pic单片机的rs232通讯程序

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1、SensorInterfaceDigitempJunior–AnRS-232Port-PoweredDigitalThermometerDdigitisthetenthsdigitofthetemperaturereading.Author:MichaelKirkhartSincetheDS1620hasaresolutionof0.5°C,thetenthsGSE.Inc.digitwilleitherbea‘0’ora‘5’.FarmingtonHillsMIEmail:kirkhart@rust.netTheCRandLFcharac

2、tersaretheASCIIcarriagereturn(ASCIIcode0x0d)andlinefeed(ASCIIcode0x0a)characters.ThesecharactersareusedtoforceOVERVIEWtheterminalprogramtoprintthenexttemperaturereadingonthenextlineonthescreen.TheyalsoserveDigitempJr.isadevicethatisdesignedtomeasureasdelimitingcharactersbe

3、tweentemperatureread-andreportambienttemperature.Whenconnectedtoings,allowingeasyimportingofacaptureddataintoaanRS-232portonanyPC,itwillperiodicallymeasurespreadsheetprogram.andreportinASCIIformtheambienttemperatureinExamples:degreesCelsius.Thesetemperaturereadingscanbemon

4、itoredwithanyterminalprogram.Iftheterminal0°Cwillbetransmittedas0.0(CR)(LF)programsupportscapturetodisk,thetemperature27.5°Cwillbetransmittedas27.5(CR)(LF)-9.5°Cwillbetransmittedas-9.5(CR)(LF)readingscanbesavedtodiskforfurtheranalysiswith-15.5°Cwillbetransmittedas-15.5(CR)

5、(LF)aspreadsheetprogramorotherdataanalysistool.ThesimpleASCIIoutputformatofDigitempJr.makesitrel-Thedataistransmittedinasynchronous,NRZformatatativelyeasytowritecustomsoftwareforreceiving,9600bpswithonestartbit,onestopbit,eightdatabits,recording,andanalyzingambienttemperat

6、uredata.andnoparity.WhileneitherhardwareorsoftwareflowBestofall,DigitempJr.requiresnoexternalpowersup-controlisused,theRTSsignalfromthePCmustbepliesorbatteries.ItispowereddirectlybytheRS-232assertedbecauseDigitempJr.derivesitsV+supplyport.fromthePC’sRTSoutput.DATATRANSMISSI

7、ONSPECIFICATIONSWhenconnectedtoaPCRS-232port,DigitempJr.willobtainanambienttemperaturereadingandtransmitthereadingindegreesCelsiusapproximatelyoncepersecond.Thisreadingistransmittedinthefollowingfor-mat:(-/H)(T)O.D(CR)(LF)The(-/H)charactercaneitherbeanegativesignorthehundr

8、edsdigitofthetemperaturereading.Ifthetem-peraturereadingisbetween0°Cand99.5°C,thischar-ac