Tutorial: GNU Coverage with MCUXpresso IDE

If you are developing Linux or desktop applications with GNU tools, you  very likely are familiar with gcov: the GNU coverage tool. It collects data what parts of the code gets executed and represents that in different formats, great to check what is really used in the application code or what has been covered during multiple test runs.

Coverage Information with gcov

Coverage Information with gcov

line never executed

line never executed

GNU coverage is possible for resource constraint embedded systems too: it still needs some extra RAM and code space, but very well spent for gathering metrics and improves the firmware quality. As I wrote in “MCUXpresso IDE V11.3.0 for 2021” things are now easier to use, so here is a short tutorial how to use it.

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First Steps with Ozone and the Segger J-Link Trace Pro

From time to time I face some problems which are really hard to find. Mostly these kind of bugs are very timing sensitive and depend on interrupt execution order. Maybe a dangling pointer is overwriting memory, code is running wild, or some functions are not reentrant as they should be. For these kind of bugs, good tools are worth their weight in gold. The Percepio FreeRTOS+Trace and the Segger SystemView have helped me many times to narrow down such kind problems in my applications. Another ultimate tools is hardware trace: Now I have a Segger J-Trace Pro for ARM Cortex-M in my arsenal of bug extinguishing weapons on my desk:
Dear bugs, look what I have on my desk. Your hiding time is over! 🙂

tracing-cortex-m4-with-j-trace

tracing-cortex-m4-with-j-trace

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Code Coverage for Embedded Target with Eclipse, gcc and gcov

The great thing with open source tools like Eclipse and GNU (gcc, gdb) is that there is a wealth of excellent tools: one thing I had in mind to explore for a while is how to generate code coverage of my embedded application. Yes, GNU and Eclipse comes with code profiling and code coverage tools, all for free! The only downside seems to be that these tools seems to be rarely used for embedded targets. Maybe that knowledge is not widely available? So here is my attempt to change this :-).

Or: How cool is it to see in Eclipse how many times a line in my sources has been executed?

Line Coverage in Eclipse

Line Coverage in Eclipse

And best of all, it does not stop here….

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