The float formatting support is not enabled

[Fahd]

Hello All,

I am getting this error while compiling the project " The float formatting support is not enabled ".

I have checked use float with "printf from new lib-nano" in MCU/MPU settings save and recompile the problem didn't go!!

I have added manually "-u_printf_float" in MCU/MPU GCC linker with no success.

I am using the latest version of stm32cubeide 1.16.1 the MCU is stm32g031f6p6.

my code in while loop:

HAL_ADC_Start(&hadc1);

HAL_ADC_PollForConversion(&hadc1, 20);

voltage = (HAL_ADC_GetValue(&hadc1)/4096) * 3.3f;

printf("Voltage = %0.2f\n", voltage);

HAL_Delay(1000);

[MM..1 · Accepted solution]

Your error isnt about float. You compile bigger code as flash... try change optimize level or better not use float.

[Fahd]

Thanks after changing optimizition level it works. Ididn't know float take so much space.

[Ozone]

The STM32Gxx MCUs are Cortex M0/M0+.
They have no FPU, and thus no floating point instructions.
Everything needs to be emulated. 
If not absolutely necessary, avoid float - even float constants.

  voltage = (HAL_ADC_GetValue(&hadc1)/4096) * 3.3f;
  printf("Voltage = %0.2f\n", voltage);

Things like this can easily be done with scaled integer maths.
The resulting code is an order of magnitude smaller.

[NEdom.1]

Use printf in C/C++ very carefully in embedded software. The printf family functions could be very dirty in memory access and bloated in code size.