STM32F051 External Interrupt Example

gistfile1.txt

#include "stm32f0xx_conf.h"

/*
    External interrupt example for STM32F051
    Turn on a LED when rising edge is detected.
    - LED is on GPIOC Pin8
    - Button is on GPIOA Pin0
        -> This is interrupt Line 0
        -> Interrupt Line0 is handled in NVIC
            together with Line1 on Channel0_1
*/


void EXTI0_1_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line0) != RESET){
        EXTI_ClearITPendingBit(EXTI_Line0);

        GPIO_SetBits(GPIOC, GPIO_Pin_8);
    }
}


int main(void)
{
    GPIO_InitTypeDef gpio_conf;

    // Configure LED on GPIOC Pin8
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);
    gpio_conf.GPIO_Pin = GPIO_Pin_8;
    gpio_conf.GPIO_Mode = GPIO_Mode_OUT;
    gpio_conf.GPIO_OType = GPIO_OType_PP;
    gpio_conf.GPIO_PuPd = GPIO_PuPd_NOPULL;
    gpio_conf.GPIO_Speed = GPIO_Speed_Level_1;
    GPIO_Init(GPIOC, &gpio_conf);

    // Configure Button on GPIOA Pin0
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
    gpio_conf.GPIO_Pin = GPIO_Pin_0;
    gpio_conf.GPIO_Mode = GPIO_Mode_IN;
    gpio_conf.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &gpio_conf);

    // Configure Interrupt
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
    SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);

    EXTI_InitTypeDef EXTI_InitStructure;
    EXTI_StructInit(&EXTI_InitStructure);
    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 Interrupt in NVIC
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = EXTI0_1_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPriority = 0x03;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    // Ensure LED is turned off
    GPIO_ResetBits(GPIOC, GPIO_Pin_8);

    while(1);
}