Can anyone tell me how to configure external interrupts on stm32f103c8t6? is there anything wrong, my IRQHandler is not functioning properly...(actually, i wanted my LED(PA1) to glow when i interrupted it with push button(PB3) but it is not doing so.

[Vijay Krishna]

#include "stm32f10x.h"

void EXTI3_IRQ_IRQHandler(void)

{

if(EXTI->PR & EXTI_PR_PR3)

{

 EXTI->PR |= EXTI_PR_PR3;

 GPIOA-> BRR |= GPIO_BRR_BS1;

}

}

int main(void)

{

RCC ->APB2ENR |= RCC_APB2ENR_IOPAEN;   //LED(OUTPUT PIN)(PA1)

GPIOA->CRL &= ~(GPIO_CRL_CNF1);

GPIOA->CRL |= GPIO_CRL_MODE1_0;

GPIOA->CRL &= ~(GPIO_CRL_MODE1_1);

RCC ->APB2ENR |= RCC_APB2ENR_IOPBEN;   //PUSH BUTTON(INPUT PIN)(PB3)

GPIOB->CRL |= GPIO_CRL_CNF3_0;

 GPIOB->CRL &= ~(GPIO_CRL_CNF3_1);

GPIOB->CRL &= ~(GPIO_CRL_MODE3);

RCC ->APB2ENR |= RCC_APB2ENR_AFIOEN;  //FOR ALTERNATE FUNCTION

EXTI->IMR |= EXTI_IMR_MR3;      //INTERRUPT MASK REGISTER(0:MASKING, 1:NON-MASKING)

EXTI->RTSR |= EXTI_RTSR_TR3;     // RISING EDGE TRIGGERED INTERRUPT

AFIO->EXTICR[0] = AFIO_EXTICR1_EXTI3_PB;

NVIC_EnableIRQ(EXTI3_IRQn);

NVIC_SetPriority(EXTI3_IRQn,0);

while(1)

{

  

GPIOA-> BSRR |= GPIO_BSRR_BR1;

}

}

[TDK]

Put a breakpoint in EXTI3_IRQ_IRQHandler and see if it's getting there.

Could be that the LED lights up for only a few clock cycles and your eye can't see it.

[Vijay Krishna]

Thanks, i detected the glitch/error, and you are right: i had to only add a delay (not a breakpoint exactly, but a delay function) before the line: GPIOA-> BSRR |= GPIO_BSRR_BR1; in the while loop because the interrupt handler function returns to the while loop after handling the interrupt so maybe my code looks like this:

void EXTI3_IRQHandler(void)
 
{
 
 
if(EXTI->PR & EXTI_PR_PR3)
 
{
 
 EXTI->PR |= EXTI_PR_PR3;
 
 GPIOA-> BRR |= GPIO_BRR_BS1;
 
 
}
 
 
}
 
 
 
int main(void)
 
{
 
 
RCC ->APB2ENR |= RCC_APB2ENR_IOPAEN; //LED(OUTPUT PIN)(PA1)
 
GPIOA->CRL &= ~(GPIO_CRL_CNF1);
 
GPIOA->CRL |= GPIO_CRL_MODE1_0;
 
GPIOA->CRL &= ~(GPIO_CRL_MODE1_1);
 
 
RCC ->APB2ENR |= RCC_APB2ENR_IOPBEN; //PUSH BUTTON(INPUT PIN)(PB3)
 
GPIOB->CRL |= GPIO_CRL_CNF3_0;
 
 GPIOB->CRL &= ~(GPIO_CRL_CNF3_1);
 
GPIOB->CRL &= ~(GPIO_CRL_MODE3);
 
 
RCC ->APB2ENR |= RCC_APB2ENR_AFIOEN; //FOR ALTERNATE FUNCTION
 
EXTI->IMR |= EXTI_IMR_MR3; //INTERRUPT MASK REGISTER(0:MASKING, 1:NON-MASKING)
 
EXTI->RTSR |= EXTI_RTSR_TR3; // RISING EDGE TRIGGERED INTERRUPT
 
AFIO->EXTICR[0] = AFIO_EXTICR1_EXTI3_PB; //ALTERNATE FUNCTION CONFIGURATION FOR-PB3) 
 
 
 
NVIC_EnableIRQ(EXTI3_IRQn);
 
NVIC_SetPriority(EXTI3_IRQn,0);
 
 
while(1)
 
{
 
 
for(volatile int i=0; i<=10000000; i++);
GPIOA-> BSRR |= GPIO_BSRR_BR1;
 
 
}
 
}

[EGeno.1]

I'm using STM32F10x_StdPeriph_Lib_V3.5.0 and the programme becomes more readable.

/**

 * @brief Configure the EXTI 4.

 *        The external signal is connected to EXTI4 pin (PB.4)

 *        The Rising edge is used as active edge

 * @param None

 * @retval None

 */

void EXTI4_Configuration() {

 EXTI_InitTypeDef EXTI_InitStructure;

 //select EXTI line4

 EXTI_InitStructure.EXTI_Line = EXTI_Line4;

 //select interrupt mode

 EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

 //generate interrupt on rising edge

 EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;

 //enable EXTI line

 EXTI_InitStructure.EXTI_LineCmd = ENABLE;

 //send values to registers

 EXTI_Init(&EXTI_InitStructure);

}

/**

 * @brief This function calculates left motor speed.

 * @param None

 * @retval None

 */

void EXTI4_IRQHandler(void) { 

short ms;  

__IO short h;

   //Check if EXTI_Line4 is asserted

   if(EXTI_GetITStatus(EXTI_Line4) == SET) {

     //we need to clear line pending bit manually

     EXTI_ClearITPendingBit(EXTI_Line4);

....

}

In main:

 GPIO_InitTypeDef GPIO_InitStructure;

 GPIO_StructInit (& GPIO_InitStructure);

 // EXTI4 configuration

 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;

 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;

 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;

 GPIO_Init(GPIOB, &GPIO_InitStructure);

 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource4);  

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);

 // Enable the EXTI4 Interrupt

 NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;

 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 7;

 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

 NVIC_Init(&NVIC_InitStructure);