The Research And Design Of CAN Bus Protocol Converter With Baud Rate Adaptive

In recent years, with the continuous development and progress of science and technology, industrial automation field has produced profound change, is developing towards the direction of digitalization, intellectualization and cyberization, and how to solve the integration of control network and information management network has become the focus of current research.In most case the traditional CAN bus protocol converter has single function, and without the baud rate adaptive function of CAN bus, which greatly reduces the competitiveness of protocol converter product. In view of the Ethernet and USB protocol is general used in information management network, therefore a design of CAN bus protocol converter which based on embedded Linux is proposed in this paper, the data conversion between CAN and USB, CAN and Ethernet, and the baud rate adaptive function in CAN bus network are both achieved. The system is used in industrial control field, it not only makes the interconnection between CAN control network and information management network more convenient, but also makes access to a CAN bus network which is unknown baud rate will be more intelligent.The usual methods of CAN bus baud rate adaptive method are the testing method and the direct measurement method, which both have some deficiencies and defects. Hence, an improved and optimized based on these two methods is proposed in the paper, and implemented in CAN device driver under Linux.In the hardware design of the paper, the tiny6410 core board which has been designed by FriendlyARM Company as the main control system module, the core processor is S3C6410, and also the SDRAM and NAND Flash have been integrated on the board. In this paper, the hardware circuit design mainly includes CAN interface circuit, USB interface circuit, WIFI module circuit, power supply circuit and serial debugging circuit; and each circuit is introduced and illustrated in detail. Finally the system circuit welding and debugging are completed. In the software design, an embedded software development platform which includes the establishment of cross-compiler environment, Bootloader porting, Linux kernel migration and the production of root filesystem is built. Then, the improved method of baud rate adaptive in CAN bus is proposed, and realized in CAN device driver. After that, the development of USB device driver which including UDC driver and Gadget driver is implemented, and the porting and configuration of WIFI module are realized. Finally, the protocol conversion application in Linux is designed, and the development of Windows client test software is implemented.The experimental results show that, the stability of the CAN bus protocol converter in this paper is better, not only the basic functions are achieved, but also the change of baud rate in CAN bus is automatic matched efficiently. All above achieve the effect of the early system design.