/*******************************************************************************

*  描述: C語言 范例 騰龍倚天直接使用                                           *
*         小喇叭警報(bào)聲源程序 端口P3.3                                          *
*       																					          *
*                                                                              *
*                                                                              *
********************************************************************************
*  51測(cè)試網(wǎng)論壇例程              51測(cè)試網(wǎng)版權(quán)所有轉(zhuǎn)載注明版權(quán)連接WWW.8951.COM  *
*******************************************************************************/



#include <reg51.h>
#include <intrins.h>

sbit	SPK = P3^3;

unsigned char frq; 

void delayms(unsigned char ms);

main()
{
	TMOD = 0x01;
	frq = 0x00;
	TH0 = 0x00;
	TL0 = 0xff;	
	TR0 = 1;
	IE = 0x82;
	
	while(1)
	{
		frq++;
		delayms(1);
	}
}

void timer0() interrupt 1 using 1
{
	TH0 = 0xfe;
	TL0 = frq;
	SPK = ~SPK;	
}

void delayms(unsigned char ms)	
// 延時(shí)子程序
{						
	unsigned char i;
	while(ms--)
	{
		for(i = 0; i < 120; i++);
	}
}