跑马灯.c

51单片机开发板提供的参考程序

  
/*copyright 2007,ShangHai  HaoTun Electronic Technology co.,Ltd
 *
 *This sample is used for led  .
 *
 *write by Shifang 2007-4-23
 *
 *V1.1
 */

#include <reg52.h>
////////////////////////////////////////////////////////
void delay(unsigned int cnt) //简单的延时
{
 while(--cnt);
}
///////////////////////////////////////////////////////
main()
{
 P1=0xfe;//给初始化值
 while(1)
      {
	   delay(30000);//delay at crystal frequency in 12MHz
	   P1<<=1;//左移一位
	   P1|=0x01;//最后一位补1
	   if(P1==0x7f)//检测是否移到最左端？
          { 
		     delay(30000);//delay
	         P1=0xfe;
          }
      }
}