#include <REG52.h>
typedef unsigned char BYTE;
void Sleep(int iCount);
void Main()
{
    BYTE CH=0x7F;
    P2=0x80;    
    while(1)
    {
        P0=CH;
        CH=CH>>1|0x80;
        if(CH==0xff)
            CH=0x7F;
        Sleep(20000);
    }
}
void Sleep(int iCount)
{
    while(--iCount);
}