EXTI0_IRQHandler

[baev_al]

Posted on August 15, 2014 at 18:56

Dear friends. Show me please my mistake. When I debug the following program I even cannot get to ISR... I stay in infinite loop...

Thanks! void EXTI0_IRQHandler (void); int main(void) {   /*!< At this stage the microcontroller clock setting is already configured,        this is done through SystemInit() function which is called from startup        files (startup_stm32f429_439xx.s) before to branch to application main.        To reconfigure the default setting of SystemInit() function, refer to        system_stm32f4xx.c file      */       /* Add your application code here */        /* Infinite loop */     RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOG, ENABLE); //Clck to GPIOG   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);   RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);   SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);       GPIO_InitTypeDef PortG_init, PortA_init;     PortG_init.GPIO_Mode = GPIO_Mode_OUT;   PortG_init.GPIO_OType = GPIO_OType_PP;   PortG_init.GPIO_Pin = GPIO_Pin_13;   PortG_init.GPIO_PuPd = GPIO_PuPd_NOPULL;   PortG_init.GPIO_Speed = GPIO_Speed_50MHz;   GPIO_Init(GPIOG, &PortG_init);     PortA_init.GPIO_Mode = GPIO_Mode_IN;   PortA_init.GPIO_OType = GPIO_OType_PP;   PortA_init.GPIO_Pin = GPIO_Pin_0;   PortA_init.GPIO_PuPd = GPIO_PuPd_NOPULL;   PortA_init.GPIO_Speed = GPIO_Low_Speed;   GPIO_Init(GPIOA, &PortA_init); //GPIOA_Pin_0 as input         EXTI_InitTypeDef PortA_Pin0;     PortA_Pin0.EXTI_Line = EXTI_Line0;   PortA_Pin0.EXTI_Mode = EXTI_Mode_Interrupt;   PortA_Pin0.EXTI_Trigger = EXTI_Trigger_Rising;   PortA_Pin0.EXTI_LineCmd = ENABLE;   EXTI_Init(&PortA_Pin0);     NVIC_InitTypeDef NVIC_PortA;     NVIC_PortA.NVIC_IRQChannel = EXTI0_IRQn;   NVIC_PortA.NVIC_IRQChannelPreemptionPriority = 0x01;   NVIC_PortA.NVIC_IRQChannelSubPriority = 0x01;   NVIC_PortA.NVIC_IRQChannelCmd = ENABLE;     NVIC_Init(&NVIC_PortA);           while (1)   {        }      } void EXTI0_IRQHandler (void) {   GPIO_ToggleBits(GPIOG, GPIO_Pin_13); //  delay(1000000);   EXTI_ClearITPendingBit(EXTI_Line0); } Interesting thing...I'm working in IAR. When I was debugging watching locals in this part: PortA_Pin0.EXTI_Line = EXTI_Line0;   PortA_Pin0.EXTI_Mode = EXTI_Mode_Interrupt;   PortA_Pin0.EXTI_Trigger = EXTI_Trigger_Rising;   PortA_Pin0.EXTI_LineCmd = ENABLE;   EXTI_Init(&PortA_Pin0); PortA_Pin0.EXTI_LineCmd = ENABLE stayed DISABLED until I didn't changed compiler optimization from high to medium.... What didn't I take into account? Watching for other bugs....

[Tesla DeLorean]

Posted on August 17, 2014 at 05:40

C++, or you're not actually generating an interrupt?

Does the pin have/need a pull up/down? Are you looking at the right edge? Can you print the state of the pin, via GPIO, in the while(1) loop?

[baev_al]

Posted on August 17, 2014 at 18:14

It was some sort of compiler behavior. When I checked low optimization compilation - everything started to work... One of the following steps is to understand the optimization.

''Can you print the state of the pin, via GPIO, in the while(1) loop?'' I saw the change in the IDR register - and that was very confusing. Thanks for the support, Clive1.

[Tesla DeLorean]

Posted on August 19, 2014 at 06:37

You really should test/qualify your interrupt source, but your issue here probably is the race condition in the NVIC/EXTI. You should clear the interrupt early, not as the last thing.

void EXTI0_IRQHandler (void)
{
EXTI_ClearITPendingBit(EXTI_Line0); // Do this first to stop reentry, ideally you'd qualify the source
GPIO_ToggleBits(GPIOG, GPIO_Pin_13); // before toggling
}