Posted by benjamin.brammer on 2016-10-11 12:59

don’t know why, but the post cuted some text away. Heres the complete main:

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();

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

/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
MX_TIM3_Init();

/* USER CODE BEGIN 2 */
HAL_TIM_Base_Start_IT(&htim3);

/* USER CODE END 2 */
uint32_t i = 0;
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
i++;

/* USER CODE BEGIN 3 */

}
/* USER CODE END 3 */

}

Posted by benjamin.brammer on 2016-10-11 14:59

OK found the problem!
It was due to a compiler optimization, that the empty or even used (with a never used again variable) while loop was ommited. Without optimizatin everything works fine!

Posted by MSchultz on 2016-10-14 00:23

Another way you can force the inclusion of the infinite while() loop (with optimization on) would be to declare the i variable volatile, like this:

volatile uint32_t i;
while (1)
{
i++;
}

Doing this is also useful when you want to create a software delay and don’t care about accuracy, like this:

volatile uint32_t i;
for (i = 100000; i > 0; i--) ;

As for use of compiler optimization, I normally set the optimization level to “optimize for debug (-Og)” for the debug build of my projects, and use higher level optimization, normally “optimize for size (-Os)” for the release build.