The Design And Develop Of Truck's Digital Instrument Based On SAE J1939 Protocol

Along with the incensement of complexity in automotive electronic systems, more and more electronic control units(ECU)to be added in the car system,the connection,information exchange and time sequence control between each ECU were more complexed too,the car-mounted network technology is offered a kind of good solution in order to solve problems described above.This thesis point against the application of truck digital instrument,select for use the special-purposed car instrument chip Mirconas CDC3207G as the main control unit,and introduce the Controller Area Network(CAN)and the Local Interconnect Network(LIN)to compose a pair of network structure,among them SAE J1939 protocol is CAN network communication protocol on the senior level,it can support the distribution real-time system effectively,mainly for offering the standard system structure for communication between the ECU of heavy-duty vehicle;LIN protocol is used in ECUs that needing simple communication only.The thesis has introduced the application backgrounds and technological backgrounds of this project at first,then analyze digital instrument designing requirement and confirmed main research content and chip selecting method in HOWO truck project.It provided a total solution of hardware interface design in the related sections.Secondly,the thesis made key analysis to CAN bus specification and SAE J1939 communication protocol,and due to the truck real work demand,we have joined the low-cost network of assisting——LIN bus.It explained the structure and functions of the software system in the dashboard. Specific to the of dashboard node application,we designed intact structure of SAE J1939 communication message frame and the realize function code based on CDC3207G.We carried on system simulation test to the dashboard from two respects:1.Utilize USB-CAN converter,designed J1939 communication test program related to digital instrument platform for testing J 1939 protocol communication of the instrument;2.Utilize LIN bus analyzer of Microchip Company and oscillograph to compare LIN bus communication of the instrument with testing.The test result shows that we succeeding in realizing the data communication and network management of SAE J1939 protocol,as well as the CAN/LIN bus gateway function.The dashboard system has certain practicability.