Design Of Protocol Convertor For CAN-USB Based On FPGA

As a representative of excellent BUS in industrial field, CAN bus is developed rapidly and widely used since it was made, it is widely used in industrial field, ECU(Electrical Control Unit) of automobile, aerospace aviation and other fields. Due to its unique interface and data format, the data of CAN format can not be identified by PC, so it is not that convenient in data acquisition, system adjustment and malfunction analysis, all of these factors hindered the popularity of CAN BUS to some extent. It is necessary to design a system that can convert CAN data to what can be identified by PC. This can be reached with ISA and PCI cards, but it is not suitable for popularization in the industrial field due to its complex interface, incompatible with Laptop, slow data transmission and prohibitive costs. However, USB protocol has advantages of simple interface, support for hot-pluggable, convenient for using, rapid data transmission and so on, it has become one of the standard interfaces on PC. Due to these factors, a protocol conversion system for CAN-USB based on FPGA is proposed.The four parts of the system are protocol conversion method, hardware design, software design and simulation of the system. The whole system includes the main control unit FPGA, CAN controller SJA1000, USB controller CY7C68013. When the system is on run, initialization is needed at the beginning, when it is complete, the system does data acquisition according to the order from the industrial field, the data needs to be decoded for the source protocol and encoded for the targeting type when it is stored in the asynchronous FIFO, then with the clock signal, the transferred data will be transmitted to the user or Bus nodes in the industrial field.In the process of design, full consideration of the development is made, this protocol conversion system can not only suitable for the Basic CAN mode, but also for the developed PeliCAN mode, cause decoding and encoding process made in the system. The simulation results show the designed system can fully meet the demand system compatibility. What is more, in the design FPGA is used as the main control unit, so this system can be extended due to FPGA has an excellent performance in data acquisition and data communication. FPGA can be used for video security and industrial field security, all of this can make a huge extension for this system. All of the simulation results show that the system has an advantage of easy-design, high system integration, easy to expend and cost low, in the process of design, signal reliability is considered, so the system has an excellent performance in stability, it has great practical value and bright prospects.