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TCAN1043A-Q1: Wake up not triggered for tpulse < 1.5us

Anamika Pisharody
Prodigy 60 points
Part Number: TCAN1043A-Q1

Tool/software:


I am sending a Dom-rec-dom over the bus to wake my txr up from standby mode . I am trying tpulse from 0.5us to 1.8us as mentioned in the datasheet .


But I noticed , my Rx line is not pulled low when a pulse with tpulse or twk_flter < 1.5us is send . I also noticed that , the Rx line pulled high for tpulse or twk_filter > 1.8us . Attaching both condition images 

Tperio= 1.429us , tpulse = 0.7145us > twk_filter minimum limit.
Rx line not switching low.


T period = 5us :T pulse = 2.5us > twk_filter maximum.
Rx line switching low.


Can somebody tell me if I am missing something ? 

  • 0
    Prodigy 60 points


    Datasheet_ wakeform of interest

  • 0 in reply to Anamika Pisharody
    TI__Genius 13812 points

    Hi Anamika,

    Thanks for reaching out about the TCAN1043A!

    For context, the Wake up pattern (WUP) for CAN transceivers is intended for 500kbps, which is a 2us pulse. The tWake(filter) time of 0.5 to 1.8us is specifying the bounds where a bit is classified as dominant/recessive. Since 1.8us is the max time suggested, we recommend using this as the minimum pulse length. Essentially it can be thought of like this:

    • t < 0.5us: Not a valid filtered bit
    • 0.5 < t < 1.8: Undefined/varies depending on supply voltage, temperature conditions
    • t > 1.8: Valid filtered bit

    Let me know if that makes sense,

    -Ethan