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#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit bee=P2^3;
uchar flag;
uint a;
uint num,numt;
void init()
{
bee=0;
TMOD=0x21;
TH0=(65536-2000)/256;
TL0=(65536-2000)%256;
TH1=0xfd;
TL1=0xfd;
TR1=1;
SM0=0;
SM1=1;
REN=1;
EA=1;
ES=1;
ET0=1;
bee=0;
flag=0;
}
void main()
{
init();
while(1)
{
if(flag==1)
{
ES=0;
switch (a)
{
case 1:
num=100;
TR0=1;
break;
case 2:
num=50;
TR0=1;
break;
case 3:
num=25;
TR0=1;
break;
case 4:
TR0=0;
bee=0;
break;
default:
break;
}
ES=1;
flag=0;
}
}
}
void ser()interrupt 4
{
RI=0;
a=SBUF;
flag=1;
}
void time()interrupt 1
{
TH0=(65536-2000)/256;
TL0=(65536-2000)%256;
numt++;
if(numt>=num)
{
numt=0;
bee=~bee;
}
}
這樣可以的。 |
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