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#include <reg51.h>
sbit key=P1^0;
sbit LED=P1^1;
bit flag;
unsigned char num;
void InitTimer0(void)//50ms@12MHz
{
TMOD = 0x01;
TH0 = 0x3C;
TL0 = 0xB0;
EA = 1;
ET0 = 1;
TR0 = 1;
}
void main(void)
{
InitTimer0();
while(1)
{
if(!key)flag=1;
else flag=0;
}
}
void Timer0Interrupt(void) interrupt 1
{
TH0 = 0x3C;
TL0 = 0xB0;
if(flag)
{
num++;
if(num>=2)
{
num=0;
LED=~LED;//低電平亮,閃爍頻率5Hz
}
}
else
{
num=0;
LED=1;
}
}
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