Development of Communication Manager Module for Automotive Platform Software based on AUTOSAR 4.0

Development of Communication Manager Module for Automotive Platform Software based on AUTOSAR 4.0

Neethu Mary Judy

1. Tech(Embedded Systems)

   Sree Buddha College of Engineering Pattoor, Kerala

   India

   Jayaraj V. S

   Department of ECE

   Sree Buddha College of Engineering Pattoor, Kerala

   India

   Kuruvilla Jose

   Specialist Automotive Electronics

   Tata Elxsi Trivandrum, Kerala India

   AbstractAutomotive industry is growing rapidly. This rapid growth has increased the challenges in different forms including complexity. AUTomotive Open System Architecture (AUTOSAR) provides a standardized automotive software platform. Communication Manager (ComM) module in BSW (Basic Software) layer is responsible for the control of communication services. This paper is about the development of ComM module in AUTOSAR 4.0. The functionality of ComM module is obtained by realizing specific Application Programming Interfaces (APIs).

   KeywordsAUTOSAR, ComM, API, ECU

   1. INTRODUCTION

      Development in technology and increase in demands led to tremendous growth in automotive industries. The ECUs in vehicles serve different functionality. Since ECUs are delivered by different vendors, the automobile manufacturers experienced difficulties in terms of complexity, diagnostics, inter ECU communication etc. So there arose a need for standard software in ECUs. AUTOSAR is standardized and an open automobile platform software. The goal of AUTOSAR is to have a transition from customer specific software to functional specific software. It is hardware independent.

   2. AUTOSAR SOFTWARE ARCHITECTURE

      A basic design concept of the AUTOSAR software stack is the separation between application and infrastructure. AUTOSAR standard follows a layered architecture, which provides modularity concept. The software architecture contains three basic layers: Application layer, RTE (Run Time Environment) layer and Basic Software (BSW) layer. Fig. 1 shows the software layers in AUTOSAR architecture.

      Fig.1. Software layers of AUTOSAR

      RTE allow the AUTOSAR software components to be independent from the mapping to the specific ECUs. BSW is further divided into Services, ECU Abstraction, Micro controller Abstraction and complex drivers. Being the lowest software layer, Micro controller Abstraction layer has direct access to the micro controller and internal peripherals. ECU Abstraction layer interfaces the drivers of Micro controller Abstraction layer. The highest layer in Basic Software layer is the System Service layer which serves a number of services. These services include vehicle communication management, ECU state management, diagnostics services, memory management etc. The task of complex drivers is to provide the possibility to integrate special purpose functionality.

   3. COMMUNICATION MANAGER MODULE

      Communication Manager (ComM) module acts as a resource manager. It is responsible for managing the underlying communication services. Functions of ComM include allocation of necessary resources for the requested communication mode, switches to a communication mode as requested by the user, implement channel state machine for every channel to control more than one communication channel of an ECU etc.

      1. Communication Modes

         The ComM module provides three different communication modes.

         1. COMM_NO_COMMUNICATION

         2. COMM_FULL_COMMUNICATION

         3. COMM_SILENT_COMMUNICATION

            The COMM_FULL_COMMUNICATION state has the following sub states:

            • COMM_FULL_COM_NETWORK_REQUESTED

            • COMM_FULL_COM_READY_SLEEP

              The COMM_NO_COMMUNICATION state has the following sub states:

              • COMM_NO_COM_REQUEST_PENDING

              • COMM_NO_COM_NO_PENDING_REQUEST

      A user cannot request for COMM_SILENT_COMMUNICATION. The default state of a communication channel is COMM_NO_COMMUNICATION with sub state COMM_NO_COM_NO_PENDING_REQUEST. ComM

      channel will allow communication only if CommunicationAllowed flag is TRUE in COMM_NO_COM_REQUEST_PENDING.

   4. DESIGN

      ComM module is developed by coding all the APIs realized by it for satisfying its functional specification. Communication (Com) module can transmit and receive messages only if ComM module makes the channel in COMM_FULL_COMMUNICATION state.

      COMM_NO_COMMUNICATION mode does not support transmission and reception of messages. For the design of ComM module, High Level Design (HLD) and Low Level Design (LLD) were carried out. HLD includes the identification of the APIs needed for the implementation of the ComM module and LLD gives a detailed idea and design of each APIs identified in HLD. Both HLD and LLD are done using the tool Enterprise Architect Version 9.3.

      1. High Level design of ComM

         Fig. 2 specifies the dependency diagram in which dependencies to other modules is shown. The Communication Manager Module requests the communication capabilities, requested from the users, from the Bus State Manager Modules.

         Fig. 2. High level design of ComM

         ComM module is initialized by EcuM-Fixed. All validation of wake up events is done by both EcuM (Fixed and Flex) and indicated to ComM module. If COMM_FULL_COMMUNICATION mode is requested by DCM, then only Diagnostics shall be performed. A communication mode is requested from the CAN state manager by ComM and the bus state is mapped to this mode by the CAN state manager.

      2. Low Level design of ComM

         The Low Level Design involves the activity diagram of each of the APIs to realize the module. Some of the LLD of APIs is shown below.

         Fig. 3. Flow chart of ComM_Mainfuncton()

         Fig. 4. Flow chart of ComM_DeInit()

   5. IMPLEMENTATION AND TESTING

      Coding for the development of ComM module is done using C language. The file structure contains header files and source files. The header files include ComM.h, ComM_Nm.h, ComM_EcuMBswM.h, ComM_Dcm.h, ComM_BusSm.h and ComM_Cfg.h. These header files are in AUTOSAR standard.

      ComM.h contains the declarations of the ComM APIs and type definitions of data types. ComM_Nm.h, ComM_EcuMBswM.h, ComM_Dcm.h, ComM_BusSm.h include the ComM callback declarations. The ComM_Cfg.h and ComM.c are the configuration and source file spectively. The later defines all the APIs realized by ComM module.

      Coding is performed in Visual C++ 2010 express edition. It is successfully compiled and built without any errors. Snap shot of the code successfully built in Visual C++ 2010 express edition is shown in Fig. 5.

      Fig. 5. Snap shot of code build in VC++ 2010 express edition

      Testing of ComM module is done in two phases:

      • Unit testing

      • Integrated testing

      In unit testing the functionality of all APIs are checked individually. Testing is done in Visual C++ in which test application was written for each API and functionality verified. Unit testing helps in easy debugging. Integrated testing deals validation of overall functionality of the application specified. Different BSW modules were integrated and validation was performed on MPC 5668G Evaluation board.

   6. RESULTS

In unit testing all APIs are functionally verified. The integration testing validated functional performance and reliability requirements placed on major design items. It involves the verification of basic functionality of application and BSW modules after integration. Fig.6 shows the evaluation board used for integrated testing. Fig .7 shows the integrated test set up

Fig. . MPC5668G evaluation board

Fig. 7. Integration Test Setup

ACKNOWLEDGMENT

This research was supported by ECE Dept. of Sree Buddha College of Engineering, Pattoor, kerala. The authors would also like to thank Tata Elxsi, Trivandrum for providing insight and expertise that greatly assisted the research.

REFERENCES

1. AUTOSAR, Specification of Communication Manager V4.0.0 R4.0

   Rev 3. [Online].Available.http://www.autosar.org/

2. AUTOSAR, Specification of Communication Manager V2.1.0 R3.0 Rev 7.

   [Online]. Available.http://www.autosar.org/

3. SAE, International Society of Automotive Engineers. [Online]. Available.http://automobile. sae.org/

4. S. Furst, AUTOSAR for Safety-related Systems: Objectives, Approach and Status, in Second IEEE Conference on Automotive Electronics, London, United Kingdom, March 2006.

5. G. Leen and D.Heffernan. Expanding Automotive Electronic Systems, IEEE Computer, 35(1), January 2002, pp. 8893.

6. MPC5668x Microcontroller Reference Manual, Document Number: MPC5668XRM Rev.4 01/2011