以下为 key.c

#include "key.h"
#include "delay.h" 


//°´¼ü³õʼ»¯º¯Êý
void KEY_Init(void)
{
    
    GPIO_InitTypeDef  GPIO_InitStructure;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA|RCC_AHB1Periph_GPIOE, ENABLE);//ʹÄÜGPIOA,GPIOEʱÖÓ
 
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4; //KEY0 KEY1 KEY2¶ÔÓ¦Òý½Å
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;//ÆÕͨÊäÈëģʽ
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100M
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//ÉÏÀ­
  GPIO_Init(GPIOE, &GPIO_InitStructure);//³õʼ»¯GPIOE2,3,4
    
     
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;//WK_UP¶ÔÓ¦Òý½ÅPA0
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN ;//ÏÂÀ­
  GPIO_Init(GPIOA, &GPIO_InitStructure);//³õʼ»¯GPIOA0
 
} 
//°´¼ü´¦Àíº¯Êý
//·µ»Ø°´¼üÖµ
//mode:0,²»Ö§³ÖÁ¬Ðø°´;1,Ö§³ÖÁ¬Ðø°´;
//0£¬Ã»ÓÐÈκΰ´¼ü°´ÏÂ
//1£¬KEY0°´ÏÂ
//2£¬KEY1°´ÏÂ
//3£¬KEY2°´Ï 
//4£¬WKUP°´Ï WK_UP
//×¢Òâ´Ëº¯ÊýÓÐÏìÓ¦ÓÅÏȼ¶,KEY0>KEY1>KEY2>WK_UP!!
u8 KEY_Scan(u8 mode)
{    
    static u8 key_up=1;//°´¼ü°´ËÉ¿ª±êÖ¾
    if(mode)key_up=1;  //Ö§³ÖÁ¬°´         
    if(key_up&&(KEY0==0||KEY1==0||KEY2==0||WK_UP==1))
    {
        delay_ms(10);//È¥¶¶¶¯ 
        key_up=0;
        if(KEY0==0)return 1;
        else if(KEY1==0)return 2;
        else if(KEY2==0)return 3;
        else if(WK_UP==1)return 4;
    }else if(KEY0==1&&KEY1==1&&KEY2==1&&WK_UP==0)key_up=1;      
    return 0;// ÎÞ°´¼ü°´ÏÂ
}

以下为key.h

#ifndef __KEY_H
#define __KEY_H  
#include "sys.h" 


/*ÏÂÃæµÄ·½Ê½ÊÇͨ¹ýÖ±½Ó²Ù×÷¿âº¯Êý·½Ê½¶ÁÈ¡IO*/
#define KEY0        GPIO_ReadInputDataBit(GPIOE,GPIO_Pin_4) //PE4
#define KEY1        GPIO_ReadInputDataBit(GPIOE,GPIO_Pin_3) //PE3 
#define KEY2        GPIO_ReadInputDataBit(GPIOE,GPIO_Pin_2) //PE2
#define WK_UP   GPIO_ReadInputDataBit(GPIOA,GPIO_Pin_0) //PA0


/*ÏÂÃ淽ʽÊÇͨ¹ýλ´ø²Ù×÷·½Ê½¶ÁÈ¡IO*/
/*
#define KEY0        PEin(4)     //PE4
#define KEY1        PEin(3)     //PE3 
#define KEY2        PEin(2)     //P32
#define WK_UP   PAin(0)     //PA0
*/


#define KEY0_PRES 1
#define KEY1_PRES   2
#define KEY2_PRES   3
#define WKUP_PRES 4

void KEY_Init(void);    //IO³õʼ»¯
u8 KEY_Scan(u8);        //°´¼üɨÃ躯Êý  

#endif

在主函数初始化后 在while（1）进行判断

uart_init(115200);
KEY_Init();



 while(1){

        key=KEY_Scan(0);
        if(key)
        {
            switch(key){
          case KEY0_PRES :printf("KEY0±»°´ÏÂ\r\n"); break;
            case KEY1_PRES :printf("KEY1±»°´ÏÂ\r\n"); break;
            case KEY2_PRES :printf("KEY2±»°´ÏÂ\r\n"); break;
            case WKUP_PRES :printf("KEYup±»°´ÏÂ\r\n");break;
        }
            
        }
        
        
    }