Basic FFT megacore output question

the input and output to the FFT core are basically in the same format:

you feed time domain samples sequentially into the streaming input

you receive frequency domain samples sequentially at the output

you should start with the FFT core in natural input order and natural output order mode. this uses more resources and has more latency, but its easier to work with. use the end of packet and output valid signals to reset a counter, increment the counter when the output valid signal is high. now you have a running number of the frequency bin. the bins will go in the order of a non-shifted FFT: 0 to N/2-1 then -N/2 to -1 (i think)