Design And Implementation Of CAN And ZigBee-based Hybrid Network Gateway

CAN bus is one of the most representative fieldbus. It has the advantages ofhigh communication rate, long communication distance, no master-slave node,non-destructive arbitration, excellent real-time and strong error detectioncapability. ZigBee has the advantages of low complexity, low cost, low powercomsuption and strong flexibility as a mature wireless communication protocol.Combining CAN bus and ZigBee wireless network will complement theiradvantages each other and extent their applications. According to CAN andZigBee’s principles and characteristics, the issue designs a CAN/ZigBee hybridnetwork.On the basis of analysis of CAN node and ZigBee node MCU’sdevelopment status and trend, the issue choses LPC11C24and CC2530as CANnode MCU and ZigBee node MCU respectively. LPC11C24embedded CANprotocol controller and transceiver. CC2530embedded enhancement8051coreand RF transceiver. On the basis of detailed analysis of communication modebetween LPC11C24and CC2530, the issue uses UART to exchange databetween LPC11C24and CC2530, it constitutes a gateway node with dual MCUstructure.After completed the design of CAN bus network and ZigBee wirelessnetwork’s software, the issue focuses on the design of gateway node’s software.There are three major problems in gateway node’s software design:①CAN andZigBee’s communication rate is inconsistent;②CAN and ZigBee’s messageaddressing mode is inconsistent;③CAN and ZigBee’s maximum data payloadis inconsistent. For these three problems, the issue’s workaround is:①setsbuffer in the dual MCU and uses DMA mode to store the receive data fromUART;②redefines CAN data frame’s identifier, CAN data frame’s datasegment and ZigBee’s data segment, designes address mapping table, madeCAN and ZigBee’s data frame contain the address information of the sourcenode and the destination node;③introduces fragment mechanism. The test results show that: the design of the issue’s CAN bus network,ZigBee wireless network and gateway node have the advantages of simplestructure and high efficiency and reliability of data transmission. It has provideda feasible plan to achieve seamless connection between CAN and ZigBee.