常规电路(带上拉电阻)

阻值可选3.3/4.7/5.1/10 单位K

偷懒电路

利用GPIO内部的上拉模式

代码（直接拷贝使用）

这是一个外部中断控制变量a增加减少的demo
为了新手方便我直接都写在了main.c文件

#include "stm32f10x.h"u8 keyflag=0;
u8 a=0;void KEY_Init(void)
{RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOE,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);	GPIO_InitTypeDef GPIO_in;GPIO_in.GPIO_Mode=GPIO_Mode_IPU;GPIO_in.GPIO_Pin=GPIO_Pin_3|GPIO_Pin_4;GPIO_Init(GPIOE,&GPIO_in);}void My_EXIT_Init(void)
{GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource3);GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource4);EXTI_InitTypeDef EXTI_in;EXTI_in.EXTI_Line=EXTI_Line3|EXTI_Line4;EXTI_in.EXTI_LineCmd=ENABLE;EXTI_in.EXTI_Mode=EXTI_Mode_Interrupt;EXTI_in.EXTI_Trigger=EXTI_Trigger_Falling;EXTI_Init(&EXTI_in);}void KEY_NVIC_CFG(void)
{NVIC_InitTypeDef nvic_in;nvic_in.NVIC_IRQChannel=EXTI3_IRQn;nvic_in.NVIC_IRQChannelCmd=ENABLE;nvic_in.NVIC_IRQChannelPreemptionPriority=0;nvic_in.NVIC_IRQChannelSubPriority=0;NVIC_Init(&nvic_in);nvic_in.NVIC_IRQChannel=EXTI4_IRQn;nvic_in.NVIC_IRQChannelCmd=ENABLE;nvic_in.NVIC_IRQChannelPreemptionPriority=0;nvic_in.NVIC_IRQChannelSubPriority=1;NVIC_Init(&nvic_in);
}//中断函数3
void EXTI3_IRQHandler(void)
{EXTI_ClearFlag(EXTI_Line3);keyflag=1;}//中断函数4
void EXTI4_IRQHandler(void)
{EXTI_ClearFlag(EXTI_Line4);keyflag=2;
}int main(void){	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);KEY_Init();My_EXIT_Init();KEY_NVIC_CFG();while(1){if(keyflag==1){keyflag=0;a++;}else	if(keyflag==2){keyflag=0;a--;}}}

工程获取

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