Fast Fourier Transform using the ARM CMSIS Library within the STM32 MCUs

[@metrogman2409]

Thank you for the FFT demo.

[@steppeschool3629]

you much welcome!

[@michaelalex5235]

This is great stuff - thank you and continue the good work!

[@steppeschool3629]

you are much welcome

[@ArgaAridarma]

Thank you! I need to try this for my next project.

[@steppeschool3629]

Thanks!

[@padakathu2882]

thank you, excellent, very clear explanations

[@sizuziledlamini1852]

Does the stm32f103c8 "Blue pill" support the arm_math library?

[@steppeschool3629]

I am afraid it does not support

[@dasunisaparamadu2876]

I'm using Cube IDE version 1.15.0.
The microcontroller version I'm using is STM32 NUCLEO L073RZ
DSP library is not listed under software component class.
Which version are you using?

[@vix_s_hnu]

I got error " undefined reference to 'arm_rfft_fast_init_f32'. I imported the DSP library as you mentioned in the other videos. Why i am stille getting the error?

[@kamarmeredow7644]

Thank you for the video. I tried to use this dsp lib with my stm32f103c8t6 cortex m3 with clock speed 64mhz. But i could not install it because bluepill has only 20kb. I wrote recursive fft code myself. but it took almost 70ms to finish and i lost some values from adc. sampling rate was 8khz. and window size is 128 or even with 64 it was still slow. i think arm dsp uses some kind of hardware accelerated things to make the calculations much faster for example in 1-2ms. But i could not use it as bluepill has only 64kb of flash. What can you suggest? Appreciate that thanks.

[@steppeschool3629]

The easiest solution would be to upgrade your microcontroller. Try more powerful microcontrollers, such as STM32F4, STM32L4, etc. They are not expensive and you can easily implement FFT.

[@kamarmeredow7644]

@@steppeschool3629 Hi. Thank you for the answer. Yes i had also F407 with 512kb of flash. But i wanted to try it with 64kb. Because i saw someone got fft working even with atmel processor with good performance. In the end i wrote my fft function with float type which took 70ms to calculate which is very slow. There is no fpu in bluepill. And after working 2 days i rewrote my functions in fixed point numbers and got it working. Fft took 3-4 ms for calculation, flash usage is 34kb with whole code.

[@steppeschool3629]

What you did is quite impressive

[@JohnJ-zj8ol]

Thanks a lot! what is the rest of line 106? printf("frequency %f: %f
", ((float32_t)(i * SAMPLING_RAT) / FFT_LENGTH), out...

[@steppeschool3629]

just bracket with a semicolon

[@batosato]

@@steppeschool3629 It is difficult what is the rest. Is it printf("freq %f: %f
", ((float32_t)(i * SAMPLING_RATE) / FFT_LENGTH), output_fft_mag[i]); ??

[@tolpow]

for (int i = 0; i < FFT_LENGTH / 2; ++i)
{
printf("frequency: %f", ((float32_t) (i * SAMPLING_RATE) / FFT_LENGTH ));
printf(" magnitude(float): %f",output_fft_mag[i]);
printf(" magnitude: %d
", (uint8_t)output_fft_mag[i]);
}

[@hasanoktem8792]

the repository is not public

[@gcenter1552]

does it work on stm32f103x ?

[@steppeschool3629]

I do not think it will work.