Consumer expectations for automated vehicle operations such as automatic locking, remote ignition control, navigation, and entertainment are primary drivers for the increasing complexity of embedded automotive electronics modules. The prevalent practice for procuring these modules is to develop a written behavioral specification that is then used by an outside supplier to build and test the module. Validation test plans are written separately based on an understanding of the requirements. The challenges posed by the current practice include the inability to completely specify the expected behavior in a timely manner, the need to balance the design between low cost and new features demanded by the customer, and ensuring that the product exactly implements the specified behavior.
Moreover, vehicle manufacturers desire the ability to explore sensitivity of specifications by identifying constraints on the system and assessing the product for ease of implementation. Since the cost and quality of a module are highly dependent upon ease of implementation in software, they are greatly influenced by the specification. Equally important is the ability of the supplier and manufacturer to easily validate the developed module to ensure compliance with the specification. Complete validation necessarily includes testing of the Human Machine Interface (HMI) of the module as well as any background system features. The specification must accurately describe HMI functionality so that desired behavior for each customer interaction can be validated.
Different processes have been proposed to solve the inherent problems with written specifications, including specification through prototyping, formal specification, and simulation. In this paper, we outline a process for specifying an embedded electronic module through simulation. A simulation is created to implement the specified system behavior and to identify system constraints and build-ability restrictions. The simulation also provides a model of the system HMI that can produce test case outcomes for comparison with actual system behavior during validation.