#include <reg52.h>
#define uint unsigned int
#define uchar unsigned char
sfr WDT_CONTR=0xe1;
sbit beep=P2^2;
sbit P24=P2^4;
sbit P26=P2^6;
sbit P27=P2^7;
uchar flag;
void delay()
{
uint i;
uint j;
for(i=0;i<780;i++)
for(j=0;j<160;j++);
}
void main()
{
IT0=0;
EX0=1;
EA=1;
P24=0;
delay();
P26=0;
P27=0;
while(1)
{
WDT_CONTR=0x2f;
if(!flag)//high powter
{
EA=0;
beep=0;
delay();
beep=1;
delay();
EA=1;
}
else//low powter
{
flag=0;
beep=1;
}
}
}
void int0_srv() interrupt 0
{
flag=1;
}