Low voltage error: using Segger J-Link debugger/J-Link JTAG to SWD/Xiao BLE Sense mbed

[rickmkrebs]

Hi DevZone Engineers,

  As I am unable to access my board (Xiao BLE Sense (embedded form) with Nordic 52840 SoC) through the "Connected Devices" tab in nRF Connect, I am trying to set up a Segger J-Link Mini in order to flash and debug my project.  The issue is that I repeatedly get this error when using nrfjprog on the command line: "ERROR: Low voltage detected at the target."  I've been following the link below to establish J-Link.  

https://docs.nordicsemi.com/bundle/ncs-2.6.2/page/zephyr/develop/flash_debug/nordic_segger.html

My setup: 
Hardware: Apple M2, Xiao Expansion board, Treedix JTAG to SWD cable adapter board, Segger J-Link Mini (EDU)

Software: VS Code 1.92.2, nRF v2.7.0, toolchain v2.7.0

I've checked out some posts regarding low error during debugging and low voltage mode in various Nordic chips but nothing quite like I am experiencing.  I've made sure that both my Xiao Sense board as well as J-Link debugger are connected to my desktop system via USB per usual.  The reference voltage from the Treedix is 5 V and this is what I am connecting to my expansion board (which should be tolerable).  I've added a low-voltage parameter to my overlay file for the SPI functionality but not sure this would make any difference.

I can open Segger Ozone debugger, which loads the program code but I cannot step through or see anything correlating to hardware addresses. 

I have not yet contacted Segger but am not confident yet that that is the place to start.  Any help would be greatly appreciated.

My related questions are: 

1. should I use a different Segger debugger (or other company)?  

2. are there Kconfig or overlay specifications I should use?  

[Turbo J]

Segger J-Link commander can tell you what the Vtref is on the debugger. If I'm reading the specs correctly, the EDU wants at least 1.8V here.

[rickmkrebs]

Thanks Turbo J, you are right I get 0.0 V for VTarget when I connect to my board using J-Flash (for Mac).  I really would prefer a command line utility but after much searching cannot find a binary for the Mac corresponding to J-Link Commander.   It is not part of the newest J-Link installation.  

I figure it must be a connection issue but the setup is so simple that I cannot see where the problem could be.  Thank you for any other ideas you have.

[Turbo J]

The command line utility is just called jlink in windows - this is what is referred to as "Jlink commander". It would surprise me if macos called this something else.

[Bendik Heiskel]

Hi,

The debugger needs a reference voltage from the board.  The VTref pin on the debugger must be connected to the VDD voltage of the board you are programming.

 

Since VTarget is 0V I recon this connection is missing.

 

Best regards,

Bendik

[rickmkrebs]

Yes, what a rookie mistake.  I didn't realize that macOS can run .exe files by right-clicking and just opening with Terminal that way. 

[rickmkrebs]

Thanks for your response Bendik.  Yes, I checked the connection and didn't have the header lined up correctly.  Wow, really dumb oversight.  West flashes fine now.