key.c

52单片机开发板的实例程序

#include<reg52.h>
#define uint unsigned int
#define uchar unsigned char 
sbit a=P1^0;
sbit b=P1^1;
sbit c=P1^2;
const uchar table[]={
          0x3f,0x06,0x5b,0x4f,0x66,
          0x6d,0x7d,0x07,0x7f,0x6f};
void delay(uint k)
{
  uint i;
  for(;k>0;k--)
  for(i=110;i>0;i--);
}
void HC138(uchar i)
{
  a=i&0x01;
  b=i&0x02;
  c=i&0x04;
}
void display(uchar num)
{
   uchar ge,shi;
   shi=num/10;
   ge=num%10;
   HC138(0);
   P2=table[ge];
   delay(3);
   HC138(1);
   P2=table[shi];
   delay(3);   
}
uchar keyscan()
{
    uchar num,temp;
	P0=0xfe;
	temp=P0;
	temp=temp&0xf0;
	if(temp!=0xf0)
		{
			delay(5);
			temp=P0;
			temp=temp&0xf0;
			while(temp!=0xf0)
				{
					temp=P0;
					switch(temp)
					{
						case 0xee:num=0;break;
						case 0xde:num=1;break;
						case 0xbe:num=2;break;
						case 0x7e:num=3;break;
					}
					while(P0!=0xf0)
						P0&=0xf0;				
				}
		}
	P0=0xfd;
	temp=P0;
	temp=temp&0xf0;
	if(temp!=0xf0)
		{
			delay(5);
			temp=P0;
			temp=temp&0xf0;
			while(temp!=0xf0)
				{
					temp=P0;
					switch(temp)
					{
						case 0xed:num=4;break;
						case 0xdd:num=5;break;
						case 0xbd:num=6;break;
						case 0x7d:num=7;break;
					}
					while(P0!=0xf0)
						P0&=0xf0;				
				}
		}
	P0=0xfb;
	temp=P0;
	temp=temp&0xf0;
	if(temp!=0xf0)
		{
			delay(5);
			temp=P0;
			temp=temp&0xf0;
			while(temp!=0xf0)
				{
					temp=P0;
					switch(temp)
					{
						case 0xeb:num=8;break;
						case 0xdb:num=9;break;
						case 0xbb:num=10;break;
						case 0x7b:num=11;break;
					}
					while(P0!=0xf0)
						P0&=0xf0;				
				}
		}
	P0=0xf7;
	temp=P0;
	temp=temp&0xf0;
	if(temp!=0xf0)
		{
			delay(5);
			temp=P0;
			temp=temp&0xf0;
			while(temp!=0xf0)
				{
					temp=P0;
					switch(temp)
					{
						case 0xe7:num=12;break;
						case 0xd7:num=13;break;
						case 0xb7:num=14;break;
						case 0x77:num=15;break;
					}
					while(P0!=0xf0)				
                        P0&=0xf0;
				}
		}
return num;
}
void main()
{
   uchar key=0;
   while(1)
   { 
    key=keyscan();
    display(key);
   }
}