p8_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"

unsigned char tag = 0;
unsigned char count = 0;

void  INT_T0(void) interrupt 1
{
	count ++;
	if( count >= 20 )
	{
		count = 0;
		tag += 2;
		if( tag >= 16 )
		{
			tag = 0;
		}
	}
	TH0	= 0xd8;
	TL0 = 0xf0;
} 

main()
{
	TMOD = 0x01;
	TH0	= 0xd8;
	TL0 = 0xf0;
	EA	= 1;
	ET0	= 1;
	TR0	= 1;
	while(1)
	{
		switch( tag )
		{
		case 0:
			P1 = 0x5f;
			break;
		case 2:
			P1 = 0xaf;
			break;
		case 4:
			P1 = 0xf5;
			break;
		case 6:
			P1 = 0xfa;
			break;
		case 8:
			P1 = 0x55;
			break;
		case 10:
			P1 = 0xaa;
			break;
		case 12:
			P1 = 0x00;
			break;
		case 14:
			P1 = 0xff;
			break;
		}
	}
}