modbus.c

这是基本的485通讯实例希望对大家有用。C语言编写用户可根据自己的情况修改相应的传输速率。

#include <main.h>
#define uint unsigned int
//字地址 0 - 255 (只取低8位)
//位地址 0 - 255 (只取低8位)

/* CRC 高位字节值表 */
const uint8 code auchCRCHi[]={
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
} ;
/* CRC低位字节值表*/
const uint8 code auchCRCLo[] = {
0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
0x43, 0x83, 0x41, 0x81, 0x80, 0x40
} ;

uint8   testCoil;  //用于测试 位地址1
uint16  testRegister; //用于测试 字址址16

uint8 localAddr = 1; //单片机控制板的地址
uint8 sendCount;  //发送字节个数
uint8 receCount;     //接收到的字节个数
uint8 sendPosi;     //发送位置

uint16 crc16(uint8 *puchMsg, uint16 usDataLen)
{
 uint8 uchCRCHi = 0xFF ; /* 高CRC字节初始化 */
 uint8 uchCRCLo = 0xFF ; /* 低CRC 字节初始化 */
 uint32 uIndex ; /* CRC循环中的索引 */
 while (usDataLen--) /* 传输消息缓冲区 */
 {
  uIndex = uchCRCHi ^ *puchMsg++ ; /* 计算CRC */
  uchCRCHi = uchCRCLo ^ auchCRCHi[uIndex] ;
  uchCRCLo = auchCRCLo[uIndex] ;
 }
 return (uchCRCHi << 8 | uchCRCLo) ;
}//uint16 crc16(uint8 *puchMsg, uint16 usDataLen)

//开始发送
void beginSend(void)
{
 b485Send = 1; //设为发送

 sendPosi = 0;
 if(sendCount > 1)
  sendCount--;
 ACC = sendBuf[0];
 TB8 = P;
 SBUF = sendBuf[0];

}//void beginSend(void)


//读线圈状态
void readCoil(void)
{
 uint8 addr;
 uint8 tempAddr;
 uint8 byteCount;
 uint8 bitCount;
 uint16 crcData;
 uint8 position;
 uint8 i,k;
 uint8  result;
 uint16 tempData;
 uint8  exit = 0;

 //addr = (receBuf[2]<<8) + receBuf[3];
 //tempAddr = addr & 0xfff;
 addr = receBuf[3];
 tempAddr = addr;

 //bitCount = (receBuf[4]<<8) + receBuf[5]; //读取的位个数
 bitCount = receBuf[5];

 byteCount = bitCount / 8;     //字节个数
 if(bitCount%8 != 0)
  byteCount++;

 for(k=0;k<byteCount;k++)
 {//字节位置
  position = k + 3;
  sendBuf[position] = 0;
  for(i=0;i<8;i++)
  {
   getCoilVal(tempAddr,&tempData);

   sendBuf[position] |= tempData << i;
   tempAddr++;
   if(tempAddr >= addr+bitCount)
   { //读完
    exit = 1;
    break;
   }
  }
  if(exit == 1)
   break;
 }

 sendBuf[0] = localAddr;
 sendBuf[1] = 0x01;
 sendBuf[2] = byteCount;
 byteCount += 3;
 crcData = crc16(sendBuf,byteCount);
 sendBuf[byteCount] = crcData >> 8;
 byteCount++;
 sendBuf[byteCount] = crcData & 0xff;
 sendCount = byteCount + 1;

 beginSend();
}//void readCoil(void)

//读寄存器
void readRegisters(void)
{
 uint8 addr;
 uint8 tempAddr;
 uint16 result;
 uint16 crcData;
 uint8 readCount;
 uint8 byteCount;
 uint8  finsh; //1完成  0出错
 uint16 i;
 uint16 tempData = 0;

 //addr = (receBuf[2]<<8) + receBuf[3];
 //tempAddr = addr & 0xfff;
 addr = receBuf[3];
 tempAddr = addr;

 //readCount = (receBuf[4]<<8) + receBuf[5]; //要读的个数
 readCount = receBuf[5];

 byteCount = readCount * 2;

 for(i=0;i<byteCount;i+=2,tempAddr++)
 {
  getRegisterVal(tempAddr,&tempData);
  sendBuf[i+3] = tempData >> 8;
  sendBuf[i+4] = tempData & 0xff;
 }

 sendBuf[0] = localAddr;
 sendBuf[1] = 3;
 sendBuf[2] = byteCount;
 byteCount += 3;
 crcData = crc16(sendBuf,byteCount);
 sendBuf[byteCount] = crcData >> 8;
 byteCount++;
 sendBuf[byteCount] = crcData & 0xff;

 sendCount = byteCount + 1;
 beginSend();
}//void readRegisters(void)


//强制单个线圈
void forceSingleCoil(void)
{
 uint8 addr;
 uint8 tempAddr;
 uint16 tempData;
 uint8  onOff;
 uint8 i;

 //addr = (receBuf[2]<<8) + receBuf[3];
 //tempAddr = addr & 0xfff;
 addr = receBuf[3];
 tempAddr = addr;

 //onOff = (receBuf[4]<<8) + receBuf[5];
 onOff = receBuf[4];

 //if(onOff == 0xff00)
 if(onOff == 0xff)
 { //设为ON
  tempData = 1;
 }
 //else if(onOff == 0x0000)
 else if(onOff == 0x00)
 { //设为OFF
  tempData = 0;
 }

 setCoilVal(tempAddr,tempData);

 for(i=0;i<receCount;i++)
 {
  sendBuf[i] = receBuf[i];
 }
 sendCount = receCount;
 beginSend();
}//void forceSingleCoil(void)


//设置多个寄存器
void presetMultipleRegisters(void)
{
 uint8 addr;
 uint8 tempAddr;
 uint8 byteCount;
 uint8 setCount;
 uint16 crcData;
 uint16 tempData;
 uint8  finsh; //为1时完成 为0时出错
 uint8 i;

 //addr = (receBuf[2]<<8) + receBuf[3];
 //tempAddr = addr & 0xfff;
 addr = receBuf[3];
 tempAddr = addr & 0xff;

 //setCount = (receBuf[4]<<8) + receBuf[5];
 setCount = receBuf[5];
 byteCount = receBuf[6];

 for(i=0;i<setCount;i++,tempAddr++)
 {
  tempData = (receBuf[i*2+7]<<8) + receBuf[i*2+8];

  setRegisterVal(tempAddr,tempData);
 }

 sendBuf[0] = localAddr;
 sendBuf[1] = 16;
 sendBuf[2] = addr >> 8;
 sendBuf[3] = addr & 0xff;
 sendBuf[4] = setCount >> 8;
 sendBuf[5] = setCount & 0xff;
 crcData = crc16(sendBuf,6);
 sendBuf[6] = crcData >> 8;
 sendBuf[7] = crcData & 0xff;
 sendCount = 8;
 beginSend();
}//void presetMultipleRegisters(void)


//检查uart0数据
void checkComm0Modbus(void)
{
 uint16 crcData;
 uint16 tempData;

 if(receCount > 4)
 {
  switch(receBuf[1])
  {
   case 1://读取线圈状态(读取点 16位以内)
   case 3://读取保持寄存器(一个或多个)
   case 5://强制单个线圈
   case 6://设置单个寄存器
     if(receCount >= 8)
     {//接收完成一组数据
      //应该关闭接收中断

      if(receBuf[0]==localAddr && checkoutError==0)
      {
       crcData = crc16(receBuf,6);
       if(crcData == receBuf[7]+(receBuf[6]<<8))
       {//校验正确
        if(receBuf[1] == 1)
        {//读取线圈状态(读取点 16位以内)
         readCoil();
        }
        else if(receBuf[1] == 3)
        {//读取保持寄存器(一个或多个)
         readRegisters();
        }
        else if(receBuf[1] == 5)
        {//强制单个线圈
         forceSingleCoil();
        }
        else if(receBuf[1] == 6)
        {
         //presetSingleRegister();
        }

       }
      }
      receCount = 0;
      checkoutError = 0;
     }
     break;

   case 15://设置多个线圈
     tempData = receBuf[6];
     tempData += 9; //数据个数
     if(receCount >= tempData)
     {
      if(receBuf[0]==localAddr && checkoutError==0)
      {
       crcData = crc16(receBuf,tempData-2);
       if(crcData == (receBuf[tempData-2]<<8)+ receBuf[tempData-1])
       {
        //forceMultipleCoils();
       }
      }
      receCount = 0;
      checkoutError = 0;
     }
     break;

   case 16://设置多个寄存器
     tempData = (receBuf[4]<<8) + receBuf[5];
     tempData = tempData * 2; //数据个数
     tempData += 9;
     if(receCount >= tempData)
     {
      if(receBuf[0]==localAddr && checkoutError==0)
      {
       crcData = crc16(receBuf,tempData-2);
       if(crcData == (receBuf[tempData-2]<<8)+ receBuf[tempData-1])
       {
        presetMultipleRegisters();
       }
      }
      receCount = 0;
      checkoutError = 0;
     }
     break;

   default:
     break;
  }
 }
}//void checkComm0(void)

//取线圈状态 返回0表示成功
uint16 getCoilVal(uint16 addr,uint16 *tempData)
{
 uint16 result = 0;
 uint16 tempAddr;

 tempAddr = addr & 0xfff;
 //只取低8位地址
 switch(tempAddr & 0xff)
 {
  case 0:
    break;
  case 1:
    *tempData = testCoil;
    break;
  case 2:
    break;
  case 3:
    break;
  case 4:
    break;
  case 5:
    break;
  case 6:
    break;
  case 7:
    break;
  case 8:
    break;
  case 9:
    break;
  case 10:
    break;
  case 11:
    break;
  case 12:
    break;
  case 13:
    break;
  case 14:
    break;
  case 15:
    break;
  case 16:
    break;
  default:
    break;
 }

 return result;
}//uint16 getCoilVal(uint16 addr,uint16 *data)


//设定线圈状态 返回0表示成功
uint16 setCoilVal(uint16 addr,uint16 tempData)
{
 uint16 result = 0;
 uint16 tempAddr;

 tempAddr = addr & 0xfff;


 switch(tempAddr & 0xff)
 {
  case 0:
    break;
  case 1:
    testCoil = tempData;
    break;
  case 2:
    break;
  case 3:
    break;
  case 4:
    break;
  case 5:
    break;
  case 6:
    break;
  case 7:
    break;
  case 8:
    break;
  case 9:
    break;
  case 10:
    break;
  case 11:
    break;
  case 12:
    break;
  case 13:
    break;
  case 14:
    break;
  case 15:
    break;
  case 16:
    break;
  default:
    break;
 }


 return result;
}//uint16 setCoilVal(uint16 addr,uint16 data)

//取寄存器值 返回0表示成功
uint16 getRegisterVal(uint16 addr,uint16 *tempData)
{
 uint16 result = 0;
 uint16 tempAddr;

 tempAddr = addr & 0xfff;

 switch(tempAddr & 0xff)
 {
  case 0:
    break;
  case 1:
    break;
  case 2:
    break;
  case 3:
    break;
  case 4:
    break;
  case 5:
    break;
  case 6:
    break;
  case 7:
    break;
  case 8:
    break;
  case 9:
    break;
  case 10:
    break;
  case 11:
    break;
  case 12:
    break;
  case 13:
    break;
  case 14:
    break;
  case 15:
    break;
  case 16:
    *tempData = testRegister;
    break;
  default:
    break;
 }

 return result;
}//uint16 getRegisterVal(uint16 addr,uint16 &data)

//设置寄存器值 返回0表示成功
uint16 setRegisterVal(uint16 addr,uint16 tempData)
{
 uint16 result = 0;
 uint16 tempAddr;

 tempAddr = addr & 0xfff;

 switch(tempAddr & 0xff)
 {
  case 0:
    break;
  case 1:
    break;
  case 2:
    break;
  case 3:
    break;
  case 4:
    break;
  case 5:
    break;
  case 6:
    break;
  case 7:
    break;
  case 8:
    break;
  case 9:
    break;
  case 10:
    break;
  case 11:
    break;
  case 12:
    break;
  case 13:
    break;
  case 14:
    break;
  case 15:
    break;
  case 16:
    testRegister = tempData;
    break;
  default:
    break;
 }

 return result;
}//uint8 setRegisterVal(uint16 addr,uint16 data)