Comparison of CAN Gateway Modules for Automotive and Industrial Control Applications

Bus architectures with up to five independent CAN channels are used in today's automotive and industrial control systems. Caused by the rising numbers of sensors, actuators and electronic control units over the last years, modern control concepts demand devices supporting cross-linking of these channels. This interconnection is realized with a CAN gateway that connects several CAN buses between sub networks at different speeds. Current gateway implementations are based on one of two concepts. The one concept is an application-specific multi-channel CAN controller with shared message object memory. This concept is inflexible regarding the gateway structure, especially the number of CAN channels, but it enables the transfer of messages between the networks without causing a high load on the host CPU. The other concept is a set of single channel CAN controllers served by a message handling software on the host CPU. This implementation is more flexible regarding the gateway structure, but the load on the CPU depends on the combined bus traffic of all connected CAN networks. Starting from these two solutions, a new concept has been developed, combining the advantages of a flexible structure with a low CPU load. In this paper, the three concepts are compared and advantages/disadvantages are shown. In addition, problems in the design of gateways are discussed.