STM32学习笔记——中断

重点：外部中断

代码：
main.c：

#include "stm32f10x.h"
#include "stm32f10x_exti.h"
#include "stm32f10x_rcc.h"
#include "misc.h"

void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
void Delay(__IO uint32_t nCount);
void Key_scan(void);

unsigned char _it0 = 0, num = 0;

int main()
{
    unsigned char b = 0;

    RCC_Configuration();
    NVIC_Configuration();
    GPIO_Configuration();
    while(1){
        Key_scan();
        if(num == 2 && b == 0){
            GPIO_SetBits(GPIOD, GPIO_Pin_2);
            b = 1;
        }else if(num == 2 && b == 1){
            GPIO_ResetBits(GPIOD, GPIO_Pin_2);
            b = 0;
        }
    }
}

void Key_scan()
{
    num = 0;

    if(_it0 == 2){
        if(GPIO_ReadInputDataBit(GPIOC, GPIO_Pin_4) == 0){
            Delay(0xffff);//GPIO_ReadInputDataBit（）函数读取PC4引脚的状态
            if(GPIO_ReadInputDataBit(GPIOC, GPIO_Pin_4) == 0){
                while(GPIO_ReadInputDataBit(GPIOC, GPIO_Pin_4) == 0);
                num = 2;
            }
        }
        _it0 = 0;
    }
}

void Delay(__IO uint32_t nCount)
{
    for(; nCount != 0; nCount--);
}

void RCC_Configuration(void)
{
    SystemInit();
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);//打开AFOI时钟，使用复用I/O功能
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//PC4被复用做中断
    GPIO_Init(GPIOC, &GPIO_InitStructure);
}

void NVIC_Configuration(void)//配置中断控制器
{
    NVIC_InitTypeDef NVIC_InitStructure;
    EXTI_InitTypeDef EXTI_InitStructure;

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
    NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x03;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    GPIO_EXTILineConfig(GPIO_PortSourceGPIOC, GPIO_PinSource4);
    EXTI_InitStructure.EXTI_Line = EXTI_Line4;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);
}

stm32f10x_it.c：

#include "stm32f10x_it.h"
#include "stm32f10x_exti.h"
#include "stm32f10x_rcc.h"
#include "misc.h"

extern unsigned char _it0;

void EXTI4_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line4) != RESET){
        _it0 = 2;
        EXTI_ClearITPendingBit(EXTI_Line4);
    }
}

小结：
1，I/O口与中断线有确定的对应关系

2，外部中断要将GPIO管脚设置成浮空输入模式