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Basic timer interrupt example​

1 Brief​

The function of this code is to flip the state of the LED in the interrupt service function of the basic timer 6.

2 Hardware Hookup​

The hardware resources used in this experiment are:

  • LED - PA8
  • USART1 - PA9\PA10
  • TIM6

The TIM6 used in this experiment is the on-chip resource of STM32H503, so there is no corresponding connection schematic diagram.

3 STM32CubeIDE Configuration​

Let's copy the project from 04_UART and name both the project and the.ioc file 07_BTIM. Next we start the BTIM configuration by double-clicking the 07_BTIM.ioc file.

First, click Timers > TIM6, and the configuration is as follows:

As can be seen from the figure above, we configure the automatic reload value as (10,000-1), the pre-divider value as (25,000-1), and the clock frequency of TIM6 is 250MHz, so the count frequency of TIM6 is 1KHz.

The configuration of the NVIC is shown below:

Click File > Save, and you will be asked to generate code.Click Yes.

code​

We add some code to the tim.c file's initialization function MX_TIM6_Init, as follows:

tim.c​
  /* USER CODE BEGIN TIM6_Init 2 */
  HAL_TIM_Base_Start_IT(&htim6);    /* Enable timer 6 and its update interrupt */
  /* USER CODE END TIM6_Init 2 */

The above function HAL_TIM_Base_Start_IT is used to enable TIM6 and start the update interrupt.

An interrupt callback function has also been added, as shown below:

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
    if (htim->Instance == TIM6)
    {
        LED_TOGGLE(); /* turn over LED */
    }
}

The LED is flipped in the update interrupt callback function HAL_TIM_PeriodElapsedCallback. We will determine whether the update is interrupted by TIM6, and if so, perform an LED flip operation.

main.c​

Only the delay function is called in the while loop of the main function, the code is as follows:

int main(void)
{
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_ICACHE_Init();
  MX_USART1_UART_Init();
  MX_TIM6_Init();
  /* USER CODE BEGIN 2 */
  stm32h503cb_show_mesg();
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    HAL_Delay(500);   /* delay 500ms */
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

4 Running​

4.1 Compile & Download​

After the compilation is complete, connect the DAP and the Mini Board, and then connect to the computer together to download the program to the Mini Board.

4.2 Phenomenon​

Press the reset button to restart the Mini Board, open the serial port host computer ATK-XCOM, and you can see the experimental prompt message, indicating that the code has been successfully downloaded. Observe the LED flashing every 500 milliseconds on the Mini Board.

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