Design And Implementation Of Data Link Layer And Transport Layer In Automotive CAN Network

Electronic technology improves the vehicle dynamic, safety and comport whichprompts the transformation of vehicle products from mechanization to mechatronics andintelligent. The car network has become an important part in the automotive electronics,as a mass of ECUs deployed in car. Bus technology supports data exchange effectivelybetween ECUs as compared to traditional hard-wired technology which faces hugechallenges at present. CAN bus is widely applied to chassis control system, driverassistance system and power train.The urgent requirement for the automotive electronic embedded software isproposed by networked communication. The current automotive electronic softwarewhich is developed with private solutions can’t cope with the increasingly complexfunctional requirements due to poor portability and maintainability. AUTOSAR is henceproposed to provide a feature-driven development approach and standardized solutionfor architecture integration, aiming to improve software reusability and reducedevelopment cost.After investigating CAN network architecture of AUTOSAR communicationspecifications, this thesis designs and implements layered and function-clippingcommunication software based on CAN bus protocol. Bottom-up, the driver performsthe hardware access and offers hardware independent API to the upper layer. The CANinterface provides a unique interface to access different CAN hardware, managehardware state and guarantee the L_PDU transmission services depending on bufferingmechanism. CAN transport layer provides services for segmentation of data in transmitdirection and reassembling of data in receive direction. At the same time, conformancetest system used for validating the production is developed according to the presentresearch results of test domain in communication system.The main work of this thesis can be summarized in the following aspects:The AUTOSAR standard communication mechanism is analyzed, and thevehicle CAN network data linklayer and transport layer in accordance with thelayered AUTOSAR architecture are implemented. Combined with the transmission characteristics of CAN bus, invatgated thereliable transmission theories and practical experience on computer network,this paper put forword a series of methods to guarantee the quality of vehiclenetwork communication between varies of nodes.After analizing ETSI specification about comformance test, developedcomformance test system based on TTCN-3which is powerful test descriptionlanguage. This paper designed the test suit and fixed configuration set forvalidating the communicaton software abve.Local enterprises mostly concentrate on functional integration, which accumulatebus technology and automotive software technology weakly and lack the research ofembedded software architecture conforming to their own situation.The implementationof subject improves the reliability and reusability of the communication software inautomotive electronics, makes the exporatory contribution to the developing of Chineseautomotive electronic software.