Abstract

As part of the software development cycle engineers regularly need a systematic method of testing a product prior to release. In the automotive industry this testing is critical to the safety of the users. Complex embedded control units must be tested under precise conditions representative of an automobile. This paper looks at the signals and system requirements necessary to simulate a vehicle environment in hard real-time, the development of an automated test facility for an embedded transmission control unit and the RTL tricks and techniques used along the way. Many of the complexities in developing a vehicle simulation lie in the diverse range of signals required. In the past vehicle manufacturers have relied on wiring looms to share signals between sensors and electronic modules. Today, in-vehicle networks are replacing the need for looms and simplifying the sharing of information between electronic modules. Any vehicle simulation must be able to synchronize packet data with digital and analogue signals and be highly configurable. Extended simulations require an efficient method of describing a sequence of time critical events. These sequences must combine all data types, be repeatable with sub-millisecond precision and provide a true representative of in-vehicle signals. This paper describes the use of language tools, operating from user-space, cleverly controlling real-time signal sequences One of the best methods to verify the simulation is by recording I/O signals in-vehicle for direct comparison. By developing a miniRTL based "black box" we created an in-vehicle data recorder backward compatible with the test facility. This not only allows vehicle signals to be logged but also replayed as a real-time simulation at will. This paper describes methods of data synchronization, the development of language tools for writing real-time signal sequences, the incorporation of a miniRTL based system in the recording and playback of vehicle signals and automated processes for benchmarking the controllers behavior.

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