NO connection to chips debug port on the MCXN236?

1. Close every other projects, and select debug option.

2. Sometimes the IDE will hang trying to open the linkserver. In that case, close the IDE, locate the axf or hex file and flash it using standalone link flash application.

You can close other projects by right clicking on your current project, select "Close unrelated projects".

balajivan1995 said:

Close every other projects, and select debug option.

balajivan1995 said:

Sometimes the IDE will hang trying to open the linkserver. In that case, close the IDE, locate the axf or hex file and flas

hello balajivan1995 

balajivan1995 said:

2. Sometimes the IDE will hang trying to open the linkserver. In that case, close the IDE, locate the axf or hex file and flash it using standalone link flash application.

UPDATE I found the location of the .axf file and ran the LinkfFash and received a similar error

Nc: Connecting to probe 1 core 0 (using server started externally) reports:

    'Ee(42). Could not connect to core.'

skruglewicz said:

Also, do you think I need to update the MCU-Link firmware using the firmware update utility for my board? Wondering if that might be causing problems with the debug port not connecting.

Hi, sorry for the late reply. I have attached a n236 board project file that will automatically toggle the RGB led. You can compile with your own IDE or use the .axf file directly. Can you please flash with this file?
n236_led.zip
Also, please ensure you have connected to the correct USB port.

skruglewicz said:

I’m still having problems with the MCXN236 . Can't find the probe 

CONSOLE log:

LinkServer RedlinkMulti Driver v25.6 (Jun 26 2025 19:34:05 - crt_emu_cm_redlink build 1017)
Found chip XML file in C:/nxp/workspace/frdmmcxn236_hello_world/Debug\MCXN236.xml
( 5) Remote configuration complete
Reconnected to the existing LinkServer process.
Connecting to probe 2 core 0 (using server started externally) reports:
'Ee(42). Could not connect to core.'
Retrying...
Reconnected to the existing LinkServer process.
Server OK but no connection to probe 2 core 0 (after 3 attempts) - Ee(42). Could not connect to core.
Failed on connect: Ee(42). Could not connect to core.
No connection to chip's debug port

 I'm dead in the water with the MCXN236 and can not develop my project without it Does any one know why thus is happening? Is my board defective? 

any help here would be appreciated.

Thanks 

Steve K

I am currently facing a critical and complete standstill in my project development due to a severe and unresolved issue with the MCXN236 device. To be absolutely clear, this development board or component is entirely non-functional; it is, in effect, a useless brick. All attempts to utilize the device have failed, rendering it completely unusable for its intended purpose. Consequently, I am dead in the water, as the lack of a working MCXN236 has created an insurmountable bottleneck, making any further progression on my project impossible until this fundamental hardware issue is resolved. This is not a minor setback; the device is fundamentally broken and cannot be leveraged for any stage of my necessary development work.

Here are the four troubleshooting steps I attempted to fix the "No connection to chip's debug port" error with your NXP FRDM-MCXN236 board, along with the reported status for each:

The persistent error across all attempts was: Ee(42). Could not connect to core. and No connection to the chip's debug port.

Thanks balajivan1995 or all your suggestions, but unfortunately your suggestions di not fix the problem. 

I'm closing my question but the debug Probe is still not working. I cannot use the board. 

UPDATE STATUS on this problem

It works on the new PC with a clean MCUXpresso + SDK install, so the board and probe are fine, and the root cause is almost certainly something broken or conflicting on the original PC’s toolchain/driver side rather than the hardware.

Brief summary

On a new PC I installed MCUXpresso (24.12) and the SDK (24.12.00), connected the FRDM‑MCXN236, built an example, and debug worked immediately. On the original PC I have MCUXpresso 25.6 with SDK 25.09.00, and despite reinstalling, updating LinkServer, trying LinkFlash, firmware updates, and ISP/bootloader mode, you still get Ee(42). Could not connect to core / No connection to chip's debug port.That confirms the FRDM‑MCXN236 and MCU‑Link firmware are good and isolates the problem to the original  Windows environment.

Likely causes on the original  PC

Most probable categories, given that the exact same board works elsewhere:

• Corrupted or conflicting USB/debug drivers (MCU‑Link / CMSIS‑DAP / WinUSB) on the   original  PC, possibly from prior NXP, SEGGER, PE Micro, or other probe installs.
  
  
• A stale or mismatched LinkServer instance or config on the   original  PC that the IDE keeps reusing, so the probe enumerates but SWD never actually connects to the target core.
  
  
• Security/IT software (AV, endpoint protection, USB control) on the   original  PC interfering with USB enumeration or blocking the debug interface, while the new laptop is more “clean.
  
  
• Leftover MCUXpresso or SDK fragments from original versions in different paths, causing the IDE to point at the wrong debug driver or XML/config for MCXN236 even though the latest SDK is installed.
  

I have researched a few things I could try which I will and update this post. so stay tuned

UPDATE STATUS on the problem 

Success

What was the reason?

Turns out there were multiple versions of the MCU-Link firmware on my troubled PC. And as I found two Common Causes of Persistent Debugging Connection Failures may be the reason for persistent debugging problems:

• Corrupted or Conflicting USB/Debug Drivers: Drivers (MCU-Link / CMSIS-DAP / WinUSB) on the original PC may be corrupted or conflicting. This can result from prior installations of probes from NXP, SEGGER, PE Micro, or others.
• Stale LinkServer Instance or Configuration: The IDE may be repeatedly reusing a stale or mismatched LinkServer instance or configuration on the original PC. This allows the probe to enumerate, but the SWD connection to the target core never actually establishes.

What I did to get it working without getting the Error.

I went into add/remove programs and noticed there were 3 versions of the MCU-Link Firmware install on my PC
Here is the program screen showing 3 versions!

I uninstalled all but
Mcu-Llnk firmware V3.148
MCUXpresso ID V25.6
I didn't need the other tools.

Now debug does not get the error as I described and works all the time?
SUCCESS !!! I'm back on track with debugging on the MCXN236