p16_1.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"

bit tab = 1;

void Delay()
{
	unsigned char i, j;
	for( i = 0; i < 0xff; i++ )
	{
		for( j = 0; j < 0xff; j++ )
		{
		}
	}
}

void INT_0(void) interrupt 0
{
	EX0 = 0;
	Delay();
	tab = !tab;
	EX0 = 1;
}

main()
{
	unsigned char m = 0x33;
	unsigned char i, j;
	EX0		= 1;
	IT0		= 1;
	EA	 	= 1;
	while(1)
	{
		P0 = m;
		Delay();
		if( tab == 1 )
		{
			i = m << 1;
			j = m >> 7;
			m = i | j;
		}
		else
		{
			i = m >> 1;
			j = m << 7;
			m = i | j;
		}
	}
}