The FFT algorithm is mainly used for for signal processing applications for which it is required reliable resolution, because of the number of math opperations which could cascade any error . For many cases a fixed point notation suffice, however there are situations on which a float point ALU is needed. Moreover, the lenght of the array to be computed may vary from case to case, therefore don't seem to make much sense to have uC's with built in FFT peripherals. The only thing that makes sense to me if you want some hardware acceleration, is to have a SoC comprising one microcontroller with an FPGA fabric in order to sinthesize there fast performance APIs to be instantiated from the microcontroller core.
I am not looking for floating point FFT. Fixed point FFT is fine
it will help in case of signal processing. I tried to search but couldn't reach any info.
even dsPIC doen't have it !
The dsPIC is not a DSP, it is rather a microcontroller with an ALU a few bigger than the PIC's relatives, and it have one or two accumulator instructions that make computation a bit faster, but it is just that. If you want to run FFT routines to get precise results, think about real DSP processors ( e.g Texas TMSxxxx ).
Usually DSPs are made for this.
You need some RAM for the two arrays: input data and output data and a sine lookup table.
And a useful command is "Multiply and accumulate".
The rest is pretty standard.
@KluasST , using DSP or FPGA will solve the problem but it needs a lot of work in pcb and integration of RAM.
MCU is the easiest and fastest solution ever.
As said, if you really want some MCU with FFT accelerator implemented in HW, you could consider a hibrid solution within a single chip. Take a look on SoC products from FPGA manufacturers.
I don't think your question is the right one.
If you say, for instance, I have to make a 1024 x 104 FFT in less than 10 ms, then
it might point you to the right device, accelerator or not.
So what resolution do you need and what speed?
I started using the Cortex F7 series recently, and I would guess you probably don't need
an accelerator, but it really depends on your specs.