SLOA101B August   2002  – May 2016 SN55HVD233-SEP , SN65HVDA1040A-Q1 , SN65HVDA1050A-Q1 , SN65HVDA540-5-Q1 , SN65HVDA540-Q1 , SN65HVDA541-5-Q1 , SN65HVDA541-Q1 , SN65HVDA542-5-Q1 , SN65HVDA542-Q1

 

  1.   Introduction to the Controller Area Network (CAN)
    1.     Trademarks
    2. 1 Introduction
    3. 2 The CAN Standard
    4. 3 Standard CAN or Extended CAN
      1. 3.1 The Bit Fields of Standard CAN and Extended CAN
        1. 3.1.1 Standard CAN
        2. 3.1.2 Extended CAN
    5. 4 A CAN Message
      1. 4.1 Arbitration
      2. 4.2 Message Types
        1. 4.2.1 The Data Frame
        2. 4.2.2 The Remote Frame
        3. 4.2.3 The Error Frame
        4. 4.2.4 The Overload Frame
      3. 4.3 A Valid Frame
      4. 4.4 Error Checking and Fault Confinement
    6. 5 The CAN Bus
      1. 5.1 CAN Transceiver Features
        1. 5.1.1  3.3-V Supply Voltage
        2. 5.1.2  ESD Protection
        3. 5.1.3  Common-Mode Voltage Operating Range
        4. 5.1.4  Common-Mode Noise Rejection
        5. 5.1.5  Controlled Driver Output Transition Times
        6. 5.1.6  Low-Current Bus Monitor, Standby and Sleep Modes
        7. 5.1.7  Bus Pin Short-Circuit Protection
        8. 5.1.8  Thermal Shutdown Protection
        9. 5.1.9  Bus Input Impedance
        10. 5.1.10 Glitch-Free Power Up and Power Down
        11. 5.1.11 Unpowered Node Protection
        12. 5.1.12 Reference Voltage
        13. 5.1.13 V-Split
        14. 5.1.14 Loopback
        15. 5.1.15 Autobaud Loopback
      2. 5.2 CAN Transceiver Selection Guide
    7. 6 Conclusion
    8. 7 Additional Reading
  2.   Revision History

2 The CAN Standard

CAN is an International Standardization Organization (ISO) defined serial communications bus originally developed for the automotive industry to replace the complex wiring harness with a two-wire bus. The specification calls for high immunity to electrical interference and the ability to self-diagnose and repair data errors. These features have led to CAN’s popularity in a variety of industries including building automation, medical, and manufacturing.

The CAN communications protocol, ISO-11898: 2003, describes how information is passed between devices on a network and conforms to the Open Systems Interconnection (OSI) model that is defined in terms of layers. Actual communication between devices connected by the physical medium is defined by the physical layer of the model. The ISO 11898 architecture defines the lowest two layers of the seven layer OSI/ISO model as the data-link layer and physical layer in Figure 1.

layrd_arch_lou101.gifFigure 1. The Layered ISO 11898 Standard Architecture

In Figure 1, the application layer establishes the communication link to an upper-level application specific protocol such as the vendor-independent CANopen™ protocol. This protocol is supported by the international users and manufacturers group, CAN in Automation (CiA). Additional CAN information is located at the CiA Web site, can-cia.de. Many protocols are dedicated to particular applications like industrial automation, diesel engines, or aviation. Other examples of industry-standard, CAN-based protocols are KVASER's CAN Kingdom and Rockwell Automation's DeviceNet™.