AUTOSAR

AUTOSAR (Classic) defines its own software component technology for specifying the application software of embedded control units. The concepts are specified in the AUTOSAR meta-model and described in the Software Component Template (Check out this link and use the Documentation search on the link’s home page to find the Software Component Templates: Link).

In AUTOSAR (Classic), the application logic is defined in so-called software components. Software components communicate with each other over ports. Ports are typed through interfaces which specify what is communicated between the software components, and how. To establish communication between software components, ports are connected to each other through explicit connectors. To organize the application logic defined in the software components, these can be aggregated to compositions.

Why is that?

In previous concepts prior to the AUTOSAR (Classic) standard, e.g. the ASAM MDX standard, communication between the components of the application software was established through name-based communication:

Two functions A and B communicate with each other if function A writes a signal of the same name msg as function B reads. Through global variables (often referred to as messages) in the C-code implementation, an implicit communication was realized. One drawback of global variables is that the collaborating parties have to strictly agree on who defines which variable. This is necessary in order to avoid late problems at integration time.

Deducing dependencies between components of the application software purely based on implicit, name-based communication is rather straight forwards: you only have to follow the read/write dependencies.

With AUTOSAR (Classic), the problem of collaboration amongst multiple was resolved by introducing a software component technology with rules for interface compatibility and an explicit mechanism for establishing connections between software components.

Consequently, in order to deduce a dependency between software components and for example follow a signal flow over multiple software components, it is necessary to infer this information from the software components, and the elements in the interfaces.

Analyzing all these details just to find out if and how two software components are connected is challenging as it requires more than checking equivalence of names of global variables. It can also be more tricky and thus error-prone, e.g., a when connector between two compatible ports is missing.

With the AUTOSAR (Classic) support in EHANDBOOK, we address these challenges and make the dependencies between software components as easy as possible to follow and understand.