Software Realization Of CANBus Protocol On RISC Processor

Fieldbus is a hotspot of technology development in the field of automation nowadays, its appearance signs the beginning of a new epoch in the industry control technology.The subject chooses CANbus to realize all functions of CAN protocol specification by software. First, the paper describes CAN protocol specification, on the basis of which CAN protocol realized by software is implemented on the AT90S8515 with RISC architecture of ATMEL Co., and this realization is introduced in Data Link Layer and Physical Layer.Secondly, RS232/CAN intelligent converter is designed for the Railway Science Academe, which is used to improve the system performance of dispatching centralization extension in the station. The design adopts CAN controller SJA1000.Finally, the test validates the feasibility of realizing CAN protocol by software with RS232/CAN intelligent convertor as a testing flat roof, and the test result is: the maximum bit speed can reach 27. Skbps when the frequency of AT90S8515 is 8MHz. Though realizing CAN protocol by software is based on AT90S8515, software design idea can be referred by other microcontrollers.The subject validates that CAN protocol by software is a good resolution to reduce system cost.