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TCAN1146-Q1: Does our device support normal CANFD frame wakeup?

Sherry Liang
Genius 10255 points
Part Number: TCAN1146-Q1


Dear team,

The test condition is that  KL30 is always on(12V battery), KL15 is disconnected. After KL15 is turned off completely, they use CANoe sends CANFD frame(CANID: 0x400, baud rate is 500k+2M, data is all zero), but the INH pin is always ~0.44V. Under the same condition, if they sends CAN frame, INH pin will rise to 12V.

Therefore we want to know whether our device support such normal CANFD frame wakeup. If so, could you please help analyze why the customer failed the test? Thanks!

Thanks & Best Regards,

Sherry

  • 0
    TI__Guru 74352 points

    Sherry,

    Yes, the TCAN1146-Q1 will wake on a CANFD WUP. The ID 0x400 and all 0 data should transmit a dominant -> recessive -> dominant at some point due to bit stuffing, so I'm surprised that it did not wake on this frame. Is it possible to change the data to 0x55 through so there is a definite dominant -> recessive -> dominant to make sure the device is waking?

    Regards,

    Eric Hackett

  • 0 in reply to Eric Hackett
    TI__Genius 10255 points

    Hi Eric,

    It means that the customer should follow below format, right? In below format we request dominant -> recessive -> dominant format, all zero data can't achieve this format in my understanding, I am wondering how does the all zero data transmit dominant -> recessive -> dominant format. 

    Thanks & Best Regards,

    Sherry

  • +1 in reply to Sherry Liang
    TI__Guru 74352 points

    Sherry,

    That is the correct format. And with bit stuffing in the CAN protocol, if 5 bits of the same polarity are transmitted consecutively, a bit of the opposite polarity will automatically be inserted. In this case, 5 0s in a row, followed by a 1, then more 0s would be dominant -> recessive -> dominant. That being said, still try a different ID and see if that initiates the WUP for the customer.

    Regards,

    Eric Hackett 

  • 0 in reply to Eric Hackett
    TI__Genius 10255 points

    Hi Eric,

    Thanks for your clarification. They can wake up our device after they changing SW_EN bit from 1 to 0.

    Thanks & Best Regards,

    Sherry

  • +1 in reply to Sherry Liang
    TI__Guru 74352 points

    Sherry,

    Oh okay, understood. The device should still be able to wake up from WUP with that bit set to 0, it just won't allow selective wake configuration to complete.

    Regards,

    Eric Hackett