#include

#define uchar unsigned char

sbit LED=P1^0;

uchar time;

void initT0( )

{

TMOD = 0x01; //定時器0，工作方式1

TH0 = (65536-50000)/256;

TL0 = (65536-50000)%256; //50ms中斷一次

EA = 1;

ET0 = 1;

TR0 = 1;

}

void main(void)

{

initT0();

while(1)

if(time==20) //中斷20次，1s

{

time=0;

LED=！LED; //P1.0上的LED，1s亮或滅一次

}

}

void T0int( ) interrupt 1

{

TH0 = (65536-65536)/256;

TL0 = (65536-65536)%256;

time++;

}