Sae J1939 Protocol Analysis And Smartj1939 Of System Design And Implementation

For applying a great deal electronic equipments, running dependably, maintaining, sharing information and cortrolling real time, BOSCH Co. explored CAN (Controller Area Network) bus, which has the widest field of usage among the Fieldbus. CAN Specification has been set down the international standard by ISO, get hold of many Co.' s sustain, such as Motorola, Intel, Philips, Siemence, NEC, and applyed to the scatter field abroad.CAN protocol is based on ISO's OSI,but its models tructure only has three layers,which are OSI'physical layer,data link layer and application layer. The known famous higher layer protocol, such as DeviceNet. CANopen, J1939/ISO 11783 and so on,has different functions for differently emphasizing particularly on.Thereinto, SAE J1939 is a high speed communication network, supports ECUs(Electronic Control Unit,computer based on electronic series, J1939 info achieves real time conclude control function between acceptation and tranmission through it) which may be physically distributed in vehicles.Nowadays the analyse of SAE J1939 protocol has just begun, and the material of SAE J1939 is very limited in domestically, so the analyse and study of SAE J1939 is quite necessary.Firstly, Based on the reason described above, this paper analyse the SAE J1939 protocol, include SAE J1939-21 data link layer protocol, SAE J1939-81 network management layer protocol, SAE J1939-71 application layer protocol.Subsequently, this paper describes a vehicle network system that implementsJ1939 protocol-SmartJ1939 which is composed of Data Link layer module,Network Management layer module and Timer module.After the description of design, implementation, and test results of these modules,this paper will present a demonstration of SmartJ1939------the control of RetarderRequesting Brake Light.Finally, this paper summarizes the SmartJ1939 system.