Controller Area Networks, or CAN buses, allow electronic devices in vehicles to communicate quickly and reliably over a standardized interface. Early automotive communication networks had limitations like slow speeds, many wires, and connections prone to troubles. CAN buses improved on these with a two-wire circuit shared by all inputs and outputs, supporting speeds up to 500kb/sec. Examples of wireless networks now used in vehicles include OnStar, GPS, Bluetooth, and keyless entry systems like Toyota Smart Key. CAN buses helped enable advanced vehicle electronics and continue to support new wireless technologies.

2. Controller
Area
Network
The Rise of the Automotive Intranet

3. In the Beginning…

4. In the Beginning…
• Fred and Barney’s ride would have had
ANALOG type gauges because they:
• Were simple
• Reliable
• Cheap

5. In the Beginning…
• Did I mention simple?

6. Functional, but no personality
In a word, BORING

7. Electronics changed things…
• But there were limitations
Lots of wires, lots of connections, lots of troubles

8. And important information traveled
S….L…O…W…L…Y…

9. Early Auto Comm Networks
• GM Assembly Line Diagnostic Link (ALDL)
– 160 Baud, might as well be handwritten notes
• J1820 Serial Data
– 10.4kb/sec one wire, 41.6kb/sec two wire.
– Phone modems are faster
• ISO 9141
– Used by Chrysler, European, Japanese
– 56.6kb/sec modem still beats it by a mile
• Slow speeds prevent fast data transfer

10. Enter Controller Area Networks

11. Controller Area Networks features
• All inputs and outputs to CAN system share a
common circuit, think of a race track
• CAN circuit is two wire, twisted pair of wires
to reduce electrical interference
• CAN L is low speed circuit at 250kb/sec, used
for body control functions
• CAN H is high speed circuit at 500kb/sec. used
for engine, trans, ABS, SRS controls
• CAN system will function if one wire damaged

12. Controller Area Networks

13. Controller Area Networks

14. Controller Area Networks
Different type of CAN: Car and Automotive Network

15. Controller Area
Networks

16. Controller Area Networks

18. Controller Area Networks

19. Controller Area Networks

20. Controller Area Networks

22. Can you think of an example of a
Wireless network in a car?

23. Wireless?
• OnStar (GM)
• Global Positioning System
• Blue Tooth
• Blue Connect
• Personal Data Assistant
• Tire Pressure Monitoring System
• Smart Key
• FUTURE?

24. TPMS

25. Toyota Smart Key

26. Toyota Smart Key