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

3.3 Error Counter

PN capable transceivers have an error counter to track issues. The error counter will increment for the following reasons:

  • If any CAN frame is not decoded properly, which can include a ‘1’ where a ‘0’ is expected, a ‘0’ where a ‘1’ is expected
  • A run length of 6 consecutive bits of the same polarity occurs
  • If the received CRC does not match the calculated CRC
  • A CAN-FD frame is recognized and SW_FD_PASSIVE=0b

When the CAN frame is decoded properly, either WUF or non-WUF, the error counter will decrement by 1, down to 0. If this error counter exceeds a designated threshold (selected by the register FRAME_CNT_THRESHOLD, default of 31), an overflow will occur, the part will wake-up if in sleep and transition to standby mode. The device will set an interrupt FRAME_OVF. These errors indicate that CAN frames are not being decoded properly, so an actual WUF can not be decoded. As such, when the device wakes from an error counter overflow, selective wake is disabled (SW_EN=0). It is recommend to set SW_EN=1 again.