led.c

本例通过2 2矩阵键盘对矩阵键盘的原理说明

#include<reg51.h>
#define uchar unsigned char
#define uint unsigned int

sbit P10=P1^0;
sbit P11=P1^1;
sbit P16=P1^6;
sbit P17=P1^7;

sbit P20=P2^0;
sbit P21=P2^1;

uchar count;

uchar button(uchar temp)
{   
   if(temp==3||temp==2)
     {  P10=0;P11=0;
	   if(P16==0&&P17==1)
	     return 2;
	   if(P16==1&&P17==0)
	     return 3;
	 }
   if(temp==4||temp==1)
     {  P10=0;P11=1;
	    if(P16==0&&P17==0)
		  return 1;
		 if(P16==1&&P17==1)
		 return 4;
	 }
	else 
	 return 0;
    
}





void main()
{
 
  TMOD=0x01;
  EA=1;
  ET0=1;
  TH0=(65536-50000)/256;
  TL0=(65536-50000)%256;
  TR0=1;

  while(1)
  {
      P20=1;
    P21=1;
	count=0;
    while(2==button(2))
	  {P20=0;P21=1;}
    while(1==button(1))
	  { 
        if(count==20) {P20=!P20;count=0;}
	  }

	while(3==button(3))
	  {
	    if(count==40) {P21=!P21;count=0;}
	  }
	
	
  }
}

void time_0() interrupt 1
{
  TH0=(65536-50000)/256;
  TL0=(65536-50000)%256;
  count++;
}