SEE THE REFERENCES

Automotive Embedded System

Introduction

The details of embedded electronics in automotive systems is depicted very nicely in this picture from Clemson University: http://

www.cvel.clemson.edu/auto/systems/auto-systems.html

Lets go through a fine introduction to automotive embedded system by Hiro Takada

Steve Corrigan. Introduction to the Controller Area Network (CAN), Texas Instruments. Industrial interface: July 2008

Internet of Things

Devising sensors and algorithms to handle the front- and back-ends of the IoT are the easy part.

Securing/protecting the IoT from the hackers (malicious attacks) and inadvertent misuse/interference are critical issues to be addressed.

Yet to be explored: The middleware between the sensors in things at the edge of the internet, and the data collection and analysis on the cloud.

Just hot off the press

From the Design Automation Conference 2014:

http://www.embedded.com/print/4430404

Clemson’s View of Automotive Electronics Systemhttp://www.cvel.clemson.edu/auto/systems/auto-systems.html

CAN Bus

Controller Area Network (CAN)Reference: SLOA101A–August 2002–Revised July 2008

Introduction to the Controller Area Network (CAN)The CAN bus was developed by BOSCH as a multi-

master, message broadcast system that specifies a maximum signaling rate of 1 megabit per second (bps).

Unlike a traditional network such as USB or Ethernet, CAN does not send large blocks of data point-to-point from node A to node B under the supervision of a central bus master.

In a CAN network, many short messages like temperature or RPM are broadcast to the entire network, which provides for data consistency in every node of the system.

CAN Bus (contd.)

The specification calls for high immunity to electrical interference and the ability to self-diagnose and repair data errors.

These features have led to CAN’s popularity in a variety of industries including building automation, medical, and manufacturing.

See figure 1 for architecture: this is a good example for the architecture of your term project.

See figure 2 for standard CAN message format

See figure 3 extended CAN message format

Distinctive features of CAN Bus

Inverted (voltage) logicThe allocation of priority to messages in the identifier is a

feature of CAN that makes it particularly attractive for use within a real-time control environment.

Automatic arbitration based on the priority, in case more than one transmission is encountered.

Details of the CAN bus figure 6: CAN Device (DSP/Microcontroller), CAN controller, CAN Transceiver, CAN Bus lines (CANL…CANH)

The High-Speed ISO 11898 Standard specifications are given for a maximum signaling rate of 1 Mbps with a bus length of 40 m with a maximum of 30 nodes.

Different types of messages.Payload semantics: advantage.

Conclusion as given in the report

CAN is ideally suited in applications requiring a large number of short messages with high reliability in rugged operating environments. Because CAN is message based and not address based, it is especially well suited when data is needed by more than one location and system-wide data consistency is mandatory.

Fault confinement is also a major benefit of CAN. Faulty nodes are automatically dropped from the bus, which prevents any single node from bringing a network down, and ensures that bandwidth is always available for critical message transmission. This error containment also allows nodes to be added to a bus while the system is in operation, otherwise known as hot-plugging.

Has wide practical application in a number of industries other than automobile.

Hmm.. How about scalability?

How about bandwidth for communications? How about different types for different systems? Kind of hybrid? Flexray? Lin? MOST? CAN-FD? Ethernet? See this paper… lets read and understand.. D. Thiele, P. Axer, R. Ernst, J. Diemer, and K. Richter, “Cooperating

on real-time capable ethernet architecture in vehicles,” in Proc. Of Internationaler Kongress Elektronik im Fahrzeug, oct 2013. https://ece.uwaterloo.ca/~sfischme/rate/S1P2.pdf

(Afterall, the ECUs are moving an automobile towards a computign system, why not use the bus that is so sucessful in general computer communications?)

Summary

We had a high-level view of the automotive embedded system.

We will further explore these units in depth in the next week’s lecture and as per need by the various projects chosen by you.

We will also look into to the “manager” AUTOSAR that brings all things together.