#include <reg51.h>


void delay(unsigned int t);

unsigned char buffer;
sbit PB = P3^2;     //設定PB代表P3.2

void main(void)
{
  buffer = 0;     //設定buffer初值為0
  while(1)
   {  
      while(PB == 0)       //檢查PB是否為0
       {
         delay(3);          //延遲, 判斷是否為彈跳訊號
         if (PB == 0)         //如果PB仍然為0, 則
           {
            buffer++;         //buffer內的值加1
            P2 = ~buffer;   //將buffer內的值反向送到P2顯示
           }
         while(PB == 0);     //如果PB仍然為0, 則停在此行，直到放開
       }
   }
}


void delay(unsigned int t)
{
   unsigned int i;
   while(t--)
     {
      i=10000;
      while(i--);
     }
}