51单片机入门——矩阵建盘的基本操作（待更新）

浅浅的花香味﹌ 2022-09-12 06:47 132阅读 0赞

### 矩阵建盘的基本操作 ###

*  矩阵键盘的原理图和基本原理
 *  例题

# 矩阵键盘的原理图和基本原理 #

*  **原理图**

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA57u05YWL5aSa55qE6YCG6aOO_size_20_color_FFFFFF_t_70_g_se_x_16]

*  **基本原理**

首先我们要进行扫描，扫描矩阵键盘中每个按键的状态，对与矩阵键盘，我们只能逐行扫描，然后读取列的状态信号。如果R3行输出低电平，那么黄色按键如果有按下动作的话，那读取C2列信号也应该为低电平，而该行上其他没有按下动作的按键的列信号则为高电平。  
**每个按键内部的结构**

*  **独立按键**  
    ![在这里插入图片描述][1331352572614799bb39e0d89ad2259a.png]

**- 矩阵键盘**  
![在这里插入图片描述][b8386f22b5e5429a898729010c92d83b.png]

**检测**  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA57u05YWL5aSa55qE6YCG6aOO_size_20_color_FFFFFF_t_70_g_se_x_16 1]  
每次输入检测是都只保证一个为低电平，其余为高电平，只要某一行输入0,在某一列也输出0，则检测成功（成功按下）

# 例题 #

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA57u05YWL5aSa55qE6YCG6aOO_size_18_color_FFFFFF_t_70_g_se_x_16]

**代码如下**

#include "reg52.h" 
    
    sfr P4   = 0xC0;    
    
    sbit HC138_A = P2^5;    
    sbit HC138_B = P2^6;    
    sbit HC138_C = P2^7;    
    
    sbit R1 = P3^0;  
    sbit R2 = P3^1;
    sbit R3 = P3^2;
    sbit R4 = P3^3;
    
    sbit C1 = P4^4;
    sbit C2 = P4^2;
    sbit C3 = P3^5;
    sbit C4 = P3^4;
    
    unsigned char keyNum = 0x10;
    unsigned char code SMG_NoDot[18] = 
        { 0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,
         0x80,0x90,0x88,0x80,0xc6,0xc0,0x86,0x8e,
         0xbf,0x7f};
    
    void Delay(unsigned char t)
    { 
        while(t--);
    }
    
    void Init74HC138(unsigned char n)
    { 
        switch(n)
        { 
            case 4:
                HC138_A = 0;
                HC138_B = 0;
                HC138_C = 1;
                break;
            case 5:
                HC138_A = 1;
                HC138_B = 0;
                HC138_C = 1;
                break;
            case 6:
                HC138_A = 0;
                HC138_B = 1;
                HC138_C = 1;
                break;
            case 7:
                HC138_A = 1;
                HC138_B = 1;
                HC138_C = 1;
                break;
            case 8:
                HC138_A = 0;
                HC138_B = 0;
                HC138_C = 0;
                break;
        }
    }
    
    void ShowKeyNum(unsigned char value)
    { 
        Init74HC138(6);
        P0 = 0x01;
        Init74HC138(7);
        P0 = value;
    }
    
    void ScanKeys()
    { 
        keyNum = 16;
        R1 = 0;
        R2 = R3 = R4 = 1;
        C1 = C2 = C3 = C4 = 1;
        if(C1 == 0)
        { 
            while(C1 == 0);
            keyNum = 0;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C2 == 0)
        { 
            while(C2 == 0);
            keyNum = 1;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C3 == 0)
        { 
            while(C3 == 0);
            keyNum = 2;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C4 == 0)
        { 
            while(C4 == 0);
            keyNum = 3;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        
        R2 = 0;
        R1 = R3 = R4 = 1;
        C1 = C2 = C3 = C4 = 1;
        if(C1 == 0)
        { 
            while(C1 == 0);
            keyNum = 4;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C2 == 0)
        { 
            while(C2 == 0);
            keyNum = 5;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C3 == 0)
        { 
            while(C3 == 0);
            keyNum = 6;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C4 == 0)
        { 
            while(C4 == 0);
            keyNum = 7;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        
        R3 = 0;
        R2 = R1 = R4 = 1;
        C1 = C2 = C3 = C4 = 1;
        if(C1 == 0)
        { 
            while(C1 == 0);
            keyNum = 8;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C2 == 0)
        { 
            while(C2 == 0);
            keyNum = 9;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C3 == 0)
        { 
            while(C3 == 0);
            keyNum = 10;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C4 == 0)
        { 
            while(C4 == 0);
            keyNum = 11;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        
        R4 = 0;
        R2 = R3 = R1 = 1;
        C1 = C2 = C3 = C4 = 1;
        if(C1 == 0)
        { 
            while(C1 == 0);
            keyNum = 12;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C2 == 0)
        { 
            while(C2 == 0);
            keyNum = 13;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C3 == 0)
        { 
            while(C3 == 0);
            keyNum = 14;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
        else if(C4 == 0)
        { 
            while(C4 == 0);
            keyNum = 15;
            ShowKeyNum(SMG_NoDot[keyNum]);
        }
    }
    
    void main()
    {     
        while(1)
        { 
            ScanKeys();
        }
    }

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[1331352572614799bb39e0d89ad2259a.png]: /images/20220828/cef60b77a2e84b238fbac6ea268fca56.png
[b8386f22b5e5429a898729010c92d83b.png]: /images/20220828/ae205ca4149c43e295d28519b47d43de.png
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