串口中断通讯

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
//uchar trdata[]={'B','i','g','B','i','g',0x0d,0x0a,0x00};
uchar  code trdata[]={'R','I','C','H','M','C','U',0x0d,0x0a,0x00};
sbit K1=P3^2;
void uart_init()
{
    SCON=0x50;
	PCON=0x80;
    TMOD=0x20;
    TH1=0xf3; //4800bps, fosc=12MHz
    TL1=0xf3;
    ES=1;
    TR1=1;
    EA=1;
}
void delay1ms(uint i)
{
    uchar j;
    while(i--)
    {
        for(j=0;j<115;j++);
    }
}
void uart_sendchar(uchar dat)
{
    SBUF=dat;
    while(!TI);
    TI=0;
}
void uart_sendstring()
{
    uchar i=0;
    while(trdata[i]!=0x00)
    {
        SBUF=trdata[i];
        while(!TI);
        TI=0;
        i++;
    }
}
void main()
{
    uart_init();
    while(1)
    {
        if(K1==0)
        {
            delay1ms(20);
            if(K1==0)
            {
                uart_sendstring();
                while(!K1);
            }
        }
    }
}
void int_uartrcv()interrupt 4
{
    uchar rcv=0;
    if(RI)
    {
        RI=0;
        rcv=SBUF;
        P2=SBUF;
        uart_sendchar(rcv);
    }
}