p10_2.c

单片机原理与应用实例教程 单片机原理与应用实例教程

#include "REG51.H"

void Delay()
{
	int i,j,k;
	for( i = 0; i < 5; i ++ )
	{
		for( j = 0; j < 0x82; j ++ )
		{
			for( k = 0; k < 0xff; k ++ )
			{
			}
		}
	}
}

sbit P3_3 = P3^3;
main()
{
	unsigned char xdata* pXRAM = 0x00;
	unsigned char m, i, j;
	pXRAM[0x1200]	= 0x55;
	while(1)
	{
		m 		= pXRAM[0x1200];
		i		= m >> 7;
		j		= m << 1;
		m		= i | j;
		P3_3  	= m & 0x01;
		Delay();
		pXRAM[0x1200] = m;
	}
}