connection fail via swd with jlink

We're using nrf52833 and our target board is already running our program well.

Then 

we'd like to flash by using Jlink SWD programmer.

So, we connected vref, gnd, swdio swclk pin between our target and jlink's 20 pin connector by wire.

When we use jlink flasher program, we got the following errors.


Connecting to target via SWD
InitTarget() start
InitTarget()end
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
InitTarget() start
InitTarget() end
RESET (pin15) high, but should be low. Please check target hardware.
RESET (pin15) high, but should be low. Please check target hardware.
Cannot connect to target.

It seems errors in connection nrf52833 and jlink.

Currently, our target don't use RESET pin (p0.18) after looking into our schematic.

please check and advice us.

  • Today, I use nrf52833 DK board as a debugger for our target device following this link.
    The link is "">docs.nordicsemi.com/.../hw_debug_out.html" .

    After test as above,

    Our target is working good with debugger as DK board.

    It is so good for us.

    Then the connection problem with j-link device still happen as before.

    Please advice us why to happen and how to solve.

  • Hello,

    From your response, I understand that the issue occurs when you use an external debugger, but there is no issue when using the nRF52833 DK as the debugger. Please correct me if I’m wrong.

    If that is the case, the problem is likely related to the connection between your J-Link debugger and your custom board. Could you please ensure that the power supply is stable while using the external debugger?

    From the last shared logs, it appears that the target device is not being detected.

    Kind Regards,

    Abhijith

  • Hi Menon,

    Yes,

    the issue occurs when you use an external j-link debugger, but there is no issue for programming when using the nRF52833 DK as the debugger. 

    However, there is still the issue for debugging for using RTT viewer even when using the nRF52833 DK as the debugger.

    So,

    I have looked more into the following link referring to nRF52832 DK. "docs.nordicsemi.com/.../ext_programming_support_P20.html"

    Here, it says the more connection for reset pin ,apart from pins connection of swclk, swdio, vcc and gnd.

    So,

    can you tell me about the pin connections between our external target board and nRF52832 DK debugger.

    Then the next time after solving it, I may have to solve issues between our board and j-link external debugger. 

    Thanks,

  • Hi,

    I have tested j-link connection between our target and DK board.

    When DK board was connected with RTT Viewer on my PC, the noti message with "update on Jlink OB fw"showed on RTT Viewer.

    And I update Jlink OB on my DK board and I tested again j-link via swd with my target.

    Then the following errors happened. please advice me why this happened and jlink OB connection failed even with our target.

    C:\Program Files\SEGGER\JLink_V794e>JLink.exe
    SEGGER J-Link Commander V7.94e (Compiled Jan 15 2024 15:20:36)
    DLL version V7.94e, compiled Jan 15 2024 15:18:46
    
    Connecting to J-Link via USB...O.K.
    Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Oct  9 2024 11:00:56
    Hardware version: V1.00
    J-Link uptime (since boot): 0d 00h 02m 58s
    S/N: 685079944
    License(s): RDI, FlashBP, FlashDL, JFlash, GDB
    USB speed mode: High speed (480 MBit/s)
    VTref=3.300V
    
    
    Type "connect" to establish a target connection, '?' for help
    J-Link>connect
    Please specify device / core. <Default>: NRF52833_XXAA
    Type '?' for selection dialog
    Device>
    Please specify target interface:
      J) JTAG (Default)
      S) SWD
      T) cJTAG
    TIF>S
    Specify target interface speed [kHz]. <Default>: 4000 kHz
    Speed>
    Device "NRF52833_XXAA" selected.
    
    
    Connecting to target via SWD
    InitTarget() start
    InitTarget() end - Took 108ms
    Connect fallback: Reset via Reset pin & Connect.
    InitTarget() start
    InitTarget() end - Took 109ms
    Cannot connect to target.
    J-Link>

    Please help me.

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