overview and working of CAN protocol . application of CAN protocol. CAN protocol fault confinement what can is? why we need CAN protocol? how CAN protocol works

1. SIDDAGANGA INSTITUTE OF TECHNOLOGY
“CAN (Controller Area Network )
Protocol”
Technical seminar
on
Darshan K S
1SI12EC129
VII sem, EC ‘A’
Guided by
Dr. R.KUMARASWAMY
Professor & Head,
Dept. of E&C
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2. Outline
1. What/Why CAN ?
2. CAN bus introduction
3. Overview of CAN
4. CAN Application / Bus level
5. Message Frames
6. Error Handling / Fault confinement
7. Bit Stuffing
8. References
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3. Why CAN ?
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• Wiring-reduction, Cost reduction with CAN.
Figure 1 Figure 2

4. What CAN ?
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• CAN is a multi-master serial bus that allows an
efficient transmission of data between different
nodes. With its flexibility and robustness against
electrical interferences

5. CAN Node Consists of …
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• Host Processor
• CAN Controller
• CAN Transceiver

6. CAN bus introduction
• Controller Area Network (CAN)
• Originally developed by Robert Bosch for
automobile in- vehicle network
• CAN bus provides communication between
controllers, sensors, and actuators.
• Very reliable and robust well proven
technology
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7. Overview of CAN
• Multi drop, multi-Master Bus Access
• Message Broadcasting
• Message Priority (No Node IDs)
• Limited Data Length (0…8 bytes)
• 1 Mbit/sec Data Rate
• Excellent Error Detection & Fault
Confinement
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8. CAN Application
• Automotive
• Military vehicles
• Industrial machinery
• Medical systems
• Agricultural machinery
• Marine control and navigation
• Elevator control systems
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9. Bus Level
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0 - Dominant bit
1 - Recessive bit

10. Bus Level
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11. Message Frame Format
• There are two types of CAN implementations
depending on the size of the identifier field
1. Standard CAN Frame format :(11 bit wide
identifier field)
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12. Message Frame Format
2. Extended CAN Frame format : (29-bit wide
identifier field)
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CAN Base frame format with the addition of :
• Substitute remote request (SRR)
• Identifier extension (IDE)
• r1 – reserve bit

13. Bus Arbitration Principle
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• Bit wise arbitration across the Arbitration Field
• Dominant Bus Level = 0, Recessive Bus Level = 1

14. Message Frames
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• Data Frame – Broadcasts a message to the CAN bus
• Remote Frame – Requests transmission of message
• Error Frame – Signals error condition
• Overload Frame – Special Error Frame

15. Error Detection Method
The CAN protocol implements following type of errors
detection
• Bit Error : The sending node monitors the bus to ensure that
the data transmitted is same as the data received.
• Stuff Error : If a 6th successive bit (either 0’s or 1’s ) is
detected, the stuff error is reported.
• CRC Error : Comparison of received CRC sequence and
calculated CRC. Provides detection of local receiver errors.
• Form Error : A form error is detected when a fixed form bit
(constant bit ) is different than what is expected.
• Acknowledgement Error : An ack. Error is detected whenever
sender does not monitor a dominant bit in the ACK slot.
ACK confirms only the successful transmission.
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16. Fault Confinement
• CAN Node Error States
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17. Maximum Bus Length
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• Bus Length is limited due to Bit Monitoring
(Signal Propagation Time)

18. Conclusion
• Controller Area Networks applications are
emerging and gaining high ground in many
applications from automobile industry to
automation and factory industries.
• CAN is ideally suited in applications requiring a
large number of short messages with high
reliability in rugged operating environments
• it is especially well suited when data is needed by
more than one location and system-wide data
consistency is mandatory.
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19. References
[1] Othman, H.F.; Aji, Y.R.; Fakhreddin, F.T.; Al-Ali, A.R. Controller
Area Networks: Evolution and Applications, 2nd Information and
Communication Technologies, 2006,vol. 2, pp. 3088 - 3093.
[2] Robert Bosch GmbH, “CAN Specification”, Version 2.0, 1991.
[3] Pazul, K. Controller Area Network (CAN) Basics, Microchip
Technology Inc, 1999.
[4] Steve Corrigan, Introduction to the Controller Area Network
(CAN), Texas Instrument, Application Report, 2008.
[5] Controller Area Network (CAN), LAN in vehicle communications
protocol, SAE JI583 Mar90, SEA Information Report, pg, 20, 226-248
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20. THANK YOU
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