STM32F0 memory usage skyrockets with very little code.

[XanCraft21]

Please, before reporting any issue

• Make sure you are using the latest Arduino_Core_STM32 version.
  https://github.com/stm32duino/Arduino_Core_STM32/releases/latest
• Make sure the issue is not already reported/fixed on GitHub or discussed on the stm32duino forum
• Submit a GitHub issue only for reporting a problem related to the Arduino_Core_STM32.
• Avoid to submit a GitHub issue for project troubleshooting.

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• questions on the STM32 Core
• bugs/enhancements on the STM core: Bugs and enhancements

⚠ When reporting any issue, please try to provide all relevant information to help on its resolution.

Describe the bug
Hello, i am having a problem with memory usage on my STM32F030 board. This is just for compiling and not for uploading. When i write a very small amount of code, i noticed that the used memory after a compile rapidly increases, even just to blink an LED is already at 66% flash usage. And a bare bones sketch already uses 49%. This value increases unusually quickly and i have never seen this happen with my other boards packages before. If anyone can help me figure this out i will gladly appreciate it, thank you foe your help.

To Reproduce
There is really no good code to show, just write as you go and frequently verify the code.

Steps to reproduce the behavior:

1. Start with a bare bones sketch, hit verify or compile, the used flash memory is 49%
2. Write a code to blink the led, 66% is used.
3. Write a code to slowly fade the led with pwm, including a value to keep track of current brightness, a delay value, a speed value, and a boolean value used to invert the fade, 88% used.
4. Or just simply include the Wire library in a bare bones sketch, 79% used.

Expected behavior
Memory usage goes up slowly as more code is being added, and not very quickly.

Screenshots
Will add soon.

Desktop (please complete the following information):

• OS: Windows
• Arduino IDE version: 1.8.19
• STM32 core version: 2.5.0
• Tools menu settings: default
• Upload method: Serial (using hacked drivers).

Board (please complete the following information):

• Name: Generic STM32F030F4x
• Hardware Revision: unsure, the board is a clone from china.
• Extra hardware used if any: FTDI adapter

Additional context
Uploading to the board works fine, it’s just the memory usage on the Arduino side is crazy, even for a very tiny code. I believe my other STM32 boards don’t have this issue. I am not sure if these memory problems are normal, but I believe i’m the only person with this issue. I truly believe this is a real bug, and as far as i can tell no-one else posted anything about this problem. I hope a solution can be made to fix this problem. Thank you again for your help.

[fpistm]

See the wiki:
https://github.com/stm32duino/Arduino_Core_STM32/wiki/HAL-configuration#example-of-blinkino-for-nucleo-l031k6-with-32768-bytes-of-flash-and-8192-bytes-of-ram

https://github.com/stm32duino/Arduino_Core_STM32/wiki/Custom-definitions#custom-pinmap-array

[XanCraft21]

Wait this is not fully resolved yet, i’m still having memory usage issues making the controller useless.

Disabling the HAL drivers makes some features not work. Even if i just use one of the drivers for example the I2C driver, the used memory is still too high to be usable.

I am unsure what to do and i feel that no-one really wants to help me at this time.

[fpistm]

Well we cannot do anything. This core is generic for all STM32 which leads to some oeverhead. Anyway, with some customization or using direclty HAL/LL you can drastically reduce size. Redefine peripheralPins arrays, disable all unused HAL, redefine systemCoreClock_config using LL,... Seems you used an external library and it can be also optimized. Check which part of the code uses lot of space using objdump also.

[fpistm]

STM32F030F4Px has a very limited flash size: 16k is very small.
Example to get Wire available:

Config:

• Gerneric STM32F030F4Px
• Serial disabled

build_opt.h file

-DHAL_ADC_MODULE_DISABLED -DHAL_RTC_MODULE_DISABLED -DHAL_SPI_MODULE_DISABLED -DHAL_TIM_MODULE_DISABLED -DHAL_EXTI_MODULE_DISABLED

Sketch

// Wire Master Writer
// by Nicholas Zambetti <http://www.zambetti.com>

// Demonstrates use of the Wire library
// Writes data to an I2C/TWI slave device
// Refer to the "Wire Slave Receiver" example for use with this

// Created 29 March 2006

// This example code is in the public domain.

#include <Wire.h>
#include "stm32yyxx_ll_bus.h"
#include "stm32yyxx_ll_rcc.h"
#include "stm32yyxx_ll_system.h"
#include "stm32yyxx_ll_utils.h"

extern "C" void SystemClock_Config(void)
{
  LL_APB1_GRP2_EnableClock(LL_APB1_GRP2_PERIPH_SYSCFG);
  LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR);
  LL_FLASH_SetLatency(LL_FLASH_LATENCY_1);
  while(LL_FLASH_GetLatency() != LL_FLASH_LATENCY_1)
  {
  }
  LL_RCC_HSI_Enable();

   /* Wait till HSI is ready */
  while(LL_RCC_HSI_IsReady() != 1)
  {

  }
  LL_RCC_HSI_SetCalibTrimming(16);
  LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSI_DIV_2, LL_RCC_PLL_MUL_12);
  LL_RCC_PLL_Enable();

   /* Wait till PLL is ready */
  while(LL_RCC_PLL_IsReady() != 1)
  {

  }
  LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
  LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_1);
  LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);

   /* Wait till System clock is ready */
  while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL)
  {

  }
  LL_Init1msTick(48000000);
  LL_SetSystemCoreClock(48000000);
}

void setup()
{
  Wire.begin(); // join i2c bus (address optional for master)
}

byte x = 0;

void loop()
{
  Wire.beginTransmission(4); // transmit to device #4
  Wire.write("x is ");        // sends five bytes
  Wire.write(x);              // sends one byte  
  Wire.endTransmission();    // stop transmitting

  x++;
  delay(500);
}

result:

Sketch uses 11380 bytes (69%) of program storage space. Maximum is 16384 bytes.
Global variables use 764 bytes (18%) of dynamic memory, leaving 3332 bytes for local variables. Maximum is 4096 bytes.

Serial uses lot of flash so if possible avoid to use it.

[XanCraft21]

I did not expect this core to have so much customization. I will do more testing soon. I will see if i can get manually driving a small SSD1306 display to work. So far no luck but i will check out more settings to see what i can do.

Thanks again for your help.

[XanCraft21]

I got the I2C working. I was able to remove the large function at the top and some of the library includes and still get the desired result, but i had to increase the I2C clock speed a lot.

although i can’t use a pre-made library to drive the display i am using i was able to do it manually. Thanks again for your help.