The design of communication convertor based on CAN bus

With the plentiful application of various electronic equipments and control devices which used in industry, the communication networks based on field bus are produced. Connection between CAN bus and normal bus RS-232 which is used in existing serial communication, could realize to construct network with multidrop and long-distance communication. Method of conversion between RS-232 and CAN bus is discussed and a communication convertor with new design and debug is introduced in the paper. In order to conquer the illogicalities or conflictions brought from bus configuration and communication protocol of various controller, it is chosen unattached bus controller SJA1000 and singlechip AT89C51 to constitute CAN bus brainpower node in the convertor; made use of MAX232 to complete the level conversion from 232 to micro controller interface card TTL; provided differential sending capability of bus and differential incepting capability of CAN controller. RS-232 with the excellences of working in ISM (industry, science, medicine) domains and having built-in UART (asynchronism serial receival) interface, combined with CAN, could realize data communication between PC serial interface and CAN bus fleetly and exactly. It was examined through debug that there are some advantages of long direct communication distances, high communication velocity, simple configuration, low cost with the design. And it could replace the CAN interface card with high price in current market for reasons of simple configuration and low-cost.