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On-chip Trace debugging, OCI and FS2 - missing features?

New Contributor I

I've been trying to figure out how to make use of the Nios II on-chip trace feature (contained in the 'JTAG Debug' tab of the Nios II processor). 

This outdated document is the only document I could find that provides any hint as to how to use this feature. It mentions the 'FS2 console' which no longer appears to be bundled with the Nios SBT. 

The only other information I found was from this post in 2019  that seems to indicate that FS2 stopped appearing in Quartus back in version 10. 

I really need to make use of this feature so can provide me with a starting point on how to do so? 



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5 Replies

Hi @Broddo,

Thank you for posting in Intel community forum and hope this message find you well.
Apologies for the inconvenient cause, there might be some confusion on the document and some older version of document are still available to support older version tools.
For the mention section that you are referring to, please refer to updated document embedded design handbook here.
Please do let us know if that helps clarify your doubts.

Best Wishes

New Contributor I

Thank you! I have not seen this document yet. I'll take a look and let you know if it answers my questions.

New Contributor I

Unfortunately, the document you linked also skips over the details on how to use these features. It simply states that these features exist. For example, page 202 states:

In addition, the program counter trace collection tool is available for some Nios II processors. However, the tutorials do not use this tool.

And page 203 states:

The Nios II processor can generate complete and accurate program counter trace information. However, the GNU profiler does not use this information. To generate this information, you must have a Nios II processor configured with a JTAG debug module of level 3 or greater. The level 3 JTAG debug module creates on-chip trace data. You can capture approximately a dozen instructions in the on-chip trace buffer.

I already have the Nios II configured with an on-chip trace buffer and the I have the JTAG debug level set correctly. What I would like to know is how do I view the captured instructions? 


Hi @Broddo,


Apologies for the delayed in response, so if I understand correctly, you have managed to setup the JTAG configuration as as per required here.
And how for viewing the the capture variable value perhaps you can look into the Lauterbach tool, more details on how it can be done are in the guide here.
Hope that helps.


Best Wishes

New Contributor I

Yes indeed - I have the JTAG configuration working. GDB debugging is working perfectly for me. But like I mentioned, I have still yet to find information on how to use the on-chip trace feature.

Just to be clear - the Lauterbach Tool is for off-chip tracing - this is not what I'm asking about. A 3rd party tool like this is not required for on-chip tracing. The features are built directly into the NIOS2. But there doesn't seem to be a clear way of working with this feature.