CAN

CAN is Controller Area Network. It looks like a relatively heavyweight protocol one might use to communicate between embedded devices, rather than for talking to simple devices in the way I2C and SPI are used.

http://www.interfacebus.com/Design_Connector_CAN.html

A special Wiki Site is dealing with CAN http://www.can-wiki.info A great pool of information provides the CAN in Automation user association CiA. CiA has more than 400 members. Search for information at http://www.can-cia.org

As with RS232, one needs a device to convert from logic levels to CAN line voltages. This is a CAN/Transceiver.

All CAN controllers, stand alone ones ore integrated, have the basic Data Link Layer DLL implemented. Easy usage is therefore guaranteed. But besides this, all applications, automotive and industrial ones, are using so-called higher-layer protocols like CANopen, DeviceNet or J1939 (there are others). For an example of the functionality of an CANopen Implementation for the ATMEL AT92SAM7 Series see: http://www.port.de/Atmel.html . An CANopen implementation for the Philips LPC2100 is available too http://www.port.de/Philips.html .

The current version 4.0x of the CANopen communication profile is standardized as EN 50325-4. The essential communication services are defined in the CANopen communication-profile (CiA DS-301). Furthermore there are several device, interface and application-profiles (CiA DS 3xx, 4xx), that are administered by CAN in Automation e.V. (CiA -international users' and manufacturers' group). Standards can be downloaded at CiA free of charge.