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TCAN1043A-Q1: Will the device start up in Sleep mode if only VSUP applied?

Masatoshi Oguri
Expert 4780 points
Part Number: TCAN1043A-Q1

Hello,

Will the device start up in Sleep mode if only VSUP applied? If it will, is that the same condition as it transitions to Sleep Mode from Normal Mode via Go-To-Sleep Mode?

Thank you.

Regars,

Oguri (TIJ automotive FAE)

  • 0
    TI__Guru 74252 points

    Oguri-san,

    The TCAN1043A-Q1 will power up into Standby mode, and then transition to Sleep mode because VCC and VIO are not supplied and the under voltage flags will be asserted.

    Does this make sense?

    Regards,

    Eric Hackett 

  • 0 in reply to Eric Hackett
    TI__Expert 4780 points

    Hi Eric,

    Thank you for the feedback.

    So, even if the user want the system is in sleep state from the beginning (turn key) to wait for WUP, does the CAN transceiver have to be configured as Standby -> Normal -> Go-To-Sleep by MCU? It should be easy if TCAN1043A to startup in Sleep mode automatically, but it seems it requires some process.

    Regards,

    Oguri

  • 0 in reply to Masatoshi Oguri
    TI__Guru 53555 points

    Hi Oguri,

    Initial power up on Vsup is treated as a wake condition so the device will power up into Standby mode. This is the same behavior as if the device were in Sleep mode and received a WUP or LWU. The device expects that Vcc and Vio will be provided soon after a transition to Standby mode as the INH signal will assert high. In order for the device to move to Sleep mode, I would recommend to use the mode control pins nSTB and EN to follow the sequence you describe: moving to Normal mode and then Go-To-Sleep mode. Because there is no way for the system to otherwise distinguish a POR event from a LWU or WUP, this sequence will be needed to avoid a scenario where the node cannot wake from these other sources. 

    Regards,
    Eric Schott

  • 0 in reply to Masatoshi Oguri
    TI__Guru 74252 points

    Oguri-san,

    The TCAN1043A-Q1 can go from Standby immediately to Sleep mode if the EN and nSTB pins are in the correct state upon power up, but there will be a brief amount of time (tmode) where the device will be in Standby before transitioning to Sleep mode. It does not have to go through Normal mode.

    Regards,

    Eric Hackett