A complete STM32 FreeRTOS project example for a basic multitasking application

Here’s a complete STM32 FreeRTOS project example for a basic multitasking application:
LED blinking + UART message + ADC voltage readout, running on STM32F4 (e.g., STM32F407VG) using FreeRTOS and STM32CubeIDE.

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Project Overview

arduino

                  - Task 2: Send UART message every 1 s  
                  - Task 3: Read ADC and print result every 2 s |

| Tool | STM32CubeIDE (no external libraries needed)

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Step-by-Step: Creating the Project

1. Create a New Project

• Open STM32CubeIDE

• Create New STM32 Project

• Select target (e.g., STM32F407VG)

• Name it: RTOS_Blink_UART_ADC

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2. Enable Peripherals

In .ioc (Pinout & Configuration) view:

• PA5 – Output GPIO (for LED)

• USART2 – Asynchronous (e.g., TX = PA2, RX = PA3)

• ADC1 – IN0 (e.g., PA0)

• SYS → Timebase Source = TIM6

• Middleware > FreeRTOS → Enable CMSIS v2 interface

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3. Configure FreeRTOS

• Go to Middleware > FreeRTOS > Configuration

• Create 3 Tasks:

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4. Generate Code

• Click Project > Generate Code

• Open blinkLED.c, uartTask.c, adcTask.c or define them in app_freertos.c

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Example Task Implementations

blinkLED Task

c

void blinkLED(void *argument) {
  for(;;) {
    HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_5);
    osDelay(500);
  }
}

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uartTask Task

c

extern UART_HandleTypeDef huart2;

void uartTask(void *argument) {
  char msg[] = "Hello from UART!\r\n";
  for(;;) {
    HAL_UART_Transmit(&huart2, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY);
    osDelay(1000);
  }
}

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adcTask Task

c

extern ADC_HandleTypeDef hadc1;

void adcTask(void *argument) {
  char buffer[64];
  uint32_t adcValue;

  for(;;) {
    HAL_ADC_Start(&hadc1);
    if (HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY) == HAL_OK) {
      adcValue = HAL_ADC_GetValue(&hadc1);
      float voltage = (adcValue / 4095.0) * 3.3;
      snprintf(buffer, sizeof(buffer), "ADC: %lu (%.2f V)\r\n", adcValue, voltage);
      HAL_UART_Transmit(&huart2, (uint8_t*)buffer, strlen(buffer), HAL_MAX_DELAY);
    }
    HAL_ADC_Stop(&hadc1);
    osDelay(2000);
  }
}

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Final Steps

• Compile and flash to your STM32 board

• Open Serial Monitor (baud: 115200)

• You should see:

  • LED toggling

  • UART message every second

  • ADC voltage printed every 2 seconds

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Optional Enhancements

• Use Queue or Semaphore to synchronize ADC and UART

• Add button interrupt to start/stop tasks dynamically

• Use CubeMX timers instead of osDelay for more precision