Agenda

Todays lecture gives an overview over fieldbusses and goes into details about the CANBUS.

The next lecture will be dedicated to coding on Henriks quatumm Teensy setup.

CANBUS

The primary litterature is a wiki page. I have found it of high quality and it covers the area very well.

• Fieldbusses gives an excellent overview. Read it :-)

• CANBUS

Slides and litterature for today

• NEW SLIDES HERE

and

• fieldbus slideshow

  • which gives an overview

  • from LOMI Universität Ulm, 2004. Lecture. Computer Networks. Fieldbus Systems. Prof. Dr. H. P. Großmann. Dipl.-Ing. Andreas Schmeiser

• Andreas slides

Some additional litterature if you have time and energy. But mostly to give you all some references.

• Kvasers Can homep

• Wiki about CAN

• Latency on CANBUS

• TTP - a timed failresilient CANBUS

• TTP on CAN

• TTP FAQ

• Fieldbus from an OSI arch point of view

• canbus for critical systems

• 61508 safety critical standard - short …

Slides for the exercise

• slides with ideas to fieldbus protocol

Exercise I

Given a network based on CANBUS technology … for a 1 Mbit and 125 kbit

• calculate and argue for a max cable lenght. hint: how long is a bit ?

• Caculate max number of packages on net

• Given a number of nodes with the following tuples of transmission period and message prio. calculate/… how the traffic will be on the network. hint scheduling theory ? Assume lower number as higher priority (in access)

  • {2 msec,000…}

  • {3 msec,0001…}

  • {5msec,0002…}

  • {10msec,0003…}

  • {14msec,0004…}

• Design and comment a simple peek and poke protocols which shall be able to react “quick”. Comment and explain quick and find a better way of expresing performance

Exercise II

Develope your own protocol either on I2C

You will need two Arduinos

See some rs232 inspiration

• I2C master generic

• I2C slave generic

• Hint:

  • who is master who is slave

  • how to move data from one slave to another

Exercise III

Prepare for next lecture

• install teensy support in your Arduino environment

  • left as an exerciuse to find out how

• install flexcan on your Arduino

  • its left as …

  • see here