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TPS653860-Q1: How to turn off CANwake programatically

Ben holter
Intellectual 295 points
Part Number: TPS653860-Q1
Other Parts Discussed in Thread: TCAN1043

Tool/software:

Hello,

is there a way for the PMIC to ignore CAN wake functions?

Depending on application we want to wake on CAN, and sometime not. In the times we dont want to wake on CAN, we do not want to turn on every time there is a message (sometimes every mS, sometime a few times a minute), check that it was can wake, then go back to sleep, we just want to ignore it. Is there a way to do this in the PMIC, in hardware (software changeable), or in a can chip (right now using the TCAN1043).

  • 0
    TI__Genius 13850 points

    Hi Ben,

    From TPS65386-Q1 side i'm not seeing option to ignore WAKEx pin request to high. I'll consult system team on this but would assume there is no way. 

    What comes to TCAN1043 operation that would need to checked from interface team. 

    Br, Jari

  • 0 in reply to Jari Niemela13
    Intellectual 295 points

    The INH pin output on the CANchip goes high when there is a CANwake on the chip. This could go to one of the wakex pins, but since the 1043 cant turn off the inh pin going high, i was hoping the PMIC could arbitrate this without starting up

  • 0 in reply to Ben holter
    TI__Genius 13850 points

    Hi Ben,

    Thanks for clarification. Just wondering how this is then handled on system level if CAN wake-up is omitted and PMIC is in OFF mode? There has to be some other function "alive" to do decision when wake-up PMIC as will?

    Trying to understand bigger picture on system level if this is more general requirement. Should this wake-up then happen after request has been active certain time or should there be a "blank" period so that wake-up is omitted. 

    Br, Jari

  • 0 in reply to Jari Niemela13
    Intellectual 295 points

    Hello,

    Yes, this is what we are trying to figure out, does the PMIC (or something else) has capabilities for checking functionality without waking everything up if the CAN wake is not a wanted feature. there is a TCAN1146 device which requires a selective pattern to actually wake, but this takes 500uA. Ideally the PMIC would turn on with CANwake state change, but then check a register (programmed) and not wake up the whole device if the register says not to (and ideally only use 100uA for a few mS when checking). Or something along these lines seems ideal. 

  • 0 in reply to Ben holter
    TI__Expert 5111 points

    Hello Ben,

    As I already mentioned in your previous thread, this device is NDA restricted and this discussion needs to take place with your field engineering team.

    There may be a solution involving a configurable deglitch time on WAKE pins, provided your CAN wake signal lasts less than the deglitch duration.

    Best regards,

    Florian