MCU：STM32F334C81.掃描模式首先配置按鍵引腳為上拉輸入模式，根據原理圖按鍵接PA0，按鍵沒有按下的時候引腳輸入為低電平0，按鍵按下輸入高電平1，松開又回到低電平0然后在死循環中不斷讀取相應引腳的輸入狀態，并根據返回結果判斷按鍵是否按下，做出相應處理下面的代碼完成的功能是：按鍵第一次按下，點亮燈，再按一次，熄滅，重復。#include "Userkey.h"u8 flag=0;void key_GPIO_Config(void){GPIO_InitTypeDef GPIO_InitStructure;RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,ENABLE);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);}void key_scanmode(void){key_GPIO_Config();while(1){if(GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0)){flag =~flag;if(flag)//第1?3?5，，次按下{GPIO_SetBits(GPIOB, GPIO_Pin_6);}else//第2?4?6，，，次按下{GPIO_ResetBits(GPIOB, GPIO_Pin_6);}}}}2.中斷模式第一步和上面相同，將接按鍵的引腳配置為上拉輸入，然后配置相應中斷，PA0對應外部中斷0功能：按鍵按下，點亮LED并向串口發送按鍵按下到PC，按鍵松開，關掉LED并發送按鍵松開void key_interruptmode(void){EXTI_InitTypeDef EXTI_InitStructure;NVIC_InitTypeDef NVIC_InitStruct;RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG,ENABLE);key_GPIO_Config();NVIC_InitStruct.NVIC_IRQChannel =EXTI0_IRQn;NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;NVIC_InitStruct.NVIC_IRQChannelSubPriority = 1;NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;NVIC_Init(&NVIC_InitStruct);SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);EXTI_ClearITPendingBit(EXTI_Line0);EXTI_InitStructure.EXTI_Line=EXTI_Line0;EXTI_InitStructure.EXTI_LineCmd =ENABLE;EXTI_InitStructure.EXTI_Mode=EXTI_Mode_Interrupt;EXTI_InitStructure.EXTI_Trigger=EXTI_Trigger_Rising_Falling;EXTI_Init(&EXTI_InitStructure);}void EXTI0_IRQHandler(void){if(EXTI_GetITStatus(EXTI_Line0)){if(GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0))//按鍵按下{GPIO_SetBits(GPIOB, GPIO_Pin_6);printf("按鍵按下\n");//串口打印狀態}else//按鍵松開{GPIO_ResetBits(GPIOB, GPIO_Pin_6);printf("按鍵松開\n");}}EXTI_ClearITPendingBit(EXTI_Line0);}注：如果要實現和1一樣的功能，將EXTI_Trigger改為上升沿或者下降沿，再改一下中斷處理函數即可STM32按鍵掃描按鍵中斷外部中斷(mbbeetchina)