Using GPIO on STM32

0. Pin Map

On the STM32F446RET6 Nucleo board, the LD2 LED is connected to PA5, and the USER Button is connected to PC13.

Note: the LED is active high.

We will demonstrate how to set up a generic GPIO output pin with the LED, and a generic GPIO input pin with the user button.

1. Configure STM32

First, set the configuration from the Starter Project.

Click on PA5, set it to "GPIO_Output".

Click on PC13, set it to "GPIO_Input".

Save the .ioc file and generate code.

2. Code

First, add the code from the Starter Project.

In main.c, add the following code

  /* USER CODE BEGIN 2 */
  char str[64];
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
    HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_SET);
    HAL_Delay(250);
    HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);
    HAL_Delay(250);

    uint8_t val = HAL_GPIO_ReadPin(GPIOC, GPIO_PIN_13);
    sprintf(str, "button value: %d\r\n", val);
    HAL_UART_Transmit(&huart2, (uint8_t *)str, strlen(str), 100);
  }
  /* USER CODE END 3 */

After saving, upload the code

3. Result

We can see LED LD2 blinking, and when we press/release the USER Button, the serial output changes.