最近做项目用需要用到两个串口，分别是串口1和串口2，

串口1接调试，传感器等，串口2对接蓝牙与APP通讯

芯片型号：STC8H3K64S4

#include "stc8h.h"
#define S2RI 0x01        //串口2接收中断请求标志位
#define S2TI 0x02        //串口2发送中断请求标志位
 
char flag = 0;
unsigned char UART2_ReceiveBuffer[10]={0};
void Uart2_Init(void)		//9600bps@22.1184MHz
{
	S2CON = 0x50;		//8位数据,可变波特率
	AUXR |= 0x04;		//定时器2时钟为Fosc,即1T
	T2L = 0xC0;			//设定定时初值
	T2H = 0xFD;			//设定定时初值
	AUXR |= 0x10;		//启动定时器2
	EA = 1;
	IE2 = 0X01;        //打开接收中断
}


void UART2_SendByte(unsigned char mydata)
{
    IE2 = 0X00;
	S2CON&=~S2TI; //TI = 1
    S2BUF=mydata;
    while((S2CON&S2TI)==0);
	S2CON&=~S2TI; //TI = 1//清除发送标志位
    IE2 = 0X01;
}

void Uart2_SendString(unsigned char *p)   //串口2发送一个字符串
{
    while(*p!='\0')
    {
        UART2_SendByte(*p);
        p++;
    }
}
void Uart2_InterruptService(void) interrupt 8
{
	unsigned char temp;
	static char i = 0;
    if(S2CON&S2RI)		//RI == 0
    {
		flag = 1;
        S2CON&=~S2RI;	//RI = 1
        temp = S2BUF;
		UART2_ReceiveBuffer[i] = temp;
		if(i == 10)
		{
			i=0;
		}else{
			i++;
		}
    }
}
void main()
{
	Uart2_Init();
	Uart2_SendString("start\n");
	while(1)
	{
		if(flag == 1)
		{
			IE2  &= ~S2RI; 
			S2BUF = temp;
			while(!(S2CON&S2TI));
			S2CON&=~S2TI;
			IE2  |= S2RI; 
			flag = 0;
		}
	}
}

注意：

在用STC_60s2单片机进行双串口同时收发时，要注意一些容易配置错误的地方。

AUXR寄存器有很多功能。

在对其中的位置位和复位时，很可能在不同的地方多次进行，应该使用 AUXR |= bitx 和 AUXR &=~bitx 语句进行对某一位的置位和复位。

这样就不会影响其他功能位了。
附上程序： 

#include <STC12C5A60S2.h>
//sfr AUXR = 0x8E;
#define uchar unsigned char//
#define uint unsigned int //
#define BUADRATE 38400
#define FOSC 24000000
#define S2RI 0x01
#define S2TI 0x02
sbit LED1 = P2^7;
uchar ReceBuf[200]= {0};
bit finishflag = 0;
uchar revcnt = 0;
uchar startflag = 0;
void InitUART1(void) //baudrate 115200
{
    TMOD = 0x20;
    SCON = 0x50;
    TH1 = 0xf3; //115384
    TL1 = TH1;
    PCON = 0x80; //SMOD = 1;
    ES = 1;
    TR1 = 1;
}
void InitUART2() //baudrate 38400
{
    S2CON = 0x50; //8-Bit 串口模式 允许接收
    BRT = 236; //[24000000/(256-236)]/32 = 37500 error2.34%
    AUXR |= 0x14; //BRTR=1使能BRT BRTx12=1 不分频 （AUXR 第二次出现，不能用‘=’应该用“|=”）
    IE2 = 0x01; //enable UART2 interrupt
    AUXR1 = 0; //UART2 TXD->P1.3 RXD->P1.2
}
void SendOneByte(unsigned char c)
{
    SBUF = c;
    while(!TI);
    TI = 0;
}
void U1SendString(uchar *dat)
{
    while(*(dat)!='\0')
    {
        SendOneByte(*dat);
        dat ;
    }
}
void U2SendOneByte(unsigned char c)
{
    S2BUF = c;
    while(!(S2CON & S2TI));
    S2CON &= ~S2TI;
}
void U2SendString(uchar *dat)
{
    while(*(dat)!='\0')
    {
        U2SendOneByte(*dat);
        dat ;
    }
}
void main()
{   uchar temp = 0x01;
    AUXR = AUXR|0x40; // T1, 1T Mode AUXR 第一次出现
    InitUART1();
    EA = 1;
    SendOneByte(0xaa);
    SendOneByte(0xbb);
    SendOneByte(0xcc);
    InitUART2();
    SendOneByte(0xdd);
    while(1)
    {   // temp = ~temp;
// U2SendOneByte(temp);
        if(finishflag)
        {   LED1 = 1;
            finishflag = 0;
            U1SendString(ReceBuf);
            LED1 = 0;
        }
    }
}
void UART1ISR(void) interrupt 4
{
    if(RI)
    {
        RI = 0;

    }
    else
        TI = 0;
}
void UART2ISR(void) interrupt 8
{   static bit flash=0;
    static uchar i=0;
    static uchar endcnt = 0;
    uchar tempdat = 0;
    if(S2CON & S2RI)
    {
        S2CON &= ~S2RI;
        if(~finishflag)
        {
            flash=~flash;
// LED1 = flash;
            tempdat = S2BUF;
            if(tempdat=='$')
            {
                startflag = 1;
            }

            if(startflag)
            {
                ReceBuf[i] = tempdat;
                i ;

                if(i==6&&ReceBuf[3]!='R'&&ReceBuf[5]!='C') //判断是不是$GPRMC帧
                {
                    startflag = 0;
                    i = 0;
                }
                else if(ReceBuf[i-1]=='*')
                {
                    endcnt ;
                    if(endcnt==2)
                    {
                        revcnt = i;
                        endcnt = 0;
                        i = 0;
                        finishflag = 1;
                        startflag = 0;
                    }
                }
                else ;
            }
        }
        else ;
    }
    else
        S2CON &= ~S2TI;
}