The basis for configuration of an AUTOSAR ECU is the ECU Extract of System Description (ECUEX). This is an XML file (*.arxml) in a schema defined by AUTOSAR. It contains the specifications for ECU configuration and is typically generated by the OEM.

By allowing certain content of this file to be optional, AUTOSAR offers great latitude regarding the precise content. The specific content included depends on the OEM. The following general variants are conceivable:

• Network description (use case 1)
• Network description and software components as a specification (use case 2)
• Network description and implemented software components (use case 3)

Based on the ECUEX, the Tier1 must generate the ECU Configuration Description (ECUC). The detailed configuration of the basic software is saved in this description.

During transition to AUTOSAR, it is likely not all participants will use a pure AUTOSAR method. Therefore, it is very easy to imagine that during this period the supplier will only receive a .dbc, .ldf or FIBEX database from its OEM and will need to generate the ECUC based on this database.