MPU9250 STM32F411re

[JoergSH]

Hello I have problems with the sparkfun dmp libary. https://github.com/sparkfun/SparkFun_MP ... no_Library

Lib runs fine on Sam21d (m0 without FPU)

on the 411 filter is not working correct. I think it is a problem of the FPU. Any suggestions ?
there are other libs witch have same problem. on device with fpu calculations are bad.

regards

[stevestrong]

Do you have an example which shows the bad calculation?
Any reference to other lib which have the same problem?
Which core do you use?
Which board?
viewtopic.php?f=2&t=301

[JoergSH]

thats not so easy to explain.
Board is a Blackpill with STM32f411.

[env:blackpill_f411ce]
platform = ststm32
board = blackpill_f411ce
framework = arduino

The code was written for the sam21d.
On sam after reset Kompass are fast in right direction. On the 411 compas starts count from 0 up to 50 degrees in about 10 seconds. Than is stabel but did not have the correct direction to north. there are no changes in code. I think there went something wrong when the fpu does the calculation.

[stevestrong]

I have a black F411 board, so I could eventually check, but without any example I cannot figure out what can go wrong.
I assume you use PIO. Have you tried with Arduino?
Again, which core do you use?

[JoergSH]

I have blackpill too.
I use VS Code with PlattfomIo. Using as standard STM32Duino
it makes no difference when I use arduino IDE.

The Sample from github is for a MPU9250. There a Quaternions and Kalman Filter calculated. So my thought is a problem when compiler use FPU.

[fpiSTM]

My 2 cents is that some rounding in the operation...

[JoergSH]

My 2 cents is that some rounding in the operation...

Maybe but why only when using fpu ?

[JoergSH]

is it possible to say the compiler not to use the fpu?