STM32CubeIDE Setup and Your First Project with Debugging

/* USER CODE BEGIN PV */
/* 'volatile' stops the compiler from keeping these only in registers,
   so the debugger always reads the real value from memory. */
volatile uint32_t loop_count = 0;     /* how many times the loop ran   */
volatile uint32_t seconds_alive = 0;  /* whole seconds since reset     */
volatile uint8_t  button_pressed = 0; /* 1 while B1 is held down      */
/* USER CODE END PV */

int main(void)
{
  HAL_Init();              /* reset peripherals, start the 1 ms SysTick */
  SystemClock_Config();    /* 84 MHz from HSI through the PLL           */
  MX_GPIO_Init();          /* LD2 (PA5) output, B1 (PC13) input         */
  MX_USART2_UART_Init();   /* virtual COM port, not used yet            */

  /* USER CODE BEGIN 2 */
  uint32_t last_tick = HAL_GetTick();
  /* USER CODE END 2 */

  while (1)
  {
    /* USER CODE BEGIN 3 */
    loop_count++;

    /* B1 on the Nucleo pulls PC13 low when pressed */
    button_pressed = (HAL_GPIO_ReadPin(B1_GPIO_Port, B1_Pin) == GPIO_PIN_RESET);

    /* HAL_GetTick() returns milliseconds since HAL_Init() */
    if (HAL_GetTick() - last_tick >= 1000)
    {
      last_tick += 1000;
      seconds_alive++;     /* put a breakpoint on this line */
    }
  }
  /* USER CODE END 3 */
}