Can't seem to generate external interrupt

[hassan2]

Posted on January 19, 2016 at 23:54

On stm32f072xb (Discovery board), I am able to detect an interrupt on PA0.

Using the example provided, I configured the external interrupt as such.

   EXTI->IMR = 0x0001; /* (3) */

   EXTI->RTSR = 0x0001; /* (4) */

   EXTI->FTSR = 0x0001; /* (5) */

I enabled the interrupt

   /* Enable and set Button EXTI Interrupt to the lowest priority */

   HAL_NVIC_SetPriority((IRQn_Type)(EXTI0_1_IRQn), 0x03, 0x00);

   HAL_NVIC_EnableIRQ((IRQn_Type)(EXTI0_1_IRQn));

My IRQHandler function looks like this

void EXTI0_1_IRQHandler(void)

{

  BSP_LED_Toggle(LED_ORANGE);

  if ((EXTI->PR & 0x0001) != 0)  /* Check line 0 has triggered the IT */

  {

    EXTI->PR |= 0x0001; /* Clear the pending bit */

    BSP_LED_Toggle(LED_GREEN); /* Toggle green led on PC9 */

  }

  else /* Should never occur */

  {

     BSP_LED_Toggle(LED_ORANGE); /* Switch on orange led to report an error */

  }

}

I enabled all the peripheral clocks

 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);

 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);

When I connect a 5V supply to PA0, I can see the ORANGE and GREEN leds light up.

I am not clear why the example works. I don't see how the code knows that the interrupt is connected to PA0 and not PB0 or PC0. Let's ignore that for now.

*******

I am unable to detect an interrupt on a different pin of my choice.

I configured pin PB12 with Mode GPIO_MODE_IT_RISING_FALLING and GPIO_NOPULL

I modified the example to make it work for PB12

   EXTI->IMR = 0x1000;   /* I am thinking that this should point to pin 12 */

   EXTI->RTSR = 0x1000;

   EXTI->FTSR = 0x1000;

I enabled the interrupts and am using the same IRQHandler but after connecting 5V to PB12 pin, no LED lights up.

   /* Enable and set Button EXTI Interrupt to the lowest priority */

   HAL_NVIC_SetPriority((IRQn_Type)(EXTI4_15_IRQn), 0x03, 0x00);

   HAL_NVIC_EnableIRQ((IRQn_Type)(EXTI4_15_IRQn));

I then tried to use a different IRQHandler, but still no leds light up

void EXTI4_15_IRQHandler(void)

{

  BSP_LED_Toggle(LED_ORANGE);

  if ((EXTI->PR & 0x0001) != 0)  /* Check line 0 has triggered the IT */

  {

    EXTI->PR |= 0x0001; /* Clear the pending bit */

    BSP_LED_Toggle(LED_GREEN); /* Toggle green led on PC9 */

  }

  else /* Should never occur */

  {

     BSP_LED_Toggle(LED_ORANGE); /* Switch on orange led to report an error */

  }

}

Hope you can shed some light on this.

Thanks

#exti

[Tesla DeLorean]

Posted on January 20, 2016 at 00:29

/* Enable SYSCFG clock */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

/**
* @brief Configure PA0 in interrupt mode
* @param None
* @retval None
*/
static void EXTI_Config(void)
{
EXTI_InitTypeDef EXTI_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
/* Enable GPIOA clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* Configure PA0 pin as input floating */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* Enable SYSCFG clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
/* Connect EXTI0 Line to PA0 pin */
SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);
/* Configure EXTI0 line */
EXTI_InitStructure.EXTI_Line = EXTI_Line0;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
/* Enable and set EXTI0 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = EXTI0_1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 0x00;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}