The approach for developing ECU software was defined by the AUTOSAR organization in its AUTOSAR methodology. It subdivides the development process into actions and standardizes data exchange between development partners with a set of XML files.

In system design, the architecture of the application is established. This is accomplished by defining SWCs and their distribution to the ECUs. The network communication is also defined in this step. The result is the System Description – an AUTOSAR XML file, from which a specific ECU Extract of System Description is generated for each ECU.

During ECU development, the SWCs are implemented, and the BSW and RTE are configured. During the configuration, the developer defines the basic software contents that are needed for a specific project. This lets the developer optimize the entire ECU software. As a result of the configuration the developer obtains an ECU Configuration Description (AUTOSAR XML file), which is aligned with the ECU Extract of System Description.

Code generators are used to generate or modify the Basic Software component of the ECU software based on the ECU Configuration Description. The RTE is also generated to be ECU-specific.

The development of the application can be considered to be independent of this process. The interfaces of the SWCs are described in the SWC Descriptions (AUTOSAR XML file). Based on these descriptions, SWCs can be implemented and tested independently of other SWCs. This simplifies integration of application components from the OEM and the Tier1.