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Mercedes-Benz Research and Development India
Mercedes-Benz Research and Development India
Controller Area Network (CAN)
SUKRUTH RAMESH BABU, EE, MBRDI Embassy Crest, Banglaore, 14-August-2015
Mercedes-Benz Research and Development India
Contents
1. Motivation2. Introduction3. CAN communication4. CAN framing5. CAN bus access6. CAN data protection
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
Motivation….
Intensive electronics Creating communication between electronic units would enhance automobile
features completely.
Engine
Chassis
Music System
Brakes
Lighting SystemBattery
Sensors
oorsWindows
GaugesClimate Control
eters
Engine
BodyChassis
Music System
Brakes
Lighting SystemBattery
Sensors
DoorsWindows
Gauges
Climate Control
Meters
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
Introduction
CAN (Controller Area Network) is a serial communication technology used especially for reliable data exchange between electronic control units (ECUs) in the automobile.
Originally introduced by Bosch in 1983. Point to Point wiring is being replaced by one serial bus connecting all control
systems. Standardized by ISO and SAE.
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
CAN communication
Basic concepts
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
CAN network
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
CAN BUS COMMUNICATION PRINCIPLEData that are transmitted from any Node, contains MESSAGE labelled with IDENTIFIER, which is unique throughout the network
All other nodes receive the message and each performs an acceptance test on the identifier to determine if the message, and thus its content, is relevant to that particular node.
If the message is relevant, it will be processed; otherwise it is ignored
Allows integration of additional CAN nodes without requiring modification of the CAN network. The maximum number of nodes is not specified. Networks are limited by
electrical loading, up to 64 nodes is normal05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
CAN bus logic
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
Vehicle Bus Protocol
Protocol Abbreviation Nature
CAN Controlled Area Network an inexpensive low-speed serial bus for interconnecting automotive components
D2B Domestic Digital Bus a high-speed multimedia interface
FlexRay - a general purpose high-speed protocol with safety-critical features
I²C Inter-Integrated Circuit for attaching low-speed peripherals
KWP 2000 Keyword Protocol 2000– a protocol for automotive diagnostic devices (runs either on a serial line or over CAN)
LIN Local Interconnect Network a very low cost in-vehicle sub-network
MOST Media Oriented Systems Transport a high-speed multimedia interface
SPI Serial Peripheral Interface for communication with slow peripheral devices, which are accessed infrequently
Mercedes-Benz Research and Development India
CAN Bus characteristics
Bus length / Bit rate tradeoff 1M bit/sec 40 meters (131 feet)
500K bit/sec 100 meters (328 feet) 250K bit/sec 200 meters (656 feet) 125K bit/sec 500 meters (1640 feet)
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
CAN FRAMES
Data Frame – For transmitting user data Remote Frame – Used for requesting 'data frame' from any other CAN node Error Frame – To indicate errors detected during communicationOverload Frame-To introduce delay in the transmission
CAN FRAME TYPES
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
DATA FRAME
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
DATA FRAME (Standard format and Extended Format)
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
CAN Presentation | Sukruth Ramesh Babu
• The DLC (Data Length Code) communicates the number of payload bytes to the receivers
05/01/2023
Mercedes-Benz Research and Development India
REMOTE FRAME
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
Error Frame
Types of error: There are five types of error are there in CAN and are listed below. And in case any one of these error is observed the error frame is transmitted.
Bit error Stuff error CRC error Form error Acknowledgement error
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
05/01/2023
BUS ACCESS IN CAN NETWORK
CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
PRIORITIZATION OF CAN MESSAGES
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
CAN data protection
Reliable data transmission. Because CAN is also used in very time and safety critical applications within
the motor vehicle, requirements for data integrity are extremely high.
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
05/01/2023
NRZ Coding
CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
BIT STUFFING
CAN Presentation | Sukruth Ramesh Babu 05/01/2023
Mercedes-Benz Research and Development India
Error detection: Bit monitoring : Compares the bit and the bus level
ACK Check : Checks for the dominant bit Stuff Check : Detection of sixth consecutive bit
Form Check : Compares the bit stream with message format
Cyclic Redundancy Check: Compares the bit stream with the generator polynomial
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
Error Confinement and Error states:
Active
Passive
Bus OFF REC/TEC > 127
REC/TEC < 128
TEC > 255
Reset or Configuration of 128x11 recessive bits
REC: Receiver Error Counter
TEC: Transmit Error Counter
05/01/2023CAN Presentation | Sukruth Ramesh Babu
Mercedes-Benz Research and Development India
Thank you !!
CAN Presentation | Sukruth Ramesh Babu 05/01/2023