Project Analog - March 2008 - (Page 17)

ease into the flexible CANbus Network Contributed by Microchip Technology www.microchip.com Contents Viewpoint Wireless Communication Using IrDA® Wireless Design Choices Advanced Communication Solutions for Lighting Analog news C ANbus networks have been around for over 15 years. Initially this bus was targeted at automotive applications, requiring predictable, error-free communications. Recent falling prices of CAN (Controller Area Network) system technologies have made it a commodity item. The CANbus network has expanded past automotive applications. It is now migrating into systems like industrial networks, medical equipment, railway signaling and controlling building services (to name a few). These applications are utilizing the CANbus network, not only because of the lower cost, but because the communication that is achieved through this network is robust, at a bit rate of up to 1 Mbits/sec. A CANbus network features a multi-master system that broadcasts transmissions to all of the nodes in the system. In this type of network, each node filters out unwanted messages. A classical client/server network (such as Ethernet) relies on network addressing to deliver data to a single node. If multiple nodes exist in this network, a star configuration implements a centralized control (Figure 1). Fewer microcontrollers are 17 · ProjeCt ANALog · mAr 08 needed to perform the varied tasks, but the MCUs are usually more complex with higher pin counts In contrast, every node in a CAN system receives the same data at the same time. By default, CAN is messagebased, not address-based. Multiple nodes are integrated in the system using a distributed control implementation (Figure 1). One of the advantages of this topology is that nodes can easily be added or removed with minimal software impact. The CAN network requires intelligence on each node, but the level of intelligence can be tailored to the task at that node. Consequently, these individual controllers are usually simpler, with lower pin counts. The CAN network also has higher reliability by using distributed intelligence and fewer wires. Ethernet differs from CAN in that Ethernet uses collision detection at the end of the transmission. At the beginning of the transmission, CAN uses collision detection with resolution. When a collision occurs during arbitration between two or more CAN nodes that transmit at the same time, the node(s) with the lower priority message(s) will detect the collision. The Microchip analog page Interface products overview Sample center microchipDIRECT Reference designs/ app notes Technical training http://www.microchip.com http://www.microchip.com http://www.microchip.com/analog http://www.microchip.com/analog http://www.microchip.com/interface http://www.microchip.com/interface http://sample.microchip.com/Default.aspx?testCookies=true http://www.microchipdirect.com/catalogselection.aspx?returnURL=default.aspx http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1423

Table of Contents Feed for the Digital Edition of Project Analog - March 2008

Project Analog - March 2008 Contents Viewpoint About Project Analog Sponsor Wireless Communication Using the IrDA® Standard Protocol Wireless Design Choices Advanced Communication Solutions for Lighting Putting 10-GbE PHY Options Into Perspective Ease Into the Flexible CANbus Network Technology and Drivers for Mobile WiMAX Analog News—Analog News from Multiple Sources Enter to Win an iPhone Contact Project Analog Sponsor Treelink Microchip Advanced Parts Selector (MAPS)

Project Analog - March 2008

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