[SOLVED] How to supply power to MCU with 9 pin header on J-Link Cortex M Adapter

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  • [SOLVED] How to supply power to MCU with 9 pin header on J-Link Cortex M Adapter

    My j-link Base works perfectly fine to supple power when my MCU is powered externally. However, I need to power my MCU from the J-Link to flash the MCU outside my system.

    On the 9-pin header I do not see a power supply output? I do see a 5V output on pins 13 and 15 of the 19 pin header. I can type "power on" in J-Link commander, and see pins 13 and 15 go to 4.5V. My custom board however expects the 9-pin header to be used, and it looks like it expects the power to come in on pin 1 of the 9-pin header, which is VTREF, which is used for power sensing, and an Input on the 9pin header.

    I attached my current hardware schematic for the J-Link 9-pin connector on my board. It looks like power is being expected on pin 1 of the 9-pin header. How would I apply power from the J-link across the VTREF Pin. Is it possible to power the MCU from the 9pin header.

    My hardware designer can power the MCU from the 9pin header, but it looks like he is using an older J-Link, before the J-Link was broken into Base, Plus, Pro, ect. I have attached a picture of his J-Link as well if you could maybe help identify it, and let me know if it can still be purchased, and why it would be able to power the MCU wheras the J-Link base cannot.
    Images

    • Jlink Connector - Custom HW.PNG

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    • P80824-145718.PNG

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    • P80824-145718 (1).PNG

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  • Hello,

    Thank you for your inquiry.
    For verification, could you provide a picture of the top and bottom of the J-Link you used and its serial number?
    Per definition VTref is only an input pin for J-Link: segger.com/products/debug-prob…gy/interface-description/
    So it can't be used to power a target.
    The 9-Pin header has no 5-V Power pin defined by Arm so the 9-Pin adapter can't be used directly to power your target.

    EDIT: We received your inquiry via e-mail as well. To avoid duplicate information this thread will be closed now. For future requests please try to use only one communications channel at a time to avoid unnecessary delays.

    Best regards,
    Nino
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