程序：

#include
bit point=1; //標志位
unsigned char temp;
unsigned char i;

//---------------------------------------------------------
void init() //串口初始化
{
TMOD=0x20;
SCON=0x50;
TH1=0xfD;
TR1=1;
ES=1;
EA=1;
}

//-------------------------------------------------------------------------------
void send()
{
SBUF=temp;
while(TI==0);
TI=0;

}

//----------------------------------------------------------------------------------
void UART ()interrupt 4 //串口通訊中斷
{
if(RI==1)
{
RI=0;
temp=SBUF;
point=1;
for(i=0;i<10;i++);
}
}

//-------------------------------------------------------------------------------------
void main()
{
temp=0x00;
init();
while(1)
{
if(point==1)
{
point=0;
send();
}
}
}