Fundamental Concepts of ECU Software

The ETAS EHANDBOOK solution is based on a set of fundamental concepts for how to capture how an ECU software works.

The building blocks of ECU software (or: the notion of functions in EHANDBOOK)

The application software of an electronic control unit (ECU) typically consists of a set of software components or functions which are connected to each other through input and output signals. In EHANDBOOK, these entities are generically called functions.

Functions have an interface description which is constituted by a set of input and output signals.

EHB function with interface description
Figure 1. A single function with interface description
EHB functions with interface descriptions
Figure 2. A set of functions with interface descriptions

Two functions communicate with each other when one function A writes a signal of name X and another function B reads a signal of name X (name-based communication). This is also referred to as name-based communication.

EHB communication between functions same EHB Container file
Figure 3. Name-based communication between functions from the same EHB Container file

Functions can be contributed by different providers. Such providers can be automotive supplier’s (typically referred to as Tier-1’s) or software development departments within a vehicle manufactuer (typically referred to as OEM).

EHB communication between functions multiple EHB Container files
Figure 4. Name-based communication between functions from the same EHB Container file

Capturing knowledge about ECU software in EHANDBOOK Container files

The knowledge about how an ECU software works in detail can be captured in EHANDBOOK Container files. An EHANDBOOK Container contains zero, one or multiple functions

EHB Container file single function
Figure 5. EHANDBOOK Container file with a single function
EHB Container file multiple functions
Figure 6. EHANDBOOK Container file with multiple functions

EHANDBOOK-NAVIGATOR can load and combine data from multiple EHANDBOOK Containers files.

EHB NAV multiple EHB Container files
Figure 7. EHANDBOOK-NAVIGATOR can load and combine functions from multiple EHB Container files

Multiple EHANDBOOK Container files can be aggregated to an EHANDBOOK project file.

EHB Project file with multiple EHB Container files
Figure 8. EHANDBOOK Project file with multiple EHB Container files