Increasing demands for safety, security, and certifiability of embedded automotive systems require additional development effort to generate the required evidences that the developed system can be trusted for the application and environment it is intended for.Safety standards such as ISO 26262 for road vehicles have been established to provide guidance during the development of safety-critical systems. The challenge in this context is to provide evidence of consistency, correctness, and completeness of system specifications over different work-products. One of these required work-products is the hardware-software interface (HSI) definition. This work-product is especially important since it defines the interfaces between different technologies. Model-based development (MBD) is a promising approach to support the description of the system under development in a more structured way, thus improving resulting consistency.Therefore, this paper presents a tool approach for an ISO 26262 aligned hardware-software interface definition. More specifically, the approach combines the versatility and intuitiveness of spreadsheet tools (such as Excel) and the properties of MDB tools (e.g. different views, levels of abstraction, central source of information, and information reuse) bidirectionally. The approach is capable of defining an ISO 26262 compliant HSI definition and enables automatic derivation of basic software configurations according to the HSI definition. This simplifies concurrent development of software and hardware across domain and company borders.