#include  
unsigned char code taba[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f}; 
unsigned char code tabb[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80}; 
void delay(void)
 {     
      unsigned char i,j;    
        for(i=10;i>0;i--)    
     for(j=248;j>0;j--); 
 } 
void delay1(void) 
 {     
       unsigned char i,j,k;     
    for(k=10;k>0;k--)     
      for(i=20;i>0;i--)     
     for(j=248;j>0;j--); 
 } 
void main(void)
 {     
      unsigned char i,j;     
       while(1)     
    {         
      for(j=0;j<3;j++) //from left to right 3 time       
    {             
      for(i=0;i<8;i++)             
       {                 
      P0=taba[i];                
      P3=0xff;                 
    delay1();             
    }

          }        
     for(j=0;j<3;j++) //from right to left 3 time       
             {            
          for(i=0;i<8;i++)             
         {                
       P0=taba[7-i];
       P3=0xff;                
       delay1();            
       }        
       }        
           for(j=0;j<3;j++) //from top to bottom 3 time        
         {            
         for(i=0;i<8;i++)             
           {                 
        P0=0x00;                 
        P3=tabb[7-i];                 
        delay1();             
        }        
       }        
           for(j=0;j<3;j++) //from bottom to top 3 time       
         {             
           for(i=0;i<8;i++)             
         {                 P0=0x00; 
                           P3=tabb[i];                
               delay1();            
         }        
               }  
   }
 } 
  仿真原理图：