SLLA651 April   2025 TCAN2845-Q1 , TCAN2847-Q1 , TCAN2855-Q1 , TCAN2857-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Device States
    1. 2.1 Init Mode
    2. 2.2 Restart Mode
    3. 2.3 Standby Mode
    4. 2.4 Normal Mode
    5. 2.5 Sleep Mode
    6. 2.6 Fail-Safe Mode
  6. 3Power Electronics
    1. 3.1 VSUP
    2. 3.2 VHSS
    3. 3.3 VCAN
    4. 3.4 VCC1
    5. 3.5 VCC2
    6. 3.6 VEXMON, VEXCTRL, and VEXCC
    7. 3.7 HSSx
  7. 4Communication Capabilities
    1. 4.1 CAN-FD and Classical CAN
    2. 4.2 CAN-SIC
    3. 4.3 LIN
  8. 5Protection Features
    1. 5.1 Undervoltage (UV) Monitors
      1. 5.1.1 VSUP
      2. 5.1.2 VHSS
      3. 5.1.3 VCAN
      4. 5.1.4 VEXCC
      5. 5.1.5 VCC1
      6. 5.1.6 VCC2
    2. 5.2 Overvoltage (OV) Monitors
      1. 5.2.1 HSSx
      2. 5.2.2 VCC1
      3. 5.2.3 VCC2
      4. 5.2.4 VEXCC
    3. 5.3 Short Circuit (SC) Monitors
      1. 5.3.1 VCC1
      2. 5.3.2 VCC2
      3. 5.3.3 VEXCC
    4. 5.4 Electrical Faults and Impact on SBC Mode
    5. 5.5 Temperature Sensors
    6. 5.6 Watchdog
      1. 5.6.1 Watchdog Error Counter
      2. 5.6.2 Timeout
      3. 5.6.3 Window
      4. 5.6.4 Initial Long Window
      5. 5.6.5 Q&A
    7. 5.7 Communication Fault Monitoring
      1. 5.7.1 CAN
      2. 5.7.2 LIN
    8. 5.8 LIMP
  9. 6Programming, Memory, and Control
    1. 6.1 SPI
    2. 6.2 EEPROM
    3. 6.3 Interrupts
    4. 6.4 Control
  10. 7Miscellaneous Features
    1. 7.1 Local Wake Ups
    2. 7.2 CAN Bus Wake Up (BWRR)
    3. 7.3 Partial Networking
    4. 7.4 GFO, nRST, and SW
  11. 8Summary
  12. 9References

5.6.4 Initial Long Window

There is a special window watchdog used when the SBC transitions from restart mode to standby mode. This is called the initial long window – and operates the same way as the standard window watchdog – but uses a different timing scheme to implement. The reason this is called a long window is because the shortest long window duration is a 150ms window and the default is 600ms where with typical window timing this is possible to have windows <150ms. The reason that this longer period exists is because all watchdog configuration must be done before the long window can be triggered as the watchdog registers lock after the long window has expired. This is also separate from other watchdog options available in standby mode and only occurs once on the transition from restart to standby.