16 February 2007

Auto Trends Drive Processor Choice

There is no shortage of potential new applications for the deployment of electronics in vehicles. The latest functionality enhancements result largely from car manufacturers’ desire to innovate and differentiate through electronics, but also from legislation around safety or tightening emissions control.

Electronic systems are at the heart of the driver-assistance systems currently in development. In the not so distant future, expect to see vehicles that feature a raft of safety enhancements that includes adaptive cruise control, monitoring systems for lane wandering, and means of detecting driver fatigue and inattention.

New features will combine convenience with higher levels of safety. For example, in addition to unlocking the car, a key fob remote could be used to identify a driver and move a seat to a pre-set position to suit the driver’s preference. The position of the driver’s seat will determine how the airbags are deployed in the event of a collision, and the collision detection will ensure that the doors are unlocked to facilitate escape and rescue.

These developments are driving automotive semiconductor revenue growth forecasts towards an annual compound rate of more than 8 percent between 2005 and 2010.

Development Challenges
To take advantage of these growth opportunities, developers must address a number of emerging technical challenges.
Many automotive applications, such as braking and vehicle stability control systems, must meet stringent IEC61508 standards for functional safety. The need for fault tolerance and high reliability is expected to grow as automotive systems become increasingly connected and safety requirements expand across automotive features.

Cost reduction is an ongoing ambition to ensure the successful propagation of technology to the mainstream market on even the most affordable cars. Vehicles today contain as many as 70 electronic control units, many of them implemented with 8-bit or 16-bit processors. This presents an opportunity to consolidate automotive functions into a reduced number of more capable processors. Integrating the functions of several 8-bit processors into a single 32-bit device will reduce cost by minimising discrete part count and bill of materials. It will also help to simplify the overall development process and limit the proliferation of fragmented development systems within automotive R&D labs, which are expensive to own and maintain.

Consolidating complex functions onto a single processor can also reduce communication overhead, and the reduction in interprocessor communication improves reliability. High-performance 32-bit processors are ideal platforms for enabling function consolidation and more sophisticated implementation for automotive systems.

Processors for Automotive
The 32-bit ARM® Cortex™-R4F  processor has been designed specifically with embedded automotive applications in mind. It builds on the ARM Cortex-R4 processor, which has already been adopted for automotive and other deeply embedded applications, including storage, networking and imaging. While maintaining all the benefits of the Cortex-R4 processor, the Cortex-R4F adds enhanced configurability, an optional floating point unit (FPU), and fully integrated support for error correction on the cache and local memories.

There are a number of reasons why specifying floating point capability now makes sense for automotive electronics applications. More stringent emissions control standards require higher performance algorithms and increased accuracy and timing to enable better efficiency from the engine. The Cortex-R4F processor’s FPU enables a greater dynamic range and accuracy than fixed-point calculations.

The use of an FPU means that algorithms modelled as floating point can also be mapped directly from popular modelling environments such as The MathWorks’ MATLAB. Using a code-generation and modelling-based methodology improves quality and reduces development time compared to hand-coding in assembly language.

Taking a high-level approach to code development, whether in ‘C’, UML or from a high-level tool, means that a platform approach can be taken, where an application can be developed once and retargeted multiple times.

The Cortex-R4F processor is designed to enable ARM Partners to meet error-free automotive safety standards by enabling error detection from the processor, through the interconnect and into peripherals, providing system-wide protection.

There is no doubt that the requirements for automotive electronics are set to become increasingly complex and demanding as manufacturers continue to use features that are implemented in silicon to innovate and differentiate. Successful development teams will increasingly turn to high-performance 32-bit processors to drive new product development in automotive markets.