External interrupts

External interrupts (falling edge) on PD.03 (INT_ARM) pin When the EXTI interrupt occurs PD.04 pin is toggled.

Code Example

#include "exti.h"

EXTI_InitTypeDef	EXTI_InitStructure;
GPIO_InitTypeDef	GPIO_InitStructure;
NVIC_InitTypeDef	NVIC_InitStructure;

volatile int G_led_state = 0;


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

int main (void)
{
	tprintf("\n\rMini-Max/STM32F1");
	tprintf("\n\rEXTI TEST REV 1.01");

	/* Enable GPIOD clock */
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);

	/* Configure PD.03 pin as input floating */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
	GPIO_Init(GPIOD, &GPIO_InitStructure);

	/* Configure PD.04 pin as output */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_Init(GPIOD, &GPIO_InitStructure);

	/* Enable AFIO clock */
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

	/* Connect EXTI Line to PD.03 pin */
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOD, GPIO_PinSource3);

	/* Configure EXTI line */
	EXTI_InitStructure.EXTI_Line = EXTI_Line3;
	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 to the lowest priority */
	NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_Init(&NVIC_InitStructure);

	tprintf("\r\n");
	
	for(;;);
	
	return 0;
}

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

void EXTI3_IRQHandler(void)
{
	if(EXTI_GetITStatus(EXTI_Line3) != RESET)
	{
		if (1 & G_led_state++)	
		{
			GPIOD_BSRR = 1UL<<(16+4); 	// Reset GPIO_Pin_4

			tprintf("\r\nReset PD.04");
		}
		else					
		{
			GPIOD_BSRR = 1UL<<4; 		// Set GPIO_Pin_4

			tprintf("\r\nSet PD.04");
		}
		
		/* Clear the  EXTI line 3 pending bit */
		EXTI_ClearITPendingBit(EXTI_Line3);
	}
}
/* EOF */