[SOLVED] J-Link Pro cannot connect to NXP MKV31F512 when power on via J-Link

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  • [SOLVED] J-Link Pro cannot connect to NXP MKV31F512 when power on via J-Link


    I am trying to connect to an NXP MKV31F512 with a J-Link Pro using the power supply feature of the J-Link.

    This is with a custom board.

    When using an external power supply to power the board (so the MCU gets its power from a DCDC converter), I can connect with the J-Link just fine (with power off).

    Connecting fails with Commander, J-Flash and Ozone. From Ozone, I received a log file, which I attached. I hope I removed all the sensitive information like serial numbers from it.

    Any idea why I cannot connect to the MCU when the J-Link powers the board but I can if the CDCD converter supplies the voltage?

  • How much current does your board draw?
    Did you make sure that it is within the specs of J-Link?

    Did you make sure that you have connected J-Link to a USB hub that has its own power supply? If not: Did you make sure that J-Link is the only device connected to the hub?

    Do you use the power on perm feature of J-Link or do you switch on the power automatically at debug session start?
  • Hi,

    our board draws arounf 40mA and the J-Link is the only device on a USB hub. I did a "power on" in Commander before connecting to the device.

    Anyway, we could now see that Ozone cannot connect but the Atollic TRUEStudio with a slightly older J-Link driver version on another laptop had no trouble connecting. So we need to investigate this further.

    Thanks for your answer.

  • Hi,
    Okay. We will close this thread for now.

    Best regards,
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