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Original question:

TCAN1145-Q1: Selective wake up configuration from sleep mode to standby mode

TCAN1145-Q1: Selective wakeup with WUF problem

Scarlett Cao
Expert 4000 points
Part Number: TCAN1145-Q1

Hi team, 

My customer is using TCAN1145-Q1 in their OBC application and would like to configure selective wakeup through WUF.  When the OBC machine is power up and host PC send the correct wakeup frame 0x5xx as configuration, TCAN1145 can be wake up normally. If send other frame like 0x333, TCAN1145 will not be wake up.

The problem is, when customer power down the OBC machine and host PC still constantly sending out the incorrected wakeup frame 0x333. If the OBC is powered up at this time, the IC will be wake up by this wrong frame, showing INH high and CANINT high. Is it related with some power up sequence requirement? Is their any way to configure the device not to be wake up by wrong frame in this case?

Thanks

Scarlett

  • 0
    TI__Guru 53555 points

    Hi Scarlett,

    During the OBC machine power off, has TCAN1145 been configured for SW and put into Sleep mode? Does the Vsup supply of the transceiver ever power-off? If there is an undervoltage event (on Vcc or Vio) while the transceiver is in Normal mode, the transceiver will eventually move to Sleep mode with SW disabled and will wake to any CAN activity. Similarly, if Vsup is removed, the transceiver will lose all configuration data and start-up in its default Standby mode and drive INH high. 

    Another note; TCAN1145 has an error detection feature while in SW mode and can identify certain CAN errors. If enough CAN errors are detected while the transceiver is in Sleep mode, it will automatically wake up. A wake from this condition will set the FRAME_OVF interrupt flag. 

    Can you please clarify what the power-down sequence for the transceiver is in this test case? I'm interested to see what was the last configuration and device mode before specific power rails power-down. It would also be good to see a block diagram showing the power circuitry and their control sources (is INH a control signal for this?). 

    Lastly, does the TCAN1145 move into Standby mode (INH high) when the OBC powers up and the CAN bus is idle (PC is not sending any CAN data)?

    Let me know if you find out more information or have additional questions in the meantime. 

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    TI__Expert 4000 points

    Hi Eric, 

    Thanks for your detailed reply. Yes, TCAN1145 INH pin is used to control the OBC power. The power off sequence is TCAN1145 to sleep mode-> INH LOW -> OBC stop working

    Before TCAN1145 been put to sleep, customer run the SPIIF_TCAN1145_0_GoSleep() function to configure WUF ID 0X500, mask 0Xff

    Customer read the FRAME_OVF and WKERR value when TCAN1145 been wake up by wrong flame, they are both 0, but CANINT=1. Customer read MODE_SEL register, the value is 0x4, which signifies standby mode

    Could you please help us understand why FRAME_OVF=0 in customer's case? Please also find customer's program as below:

    CanTrcv_119_TJA1145.c

    Thanks

    Scarlett

  • 0 in reply to Scarlett Cao
    TI__Guru 53555 points

    Hi Scarlett,

    I have reviewed the go to sleep function from the attached code and the sequence looks acceptable. SWCFG is properly set after all of the configuration has been complete, SW_EN is set, and the transceiver mode is switched to Sleep mode. However, because the CANINT interrupt is set, it seems that the device is behaving as if SW is not enabled and it wakes up to a WUP. We may have to look further into this to see where the actual configuration may be different from what is in the code.

    Before sending the TCAN1145 to Sleep mode, what is the state of the SWERR interrupt? This interrupt would indicate that there is a problem with the configuration and SW cannot be enabled. 

    When the TCAN1145 is put into Sleep mode while the PC is sending data, does the INH signal fall? If so, for how long until the INH signal goes high again? Is it possible to capture a scope shot of the CAN frame that causes the TCAN1145 to wake? Please use a timescale where the CAN ID is readable. 

    Regards,
    Eric Schott