ARTICLE ON AUTOSAR COM MODULE
Tags: comstack, autosar, communication
Published: 2023-04-11 06:28:24

Hello All, I'm Sravani Jonnadula employee of LUXOFT India. Here I would like to provide a brief knowledge about "Com module in AUTOSAR:A Comprehensive Overview
## INTRODUCTION

In AUTOSAR, COM module is used to provide a standardized way for software components to communicate with one another in a distributed system. This is critical in the automotive industry, where complex systems with hundreds or even thousands of software components must work together seamlessly to provide the functionality required by modern vehicles.

AUTOSAR COM modules are built using the same principles as traditional COM modules, but with some important differences. For example, instead of using a Windows registry to register components, AUTOSAR uses an XML file called an ARXML file to describe the system and its components.

## OVERVIEW

In AUTOSAR, a COM module is called a "service component," and it provides a set of "service interfaces" that other components can use to interact with it. Service interfaces are defined using the AUTOSAR Interface Description Language (IDL), which is a standardized way of describing the methods and properties of a service interface.

Autosar COM is a service layer module lying in between RTE and the PDU Router. It is used to transfer signals to and from the RTE layer.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/qcs5eqh3kyjqczunoo1u.png)
## KEYROLE

It packs the signals to a PDU at the transmitter and unpacks received PDU to provide signal level access to the application at the receiver. Thus, signal level or PDU level communication is possible irrespective of the underlying protocol. In this module we also configure the cycle time, offset, repetition period (for Event frame) at PDU level. It is also used for grouping of PDUs.
To use a service component in an AUTOSAR system, a software component must first discover the component and its available service interfaces. This is done using the AUTOSAR System Description (ASD) file, which describes the overall architecture of the system and the components that make it up.

Once a software component has discovered a service component and its service interfaces, it can use them to communicate with the component. This might involve sending requests for data or performing actions on the component, such as starting or stopping a service.

## COM Configurations
The underlying purpose of providing COM configurations is to establish a communication of the system between the upper RTE layer and the below PDU router irrespective of communication protocol. This is done by defining and configuring four different objects, viz.
1. I-PDUs
I-PDU which contains a message related information like timeperiod of message,message transfer property,offset,repetation and here in IPDU we will pack all the signals , map the IPDU groups ,signal groups.

2.I-PDU Groups
Some of the I-PDUs will grouped into IPDU groups and then we can map into the IPDU.

3.Signals
The Signals which play an important role in IPDU by carrying the data.Signals being configured with the size in Com ,Based on the size signals are being packed into IPDU.

4.Signal Groups
Signals can be further formed into signal groups if several signals need to be sent to the same I-PDU.

## Benefits of COM module
One of the key benefits of using COM modules in AUTOSAR is that it allows software components to be developed independently of one another. This means that different teams can work on different components in parallel, without needing to worry about how they'll interact with other components in the system. As long as each component adheres to the AUTOSAR COM standard, they should be able to communicate with one another seamlessly.

## Conclusion
In conclusion, COM modules have become an essential part of the AUTOSAR standard, providing a standardized way for software components to communicate with one another in complex, distributed systems. If you're developing software for the automotive industry, understanding the AUTOSAR COM standard and how to build service components can be a valuable skill to have.