Application And Study Of CAN Bus And J1939 Protocol Based On ARM

Controller Area Network (CAN) bus has become one of the most important busworldwide. According to the OSI model defined by International Organization for Stan-dardization (OSI), CAN protocol defines the standards of physical layer and data linklayer. To build a perfect communication system, it is necessary to choose a appropri-ate application layer protocol based on CAN. As the most popular high-level protocolapplied to trucks and passenger cars, however, J1939 is limited in use for its expensivecost. Aiming at the implementation of J1939 protocol this paper reported the design ofJ1939 protocol communication system using high-powered ARM9 architecture-based32-bit microprocessor S3C2410 as core. The major achievement are as follows:(1) Built a Linux-ARM development platform, based on ARM microprocessorS3C2410 and embedded Linux operating system (OS). Firstly, the details of the op-eration of U-boot, embedded Linux kernel and root file system are included; the im-plementation of automatic actuation of application program in the process of buildingthe platform is described: CAN driver is static compile to the kernel when making theembedded Linux kernel. Then add the J1939 protocol stack and user application intoroot file system. At last, modify the system initialization functions;(2) Based on intensive analysis of the CAN2.0B protocol, the Polo car CAN dataframes are captured and their frame structure are analyzed with a USB virtual oscil-loscope;(3) CAN driver based on single chip are written, and the implementation detailsof driver are reported, including the set of CAN baud rate, how the driver operate theregister of CAN controller MCP2510 in the term of figures, text and program, as wellas how driver support the CAN extending frame;(4) New features of 100kbps baud rate supporting of and CAN extending frame isadded, in the process of writing CAN driver based on embedded Linux OS. Reportedare also the detailed calling process and realization method of driver in the embeddedLinux OS;(5) In order to realize a stable J1939 communication network, from simply to com-plex system, a simple CAN bus communication network is firstly realized, with 100kbpsbaud rate, custom application protocol and consist of ARM development board, CANbus test-bed of Polo car and monitoring node. The experiment results verified thecorrectness of the simple CAN communication network;(6) After intensively study of the J1939 protocol, a J1939 protocol with basicfunction is written. Consists mainly of the realization of data link layer and net-work management. its features includes: address claiming message, request of address claiming message, management of address con?ict, order message, broadcast message,request of engine data, transport protocol function and so on;(7) A J1939 communication network is implemented according to J1939 protocol,with 250kbps baud rate and consist of ARM development board, virtual node andsingle chip note. The experiment results verified the correctness of various functionsof the J1939 protocol stack designed. The process of experiment verified the stability,validity and security of data transport.