topic Connection problem with MCXN647 (Ee(42) error) in MCX Microcontrollers

Connection problem with MCXN647 (Ee(42) error)

Peter-D — Sun, 28 Dec 2025 13:04:08 GMT

Hi,

I am having a problem with my . Whenever I try to debug or flash my project, I get this error :

I don't know if it's related, but it started when I changed this line in a while(1) loop to increase its frequency : SDK_DelayAtLeastUs(30000, SystemCoreClock); -> SDK_DelayAtLeastUs(10000, SystemCoreClock);

I didn't update before the problem occurred, but I updated LinkFlash afterwards and it didn't solve anything.
I already tried SPT erase but it didn't work. (Maybe I did it wrong.)

On the SPT, after activating ISP mode, I was able to perform the “build image” and “write image” operations, but erasing still does not work.

Thank you in advance for your help.
PS: Please excuse my English and technical vocabulary, I am just starting this project at engineering school.

Re: Connection problem with MCXN647 (Ee(42) error)

Alice_Yang — Mon, 29 Dec 2025 03:19:06 GMT

Hi @Peter-D

Please try using the Flash Programmer inside the SPT tool to erase and program a blinky SDK demo, and check whether it works properly. For details, please refer to the video in the attachment.

If these steps work well but you still cannot debug with the onboard debugger, please use an external debugger to test.

If you still have issues, please feel free to contact me.

Thank you.

Alice

Re: Connection problem with MCXN647 (Ee(42) error)

Peter-D — Mon, 29 Dec 2025 14:34:20 GMT

Hi @Alice_Yang,
Thank you very much for your reply.

I followed the instructions in the video, and the method works to make the LED flash.
However, I get the same error when I return to the debugger from the MCUXpresso IDE.

If the problem comes from the onboard debugger, I don't think I'll buy an external debugger such as PEMicro or SEGGER J-Link (if that's what you were referring to) especially since the board I'm using was lent to me at school.

If I can't find a solution, I'll continue to use the flash programmer, which also works for my project, and I'll ask my professors if they have an external debugger.

Best regards,

Peter

Re: Connection problem with MCXN647 (Ee(42) error)

Alice_Yang — Tue, 30 Dec 2025 03:49:35 GMT

Hello @Peter-D

I’m not sure if the debugger on your board is actually broken. Please try updating the debugger firmware by following the instructions here: https://docs.nxp.com/bundle/UM12018/page/topics/Updating_MCU_Link_firmware.html

After the update, power cycle the board, create a new workspace in MCUXpresso IDE, import a fresh SDK demo, and try debugging again.

It would be better if you could take a video and share it with me. I’ll help you check it.

Thank you.

Alice

Re: Connection problem with MCXN647 (Ee(42) error)

Peter-D — Wed, 31 Dec 2025 01:01:28 GMT

Hello @Alice_Yang

Thank you for your reply.

I updated LinkServer as suggested, but I think I already had it after the problem appeared. I tried the update again anyway, then power-cycled the board, created a new workspace, and imported a demo project, but I am still getting the same Ee(42) error when trying to debug.

I have recorded a short video showing the process, which I have attached.

Thank you for your help, and I wish you a happy new year.

Best regards,
Peter

Re: Connection problem with MCXN647 (Ee(42) error)

Alice_Yang — Wed, 31 Dec 2025 02:36:28 GMT

Hello @Peter-D

Thanks for your video.

Please delete the .launch file (in below picture)and erase your board again.

Use the Debug button shown in the picture below to start debugging.

If it still doesn’t work, I recommend replacing the board.

By the way, I will be on New Year holiday and will return on January 5th. If you still have questions, please contact me on that day.

Thank you for your understanding, and Happy New Year!

Alice