STM32F4Discovery - Setting up EXTI on external button

Posted on January 27, 2014 at 17:31

I've got the example working using the on board button and now I want to use an external button on CPIOC - 11. I've used this button with GPIO_ReadInputDataBit with PuPd_UP. I've converted over the sample code but I've not getting any interrupt. I thought that the EXTI_Line needs to also be 11 and the EXTILineConfig with GPIOC and PinSource11 but I'm confused with the EXTI Line number and NVIC IRQChannel as it seems there are 5 of them. 

Thanks,

Jim.

GPIO_InitTypeDef   GPIO_InitStructure;

  NVIC_InitTypeDef   NVIC_InitStructure;

  /* Enable GPIOA clock */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

  /* Enable SYSCFG clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

  

  /* Configure PA0 pin as input floating */

GPIO_StructInit(&GPIO_InitStructure); // Reset init structure

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* Connect EXTI Line0 to PA0 pin */

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOC, EXTI_PinSource11);

  /* Configure EXTI Line0 */

  EXTI_InitStructure.EXTI_Line = EXTI_Line11;

  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;  

  EXTI_InitStructure.EXTI_LineCmd = ENABLE;

  EXTI_Init(&EXTI_InitStructure);

  /* Enable and set EXTI Line0 Interrupt to the lowest priority */

  NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

#stm32f4discovery-exti-nvic-setup