The electronic content of the automobile is expanding dramatically, driven by several concurrent forces, including consumer demand for entertainment systems and convenience functions, the addition of enhanced safety features, and government emission control regulations.

Consequently, engineers are working to raise the functionality of electronics, while simultaneously devising strategies to improve fault tolerance and provide fail-safe operation of all critical systems.

On average, a new passenger vehicle today features about 80 integrated and networked systems. And while the control of such systems as powertrain, ABS (Anti-lock Braking System), airbag control and body electronics functions has traditionally been self-contained, a great deal of value can be added by exchanging data between systems.

For example, traction control systems optimize the grip of tires on the road surface, which requires that the brakes be modulated and the powertrain system retard engine torque at the same time. This can be accomplished relatively easily through a simple serial communications link between the ABS ECU (electronic control unit) and the powertrain ECU.

However, as the number of interconnects and gateways between different systems expands, the growing number of interfaces and likely bottlenecks increases the potential that the overall vehicle electronics network may grow too complex.

Overloaded networks are not efficient. They require increased testing and validation, the complexity increases the possibility of system faults, and total system cost is not optimal. A solution to this growing complexity is evolution of the vehicle electronics into a domain architecture connected by a backbone (Figure 1 below).

Figure 1. Expected evolution of vehicle electronics architecture

In this type of in-vehicle network, mechatronic solutions (which combine mechanics, electronics and computing) will be deployed, and sensors will become active and smarter, with digital interfaces. Power components will integrate more control and diagnosis, and microcontrollers will support more robust software, as well as offer fail-safe, fail-silent and fail-functional capabilities.

The move from today's decentralized architecture to centralization with global and coherent control will result in what can be thought of as a three-part vehicle operating arrangement, where a "real" driver is supported by a "guardian angel" that provides risk management and a "virtual co-driver" for driver assistance.

Guardians and codrivers
The "guardian" will consist of both passive systems, such as passenger detection, tire pressure monitoring and collision warning, and active systems, such as collision avoidance. The "co-driver" will perform functions that make the driving experience easier and more pleasant, such as passive blind spot monitoring and vision enhancement, and active navigation, lane departure and parking assistance.

Safety, of course, is a major concern in automotive systems. When applied to a whole system, the key is dependability -- dependable sensing, dependable actuation, dependable computation, dependable communication and interconnection, and dependable power. Within the safety path, there can be no common-cause failure mechanisms.

This means moving the system guardian outside a firewall (Figure 2 below), where it services all the system elements individually. It also means a need for safety through redundancy. Safety is today the object of a substantial amount of work in the automotive market, very often using the generic IEC61508 safety standard, and is becoming so important a consideration that an automotive-specific standard, the ISO26262, is now in development.

A key to developing such systems will be a move to software-enabled functionality, with dedicated hardware being replaced by software algorithms running on a microcontroller (MCU). Signal processing and communication will move from analog to digital, and mechatronic solutions for shifting, hybrid control, steering and braking will be enabled by drive-by-wire capabilities.

Figure 2 Safety path using external "guardian" circuit

To support the enhanced capabilities of the software, the industry will move to more-powerful MCU architectures that offer real-time and fail-safe capabilities, broad peripheral sets and eFlash to support the necessary high performance and network connectivity capabilities. Multi-core MCUs are the solution that is emerging to meet all of these requirements.