CAN擴(kuò)展幀格式介紹

1、CAN20B擴(kuò)展幀格式第7位FF表示幀格式（在標(biāo)準(zhǔn)幀中FF=0,在擴(kuò)展幀中FF=1）;第6位RTR表示幀的類型（RTR=0表示為數(shù)據(jù)幀，RTR=1表示為遠(yuǎn)程幀）；DLC表示在數(shù)據(jù)幀時(shí)實(shí)際的數(shù)據(jù)長(zhǎng)度字節(jié)25為報(bào)文識(shí)別碼（過(guò)濾ID的高29位）字節(jié)613為數(shù)據(jù)幀的實(shí)際數(shù)據(jù)，遠(yuǎn)程幀時(shí)無(wú)效63.2329bitCANidentifiersTables4and5specifythe29bitCANidentifiersforlegislatedOBD,bas，diagnoSticaddresses.The29bitCANidentifiersshallcomplywiththeaccordingtoISO1

2、5765-2fsummarizedinTable4.Table4Summaryof29bitCANidentifierformatNorrCANIdbitposition2824231615FunctionalCANId18hexDBhexTPhysicalCANId18hexDAhexTNOTETheCANidentifiervaluesgiveninthistableusethedefaultvaluefortheISO15765-2.Table529bitlegislated-OBDCANCANidentifier(hex)Descriptii18DB33F1CANidentifierf

3、orfunctionallyaddressrequestmessa18DAxxF1PhysicalrequestCANidentifierfromexternaltesteqi18DAF1xxPhysicalresponseCANidentifierfromECU#xxtoexThemaximumnumberoflegislated-OBDECUsinalegislated-Ceight(8).ThephysicalECUdiagnoSticaddressofanECUhex)shallbeuniqueforalegislated-OBDECUnnagivenvehicle.Whilenotr

4、equiredforcurrentimplement戲ions,itisstronglyreapplicablelegislation)thatforfutureimplementationsthephysassignmentsfoundinSAE32仃8/1.為了十六進(jìn)制的計(jì)算方便，特把29bit的報(bào)文ID轉(zhuǎn)換為32bit,即4個(gè)16進(jìn)制字節(jié)ID29b=(ID32b_1Byte*0 x01000000+ID32b_2Byte*0 x010000+ID32b_3Byte*0 x0100+ID32b_4Byte)3)&0 x1fffffff;例如：Tools:88HC6HD0H8FH88H03H19H02H08H00H00H00H00HCSECU:88HC6HD7H88H88H10H14H59H02H0CHC1H55H01HCSECU:88HC6HD7H88H88H21H08H00H36H01H08H00H45HCSECU:88HC6HD7H88H88H22H01H08H01H16H01H08H00HCS18DA11F1=(0XC6*0 x01000000+0XD0*0 x010000+0X8F*0 x0100+0X88)3)&0 x1fffffff;