Trying to do arm_fft_fast_f32 256 bin for a 8000Hz sampled data. Taking only 8000 samples i.e. 1sec and diving into segments to do 256 fft. Not working after first iteration.

[AChan.3]

So dividing the sampled data and trying ti do each segment fft just like i did in matlab but the problem is the first segment fft is working next to that fft giving strange values. But if the second set/segment is done fft first it gives the right answer. So it means that arm_rfft function givees right answer only for the first time in a program. If I want to use the function multiple times it seems not to work.