SLLA521B January   2022  – June 2022 TCAN1145-Q1 , TCAN1146-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction – Partial Networking
  4. 2Partial Networking Application
    1. 2.1 Modes of Operation and Partial Networking
    2. 2.2 Sleep Mode and Partial Networking
    3. 2.3 Wake-Up Frame
    4. 2.4 Classical High-speed CAN, CAN FD, and PN
    5. 2.5 Mixed Network Information
  5. 3CAN Frames and Wake-up Frames
    1. 3.1 CAN Frame Structure
    2. 3.2 Wake-up Frames
      1. 3.2.1 ID Field Match
      2. 3.2.2 Data Length Code (DLC) Match
      3. 3.2.3 Data Match
      4. 3.2.4 CRC Match
      5. 3.2.5 Acknowledge Match
    3. 3.3 Error Counter
    4. 3.4 Selective Wake FD Passive
  6. 4Selective Wake Registers
  7. 5Configuring Partial Networking
    1. 5.1 Valid CAN Message ID Example
    2. 5.2 Valid Data Example
  8. 6Summary
  9. 7References
  10. 8Revision History

1 Introduction – Partial Networking

Controller Area Network (CAN) is a communication architecture used for reliable communication in environments that are considered to be noisy, one example being automobiles. Over time, CAN has evolved to include classic high-speed CAN as well as CAN flexible data rate (CAN FD). Classic high-speed CAN supports data rates up to 1 Mbps and although CAN FD is backwards compatible with classic high-speed CAN, it also supports data rates up to 5 Mbps and higher. CAN FD supports up to 64 bytes and a bit rate switching mode, which allows faster than 1 Mbps data transmission.

In an automotive CAN network, power is always a concern for situations when the vehicle is off or when only a few electrical control units (ECUs) need to be on during normal operation. The development of PN addresses this concern. PN is a method used to save power when both homogeneous (all ECUs capable of PN) or mixed (not all ECUs capable of PN) CAN and CAN FD networks are used. This process is accomplished by allowing bus communication, but sleeping nodes only wake on a specific CAN message or frame. PN was developed by the International Standard Organization (ISO) and is based upon the latest version of the ISO 11898-2:2016 standard.

This application note provides information using an example application. The application note focuses on what selective wake, also known as partial networking (PN), is and how it is used in an application. The register set from the TCAN1145-Q1 and TCAN1146-Q1 is provided for ease of understanding and finishes with two examples on how to program a device for PN.