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Hedy
Hedy

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Comparison between bare-metal programming and using an RTOS on STM32 microcontrollers

#baremetalprogramming #rtos #stm32 #stm32f0

Comparison: Bare-Metal vs. RTOS on STM32

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Example – STM32 without RTOS (Bare-Metal):

c int main(void) { HAL_Init(); SystemClock_Config(); MX_GPIO_Init(); while (1) { if (HAL_GPIO_ReadPin(B1_GPIO_Port, B1_Pin) == GPIO_PIN_SET) { HAL_GPIO_TogglePin(LD2_GPIO_Port, LD2_Pin); HAL_Delay(500); } } }
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Example – STM32 with FreeRTOS:

c void LEDTask(void *argument) { for (;;) { HAL_GPIO_TogglePin(LD2_GPIO_Port, LD2_Pin); vTaskDelay(pdMS_TO_TICKS(500)); } } int main(void) { HAL_Init(); SystemClock_Config(); MX_GPIO_Init(); xTaskCreate(LEDTask, "LED", 128, NULL, 1, NULL); vTaskStartScheduler(); while (1) {} // Never reached }
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When Should You Use Bare-Metal or RTOS on STM32?
Use Bare-Metal if:

  • Your project is simple (e.g., LED, basic sensors)
  • You need maximum control and minimum latency
  • Flash and RAM are limited (STM32F0, L0)
  • You're developing a low-power device and want to manage power manually

Use RTOS if:

  • You need to handle multiple tasks simultaneously (e.g., sensors + communication + display)
  • Your project is growing and requires modularity
  • You depend on timing precision, synchronization, and task priorities
  • You're working with middleware like USB, TCP/IP, BLE (many ST libraries are RTOS-friendly)

STM32CubeMX Advantage:
ST’s STM32CubeMX allows you to generate projects with or without an RTOS:

  • Choose “RTOS: CMSIS-RTOS2 (FreeRTOS)” in the middleware section
  • Tasks can be configured conveniently (stack size, priority, etc.)

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