The document is a technical seminar presentation on the Controller Area Network (CAN) protocol, covering its definition, applications, message formats, error handling, and fault confinement. CAN is a multi-master serial bus designed for efficient data transmission in various industries, particularly automotive and automation applications. The presentation also emphasizes CAN's reliability and robustness, making it suitable for environments requiring system-wide data consistency.

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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