topic Re: FRDM-MCXA156 and Segger J-Link in MCX Microcontrollers

FRDM-MCXA156 and Segger J-Link

rjrapier — Wed, 22 Apr 2026 16:47:08 GMT

I am trying to use a Segger J-Link JTAG with the FRDM-MCXA156, and no matter the jumper configuration I am unable to get the Segger tools to connect to the processor. Lotest Segger tools installed, J-Link firmware updated to latest version.

Ultimately I plan to use IAR tools with the Segger J-Link, but for now, I am just trying to get the J-Link to work. Any suggestions are welcome.

When I try to connect to the processor using J-Link Commander V9.36, it goes through the motions, but fails with :

****** Error: J-Link script file function InitTarget() returned with error code -1

Error occurred: Could not connect to the target device.
For troubleshooting steps visit: https://kb.segger.com/J-Link_Troubleshooting
J-Link>

Re: FRDM-MCXA156 and Segger J-Link

Celeste_Liu — Thu, 23 Apr 2026 11:18:59 GMT

Hello @rjrapier ,

Thanks for your post.

Please refer to table 21 of FRDM-MCXA156 Board User Manual . If you want to use external debugger, you must short JP7 and then connect the external debugger to J24.

I have tested on my FRDM-MCXA156 board with J-Flash, it's okay to flash the firmware. Please check again on your side. Thanks!

Have a nice day.

Celeste

Re: FRDM-MCXA156 and Segger J-Link

rjrapier — Thu, 23 Apr 2026 16:19:17 GMT

Sadly, not what I am seeing with J-Flash. I had configured my board with the jumpers in the same way as you have yours. I tried both SWD and JTAG, all I get is an error when trying to connect to the processor. I tried two different J-Link devices with two different 10 pin adapters.

Re: FRDM-MCXA156 and Segger J-Link

rjrapier — Thu, 23 Apr 2026 18:19:40 GMT

I reconfigured to no use the J-Link, and instead use the USB interface, and am able to connect and program the board that way with the IAR tools. For now we will proceed with this mechanism instead of the J-Link devices.

Re: FRDM-MCXA156 and Segger J-Link

Celeste_Liu — Fri, 24 Apr 2026 03:23:37 GMT

Hello @rjrapier ,

Thanks for your update. Glad to hear that. At least you can move forward now. If you run into any new issues, feel free to open a new post.

Celeste