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TCAN1043HG-Q1: INH PIN HIGH In the Sleep Mode

HEMANT KUMAR
Prodigy 20 points
Part Number: TCAN1043HG-Q1
Other Parts Discussed in Thread: TCAN1043

Tool/software:

Or one of Our Customer project we are using TCAN1043 and Utilizing INH Pin as wakeup.

Issue is very random where EN & STB Pin is High , Low respectively during Transceiver Sleep but some time observed that INH Pin remains high due to this system is not waking up since we have set interrupt detection at rising edge.

 

Could you please coach us how we can overcome from this situation. This issue reproduced at customer testing.

Regards,

Hemant

  • 0
    TI__Guru 50496 points

    Hi Hemant,

    Today is a holiday. Please give some time until Monday for feedback, thanks.

    Best Regards,

    Michael.

  • 0
    TI__Guru 53555 points

    Hi Hemant,

    Thanks for bringing your question to E2E, and for your patience over the US holiday. 

    When driving the TCAN1043H into Sleep mode using EN=high, nSTB=low, there is a transitional go-to-sleep mode before the device fully enters its lowest power state. While in go-to-sleep mode, the INH signal remains high and the wake sources for the device become active. This means that if the transceiver receives a wake event (WAKE pin or CAN bus activity) within this time then the device will move to Standby mode and the INH signal will remain high. Since the INH signal never went low in this scenario, any edge-based detection method may miss such a wake event. 

    My recommendation is for the system to ensure that the INH signal has gone low before assuming the transition to Sleep mode was successful. If the INH signal does not fall within 100us or so (depending on INH signal capacitance) then it should assume that a wake event was encountered and the system should return to a Normal operating mode to service the wake request. 

    Let me know if this is clear and if you have any more questions. 

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    Prodigy 20 points

    Hello Eric 

    could you please confirm on the following:

    If INH pin is high then we should do the following:

    1.Make nSTB pin High and EN pin was high already

    2.Needs to put the device in to normal state and prevent from the sleep process

    Regards,

    Hemant

  • 0 in reply to HEMANT KUMAR
    TI__Guru 53555 points

    Hi Hemant,

    Yes, this sequence will return the transceiver to normal mode so that the system can service any CAN data that may have triggered the wake source. This will also clear any wake flags internal to the transceiver so that sleep mode is accessible once again. Once the system detects an idle bus condition it can reinitiate a sleep attempt by driving EN=high, nSTB=low again. 

    Regards, 
    Eric Schott