EXTI interupt problem

[haythem]

Posted on March 31, 2014 at 02:01

Hi i have a problem with interuption EXTI. I want to execute my principal function with an interuption with EXTI but it dosen't work ! only one instruction does work, this is my code. plz some one help me.

1. void EXTI_IRconfig(void)
2. {
3. NVIC_InitTypeDef   NVIC_InitStructure;
4.  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource3);
5.  
6.   /* Configure EXTI Line3 */
7.   EXTI_InitStructure.EXTI_Line = EXTI_Line3;
8.   EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
9.   EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; 
10.   EXTI_InitStructure.EXTI_LineCmd = ENABLE;
11.   EXTI_Init(&EXTI_InitStructure);
12.  
13.  NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;
14.   NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
15.   NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
16.   NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
17.   NVIC_Init(&NVIC_InitStructure);
18. }

/*******************************************/

#include ''stm32f4xx_it.h''

/*********************************************/

1. extern capteurIR;
2. void EXTI3_IRQHandler(void)
3. {
4. if(EXTI_GetITStatus(EXTI_Line3) != RESET)
5.   {
6. capteurIR=GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_3);
7. EXTI_ClearITPendingBit(EXTI_Line3);
8. }
9. if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_3)!=1)
10. {
11.  GPIO_ToggleBits(GPIOD, GPIO_Pin_15);
12. }
13. else
14. {
15. GPIO_ResetBits(GPIOD, GPIO_Pin_15);
16. }
17. }

[Tesla DeLorean]

Posted on March 31, 2014 at 03:49

It would have helped if there more context.

Make sure you've configured the pins, and that the GPIO and SYSCFG clocks are enabled.

On a rising edge, you're likely to find the pin high when you enter the service routine.

[m_fawaz]

Posted on April 01, 2014 at 00:45

Dear Claude,

I did not get why you are trying to read PA3 in the interrupt handler ''EXTI3_IRQHandler''.

Knowing that you configured the interrupt to be on the rising edge

''EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;'', you will find PA3 to be high as Clive1 stated.

I will paste a piece of code that compiles and works fine:

1) replace the method EXTI_IRconfig with the following:

void EXTILine3_Config(void)

{

  GPIO_InitTypeDef   GPIO_InitStructure;

  NVIC_InitTypeDef   NVIC_InitStructure;

  /* Enable GPIOA clock */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

  /* Enable SYSCFG clock */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

  /* Configure PA3 pin as input floating */

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Connect EXTI Line3 to PA3 pin */

  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource3);

  /* Configure EXTI Line3 */

  EXTI_InitStructure.EXTI_Line = EXTI_Line3;

  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;

  EXTI_InitStructure.EXTI_LineCmd = ENABLE;

  EXTI_Init(&EXTI_InitStructure);

  /* Enable and set EXTI Line3 Interrupt to the lowest priority */

  NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

}

2) call the function EXTILine3_Config(); in the ''main'' in order to configure the interrupt.

3) Provided that you properly configured GPIOD, you can use the code below for the interrupt handler to toggle PD15

void EXTI3_IRQHandler(void)

{

  if(EXTI_GetITStatus(EXTI_Line3) != RESET)

  {

    GPIO_ToggleBits(GPIOD, GPIO_Pin_15);

    EXTI_ClearITPendingBit(EXTI_Line3);

  }

}

[Tesla DeLorean]

Posted on April 01, 2014 at 01:04

I might suggest a slight different instruction sequence to avoid the pipeline hazard with tail-chaining.

void EXTI3_IRQHandler(void)
{
if (EXTI_GetITStatus(EXTI_Line3) != RESET)
{
EXTI_ClearITPendingBit(EXTI_Line3); // Do Early, avoid pipeline hazard 
GPIO_ToggleBits(GPIOD, GPIO_Pin_15);
}
}

There are also F4 examples in the firmware library STM32F4xx_DSP_StdPeriph_Lib_V1.3.0\Project\STM32F4xx_StdPeriph_Examples\EXTI\EXTI_Example\main.c