July 5, 2022 CAN Abhishek Mishra Tata Consultancy Services
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May 1, 2023
CANAbhishek Mishra
Tata Consultancy Services
May 1, 2023
Contents
• What is CAN?
• History
• CAN standards
• How does CAN work?
• Message Formats
• Error detection and fault confinement
• Bit Timing
• CAN implementations
• References
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What is CAN?
• The Controller Area Network (CAN) is a serial, a synchronous, multi-master communication protocol for connecting electronic control modules in automotive and industrial applications.
• It is a message-based protocol .
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History
• Development of the CAN bus started in 1983 at Robert Bosch GmbH.
• The protocol was officially released in 1986 at the Society of Automotive Engineers (SAE) congress in Detroit, Michigan.
• The first CAN controller chips, produced by Intel and Philips, came on the market in 1987. The 1988 BMW 8 Series was the first production vehicle to feature a CAN-based multiplex wiring system.
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CAN standards
• Two specifications are in use:• 2.0A sometimes known as Basic or Standard CAN with 11 bit
message identifiers which was originally specified to operated at a maximum frequency of 250Kbit/sec - ISO11519.
• 2.0B known as Full CAN or extended frame CAN with 29 bit message identifier which can be used at up to 1Mbit/sec - ISO 11898.
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May 1, 2023Technical Center IndiaDelphi Confidential
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Layered Structure of a CAN Node
• Application Layer• Object Layer
– Message Filtering– Message and Status Handling
• Transfer Layer– Fault Confinement– Error Detection and Signaling– Message Validation– Acknowledgement
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Layered Structure of a CAN Node
– Arbitration– Message Framing– Transfer Rate and Timing
• Physical Layer– Signal Level and Bit Representation– Transmission Medium
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CAN from OSI perspectiveProtocol Overview:- Data Link Layer
- Logical link Control - Acceptance filtering
- Overload notification - Recovery management
- Medium Access control - Data encapsulation
- Frame coding - Error detection/signaling
- Acknowledgement - Serialization/de serialization
- Physical Layer - Bit encoding/decoding
- Bit timing - Synchronization
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CAN Data Frame
• CAN Data Frame
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CAN Message Frames
• Data Frame– Used to transmit up to 8 bytes of data
• Remote Frame– Used to request a data frame
• Error Frame– Used to indicate error to the entire network (Not
under CPU control).
• Overload Frame– Used to create an extra delay between frames
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CAN Arbitration
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Further reading
• www.can-cia.de
• www.bosch.de/k8/can/
• www.iso.org/ch/
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Thank You
By :Abhishek Mishra