#include <reg51.h> 
 #include<stdio.h>
void  main()
{
      int  i=10;

	  SCON = 0x50; 
TMOD |= 0x20; 
TH1 = 0xf3; 
TR1 = 1;
TI = 1; 
do
{
          printf ( "%d ", i-- );
	      }
while  ( i>0 );                    //當i >0時跳轉，別忘記分號"；"
       printf ("\n we're out of the loop.\n" );
  }