[ABANDONED] Power Board w/Segger JLink Plus Compact

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  • [ABANDONED] Power Board w/Segger JLink Plus Compact

    Can I power the board I am using (PineTime DK) from the Segger JLink Plus compact? I have the VTref connected to where the ST-Link V2 3.3v connector was. In that case it provided power and I'm not sure if I can configure the jlkink plus to supply the power.



    I see this link J-Link Interface Description (segger.com) which states what it does but not if it supplies power to the board:

    Segger wrote:

    This is the target reference voltage. It is used to check if the target has power, to create the logic-level reference for the input comparators and to control the output logic levels to the target. It is normally fed from Vdd of the target board and must not have a series resistor

  • If your target works with 5V and consumes less than 300mA, you can power it via pin 19 of J-Link.
    Supply specs:
    segger.com/products/debug-prob…#technical-specifications
    see "Target supply voltage" and "Target supply current".


    How to enable the 5V output on pin 19:
    wiki.segger.com/UM08001_J-Link…Guide#Target_power_supply
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • If you have an < 5V board, you need an adapter between J-Link and board if the board should be powered through J-Link:
    segger.com/products/debug-prob…rs/target-supply-adapter/
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • Ok. I have the adapter but now I'm worried about the battery attached to the board. It was fine with ST-Link v2, but I'm not sure it's ok with the Segger J-Link. Somebody said: "Just to make sure: If you leave the battery connected and supply voltage via the J-Link, the battery may backfeed power into the J-Link."

    Do I need to disconnect the battery from the board (cut the wires as it's a PineTime DK)?

  • Without knowing the board, I would say: Yes, it is the safe way to disconnect the battery / take it out of the socket.
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • I have 4 connections on the board SWCIO, SWCLK, VCC, and GND. I currently use the ST-Link V2 which has all 4 pins, one of which is a 3.3v and supplies power to the board. I am trying to do the same with the jlink. If I move the VCC to the vtref from the 3.3v Adaptor pin (19) on the JLink where it is currently connected, the board will not have power. I did this previously and the board did not work. I have tried both:

    SWCIO (7), SWCLK (9), VCC (1 - Vtref), GND (4)
    SWCIO (7), SWCLK (9), VCC (19 - 3.3v), GND (4)
    Neither works.

  • Pin 19 of J-Link is a 5V output.
    This needs to be converted to 3.3V for your target as supply voltage.

    At the same time, J-Link needs the target reference(!) voltage on pin 1 for its level shifters. This pin is an input to J-Link.
    You cannot power your target through pin 1.
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • You can connect pin 1 to the 3.3V output of the adapter.
    Alternatively, you do not connect pin 1 at all but use this:
    wiki.segger.com/J-Link_Commander#VTREF
    and use the value “3300”
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • Cannot connect and power board from Segger J-Link even with 3.3v adapter

    I am trying to power, program, and debug my pinetime devkit board using the seggar jlink through VS Code. I am using the PineTime DevKit.



    The battery is disconnected as the io, clk, gnd, and vcc are behind it and repacking it and charging it would be difficult if I have to do it regularly. I've been using an STLink which can power it but I don't get print statements of debugging:


    I purchased the adapter because segger jlink only has 5.5v (read about the challenge here) and connected the 19 to the vcc based on this document stating: "The supply voltage to the target is provided through pin 19 of the debug cable.":


    I can connect to the board but cannot flash it using VS Code as I get an error:

    Source Code

    1. 0002242:CRITICAL:__main__:Target type 'nrf52832' not recognized. Use 'pyocd list --targets' to see currently available target types. See <https://github.com/mbedmicro/pyOCD/blob/master/docs/target_support.md> for how to install additional target support.
    But I don't see the board being powered with the segger when I plug it in:


    While I do when I plug in the stlink:




    I don't know how to power the board with the segger so I can flash and debug it. What am I doing wrong?