a09.c

由8051组成的单片机系统通常情况下

//	“验证式”	实验九  P1口输入输出实验

//#include <reg51.h>

sfr P1=0x90;
//sbit KeyRight = P1^3;

//sbit LEDRight = P1^2;

void main()
{
 P1=0xff;
 while (1)
 {
  P1=P1<<4;
  P1=P1|0x0f;
 }
}