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

2 Device States

TCAN28xx State Diagram Figure 2-1 TCAN28xx State Diagram

The TCAN28xx devices all contain six different device states – two transitory states (init and restart), 3 standard operational states (standby, normal, and sleep) , and an optional fail-safe mode (fail-safe mode) for faults on SBC. The device states act as guardrails for features on the SBC as not all features are available in all modes. The SBC behavior is tied to which state the SBC is in and to properly design with this device all states and state transitions need to be understood. A brief overview of different subsystems and accessibility in each mode is shown in Table 2-1.

Table 2-1 SBC Block Overview by SBC Mode
Block Restart Sleep Standby Normal Fail-Safe
nINT High when VCC1 active High if VCC1 on Active Active Hi-Z
GFO Programmed active state when VCC1 on Programmed active state if VCC1 on Active Active Hi-Z
SW Off Wake Capable/Off Active Active Hi-Z
HSSx Off Off (default). HSS4 can be used for cyclic sensing wake, all other HSS pins can be configured for direct drive. As Programmed As Programmed Off -HSS4 can be set up for cyclic sensing wake.
LIMP Same as previous state, Low if leaving fail-safe mode or watchdog error Previous state prior to sleep Previous state prior to standby Previous state prior to normal Low
WAKEx Off As Programmed As Programmed Off Active
CRXD High High if VCC1 on, Hi-Z otherwise Configuration dependent Configuration dependent Hi-Z
LRXD High High if VCC1 on, Hi-Z otherwise Configuration dependent Configuration dependent Hi-Z
nRST Low Low unless VCC1 on, then high High High Off
SPI Off Active if VCC1 on Active Active Off
Watchdog Off Off but can be programmed on if VCC1 on Default on with long first pulse but programmable off Active Off
Low Power CAN RX Default On for wake-capable Default On for wake-capable On if wake capable On if wake capable Default On for wake-capable
CAN transceiver Off Off Programmable rx only Programmable Off
Low Power LIN RX Default On for wake-capable Default On for wake-capable On if wake capable On if wake capable Default On for wake-capable
LIN Transceiver Off Off Programmable rx only Programmable Off
LIN Bus Termination Weak current pull-up Weak current pull-up 35kΩ (typical) 35kΩ (typical) Weak current pull-up
VCC1 Ramping Off (default), programmable on On On Off
VCC2 Ramping Off (default), programmable on On (default), programmable off On (default), programmable off Off
VEXCC Ramping after initial configuration Off (default); programmable on Programmable Programmable Off