AUTOSAR is an open and standardized automotive software architecture jointly developed since 2003 by car manufacturers, suppliers and other companies from the electronics, semiconductor and software industry in a worldwide partnership. reduce development costs, and avoid re-development of similar ECU software components repeatedly for the same vehicular applications. It is a growing and evolving standard defining a layered architecture for software.

Automotive trends like autonomous driving, v2x connectivity, OTA updates, predictive maintenance, and many other innovative features are based on in-vehicle software functions. For all these functions to work seamlessly and to cater to real-time in-vehicle functionalities, each ECU must work efficiently. Modern-day high-end vehicles have up to 100 ECUs, which communicate with each other via CAN bus, CAN FD, or Ethernet network to support complex vehicular functions.

Earlier, ECU software used by OEMs were on different platforms. There was no standard software architecture that was being used by tier 1 suppliers and their vendors to design the ECU software for OEMs. So, whenever any OEM wishes to switch to a new tier 1 supplier or vice-versa, the transition was very difficult. The new supplier used to face enormous challenges in understanding the existing software architecture, hardware platforms, and standards used in ECU software development. Thus, it was nearly impossible for a new supplier to drive an on-going project from the midst of its production life cycle.

To streamline the coordination between OEMs and tier 1 suppliers, to improve ECU software quality and reduce development time and costs, tier 1 automotive suppliers, semiconductor manufacturers, software suppliers, tool suppliers, and others came forward in 2003 and created a consortium called Autoomotive Open System Architecture (AUTOSAR).

What is AUTOSAR?

Automotive Open System Architecture (AUTOSAR) is an open and standardized automotive software architecture, which supports standardization in interfaces between application software and basic vehicular functions and it helps in establishing common ECU software architecture for all the AUTOSAR members.

AUTOSAR is intended to provide inherent benefits to the members to manage increasingly complex E/E in-vehicle environments like easy integration and exchange of functions in complex ECU network and control over the entire product lifecycle.

AUTOSAR Architecture

AUTOSAR is an open system architecture for automotive software development and provides standards for developing common automotive software applications. It is a growing and evolving standard that defines a layered architecture for the software. The classic AUTOSAR platform runs on a microcontroller and is divided into 3 main layers; let us discuss them in detail:

  • Basic Software Architecture- It is common to any AUTOSAR ECU.
  • AUTOSAR Runtime Environment
  • Application Layer

Basic Software Architecture (BSW)

AUTOSAR Basic Software Architecture consists of hundreds of software modules structured in different layers and is common to any AUTOSAR ECU. This means the supplier who has designed BSW can share it with other suppliers that are working on ECUs of engine, gearbox, etc.

Basic software architecture in AUTOSAR consists of three layers:

AUTOSAR Basic Software Architecture consists of hundreds of software modules structured in different layers and is common to any AUTOSAR ECU. This means the supplier who has designed BSW can share it with other suppliers that are working on ECUs of engine, gearbox, etc.

The Basic Software consists of many predefined modules (around 80) that are grouped into layers. 

Microcontroller Abstraction Layer (MCAL):

The Microcontroller Abstraction Layer (MCAL) offers drivers for access to memory, communication and input/output (IO) of the microcontroller.

ECU Abstraction Layer (ECUAL) :

The ECU Abstraction Layer (ECUAL) offers uniform access to all functionalities of an ECU such as communication, memory or IO – regardless of whether these functionalities are part of the microcontroller or are implemented by peripheral components. It provides a software interface to the electrical values of any specific ECU in order to decouple higher-level software from all underlying hardware dependencies.

Services Layer:

    The Services Layer provides different types of background services such as network services, memory management and bus communication services for the application layer. The operating system is also contained in this layer


  • is the realization (for a particular ECU) of the interfaces of the Virtual Functional Bus. 
  • is a collection of ports and connectors (sender-receiver / client-server)
  • is the heart of the AUTOSAR ECU architecture.
  • The AUTOSAR RTE provides:
  • communication mechanisms:
    • between AUTOSAR software components
    • between AUTOSAR software components and Basic Software modules
  • scheduling mechanisms for software components:
    • cyclically
    • in response to events

Application software 

The AUTOSAR Software (the layer above AUTOSAR Runtime Environment) consists of AUTOSAR Software Components that are mapped on the ECU. All interaction between the different AUTOSAR Software Components is routed through the AUTOSAR Runtime Environment. 

The AUTOSAR Interface assures the connectivity of software elements surrounding the AUTOSAR Runtime Environment.

The Software Components shall never communicate between each other directly. Also the Software Components shall never access the Basic Software directly. But always through the AUTOSAR Runtime Environment.

Why Adaptive AUTOSAR?

From 2003 to 2015, Classic AUTOSAR became an established platform and was doing perfectly well to run 50-80 ECUs in a vehicle. With the evolution of advance based automotive trends like V2X and E2E connectivity and automated driving, electrification skyrocketed, and as a result, a huge demand for supporting functions and devices was created in the market.  It was discovered that the existing classic AUTOSAR platform was not suitable to support these mega-trends and new architecture with more powerful and flexible E/E architecture is required. Adaptive AUTOSAR, the new architecture was released to support these functions and 1st release of AUTOSAR adaptive platform was done in March 2017.

Adaptive AUTOSAR architecture comes with a central application server, which assists high-performance computing. Ethernet-based ECUs in this system supports real-time functionalities. Adaptive AUTOSAR is scalable and has dynamic architecture, in which applications can be updated over the vehicle’s lifecycle. It enables OEMs to deploy high-tech software features in a vehicle and update them over-the-air whenever required.

AUTOSAR adaptive architecture supports all the futuristic automotive applications like infotainment, v2x, predictive maintenance, automotive apps, ADAS functions with a camera, RADAR and LIDAR sensors, map updates, electrification, and more.