51单片机的数码管和矩阵键盘

使用4*4的矩阵键盘和一个数码管

在4*4的矩阵键盘上编码0-F的字符，和一个数码管显示每个键盘上输入的字符。

//4*4键盘检测程序,按下键后相应的代码显示在数码管上
#include<reg51.h>
typedef unsigned char UINT8;
UINT8 i=100;
UINT8 j,k,temp,key;
void delay(unsigned char i)
{
  for(j=i;j>0;j--)
    for(k=125;k>0;k--);
}
UINT8 code table[]=
{
	0x3f,0x06,0x5b,0x4f,
	0x66,0x6d,0x7d,0x07,
	0x7f,0x6f,0x77,0x7c,
	0x39,0x5e,0x79,0x71
};

void display(unsigned char num)
{
     P0=table[num];
}

void init_led()
{
	P0 = 0x00;
}

void main()
{
	while(1)
	{
		P1 = 0xef;
		temp = P1;
		temp = temp&0xf0;
		if (temp != 0xf0)
		{
			temp = P1;
			switch(temp)
			{
				  case 0xee:
					   key=0;
					   break;
				  case 0xed:
					   key=1;
					   break;
				  case 0xeb:
					   key=2;
					   break;
				  case 0xe7:
					   key=3;
					   break;
				  default:
					  break;
			}
			display(key);
			P1=0xfe;
		}
		P1 = 0xdf;
		temp = P1;
		temp = temp&0x0f;
		if(temp != 0x0f)
		{
			temp = P1;
			switch(temp)
			{
				  case 0xde:
					   key = 4;
					   break;
				  case 0xdd:
					   key = 5;
					   break;
				  case 0xdb:
					   key = 6;
					   break;
				  case 0xd7:
					   key = 7;
					   break;
				  default:
					  break;
			 }
			 display(key);
		}
		P1=0xbf;
		temp=P1;
		temp=temp&0x0f;
		if(temp != 0x0f)
		{
			temp=P1;
			switch(temp)
			{
				  case 0xbe:
					   key=8;
					   break;

				  case 0xbd:
					   key=9;
					   break;

				  case 0xbb:
					   key=10;
					   break;

				  case 0xb7:
					   key=11;
					   break;
				  default:
					   break;
			}
			display(key);
		}
		P1=0x7f;
		temp=P1;
		temp=temp&0x0f;
		if(temp!=0x0f)
		{
			temp=P1;
			switch(temp)
			{
				  case 0x7e:
					   key=12;
					   break;

				  case 0x7d:
					   key=13;
					   break;

				  case 0x7b:
					   key=14;
					   break;

				  case 0x77:
					   key=15;
					   break;

				  default:
					  break;
			}
			display(key);
		}
	}
}

这个上面有一个bug就是每进入的时候数码管不是空的而是现实“0”这个没有解决。