Evaluation Environment for AUTOSAR-Autocode in Motor Control ...

2.2 AUTOSAR basic approach
AUTOSAR Software Component The AUTOSAR Software Component is independent
from the underlying hardware. That is done with the abstraction through
the RTE and BSW.
Sensor / Actuator Software Component This component depends on sensors
and actuators which are available at the ECU. Due to performance such a component
runs on the ECU to which the sensors and actuators are physically connected. Besides
it is as independent as an AUTOSAR Software Component.
2.1.2 Basic Software
The BSW only provides infrastructural functionality to run the SWCs. In the following
is an overview of the several parts of the BSW given.
Services This provides some basic services like e.g. memory and flash management
and diagnostic protocols.
Communication This are Communication stacks for inter-ECU communication like
e.g. Controller Area Network (CAN) ([12]), Local Interconnect Network (LIN) ([2]),
FlexRay ([1]), etc.
Operating System The operating system provides priority based scheduling of
tasks and protection mechanisms. It is described in section 2.3 in more detail.
Microcontroller Abstraction Layer (MCAL) To make the higher software layers
independent from the microcontroller the MCAL is used. It avoids direct access
to registers from higher–level software and abstracts features like e.g. digital I/O, or
A/D converters. It is aimed to replace the microcontroller with another one without
changing anything at higher–level software. This assumes that a MCAL is available
for the substituting controller.
ECU abstraction Since the MCAL just abstracts the microcontroller the ECU
abstraction does the same for the whole ECU.
Complex Device Drivers Due to performance reasons the complex device drivers
directly access the hardware.
2.2 AUTOSAR basic approach
After the architecture is clarified, this section takes a look at the basic approach of
AUTOSAR for bringing software to ECUs. In AUTOSAR this is done in multiple
steps. The approach shown in figure 2.2 handles the whole view of the complete system
with multiple ECUs. The SWCs are developed using well defined interfaces and
they are connected through the Virtual Functional Bus (VFB). This is an abstract
connection, that makes it possible for the components to interact. It does not yet
say something about the later location of the SWC in the whole system and hides
5