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106 lines
4.0 KiB
C
106 lines
4.0 KiB
C
/*
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* OpenMODBUS/TCP to RS-232/485 MODBUS RTU gateway
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*
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* modbus.h - MODBUS protocol related procedures
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*
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* Copyright (c) 2002-2003, 2013, Victor Antonovich (v.antonovich@gmail.com)
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $Id: modbus.h,v 1.3 2015/02/25 10:33:57 kapyar Exp $
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*/
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#ifndef _MODBUS_H
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#define _MODBUS_H
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#include "globals.h"
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#include "crc16.h"
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/*
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* Macro for accessing data in MODBUS frame
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*/
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#define MB_FRAME(p, d) ( *(p + d) )
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/*
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* MODBUS frame lengths
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*/
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#define MB_EX_LEN 3
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#define MB_MIN_LEN 4
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#define MB_ERR_LEN 5
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#define MB_MAX_LEN 256
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/*
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* Macros for word operations
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*/
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#define HIGH(w) ( (unsigned char)(((w) >> 8) & 0xff) )
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#define LOW(w) ( (unsigned char)((w) & 0xff) )
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#define WORD_WR_BE(p, w) do \
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{ *(p) = (unsigned char)(((w) >> 8) & 0xff); \
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*(p + 1) = (unsigned char)((w) & 0xff); } \
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while (0);
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#define WORD_RD_BE(p) ( (((unsigned short)*(p) << 8) & 0xff00) + \
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(*(p + 1) & 0xff) )
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#define WORD_WR_LE(p, w) do \
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{ *(p) = (unsigned char)((w) & 0xff); \
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*(p + 1) = (unsigned char)(((w) >> 8) & 0xff); } \
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while (0);
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#define WORD_RD_LE(p) ( (((unsigned short)*(p + 1) << 8) & 0xff00) + \
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(*(p) & 0xff) )
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/*
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* MODBUS packet structure
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*/
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#define MB_TRANS_ID_H 0 /* transaction ID high byte */
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#define MB_TRANS_ID_L 1 /* transaction ID low byte */
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#define MB_PROTO_ID_H 2 /* protocol ID high byte */
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#define MB_PROTO_ID_L 3 /* protocol ID low byte */
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#define MB_LENGTH_H 4 /* length field high byte */
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#define MB_LENGTH_L 5 /* length field low byte */
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#define MB_UNIT_ID 6 /* unit identifier */
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#define MB_FCODE 7 /* function code */
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#define MB_DATA 8 /* MODBUS data */
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#define MB_DATA_ADDR_H MB_DATA /* MODBUS data: address high byte */
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#define MB_DATA_ADDR_L 9 /* MODBUS data: address low byte */
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#define MB_DATA_NVAL_H 10 /* MODBUS data: number of values high byte */
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#define MB_DATA_NVAL_L 11 /* MODBUS data: number of values low byte */
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#define MB_DATA_NBYTES 12 /* MODBUS data: number of bytes to follow (fc 15,16) */
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#define TTY_FCODE_IDX 1 /* The index of the function code in a RTU packet */
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#define TTY_ERR_MASK 0x80 /* The MSB of the response function code indicates an error response */
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/*
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* Exception codes
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*/
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#define MB_EX_CRC 4
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#define MB_EX_TIMEOUT 0x0B
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/* Prototypes */
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int modbus_crc_correct(unsigned char *frame, unsigned int len);
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void modbus_crc_write(unsigned char *frame, unsigned int len);
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void modbus_ex_write(unsigned char *packet, unsigned char code);
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int modbus_check_header(unsigned char *packet);
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#endif /* _MODBUS_H */
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