Save flash when using printf and floating-point on STM32F0

istepne · ‎2025-03-10

Originally a reply to this thread:

https://community.st.com/t5/stm32-mcus-embedded-software/how-generate-hex-file-without-link-files-hal-drivers/td-p/723141

Split as it seems to be a different issue.

Hi,

I have same issue too

I am using STM32F051R8 with STM32CubeIDE Version: 1.18.0

There is limited Flash memory. So when I am checking the memory I found some library names etc definition strings on my hex file. I tried to change some setting according to topics above but no success at all

Please let me know which settings is this. Also I am using optimization "Optimize for size -s"

Regards

Murat

Andrew Neil · ‎2025-03-10

@istepne wrote:
Please let me know which settings is this.

This one:

https://community.st.com/t5/stm32-mcus-embedded-software/how-generate-hex-file-without-link-files-hal-drivers/m-p/723990/highlight/true#M55354

PS:

It will be in your stm32xxxx_hal_conf.h file:

/* ########################## Assert Selection ############################## */
/**
  * @brief Uncomment the line below to expanse the "assert_param" macro in the
  *        HAL drivers code
  */
/* #define USE_FULL_ASSERT   1U */

As shown above, it is not defined.

istepne · ‎2025-03-11

@Andrew Neilthank you for the answer.

I realized that it comes from the floating library. I need to use printf with floating point operations enabled.

I made a new project and just compiled it, it tooks 2,99 kbyte memory. After than I enabled the floating feature on settings and compiled again (either debug or release mode) . Then it tooks 23,52kbyte (huge increase). I see the texture on the hex file again with a blank project.

I need Flash memory space on this the older board (can not change the MCU).
Is there a way to disable this strings from hex file to get more space?

Or any other solution like lightweight floating point library etc

Regards

Murat

Andrew Neil · ‎2025-03-11

This doesn't sound like the same problem as the OP - which was solved as described.

Edit: So split to a separate thread.

@istepne wrote:
I see the texture on the hex file again with a blank project

What, exactly, do you mean by that? How are you viewing it?

Please give full details of the tools & procedures used, and show what you're seeing.

@istepne wrote:
I need (sic?) to use printf with floating point operations enabled.

Do you really need to?

Both Floating Point and printf can use a lot of flash - so, when flash space is limited, maybe try to avoid both?

KnarfB · ‎2025-03-11

Look into alternative printf implementations like GitHub - charlesnicholson/nanoprintf: The smallest public printf implementation for its feature set. and avoid using the printf provided in newlib.

hth

KnarfB