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