单片机缓冲区串口读写代码   单片机通讯应用，可以读写内部缓冲区中的数据，协议如下：   1.       读数据 表1  读Len个字节数据指令格式 指令格式： 地址 读命令 01 读取数据的长度 Len 接收缓冲区的起始地址 （00，01，…） 接收Len个数据 XX，XX，… 举例： 01 01 03 05 23，44，37 说明：可在MCU内部定义一数组out_data[k]，存放要发送出去的数据。       则对于该例，读取的数据为out_data[05]，out_data[06]，out_data[07]，值依次为：23,44,37。 2.       写数据 表2  写Len个字节数据指令格式 指令格式： 地址 写命令 00 写出数据的长度 Len 发送缓冲区的起始地址 （00，01，…） 写出Len个数据 XX，XX，… 举例： 01 00 04 01 10，21，32, 56 说明：可在MCU内部定义一数组in_data[k]，存放要接收的数据。则对于该例，数据为：       in_data[01]，in_data[02]，in_data[03]，in_data[04]，值依次为：10，21，32, 56。   //--------------------------------------------------------------------------------------------------------- //     串行通讯代码//start // //--------------------------------------------------------------------------------------------------------- ////////////////////////////   RS232串行通信相关函数///////////////////////////////////////////   //       uchar out_data[16]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16};         //待发送的数据 //       uchar in_data[16];                                                   //接收数据缓冲区 /*******************************************************************/ /*                                                                                                                                                     */ /* 等待发送完毕                                                                                */ /*                                                                                                                                                      */ /*******************************************************************/ void send_wait() {          while(!TI);          TI = 0; } /*******************************************************************/ /*                                                                                                                                                      */ /* 等待接收完毕                                                                                */ /*                                                                                                                                                      */ /*                                                                                                                                                      */ /*******************************************************************/ void receive_wait() {          while(!RI);          RI = 0; } /*******************************************************************/ /*                                                                                                                                                      */ /* 串口初始化 ，11.0592M，波特率9600b/s,方式3                                                  */ /*                                                                                                                                                      */ /*                                                                                                                                                      */ /*******************************************************************/ void init_serial() { /*  数据格式：     1,8,1（1个起始位，8个数据位，1个停止位 ）   */     SCON = 0X50;                   //方式3,SM2＝0，REN = 1     TMOD = 0X20;            //T1工作于方式2     TH1 = 0XFD;                    //装入初值     TL1 = 0XFD;     PCON &=0x7F;     ET1=0;              //禁止定时器T1中断，因为T1用作波特率发生器     ES = 1;                            //串口开中断     EA = 1;                 //全局开中断     TR1 = 1;                           //启动T1 } /*******************************************************************/ /*                                                                                                                                                      */ /* 串行中断处理函数                                                                                                                */ /*                                                                                                                                                      */ /*                                                                                                                                                      */ /*******************************************************************/ void serial_int() interrupt 4 using 1 {          uchar command;        //接收字节命令          uchar rcv_length; //待接收的字节长度          uchar snd_length; //要发送的字节长度          uchar rcv_start_addr; //接收数据缓冲区起始地址          uchar snd_start_addr; //发送数据缓冲区起始地址          uchar i;           if(RI)      //接收中断          {        RI = 0;                    if(SBUF!=1)                    //判断第一字节是否本机地址（1）                             return ;                    SM2 = 0;                    receive_wait();                    command = SBUF;                    switch(command)                    {                             case 0:                        //判断第2字节是否为PC写命令（00），若是则接收来自PC机的数据                                      receive_wait();                                      rcv_length = SBUF; //待接收的字节长度                                      receive_wait();                                      rcv_start_addr = SBUF; //接收缓冲区的起始地址(0,1,2....,14,15)                                      for(i=0; i           //循环接收rcv_length个数据                                      {                                                receive_wait();                                                in_data[rcv_start_addr] = SBUF;  //将接收的数据依次存放入接缓冲区（in_data[16]）中                                                rcv_start_addr ++;                                               if(rcv_start_addr>15)                                                         break;                                      }                                      break;                             case 1:                            //判断第2字节是否为PC机读命令（01）,若是则发送数据给PC机                                      receive_wait();                                      snd_length = SBUF; //要读取的字节长度                                      receive_wait();                                      snd_start_addr = SBUF; //发送缓冲区的起始地址(0,1,2....,14,15)                                      for(i=0; i          //循环接收rcv_length个数据                                      {                                                SBUF = out_data[snd_start_addr];  //将发送缓冲区（out_data[15]）中请求的数据依次发送出去                                                snd_start_addr ++;                                                send_wait();                                                if(snd_start_addr>15)                                                         break;                                      }                                             break;                             default:                  //若是非法命令，则返回                                      return ;                                      break;                    }                 }          else        //发送中断          {          } } //--------------------------------------------------------------------------------------------------------- //     串行通讯代码//end //