用51单片机做宿舍门禁系统（2）--4*4矩阵按键

灰太狼 2022-09-16 06:08 176阅读 0赞

选用4\*4矩阵键盘作为输入，其原理是16个按键进行行列扫描，简化操作。

## 原理图 ##

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA54as5aSc6ICX5a2Q5Zyo57q_5pWy5Luj56CB_size_9_color_FFFFFF_t_70_g_se_x_16]  
用薄膜键盘代替一下，原理一样。  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA54as5aSc6ICX5a2Q5Zyo57q_5pWy5Luj56CB_size_20_color_FFFFFF_t_70_g_se_x_16]  
key.c

#include "key.h"
    
    u8 KeyValue=0;
    
    /*延时函数*/
    void delay(u16 i)
    { 
    	while(i--);	
    }
    
    /*判断按键返回值*/
    u8 Down()
    { 
     	u8 a=0;
    	GPIO_KEY=0x0f; //复位按钮
    	if(GPIO_KEY!=0x0f)//有按键按下
    	{ 
    	   GPIO_KEY==0x0f;
    	   switch(GPIO_KEY)
    		{ 
    			case(0X07):	KeyValue=0;break;
    			case(0X0b):	KeyValue=1;break;
    			case(0X0d): KeyValue=2;break;
    			case(0X0e):	KeyValue=3;break;
    		}
    		GPIO_KEY=0XF0;
    		switch(GPIO_KEY)
    		{ 
    			case(0X70):	KeyValue=KeyValue;break;
    			case(0Xb0):	KeyValue=KeyValue+4;break;
    			case(0Xd0): KeyValue=KeyValue+8;break;
    			case(0Xe0):	KeyValue=KeyValue+12;break;
    		}
    		while((a<50)&&(GPIO_KEY!=0xf0))//去抖 
    		{ 
    			delay(1000);
    			a++;
    		}
    	}
    	else
    	{ 
    		KeyValue=0xff;  //无按键按下
    	}
    	return KeyValue;  //返回KeyValue
    
    }

key.h

#ifndef _key_H
    #define key_H
    
    #include<reg52.h>
    
    #ifndef u8
    #define u8 unsigned char
    #endif 
    #ifndef u16
    #define u16 unsigned int
    #endif
    
    
    //按键引脚定义
    #define GPIO_KEY P1
    
    void delay(u16 i);
    u8 Down();
    #endif

main.c

#include "lcd.h"
    #include "key.h"
    
    #define u16 unsigned int //对数据类型进行声明定义
    #define u8 unsigned char
    
    u8 key_num;
    void main()
    { 
    	LcdInit();
    	while(1)
    	{ 
    		//ShowString(0x00," XinMin B619 "); 
    		while(1)
    		{ 	
    			key_num=Down();                   //读取输入值
    			if(key_num!=0x0b)  
    			{ 
    				switch(key_num)
    				{ 
    					case 0x00:
    					 { ShowString(0x00,"0");break;}
    					case 0x01:
    					 { ShowString(0x00,"1");break;}
    					case 0x02:
    					 { ShowString(0x00,"2");break;}
    					case 0x03:
    					 { ShowString(0x00,"3");break;}	
    					case 0x04:
    					 { ShowString(0x00,"4");break;}	
    					case 0x05:
    					 { ShowString(0x00,"5");break;}	
    					case 0x06:
    					 { ShowString(0x00,"6");break;}	
    				}
    			}
    	
    		 }			
    	}		
    }

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA54as5aSc6ICX5a2Q5Zyo57q_5pWy5Luj56CB_size_9_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/8a72dd58bdcc4650a8dd370f8fff4708.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA54as5aSc6ICX5a2Q5Zyo57q_5pWy5Luj56CB_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220828/cb3b79252131440aaf5fe5decce2debe.png