Getting started FFT STM32?

[Endika Caño de Miguel]

Posted on March 12, 2018 at 12:18

Hello everyone:

I have to make the FFT on my STM32L4 32KC board and I don�t know where to start. 

Sound is coming from the outside and I have to make the FFT.

Any tips would help a lot.

I�ve looking on the net for help, but everything was a little to messy for me. 

I�m pretty new to micro-controlers, so there are many things that I ignore unfortunately.

Thanks in advance for your time and help.

#stm32 #fft #l4 #cmsis #dsp

[Andrew Neil]

Posted on June 25, 2018 at 17:49

Did you look at the links provided by

st.mcu

‌ ?

Did you see

https://community.st.com/0D70X000006SwKPSA0

?

Why would an FFT on an STM32F4 differ from an FFT on any other Cortex-M4?

Have you looked at the standard CMSIS stuff?

CMSIS Intro:

https://www.keil.com/pack/doc/CMSIS/General/html/index.html

https://www.keil.com/pack/doc/CMSIS/DSP/html/index.html

https://www.keil.com/pack/doc/CMSIS/DSP/html/arm_fft_bin_example_f32_8c-example.html

[Andrew Neil]

Posted on June 25, 2018 at 18:11

evading wrote:

FFT single point calculation

What do you mean by 'single point'?

Surely, a single point is just an impulse - so the FFT is known?

[AvaTar]

Posted on June 26, 2018 at 07:24

What do you mean by 'single point'?

Perhaps he is meaning something like the Goertzel algorithm, to calculate individual terms (spectral 'points') ?

There is no specific example for that in ARM's DSP-Lib, but surely elsewhere on the web.

And as said, these algorithms are hardware-independant.

[Amel NASRI]

Posted on June 26, 2018 at 11:52

Hi,

I recommend you to have a look to the tutorial

https://community.st.com/0D50X00009bMMAwSAO

created by

Majerle.Tilen

‌.

-Amel

[tinymanta]

Posted on June 27, 2018 at 16:11

Hi,

I want just to customize the arm_cfft_f32 to get some specific elements 

of the the complex data buffer and calculate its FFT value.

arm_cfft_f32 ( const arm_cfft_instance_f32 * S,

float32_t * p1,uint8_t ifftFlag,uint8_t bitReverseFlag )

Otherwise, any sinus generated data buffer can be used for testing ? at least to be sure of the FFT results ?

Thanks.

[AvaTar]

Posted on June 28, 2018 at 08:21

I never hacked the arm_cfft functions, but surely you can adapt it to drop the calculations you don't need.

I used to calculate all frequencies, to evaluate one (or more) spectral components in relation to the others.

...any sinus generated data buffer can be used for testing ? at least to be sure of the FFT results ?

Yes. This is recommended.

The ARM example comes with a reference input signal, however not a 'sinus' wave shaped.