p9_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"

main()
{
	TMOD 	= 0x20;
	TH1		= 0xe8;
	TL1		= 0xe8;
	PCON	= 0;
   	SCON	= 0x50;
	P1		= 0xff;
	TR1		= 1;
	ES		= 1;
	EX1		= 1;
	IT1		= 1;
	EA		= 1;
	while(1)
	{
	}
}
void  INT_1(void) interrupt 2
{
	SBUF = P1;
} 

void INT_TR(void) interrupt 4
{
	if( RI == 1 )
	{
		P1 = SBUF;
		RI = 0;
	}
	else
	{
		TI = 0;
	}
}