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/* Classic Ladder Project */
/* Copyright (C) 2001-2004 Marc Le Douarain */
/* http://www.multimania.com/mavati/classicladder */
/* http://www.sourceforge.net/projects/classicladder */
/* December 2004 */
/* --------------------- */
/* Modbus slave protocol */
/* --------------------- */
/* This library is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU Lesser General Public */
/* License as published by the Free Software Foundation; either */
/* version 2.1 of the License, or (at your option) any later version. */
/* This library is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU */
/* Lesser General Public License for more details. */
/* You should have received a copy of the GNU Lesser General Public */
/* License along with this library; if not, write to the Free Software */
/* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "classicladder.h"
#include "global.h"
#include "vars_access.h"
#include "protocol_modbus_slave.h"
#include "protocol_modbus_master.h" // some Modbus defines shared
/* TEMP!!! put this variable in global config instead ? */
int OffsetForVars = 1;
/* Question here start directly with function code
(no IP header or Slave number) */
int ModbusRequestToRespond( unsigned char * Question, int LgtQuestion, unsigned char * Response )
{
int LgtResponse = 0;
int ErrorCode = 0;
int ScanEle;
printf("FUNCTION CODE=%d\n", Question[ 0 ] );
switch( Question[ 0 ] )
{
// Read n bits (read or write bits)
case 1:
case 2:
if ( LgtQuestion>=5 )
{
int FirstBit = (Question[1]<<8) | Question[2];
int NbrBits = (Question[3]<<8) | Question[4];
int NbrRealBytes = (NbrBits+7)/8;
int ScanByte, ScanBit;
// validity request verify
if ( FirstBit+1+NbrRealBytes*8>InfosGene->GeneralParams.SizesInfos.nbr_bits )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( NbrBits>2000 )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( ErrorCode==0 )
{
// Code Function for response
Response[ LgtResponse++ ] = Question[ 0 ];
// Length in bytes
Response[ LgtResponse++ ] = NbrRealBytes;
// Bits values
ScanEle = 0;
for( ScanByte=0; ScanByte<NbrRealBytes; ScanByte++ )
{
unsigned char BitsValues = 0;
unsigned char Mask = 0x01;
for( ScanBit=0; ScanBit<8; ScanBit++ )
{
if( ReadVar( VAR_MEM_BIT, FirstBit+OffsetForVars+ScanEle++ ) )
BitsValues = BitsValues|Mask;
Mask = Mask<<1;
}
Response[ LgtResponse++ ] = BitsValues;
}
}
}
else
{
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
}
break;
// Read n words (read or write words)
case 3:
case 4:
if ( LgtQuestion>=5 )
{
int FirstWord = (Question[1]<<8) | Question[2];
int NbrWords = (Question[3]<<8) | Question[4];
// validity request verify
if ( FirstWord+1+NbrWords>InfosGene->GeneralParams.SizesInfos.nbr_words )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( NbrWords>200 )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( ErrorCode==0 )
{
// Code Function for response
Response[ LgtResponse++ ] = Question[ 0 ];
// Length in bytes
Response[ LgtResponse++ ] = NbrWords*2;
// Words values
for( ScanEle=0; ScanEle<NbrWords; ScanEle++ )
{
int ValueWord = ReadVar( VAR_MEM_WORD, FirstWord+OffsetForVars+ScanEle );
Response[ LgtResponse++ ] = (unsigned char)(ValueWord>>8);
Response[ LgtResponse++ ] = (unsigned char)ValueWord;
}
}
}
else
{
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
}
break;
// Write one bit (write bit)
case 5:
if ( LgtQuestion>=5 )
{
int FirstBit = (Question[1]<<8) | Question[2];
int OffsetQuest = 3;
int ValueBit;
ValueBit = (Question[ OffsetQuest++ ]<<8 );
ValueBit = ValueBit | Question[ OffsetQuest++ ];
// validity request verify
if ( FirstBit+1>InfosGene->GeneralParams.SizesInfos.nbr_bits )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( ValueBit!=MODBUS_BIT_ON && ValueBit!=MODBUS_BIT_OFF )
ErrorCode = MODBUS_ILLEGAL_DATA_VALUE;
if ( ErrorCode==0 )
{
WriteVar( VAR_MEM_BIT, FirstBit+OffsetForVars, ValueBit?1:0 );
// Code Function for response
Response[ LgtResponse++ ] = Question[ 0 ];
// First Bit
Response[ LgtResponse++ ] = (unsigned char)(FirstBit>>8);
Response[ LgtResponse++ ] = (unsigned char)(FirstBit);
// Bit value
Response[ LgtResponse++ ] = (unsigned char)(ValueBit>>8);
Response[ LgtResponse++ ] = (unsigned char)(ValueBit);
}
}
break;
// Write n bits (write bits)
case 15:
if ( LgtQuestion>=7 )
{
int FirstBit = (Question[1]<<8) | Question[2];
int NbrBits = (Question[3]<<8) | Question[4];
// validity request verify
if ( FirstBit+1+NbrBits>InfosGene->GeneralParams.SizesInfos.nbr_bits )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( NbrBits>2000 )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( (NbrBits+7)/8>Question[5] )
ErrorCode = MODBUS_ILLEGAL_DATA_VALUE;
if ( ErrorCode==0 )
{
int ScanByte = 6;
int ScanBit = 0;
int CurrentBit = FirstBit;
unsigned char Mask = 0x01;
do
{
int Value = 0;
if ( Question[ ScanByte ]&Mask )
Value = 1;
WriteVar( VAR_MEM_BIT, CurrentBit+OffsetForVars, Value );
ScanBit++;
Mask = Mask<<1;
if ( ScanBit>=8 )
{
ScanBit = 0;
ScanByte++;
Mask = 0x01;
}
CurrentBit++;
}
while( CurrentBit<FirstBit+NbrBits );
// Code Function for response
Response[ LgtResponse++ ] = Question[ 0 ];
// First bit
Response[ LgtResponse++ ] = (unsigned char)(FirstBit>>8);
Response[ LgtResponse++ ] = (unsigned char)(FirstBit);
// Nbr bits
Response[ LgtResponse++ ] = (unsigned char)(NbrBits>>8);
Response[ LgtResponse++ ] = (unsigned char)(NbrBits);
}
}
break;
// Write 1 or n words (write words)
case 6:
case 16:
if ( ( LgtQuestion>=5 && Question[0]==6 ) || ( LgtQuestion>=8 && Question[0]==16 ) )
{
int OffsetQuest = 3;
int FirstWord = (Question[1]<<8) | Question[2];
int NbrWords = 1;
int ValueWord = 0;
// is type n words ?
if ( Question[0]==16 )
{
NbrWords = (Question[3]<<8) | Question[4];
OffsetQuest = 6;
if ( NbrWords*2>Question[5] )
ErrorCode = MODBUS_ILLEGAL_DATA_VALUE;
}
// request verify
if ( FirstWord+1+NbrWords>InfosGene->GeneralParams.SizesInfos.nbr_words )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( NbrWords>200 )
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
if ( ErrorCode==0 )
{
// Words values
for( ScanEle=0; ScanEle<NbrWords; ScanEle++ )
{
ValueWord = (Question[ OffsetQuest++ ]<<8 );
ValueWord = ValueWord | Question[ OffsetQuest++ ];
WriteVar( VAR_MEM_WORD, FirstWord+OffsetForVars+ScanEle, ValueWord );
}
// Code Function for response
Response[ LgtResponse++ ] = Question[ 0 ];
// First word
Response[ LgtResponse++ ] = (unsigned char)(FirstWord>>8);
Response[ LgtResponse++ ] = (unsigned char)(FirstWord);
// is type n words ?
if ( Question[0]==16 )
{
// Nbr Words
Response[ LgtResponse++ ] = (unsigned char)(NbrWords>>8);
Response[ LgtResponse++ ] = (unsigned char)(NbrWords);
}
else
{
// Word value
Response[ LgtResponse++ ] = (unsigned char)(ValueWord>>8);
Response[ LgtResponse++ ] = (unsigned char)(ValueWord);
}
}
}
else
{
ErrorCode = MODBUS_ILLEGAL_DATA_ADDRESS;
}
break;
default:
Response[ LgtResponse++ ] = 0x80 | Question[ 0 ];
Response[ LgtResponse++ ] = MODBUS_ILLEGAL_FUNCTION;
break;
}
if ( ErrorCode>0 )
{
LgtResponse = 0;
Response[ LgtResponse++ ] = 0x80 | Question[ 0 ];
Response[ LgtResponse++ ] = ErrorCode;
}
return LgtResponse;
}
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