CAN-Ethernet Gateway Design And Implementation Based On ARM9

In the network of mine safe monitoring system based on field-bus technology,general information transfers on the local network, and can not directly communicate with external network. Information can not be directly vertically integrated with the management. If you want to achieve directly communication between the field devices and the enterprise management, you must shield field-bus network protocols and other network differences, make field devices to enable seamless connection to Ethernet. Therefore, this paper presents gateway to resolve the field-bus and Ethernet communication between field-bus and Ethernet. The entire system solution for communications links takes CAN for field devices and Ethernet for management. This paper presents a design of interconnection between CAN and Ethernet,and put forward gateway design.CAN bus has became the one of most popular field buses with the advantage of reliability, real-time and flexibility. And Ethernet has become the most widely used as internet technology with its lower cost, more open, wider range of hardware and software support. As the transmission rate of CAN bus is limited by transmission distance , the CAN bus often is used to be the local network of control and connect to field monitoring equipment in the application; and Ethernet as an enterprise backbone network is used to connect each local field control network. Therefore, CAN bus which will connect to the internet has became a trend of the times.In recent years, ARM microprocessors are widely used in consumer electronics, communications systems and other fields. RISC-based 32-bit ARM9 microprocessor that has the features of low power consumption, high reliability and computing speed. ARM9 microcontroller S3C2410 is taken as hardware core in the system. It connects CAN with the CAN protocol controller chip MCP2515,connects Ethernet with the 10/100M Ethernet controller DM9000, and connects NAND FLASH and SDRAM as external memory.The gateway used ported Linux 2.4.18 core as operating system, constructed embedded file system with CRAMFS+YAFFS. It realizes the development of protocols conversion layer on this basis.The paper covers the topics as follows:Analyzed layers architecture of CAN protocol, the main content of this Ethernet protocol and TCP/IP protocol, and puts forward the design of protocol gateway; Analyzed gateway functions,designed CAN application layer protocol rules, putted forward system software and hardware architecture; Realized CAN network interface hardware design and MCP2515 device driver development; Established data channels of gateway using FIFO (First In First Out), encapsulated and parsed CAN application layer protocol, realized protocols conversion layer function.The design of CAN-Ethernet gateway, realized intercommunication between field devices and the device node of Ethernet, made field devices to seamless access internet, masked protocol difference, realized transparent data transmission.