蓝桥杯单片机矩阵按键扫描编程

蓝桥杯的矩阵按键的扫描，使用reg52.h头文件的时候需要自定义P4接口，因为在该头文件中并没有定义P4接口。

#include "reg52.h"
#include "intrins.h"

typedef unsigned char u8;
typedef unsigned int u16;

sfr P4 = 0xc0;        // 自定义P4接口，P4^4代替P3^7，P4^2代替P3^6

sbit R1 = P3^0;      // 行
sbit R2 = P3^1;
sbit R3 = P3^2;
sbit R4 = P3^3;

sbit C1 = P4^4;       // 列
sbit C2 = P4^2;
sbit C3 = P3^5;
sbit C4 = P3^4;

u8 temp_keys = 0;             // 按键的位数

u8 code shuma[12] = {
   0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0xbf,0xbf};


  // 外设初始化函数
void init_system()
{
   
    P2 = (P2 & 0x1f) | 0x80;
	P0 = 0xff;
	P2 = (P2 & 0x1f);

	P2 = (P2 & 0x1f) | 0xa0;
	P0 = 0x00;
	P2 = (P2 & 0x1f);

	P2 = (P2 & 0x1f) | 0xc0;
	P0 = 0x00;
	P2 = (P2 & 0x1f);
}


	// 外设选通函数
void select(u8 local)
{
   
    switch(local)
	{
   
	    case(4): P2 = (P2 & 0x1f) | 0x80; break;
		case(5): P2 = (P2 & 0x1f) | 0xa0; break;
		case(6): P2 = (P2 & 0x1f) | 0xc0; break;
		case(7): P2 = (P2 & 0x1f) | 0xe0; break;
	}
}

  // 简单延时函数
void delay()
{
   
    u8 t = 200;
	while(t--);
}

// 数码管点亮函数，单个数码管
void display(u8 local, u8 num)
{
   
    select(6);
	P0 = 0x80 >> (local - 1);
	P2 = P2 & 0x1f;

	select(7);
	P0 = num;
	P2 = P2 & 0x1f;

	delay();
}

// 数码管消隐函数
void close_display()
{
   
    // 消隐
	select(6);
	P0 = 0x00;
	P2 = P2 & 0x1f;
}

// 按键扫描函数
void scan_keys()
{
   
	R1 = 0;
	R2 = R3 = R4 = 1;
	C1 = C2 = C3 = C4 = 1;
	if(C1 == 0)
	{
   
	    delay();
		if(C1 == 0)
		{
   
		    temp_keys = 7;
		}
		while(!C1);
	}
	else if(C2 == 0)
	{
   
	    delay();
		if(C2 == 0)
		{
   
		    temp_keys = 11;
		}
		while(!C2);
	}
	else if(C3 == 0)
	{
   
	    delay();
		if(C3 == 0)
		{
   
		    temp_keys = 15;
		}
		while(!C3);
	}
	else if(C4 == 0)
	{
   
	    delay();
		if(C4 == 0)
		{
   
		    temp_keys = 19;
		}
		while(!C4);
	}


	R2 = 0;
	R1 = R3 = R4 = 1;
	C1 = C2 = C3 = C4 = 1;
	if(C1 == 0)
	{
   
	    delay();
		if(C1 == 0)
		{
   
		    temp_keys = 6;
		}
		while(!C1);
	}
	else if(C2 == 0)
	{
   
	    delay();
		if(C2 == 0)
		{
   
		    temp_keys = 10;
		}
		while(!C2);
	}
	else if(C3 == 0)
	{
   
	    delay();
		if(C3 == 0)
		{
   
		    temp_keys = 14;
		}
		while(!C3);
	}
	else if(C4 == 0)
	{
   
	    delay();
		if(C4 == 0)
		{
   
		    temp_keys = 18;
		}
		while(!C4);
	}

	R3 = 0;
	R2 = R1 = R4 = 1;
	C1 = C2 = C3 = C4 = 1;
	if(C1 == 0)
	{
   
	    delay();
		if(C1 == 0)
		{
   
		    temp_keys = 5;
		}
		while(!C1);
	}
	else if(C2 == 0)
	{
   
	    delay();
		if(C2 == 0)
		{
   
		    temp_keys = 9;
		}
		while(!C2);
	}
	else if(C3 == 0)
	{
   
	    delay();
		if(C3 == 0)
		{
   
		    temp_keys = 13;
		}
		while(!C3);
	}
	else if(C4 == 0)
	{
   
	    delay();
		if(C4 == 0)
		{
   
		    temp_keys = 17;
		}
		while(!C4);
	}

	R4 = 0;
	R2 = R3 = R1 = 1;
	C1 = C2 = C3 = C4 = 1;
	if(C1 == 0)
	{
   
	    delay();
		if(C1 == 0)
		{
   
		    temp_keys = 4;
		}
		while(!C1);
	}
	else if(C2 == 0)
	{
   
	    delay();
		if(C2 == 0)
		{
   
		    temp_keys = 8;
		}
		while(!C2);
	}
	else if(C3 == 0)
	{
   
	    delay();
		if(C3 == 0)
		{
   
		    temp_keys = 12;
		}
		while(!C3);
	}
	else if(C4 == 0)
	{
   
	    delay();
		if(C4 == 0)
		{
   
		    temp_keys = 16;
		}
		while(!C4);
	}

	if(temp_keys == 4)
	   {
   
	       TR1 = ~TR1;
		   t1_sec = t1_sec;
		   t1_min = t1_min;
		   t1_hour = t1_hour;
	   }
	else if(temp_keys == 5)
	   {
   
	       t1_sec = 0;
		   t1_min = 0;
		   t1_hour = 0;
	   }
	else if(temp_keys == 6)
	   {
   
	        select(4);
			P0 = 0xfe;
			P2 = P2 & 0x1f;
	   }
	else if(temp_keys == 7)
	   {
   
	        select(4);
			P0 = 0xff;
			P2 = P2 & 0x1f;	    
	   }	
}


void main()
{
   

	init_system();
    while(1)
	{
   
	   scan_keys(); 
	   display(1, shuma[temp_keys%10]);
	   display(2, shuma[ temp_keys/10]);
	   close_display();
	 	   
	}
}

初始化外设一般都是蓝桥杯一上电就需要完成的事情，关闭蜂鸣器以及继电器还有关闭LED灯和数码管这些外设，不然会使得上电之后无关的外设同时工作影响正常的显示效果。