Hi Team,
I am currently working with a KW45-based custom board and facing an intermittent issue during programming and debugging the firmware.
I have tested the board with both a SEGGER J-Link and an NXP MCU-Link debug probe, and the issue occurs with both probes.
The custom board has the same boot configuration as the KW45 EVK, and the JTAG/SWD connections have also been checked and appear to be correct.
However, I am seeing the following behaviour:
When I try to dump or program a known-working application:
- Sometimes the application is programmed successfully, but after programming or starting a debug session, the device eventually jumps to a fault address.
- The debugger then halts at that location.
- During some programming or dumping attempts, I receive a Wire ACK fault.
- At other times, MCUXpresso reports:
Error while executing the MI command - I also tried to erase the flash from MCUXpresso, but the flash erase operation itself does not complete successfully.
Checks already performed
- JTAG/SWD connections have been checked and appear to be correct.
- The issue was tested with both a SEGGER J-Link and an NXP MCU-Link debug probe.
Boot configuration has been compared with the KW45 EVK. - I am using a known-working application for testing.
The issue is intermittent: programming sometimes succeeds, but at other times a Wire ACK fault or MI command error occurs. - Flash erase has also been attempted, but it does not complete successfully.
My questions
- What could cause the KW45 to: Intermittently report a Wire ACK fault while dumping or programming code?
- Report Error while executing the MI command?
- Jump or halt at an unexpected or invalid memory address after programming?
- Fail even when attempting a full flash erase?
Since the issue includes intermittent Wire ACK faults and failure during flash erase, I suspect this may be related to the debug interface, SWD/JTAG signal integrity, power-supply stability, reset sequence, flash controller state, device security/configuration, boot configuration, or another hardware-level issue rather than the application itself.
- Could you please suggest the recommended procedure to:
- Recover or erase the KW45 device.
- Verify that the debug interface is functioning correctly.
- Check whether the device is secured or in a state that prevents normal programming.
- Determine whether the Wire ACK fault is caused by the target hardware, debug probe, power/reset behavior, or SWD/JTAG signal integrity.
I can provide the following information if required:
- MCUXpresso IDE version: 25.6.1
- Debug probes tested: SEGGER J-Link and NXP MCU-Link
- Complete error log, including the Wire ACK fault details
- Debug console output
- Schematic of the JTAG/SWD and boot connections
- SWD/JTAG clock frequency
- Power-supply and reset configuration
- Memory/register information from the failed state
Any guidance on the recommended troubleshooting steps would be greatly appreciated.
Thanks in advance.
