/* 6位数码管演示程序:   显示数码从0---99循环,按 P3.2 按键,显示从"0" 开始*/

#include <reg52.h>      

int count1s;        
unsigned int count1m;
unsigned char   dis_bitcount=0;
unsigned char   display_o[6];    
unsigned char   display_q[6];    

unsigned char code   SEG[11]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0xff};
unsigned char dis_bitdriver=0;

void delay5ms()
{
  register int i;
  for (i=0;i<500;i++)
  ;
}

main()
{
  unsigned char dcode;
  unsigned char p2code,p3code;
  count1m=0;
  count1s=0;
  while(1)
  {

   switch(dis_bitcount+1)
  {
   case 1:dis_bitdriver=0x01;   break;/*display 1*/
   case 2:dis_bitdriver=0x02;   break;/*display 2*/
   case 3:dis_bitdriver=0x04;   break;/*display 3*/
   case 4:dis_bitdriver=0x08;   break;/*display 4*/
   case 5:dis_bitdriver=0x10;   break;/*display 5*/
   default:dis_bitdriver=0x20; break;/*display 6 */
  
  }
  p2code=P2;
  P2=p2code&0x40;
  dcode=SEG[display_q[dis_bitcount]];
  P0=SEG[display_q[dis_bitcount]];  
  P2=(p2code&0x40)|dis_bitdriver;
  if(dis_bitcount>=5) dis_bitcount=0;
  else dis_bitcount++;
  
  
  count1s++;
  if(count1s>=400)    
  {
   count1m++;
   count1s=0;
  }
  p3code=P3&0x04;
  
  if(count1m>99) count1m=0;
  if(p3code==0) count1m=0;

  display_o[1]=count1m/10;
  display_o[0]=count1m-display_o[1]*10;
  display_q[1]=display_o[1];  
  display_q[0]=display_o[0];
  
  delay5ms();
  

  }
  
}
6位LED显示接口说明：
  
  P0.0---P0.7   通过7406 驱动LED的8个段；
  P2.0---P2.5   通过UN2003驱动6个LED 的公共端