytebybyte)intothechip’sFIFOregistersovertheSPIbusfortransmissionatalaterpointintime.IfthePHisenabled,thesestoredbytesofdataareretrievedfrominternalFIFOmemoryand“packaged”togetherwit

6、hPreamblebytesandSyncword(s)tocreateapacketstructure.Withoptionalregistersettings,additionalfieldssuchasHeaderbyte(s),aPayloadlengthbyte,andCRCchecksumsmayadditionallybeassembledintothepacketstructure.IfthePHisdisabled,onlythebytesstoredintoFIFOmemoryaretransmitted;thisallowsforcompletecustom

7、izationofthetransmitpacket.Theentirepacketistransmittedattheprogrammeddatarateanddeviation.AprimaryadvantageofTXFIFOmodeisthusthatthetransmitdatamaybeprogrammedatanytime(includingsleepmode)withouttheneedforsynchronousorreal-timecoordinationwi