c51_modbus.c

可用于 51系列单片机与触摸屏之间的通讯 （一般用modbus实现通讯）

                                                          
                    i=CommBuf[2]+3;
                    for(CommIndex=3;CommIndex<i;CommIndex++)          // send data Reg to Master
                      CommBuf[CommIndex]=SlaveOutputBuf[CommIndex-3]; // hight 8 bit is first send
                    crc16tem=crc16(CommBuf,CommIndex);                // then send low 8 bit data
                    CommBuf[CommIndex++]=(uchar)(crc16tem & 0x00ff);  // send crccheck low 8 bit is front
                    CommBuf[CommIndex]=(uchar)(crc16tem>>8);          // then send hight 8 bit 
                    CommIndexEnd=CommIndex;
                    CommIndex=0;
                    SBUF=CommBuf[CommIndex++];
                    break;
                 case ForceSingleCoil://强制单线圈
                  //  SlaveInputBuf[0]=CommBuf[4];  // get data 0x00 or 0xff
                    if (CommBuf[4]==0xff)//????
                       LED0=0;
                      else
                         LED0=1;
                  //      LED0=!LED0;  
                    ForceCoilBuf[count]=CommBuf[4];
                    forceval=CommBuf[4];
                    count++;      
                    CommBuf[CommIndexSlaveID]=SlaveID;       // 0
                    CommBuf[CommIndexFunction]=ForceSingleCoil;    // 1
                    CommIndex=2;
                //    CommBuf[CommIndex++]=0x00;
                //    CommBuf[CommIndex++]=0x01;
                //   CommBuf[CommIndex++]=0x00;
                //    CommBuf[CommIndex++]=0xff;
                //    forcesendF=1;
                    CommBuf[CommIndex++]=CommBuf[CommIndexStartAdrHi]; // 2
                    CommBuf[CommIndex++]=CommBuf[CommIndexStartAdrLo]; // 3 
                    CommBuf[CommIndex++]=CommBuf[CommIndexNoPointHi];  // 4
                    CommBuf[CommIndex++]=CommBuf[CommIndexNoPointLo];  // 5
                    crc16tem=crc16(CommBuf,CommIndex);               // then send low 8 bit data
                    CommBuf[CommIndex++]=(uchar)(crc16tem & 0x00ff); // send crccheck low 8 bit is front
                    CommBuf[CommIndex]=(uchar)(crc16tem>>8);         // then send hight 8 bit
                    CommIndexEnd=CommIndex; 
                    CommIndex=0;
                    SBUF=CommBuf[CommIndex++];                   
                    break;                                        
                 case ReadHoldReg:
                    CommBuf[CommIndexSlaveID]=SlaveID;         // 0
                    CommBuf[CommIndexFunction]=ReadHoldReg;    // 1
                    CommBuf[2]=CommBuf[CommIndexNoPointLo]*2;  // 2 Byte Count
                    
                    for (i=0;i<MaxRegLen;i++)  // sim inputval for test
                    SlaveOutputBuf[i]=SlaveAdr;  
                                                          
                    i=CommBuf[2]+3;
                    for(CommIndex=3;CommIndex<i;CommIndex++)       // send data Reg to Master
                      CommBuf[CommIndex]=SlaveOutputBuf[CommIndex-3]; // hight 8 bit is first send
                    crc16tem=crc16(CommBuf,CommIndex);             // then send low 8 bit data
                    CommBuf[CommIndex++]=(uchar)(crc16tem & 0x00ff); // send crccheck low 8 bit is front
                    CommBuf[CommIndex]=(uchar)(crc16tem>>8);         // then send hight 8 bit 
                    CommIndexEnd=CommIndex;
                    CommIndex=0;
                    SBUF=CommBuf[CommIndex++];
                    break;
                 case PresetMulReg:
                    j=CommBuf[CommIndexNoPointLo]*2;
                    for (i=0;i<j;i++)
                      SlaveOutputBuf[0]=CommBuf[i+7];  // get data that master send start 7th byte ????
                    CommBuf[CommIndexSlaveID]=SlaveID;       // 0
                    CommBuf[CommIndexFunction]=PresetMulReg;    // 1
                    CommIndex=2;
                    CommBuf[CommIndex++]=CommBuf[CommIndexStartAdrHi]; // 2
                    CommBuf[CommIndex++]=CommBuf[CommIndexStartAdrLo]; // 3 
                    CommBuf[CommIndex++]=CommBuf[CommIndexNoPointHi];  // 4
                    CommBuf[CommIndex++]=CommBuf[CommIndexNoPointLo];  // 5
                    crc16tem=crc16(CommBuf,CommIndex);               // then send low 8 bit data
                    CommBuf[CommIndex++]=(uchar)(crc16tem & 0x00ff); // send crccheck low 8 bit is front
                    CommBuf[CommIndex]=(uchar)(crc16tem>>8);         // then send hight 8 bit
                    CommIndexEnd=CommIndex; 
                    CommIndex=0;
                    SBUF=CommBuf[CommIndex++];                   
                    break;
                 default:
                    for (i=0;i<=80;i++)  // delay // error recieve again 
                      _nop_();
                    CommIndex=0;
                    T0=RECIEVE;
                    break;
              }
          }
         else
           {
              for (i=0;i<=80;i++)  // delay
                 _nop_();
              CommIndex=0;
              T0=RECIEVE;           
           } 
     }
}

/*------------- intr code is following ----------------*/

void slavecomm(void) interrupt 4 using 2
{
  uint i;
  ES=0;
  if(TI)//发送中断标志
   { 
     TI=0;
     if (CommIndex<=CommIndexEnd)
       {
          SBUF=CommBuf[CommIndex++];
       }
      else
        {
   //        if (forcesendF)
    //         _nop_();
           for (i=0;i<=SendRecieveDelay;i++)  // delay
             _nop_();
           CommIndex=0;
           T0=RECIEVE;
        }
   }
  if(RI)
   {
     RI=0;
     if (CommIndex<CommIndexEnd)  //  CommIndex less than recieve lenght
       {
         CommBuf[CommIndex]=SBUF;
         if (CommIndex==CommIndexFunction)
           {
              switch (CommBuf[CommIndexFunction])
                  {
                    case ReadCoilSta:
                           CommIndexEnd=ReadCoilStaIndexEnd;
                           break;
                    case ForceSingleCoil:
                           CommIndexEnd=ForceSingleCoilIndexEnd;
                           break;
                    case ReadHoldReg:
                           CommIndexEnd=ReadHoldRegIndexEnd;    
                           break;
                    case PresetMulReg:
                           CommIndexEnd=6+CommBuf[CommIndexNoPointLo]*2+2;
                           break;
                    default:
                           break;
                  }
           }
         CommIndex++;
       }
      else  // recieve finished  CommIndex==CommIndexEnd
        {
           CommBuf[CommIndexEnd]=SBUF;
           RecFinishF=1;
           for (i=0;i<=SendRecieveDelay;i++)  // delay
             _nop_();
           T0=SEND;  
        }              
   } 
  ES=1;//串口中断允许
} 


/*------------------ main code following -----------------*/


void main(void)
{
   uint data i;
   init();
   while(1)
     {
      //   LED0=!LED0;
        for(i=0;i<=9;i++)
          _nop_();
        if (RecFinishF)
           {
              AnalyzeRecieve();
              RecFinishF=0;
           }

     }
}