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TCAN1051GV-Q1: CRC

Carlo Marsano
Intellectual 1700 points
Part Number: TCAN1051GV-Q1
Other Parts Discussed in Thread: TCAN4550-Q1, TCAN1051

Hi,

My customer has designed in the TCAN1051GVDRQ1 and has a couple of questions coming out of reading the SLOA101b - TI CAN application note.

Would you be able to help with these questions?

  • In Section 3.1.1 it says “CRC–The 16-bit (15 bits plus delimiter) cyclic redundancy check (CRC) contains the checksum (number of bits transmitted) of the preceding application data for error detection.” I read this to mean the CRC is only calculated on the data in the Data Field, is this correct? Or is the CRC also calculated on the Identifier Field i.e. over the whole message?

  • Is the CANBus block in the micro typically implemented entirely as a HW state machine, or is it typically a controller running from ROM code in the micro?

Does TI have any recommendations for the application SW level protocol e.g. additional error detection and recovery strategies on top of what is already implemented in the CANBus system for critical data?


Thanks in advance.

  • 0
    TI__Guru 74262 points
    Carlo,

    1. The CRC checks all the bits before it, not including the stuffed bits. So that includes the start of frame, RTR, identifier, data, etc. until the CRC bits start.

    2. They are typically implemented as state machines, responding with configured responses into the MRAM of the CAN controller. So there will be configuration necessary, but the execution is typically handled by a state machine.

    We don't have any specific papers written, but it's important to know that most controllers have error handling through built-in interrupts, error messages, and error counters that will change the state of the controller error messaging real time. The TCAN4550-Q1, which is a CANFD controller and CAN transceiver integrated into one package, includes these kind of error handling mechanisms.

    Can I ask what kind of CAN controller the customer is deciding to use? And I assume the CAN transceiver they've chosen is the TCAN1051?

    Regards,
  • 0 in reply to Eric Hackett
    TI__Intellectual 1700 points
    Thanks Eric,

    The CAN controller is no the STM mcu. Yes, the tansceiver is the TCAN1051.

    Cheers, Carlo.