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Original question:

TLIN1021A-Q1: wake up source recognition

TLIN1021A-Q1: wake source - LIN wake vs. power up

Piotr F.
Intellectual 2950 points

Part Number: TLIN1021A-Q1

Hello Experts,

My customer has specific TLIN1021A-Q1 application, where he needs to detect whether wake source is LIN communication or if transcvier woke up due to power up.

How to distinguish these two conditions? It is possible? 

  • 0
    TI__Mastermind 30670 points

    Hi Piotr,

    There are three ways to wake-up the TLIN1021A-Q1 from sleep mode:

    • Remote wake-up over the LIN bus via the LIN wake-up receiver.
    • Local wake-up via the WAKE pin.
    • Local wake-up via the EN pin. The EN pin must be set high for t > tNOMINT in order for the device to wake-up.

    First we need to identify which mode does the device enter from sleep mode. Upon an EN pin transition from from low to high the TLIN1021A-Q1 transitions from sleep mode to normal mode in t ≥ tNOMINT. Standby mode is entered whenever a wake-up event occurs through LIN bus or the WAKE pin.

    Then if we want to distinguish a Remote wake-up via LIN bus or Local wake-up via WAKE, the simplest way is to monitor the TXD pin signal. When an Local wake-up event takes place, the TXD pin is pulled hard to GND letting the LIN controller know that the wake-up event was due to the WAKE pin and not a wake over LIN event.

    Please let me know if you have more questions.

    Regards,

    Sean Guo

  • 0 in reply to Sean Guo
    TI__Intellectual 2950 points

    You have not answered my question.

    Is it possible to detect/distinguish what triggered standy mode? 

    Or in another words: does TLIN1021A-Q1 indicate what is standby mode source ( Vsup>UVSUP or LIN BUS WAKE UP OR WAKE PIN WAKE UP) ? 

  • 0 in reply to Piotr F.
    TI__Mastermind 30670 points

    Piotr,

    This figure may cause confusion but let me clarify here. The answer is YES. But you can only distinguish a Remote wake-up from a Local wake-up. You can not detect an unpowered system or sleep mode as a previous state. This is because local wake-up is just power-cycling the device. You can power-cycle the device either from an unpowered system, or sleep mode. But they are essentially both local wake-up and TLIN1021 will not indicate it.

    The way to detect a local/remote wake-up is monitoring the TXD pin. It has weak pull-down for Remote wake-up,  hard pull-down for Local wake-up. I recommend refer to this E2E post for local/remote wake source recognition. 

    https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1104629/tlin1021a-q1-wake-up-source-recognition

    You will need some external power management ICs to distinguish an unpowered system from sleep mode in the case of local wake-up. Or use TLIN1431 since you can read the register bits. TLIN1021 does not have LDO or registers to achieve this function.

    Regards.