i have one of those!
but i have yet to plug it in and turn it on, so let me ask a few naive questions:
you used matlab to write some code to determine active and reactive power
you downloaded the code into the STM32F4
it did not work
i haven't used matlab in about 40 years (at least i think it was matlab we used in that class)
does matlab output code specifically for the STM32F4?
questions:
1) did the calculation work in simulation in matlab?
2) what did you test it with?
3) did the download work or not?
4) if the download didn't work, what error message did you get?
if the download worked:
5) what data did you give the processor and the downloaded software to test their operation?
6) how do you know the calculation didn't work?