Different version of libarm_cortexM4lf_math.a for STM32F4 and STM32L4

Forum|Forum|5 years ago
July 13, 2021
2 replies
2104 views

In the latest firmware for STM32F4 (STM32Cube_FW_F4_V1.26.1) the libarm_cortexM4lf_math.a file is 3025kB.

In the latest firmware for STM32L4 (STM32Cube_FW_L4_V1.17.0) the libarm_cortexM4lf_math.a file is 5235kB.

I found that in the version for STM32L4 arm_rfft_fast_init_f32() returns an error if the FFT length is 128, whereas the version for STM32F4 does not. So I replaced the STM32L4 version with the STM32F4 version, and it seems to work fine.

I'm confused:

Why there are different version for F4 and L4 in the first place?

And is it safe to use the F4 version with a L4 MCU?

And where would I report that bug with the 128 point FFT?

This topic has been closed for replies.

Best answer by SFahr

Okay, thank you.

It appears to be a bug in CMSIS 5.6.0 which has already been reported and fixed in newer versions.

https://github.com/ARM-software/CMSIS_5/issues/658

STM32Cube_FW_F4_V1.26.1 still uses CMSIS 5.4.0 which does not have that bug, either.

Peter BENSCH

ST Technical Moderator

Two folder levels above the math libs you will find e.g. a README.md containing information about CMSIS. STMicroelectronics uses this CMSIS library as is from ARM, so any bug report should be reported to ARM.

Both families use the same Cortex-M4 core, so you can safely use the F4 lib for the L4.

Good luck!

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

SFahrAuthorBest answer

Associate III

Okay, thank you.

It appears to be a bug in CMSIS 5.6.0 which has already been reported and fixed in newer versions.

https://github.com/ARM-software/CMSIS_5/issues/658

STM32Cube_FW_F4_V1.26.1 still uses CMSIS 5.4.0 which does not have that bug, either.

Sign up

Click below to sign in

Login to the community

Click below to sign in