while(key2==0);
mode=mode+1;
if(mode==20)
{

mode=0;

}

}

}
if(key3==0)
{

delay1ms();
if(key3==0)
{

while(key3==0);
mode=mode-1;
if(mode<0)
{

mode=20;

}

}

}
if(key4==0)
{

delay1ms();
if(key4==0)
{

while(key4==0);
stop=~stop;

}

}

}
/**************************************************************/
/****************主函数****************************************/
void main(void)
{

TMOD=0x10;
TH1=(65536-mode*100)/256;
TL1=(65536-mode*100)%256;
TR1=1;
PX0=1;
EX0=1;
ET1=1;
EA=1;
P1=0xff;