File content as of revision 1:8fcbafe2ca98:

#include "modbus.h"
#define   MODBUS_DEFAULT_BAUD_RATE   9600
       const  char auchCRCHi[256]={
    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
};
const  char auchCRCLo[256]={
    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
};
Modbus::Modbus(PinName tx, PinName rx,PinName txEnable, int baud)
: rs485(tx, rx,baud),
dir(txEnable)
{
    rs485.format(8, Serial::None, 1);
    }
bool Modbus::sendQuery(uint8_t address,uint8_t function,uint16_t startAddress,uint16_t points)
{  int index,i;
     index=0;
     _address=address;
     _function=function;
     _startAddress=startAddress;
     _points=points;
    sbuf[index++]=address;
    sbuf[index++]=function;
    sbuf[index++]=(startAddress>>8)&0xff;
    sbuf[index++]=startAddress&0xff;
    sbuf[index++]=(points>>8)&0xff;
    sbuf[index++]=points&0xff;
    unsigned short resultCRC =  calculateCRC16(sbuf,index); 
     sbuf[index++]=(resultCRC>>8)&0xff;
    sbuf[index++]=resultCRC&0xff;
    dir=1;
    wait_ms(2);
    for (i=0;i<index;i++)
      {
      rs485.putc(sbuf[i]);
  
      }
     wait_ms(2);
    dir=0;
    return true;
    }
int  Modbus::waitResponse(uint8_t *data)
 {  unsigned short resultCRC ,recCRC;
    
    int state,index,len,cnt,i;
    uint8_t ch;
    bool flag;
     flag=true;
     state=0;
     index=0;
     while(flag)
     {  ch=rs485.getc();
        
         switch(state)
         {
             case 0:{
                 if (ch==_address)
                   {state=1;
                   rbuf[index++]=ch;}
                 break;
                 }
            case 1:{
               
              if (ch==_function)
                   {state=2;rbuf[index++]=ch;}
                   else if(ch==(_function+0x80))
                     state=10;
                     else 
                     return 0;
                 break;
                 }
             case 2:{
                    len=ch;cnt=ch;
                    rbuf[index++]=ch;
                    state=3;
                    break;
                    } 
             case 3:{
                    rbuf[index++]=ch;
                    cnt--;
                    if (cnt==0)
                      { 
                      state=4;
                     
                      }
                    break;
                    }
              case 4:{
                     recCRC=ch;
                     state=5;
                     break;
                     } 
              case 5:{
                     recCRC=(recCRC<<8)|ch;
                      resultCRC =  calculateCRC16(rbuf,index);  
                   //  printf("CRC=%02x,%02x\n",recCRC,resultCRC);
                     if (recCRC==resultCRC) {
                         for (i=0;i<len;i++)
                           data[i]=rbuf[3+i];
                         return len;
                         }
                     else return 0;
                     }
               case 10:{
                       len=0;
                       flag=false;
                       break;
                       }                            
             }
         } 
    
        return len;
     }
bool  Modbus::waitQuery(uint8_t &address,uint8_t &function,uint16_t &startAddress,uint16_t &points)
{ 
unsigned short resultCRC ,recCRC;   
    int i;
    for (i=0;i<8;i++)
     rbuf[i]=rs485.getc();
     resultCRC =  calculateCRC16(rbuf,6);  
     recCRC=(rbuf[6]<<8)|rbuf[7];
     if ( resultCRC!=recCRC) return false;
        address=rbuf[0];
        _address=rbuf[0];
        function=rbuf[1];
        _function=rbuf[1]; 
        _startAddress=(rbuf[2]<<8)|rbuf[3];
        startAddress=_startAddress;
        _points=(rbuf[4]<<8)|rbuf[5];
        points=_points;
        return true;
    } 
 bool Modbus::sendResponse(uint8_t *data,uint8_t length)
 { 
 unsigned short resultCRC;
  int index,i;
  index=0;
     sbuf[index++]=_address;
     sbuf[index++]=_function;
     sbuf[index++]= length;
    for (i=0;i<length;i++)
     sbuf[index++]=data[i];
     resultCRC =  calculateCRC16(rbuf,index);  
     sbuf[index++]=(resultCRC>>8)&0xff;
     sbuf[index++]=resultCRC &0xff;
      dir=1;
    wait_ms(2);
   for (i=0;i<index;i++)
      rs485.putc(sbuf[i]) ;
        wait_ms(2);
    dir=0;
      return true;
     }       
unsigned int  Modbus::calculateCRC16( uint8_t *puchMsg,unsigned int  usDataLen)
{
    unsigned char uchCRCHi,uchCRCLo;
    unsigned char uIndex=0 ;                             /* will index into CRC lookup table */
    unsigned char tempp=0;
    unsigned int CRCHL=0;
    uchCRCHi=0xFF ;                             // high byte of CRC initialized 
    uchCRCLo=0xFF ; 
    tempp=0;                           // low byte of CRC initialized 
    while(usDataLen--)                       // pass through message buffer 
    {
        uIndex=uchCRCHi^*puchMsg++ ; // calculate the CRC high byte         
        tempp++;
        uchCRCHi=uchCRCLo^auchCRCHi[uIndex] ;//01-auchCRCHi[254]:0x81;02-0x01;03-0x80;04-0xC0
        uchCRCLo=auchCRCLo[uIndex] ;               
    }
    CRCHL=uchCRCHi;
    CRCHL=CRCHL<<8;
    CRCHL|=uchCRCLo;        
    return CRCHL;//(uchCRCHi<<8|uchCRCLo) ;//uchCRCHi:0xa1;uchCRCLo:2B
}