#include <reg52.h>

#include <intrins.h>

#define uint unsigned int

#define uchar unsigned char

sbit SPK = P3^7;

uchar FRQ = 0x00;

void Delayms(uint ms)

{

  uchar i;

while(ms--)

{

for(i=0;i<120;i++);

}

}

void main()

{

  P2 = 0x00;

TMOD = 0x11;//兩個16bit定時器全開

TH0 = 0x00;

TL0 = 0xff;

IT0 = 1;

IE = 0x8b;//10001011三個中斷被允許

IP = 0x01;//外部中斷0優(yōu)先級最高

TR0 = 0;

TR1 = 0;

while(1)

{

FRQ++;

Delayms(1);

}

}

void EX0_INT() interrupt 0

{

  TR0 = !TR0;

TR1 = !TR1;

if(P2 == 0x00)//當(dāng)前狀態(tài)決定了按鍵的作用

P2 = 0xe0;//同時亮3個

else 

P2 = 0x00;

}

void T0_INT() interrupt 1//響鈴

{

  TH0 = 0xfe;

TL0 = FRQ;//隨時間增加（中斷加快，頻率提高，聲調(diào)變高），之后溢出

SPK = ~SPK;

}

void T1_INT() interrupt 3//亮燈

{

  TH0 = -45000/256;

TL0 = -45000%256;

P2 = _crol_(P2,1);

}