In-Vehicle Networking - Serial Communication Requirements and Directions 860390

In recent years the functionality of automotive systems has been improved by the introduction of real time Electronic Control Units (ECUs) for engine management, anti-lock braking, and other applications. For customer comfort and convenience, body electronics options have also increased, including electronic windows, seat control, and others. Optimization of performance requires integrating the vehicle of the 90s as a system rather than a grouping of individual modules. As a result, inter - communication between real time ECUs as well as between body electronics modules is required. By linking vehicle electronics into a network or combination of networks, a cost-effective solution which guarantees required performance and maximum flexibility may be obtained.

The following features are key requirements for distributed control and networking in automobiles:

• Open systems flexibility
• High reliability in a noisy environment
• Reduction of cost and manufacturing complexity
• Minimum CPU burden for communication
• Maximum programmer transparency
• Guaranteed data consistency
• Short transmission times

To date, no network system that meets all of these objectives has been available. This paper examines: in-vehicle networking applications; protocol features needed to meet requirements; the need for an automotive serial communication standard; and briefly shows how the protocol designed for in-vehicle communication, Inter-Controller Area Network, meets these needs.