CAN 总线协议2.0

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1、BOSCHCANSpecificationVersion2.01991,RobertBoschGmbH,Postfach50,D-7000Stuttgart1ThidttdithFMk404Thedocumentasawholemaybecopiedanddistributedwithoutrestrictions.However,theusageofitinpartsorasawholeinotherdocumentsneedstheconsentofRobertBoschGmbH.RobertBoschGmbHretainsther

2、ighttomakechangestothisdocumentwithoutnoticeanddoesnotacceptanyliabilityforerrors.ImportedintoFramemaker4by:ChuckPowers,MotorolaMCTGMultiplexApplications,April5,1995.Sep.1991BOSCHCANSpecification2.0page1RecitalTheacceptanceandintroductionofserialcommunicationtomoreandmor

3、eapplicationshasledtorequirementsthattheassignmentofmessageidentifierstocommunicationfunctionsbestandardizedforcertainapplications.TheseapplicationscanberealizedwithCANmorecomfortably,iftheaddressrangethatoriginallyhasbeendefinedby11identifierbitsisenlargedThereforeaseco

4、ndmessageformat(’extendedformat’)isintroducedthatprovidesalargeraddressrangedefinedby29bits.Thiswillrelievethesystemdesignerfromcompromiseswithrespecttodefiningwell-structurednamingschemes.UsersofCANwhodonotneedtheidentifierrangeofferedbytheextendedformat,canrelyonthecon

5、ventional11bitidentifierrange(’standardformat’)furtheron.InthiscasetheycanmakeuseoftheCANimplementationsthatarealreadyavailableonthemarket,orofnewcontrollersthatimplementbothformats.InordertodistinguishstandardandextendedformatthefirstreservedbitoftheCANmessageformat,asi

6、tisdefinedinCANSpecification1.2,isused.ThisisdoneinsuchawaythatthemessageformatinCANSpecification1.2isequivalenttothestandardformatandthereforeisstillvalid.Furthermore,theextendedformathasbeendefinedsothatmessagesinstandardformatandextendedformatcancoexistwithinthesamene

7、twork.ThisCANSpecificationconsistsoftwoparts,with•PartAdescribingtheCANmessageformatasitisdefinedinCANSpecification1.2;•PartBdescribingbothstandardandextendedmessageformats.InordertobecompatiblewiththisCANSpecification2.0itisrequiredthataCANimplementationbecompatiblewith

8、eitherPartAorPartB.NoteCANimplementationsthataredesignedaccordingtopartAofthisoraccordingtopreviousCANS