用了中断，就别再用查询法
#include
unsigned char c，flag;
void send(unsigned char b);
int main()
{
TMOD=0x20;
TH1=TL1=0xfd;
PCON=0x00;
SCON=0x50;
EA=1;
ES=1;
TR1=1;
while(1)
{
if(flag==1)
{send(c);
flag=0;
}
void chuan() interrupt 4
{
if(RI==1)
{
RI=0;
c=SBUF;
flag=1;
}
}
void send(unsigned char b)
{ES=0;
SBUF=b;
while(!TI);
TI=0;
ES=1;
}
