Vehicular software is a key driver of innovation and revenue in the automotive industry. However, the increasing complexity of vehicular software, driven by shorter development cycles, more frequent updates, and tight coupling of software with hardware, presents significant challenges. Microcontroller-based vehicular software is particularly affected due to resource constraints, which limit flexibility and complicate software updates.
To address these challenges, we introduce a modular reference architecture for microcontroller-based vehicular software that prioritizes updateability and decoupling of software from hardware. The reference architecture is systematically derived from general requirements for microcontroller-based vehicular software and proposes a domain-based structure. It divides embedded vehicular software into five domains: the application domain, responsible for control, regulation, and monitoring functions; the base domain, managing hardware access; the mediator domain, providing a mediation infrastructure; and two protocol domains, which provide adaptation mechanisms between the mediator and the application or base domains, respectively.
A scenario-based evaluation assesses the reference architecture using typical software update operations, including software extension, removal, and modification, as well as hardware replacement. These scenarios are applied to a prototype implementation of an emulated door control unit with a corresponding door simulation environment.
The evaluation demonstrates the feasibility, showing improvements that simplify updates when adhering to the proposed domain structure. Results suggest that the introduced reference architecture can serve as a foundational template for designing microcontroller-based vehicular software systems, enabling streamlined updates and enhancing flexibility, maintainability, and portability. Future work will focus on refining the reference architecture and extending the evaluation to include assessments of real-time capabilities, functional safety, and security.