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

3 Standard CAN or Extended CAN

The CAN communication protocol is a carrier-sense, multiple-access protocol with collision detection and arbitration on message priority (CSMA/CD+AMP). CSMA means that each node on a bus must wait for a prescribed period of inactivity before attempting to send a message. CD+AMP means that collisions are resolved through a bit-wise arbitration, based on a preprogrammed priority of each message in the identifier field of a message. The higher priority identifier always wins bus access. That is, the last logic-high in the identifier keeps on transmitting because it is the highest priority. Since every node on a bus takes part in writing every bit "as it is being written," an arbitrating node knows if it placed the logic-high bit on the bus.

The ISO-11898:2003 Standard, with the standard 11-bit identifier, provides for signaling rates from 125 kbps to 1 Mbps. The standard was later amended with the “extended” 29-bit identifier. The standard 11-bit identifier field in Figure 2 provides for 211, or 2048 different message identifiers, whereas the extended 29-bit identifier in Figure 3 provides for 229, or 537 million identifiers.