mcuXpresso - LPC55S69 - SWO ITM Console not working at lower clock speed

[PhilV]

I am having trouble with the SWO ITM console if I try and change the core clock speed on the LPC55S69 that I am using.

At 150MHz (full speed) core & traceclk all is well.
The IDE detects the correct speed:

and the SWO ITM Console then shows the correct output (I set a breakpoint after the calls to pins, clocks, and peripherals init, and then do the SWO configuration "detect", and then finally start the SWO ITM Console):

However, I don't believe I can run at 150MHz since I need to be able to program the flash, so I have tried to slow the core (and traceclk) to 100MHz using the clock config tool.
According to the ClockConfig tool the freq. is actually 100.1MHz

Either way if I use the autodetected speed (100.1MHz) or if I override it to 100MHz the SWO ITM Console output is garbled:
At 100MHz:

At 100.1MHz:

I've attached my generated "Clock" files - any pointers as to what I'm doing wrong?

[PhilV]

As an update to this, redid the project, but reduced the clock to 96MHz (rather than the 100 / 100.1 that was giving strange results) and the ITM is working again without issue.

[Alice_Yang]

Hello @PhilV 

How about share your whole project, I help to check on my side.

BR

Alice

[PhilV]

Hi @Alice_Yang , thanks for your reply.
This is in a custom project, but I am going to try doing something similar on the EVK board, if I still have the issue there I will upload the project for you to see.