STM32f407 MCU two interrupts at some time

Posted on July 25, 2015 at 02:19

I used TIMER 2. It's interrupt time is 1us.

I made one long pulse and short pulse using GPIO output pin and TIMER 2.

but sometimes, interrupts occurred two times.

First figure is the result I want to get.

Second figure is the result I can get now.

At second figure the red circle is an error I think.

It's shivering in trigger mode.

Here is my code

void TIM2_IRQHandler(void)

{

//TIM_ClearITPendingBit(TIM2, TIM_IT_Update);

assert_param(IS_TIM_ALL_PERIPH(TIM2));

TIM2->SR = (uint16_t)~0x0001;

//////Enable pin wait.(1us)

for(a=0;a<33;a++){

GPIOB->BSRRL = GPIO_Pin_0;

}

//wait(300ns)

for(a=0;a<10;a++){

GPIOB->BSRRH = GPIO_Pin_0;}

//one more short pulse(20ns)

GPIOB->BSRRL = GPIO_Pin_0;

GPIOB->BSRRH = GPIO_Pin_0;

}