#include<reg52.h>
#include<intrins.h>
#define uchar unsigned char
#define uint unsigned int
uchar aa;
void sleep(uchar z)
{
uint i=0,j=0;
for(i=z;i>0;i--)
{
for(j=110;j>0;j--)
{
}
}
}
void main()
{
aa=0xfe; //赋初值11111110(即十六进制0xfe)
while(1)
{
P1=aa;
sleep(500);
aa=_crol_(aa,1); //aa 循环左移一位再赋值给aa
}
}