环形 缓冲区《转自数码之家》

1.环形缓冲区，命令不容易丢失
2.缓冲区大小可自定义
3.移植改写方便
看代码：
//宏定义

//系统可修改参数宏定义
#define BUFFER_SIEZ 64
//控制命令定义
#define COMMUNCIATE 0
#define SET_SYSTEM_CAL_FULL 1
#define SET_SYSTEM_CAL_MV_V 2
#define SET_SYSTEM_OL 3
#define SET_POWER_OFF_TIME 4 //设定系统关机时间
#define READ_SYSTEM_DATA 5

//变量定义
//串口缓冲区 建立一个环形缓冲区，收发
unsigned char xdata UART_Receive_Size=0;//串口缓冲区接收字节数
unsigned char xdata UART_Receive_First=0;//串口缓冲区接收字节开始位置
unsigned char xdata UART_Read_First=0;
unsigned char xdata UART_Buffer[BUFFER_SIEZ];//串口缓冲区
unsigned char xdata UART_Send_Byte_Ok=0;//发送一字节成功
//中断处理
串口初始化根据自己的单片机写就行
void UART0_Interrupt (void) interrupt 4  
{
   if(RI0)                         //如果是发中断,返回
   {  
     RI0=0;  //清除中断标志
     if(UART_Receive_Size<=BUFFER_SIEZ)//缓冲区未满，装载数据
     {
       UART_Buffer[UART_Receive_First++]=SBUF0;
       UART_Receive_Size++;//串口缓冲区接收字节数
       if(UART_Receive_First>=BUFFER_SIEZ)//循环装入缓冲区
         UART_Receive_First = 0;
     }
   }
  if(TI0)
  {          
    TI0=0;
   UART_Send_Byte_Ok=1;
  }
}

//在缓冲区中读取一帧数据
void Do_Commend()
{
  unsigned char Buf[8]={0,0,0,0,0,0,0,0};//帧数据缓冲区
  unsigned char i=0;
  unsigned char data_packge_flag=0;
  
  if(UART_Receive_Size>=8)//缓冲区字节数大于等于一个包字节数
  {
    while(UART_Receive_Size!=0)//寻找帧数据头
    {
         if(UART_Buffer[UART_Read_First]==0xaa)
         {
           if(UART_Read_First+7<BUFFER_SIEZ)
           {
              if(UART_Buffer[UART_Read_First+7]==0x55)
              {
               data_packge_flag=1;
               break;
              }
           }
           else
           {
              if(UART_Buffer[7-(BUFFER_SIEZ-UART_Read_First)]==0x55)
              data_packge_flag=1;
              break;
           }
         }
         UART_Read_First++;
         if(UART_Read_First>=BUFFER_SIEZ)//环形 缓冲区折行
         UART_Read_First=0;
         UART_Receive_Size--;
    }
    if(data_packge_flag==1)//寻找到枕头
    {
       for(i=0;i<8;i++)//读取帧数据
       {
          Buf=UART_Buffer[UART_Read_First];
          UART_Receive_Size--;
          UART_Read_First++;
          if(UART_Read_First>=BUFFER_SIEZ)//环形 缓冲区折行
            UART_Read_First=0;
       }
       data_packge_flag=0;
    }
    if(Buf[7]==0x55&&Buf[0]==0xaa)  //接收到一个正确的数据包
    {
          switch(Buf[1])
          {
            case COMMUNCIATE :UART0_Send_String(Buf,8);
            break;
            case SET_SYSTEM_CAL_FULL :System_Senser_Full=(Buf[2]|0x0000)<<8|Buf[3]; System_Zero_Display_Data=(Buf[4]|0x0000)<<8|Buf[5]; UART0_Send_String(Buf,8);save_data=1;System_K_Cal_Full();//在系统标定
            break;
            case SET_SYSTEM_OL :System_UPOL=(Buf[2]|0x0000)<<8|Buf[3];System_DWOL= (Buf[4]|0x0000)<<8|Buf[5];UART0_Send_String(Buf,8);save_data=1;//设 定系统上限报警值
            break;
            case SET_SYSTEM_CAL_MV_V :System_Senser_mv_v=(Buf[2]|0x0000)<<8|Buf[3]; System_Zero_Cal=ADC_Senser_Data_Buf;System_Zero=System_Zero_Cal; UART0_Send_String(Buf,8);save_data=1;System_K_Cal_mv_v();//电子标定
            break;
            case SET_POWER_OFF_TIME : System_Power_OFF_Time=(Buf[2]|0x0000)<<8|Buf[3]; UART0_Send_String(Buf,8);save_data=1;//设定系统自动关机时间
            break;
            case READ_SYSTEM_DATA : Buf[1]=READ_SYSTEM_DATA;Buf[3]=ADC_Senser_Data_Buf; Buf[2]=ADC_Senser_Data_Buf>>8;Buf[5]=ADC_Power_Voltage; Buf[4]=ADC_Power_Voltage>>8;UART0_Send_String(Buf,8);//获取传感器信号ADC值
                                    Buf[1]=SET_SYSTEM_CAL_FULL; Buf[3]=System_Senser_Full;Buf[2]=System_Senser_Full>>8; Buf[5]=System_Zero_Display_Data;Buf[4]=System_Zero_Display_Data>> 8;UART0_Send_String(Buf,8);//返回正确的数据包;//获取系统保存参数
                                    Buf[1]=SET_SYSTEM_OL;Buf[3]=System_UPOL;Buf[2]=System_UPOL>>8;Buf[5]=System_DWOL;Buf[4]=System_DWOL>>8;UART0_Send_String(Buf,8);
                                    Buf[1]=SET_SYSTEM_CAL_MV_V ;Buf[3]=System_Senser_mv_v;Buf[2]=System_Senser_mv_v>>8;Buf[5]=System_Zero;Buf[4]=System_Zero>>8;UART0_Send_String(Buf,8);
                                    Buf[1]=SET_POWER_OFF_TIME;Buf[2]=System_Power_OFF_Time;Buf[3]=System_Power_OFF_Time>>8;UART0_Send_String(Buf,8);
            break;
            default:save_data=0;//不保存数据
            break;
          }      
     }    
  }
}