MTB (Micro Trace Buffer) LPC812 Not Working

[jimpearce]

I am using MCUXpresso v11.5.0[Build 7232][2022-01-11] with the LPCXpresso812-MAX Board.  I have started a fresh workspace and have created a project by importing an SDK example.  When I try to use the MTB I get a notice 

"Unable to get instruction trace configuration.  Unsupported target detected when attempting to configure instruction trace........."

The data sheet for the LPC812M101JDH20 says that MTB is supported.  I must have missed setting something up to enable the tracing but I have searched many places and have not found an answer.

What has to be set to enable the trace buffer?

Thanks!

[jimpearce]

So, has anyone managed to get the MTB working with the SDK examples for the LPCXpresso812-MAX Board?  

[DanielRuvalcaba]

Hi,

Could you please show me a screenshot of how your board is enumerated once it is connected to your computer?

[jimpearce]

I hope that this is what you are asking for.  If not, please let me know.  Thank you for your help.

jimpearce_0-1652988091977.png

jimpearce_1-1652988791715.png

[DanielRuvalcaba]

Hi,

Yes, that helps, thank you very much.

What I see is that your computer/IDE is detecting your board as the LPC11U35 that mean that uses the on-board debug probe. This one doesn’t have an MTB module, this might be the reason why you are having problems.

DanielRuvalcaba_0-1653402771126.png

If you would like to debug the LPC812 (the one that has the MTB module), you will need to use an external debug probe.

For more information you can take a look to the User Manual for LPCXpresso812-MAX Board available in here.

I hope this helps, Daniel.

[jimpearce]

Thank you for clarifying that the LPCXpresso812-MAX Board does not support the MTB.  I don't see that mentioned in its documentation.  What debug probes support the MTB?  I also have a PE  USB-ML-UNIVERSAL debug probe but cannot make that work with the MTB either.  

I have searched the document "MCUXpresso IDE InstructionTrace Guide" and have found no mention of the hardware requirements for implementing instruction tracing using the MTB.  This is a quote from that:

• Instruction Trace - capturing an instruction stream within onboard RAM of the MCU. This
data can then be retrieved, decoded, and displayed within the IDE.
• Available with any supported debug probe.

Okay, where is the list of supported debug probes?

[DanielRuvalcaba]

It’s not like the board doesn’t support MTB, you just have to debug the LPC812 with an external debug probe, because the onboard debug probe uses the LPC11U35.

DanielRuvalcaba_0-1655485662109.png

For the supported external debug probes, please refer to section 4.1 of the LPCXpresso812-MAX User manual.

This article might help you.

Best regards, Daniel.

[jimpearce]

I had already tried all of the suggestions in your attached documents to no avail.  I reduced the problem to ist simplest form:

Unfortunately, that did not help.  I have reduced the problem to its simplest form:

I am using an unmodified LPC812 mbed/Xpresso (Arduino compatible) board and the lpcxpresso812max_led_blinky SDK example.

jimpearce_1-1651842692147.png

The example code shows that it includes cr_mtb_buffer.h and mtb.c as part of the project.  It builds with no errors or warnings.  When I run it in debug mode and select Window->Show View->MCUxpresso IDE Trace and Energy Measurement->Instruction Trace Config and then click on the refresh icon in the Configure window, I get this:

jimpearce_0-1651842444751.png

If you can get the tracing to work with this simple setup, please detailed instructions of how you did it or post a link to a video of it.

[DanielRuvalcaba]

Hello

Can you please make sure that your project is making use of the cr_mtb_buffer.h and the mtb.c files?

I also dropping you some links that can be useful to solve your problem.

https://www.nxp.com/docs/en/quick-reference-guide/MCUXpresso_IDE_Instruction_Trace.pdf

https://community.nxp.com/t5/LPC-Microcontrollers/Instruction-trace-not-working-on-LPCXpresso54628/m...

I hope this helps, Daniel.