J-Link, 5V Supply

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  • J-Link, 5V Supply

    Hello,

    I'm unsure, I already sent one J-Link back as the 5V Supply seems dead, it does not supply 5V.

    I try to power an STM32F4 Discovery with it and double-double-checked the wiring already.

    I expected that there would be 5V available when I plug in the J-Link (measured between pin 4 and pin 19).

    I don't think the wiring is incorrect as when I externally power the Discovery board I can read a valid VTref on pin 1:

    SEGGER J-Link Commander V6.10c (Compiled Sep 28 2016 18:30:32)
    DLL version V6.10c, compiled Sep 28 2016 18:30:23

    Connecting to J-Link via USB...O.K.
    Firmware: J-Link V9 compiled Sep 1 2016 18:29:50
    Hardware version: V9.40
    S/N: 269402916
    License(s): FlashBP, GDB
    OEM: SEGGER-EDU
    VTref = 2.958V


    Type "connect" to establish a target connection, '?' for help

    On the other hand, I can't connect to the device, I still need to clarify this.

    I use J-Link on Linux, not sure if this may be related to the issue.


    Can anybody explain if my understanding is incorrect?


    Thanks for any hints,
    Torsten
  • Hi,

    Yes, Kenny is right. In the default configuration J-Link does not supply power on pin 19.
    You can either switch it on permanently with J-Link commander and the command "power on perm" or until the next disconnect with "power on".

    Best regards
    Johannes
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