e467b61785
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4964 42af7a65-404d-4744-a932-0658087f49c3
109 lines
4.0 KiB
C
109 lines
4.0 KiB
C
/*
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* FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
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* Copyright (c) 2006 Christian Walter <wolti@sil.at>
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* All rights reserved.
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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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* 1. 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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* 2. 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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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* File: $Id: mbutils.h,v 1.5 2006/12/07 22:10:34 wolti Exp $
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*/
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#ifndef _MB_UTILS_H
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#define _MB_UTILS_H
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#ifdef __cplusplus
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PR_BEGIN_EXTERN_C
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#endif
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/*! \defgroup modbus_utils Utilities
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*
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* This module contains some utility functions which can be used by
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* the application. It includes some special functions for working with
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* bitfields backed by a character array buffer.
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*
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*/
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/*! \addtogroup modbus_utils
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* @{
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*/
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/*! \brief Function to set bits in a byte buffer.
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*
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* This function allows the efficient use of an array to implement bitfields.
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* The array used for storing the bits must always be a multiple of two
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* bytes. Up to eight bits can be set or cleared in one operation.
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*
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* \param ucByteBuf A buffer where the bit values are stored. Must be a
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* multiple of 2 bytes. No length checking is performed and if
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* usBitOffset / 8 is greater than the size of the buffer memory contents
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* is overwritten.
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* \param usBitOffset The starting address of the bits to set. The first
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* bit has the offset 0.
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* \param ucNBits Number of bits to modify. The value must always be smaller
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* than 8.
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* \param ucValues Thew new values for the bits. The value for the first bit
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* starting at <code>usBitOffset</code> is the LSB of the value
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* <code>ucValues</code>
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*
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* \code
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* ucBits[2] = {0, 0};
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*
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* // Set bit 4 to 1 (read: set 1 bit starting at bit offset 4 to value 1)
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* xMBUtilSetBits( ucBits, 4, 1, 1 );
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*
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* // Set bit 7 to 1 and bit 8 to 0.
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* xMBUtilSetBits( ucBits, 7, 2, 0x01 );
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*
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* // Set bits 8 - 11 to 0x05 and bits 12 - 15 to 0x0A;
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* xMBUtilSetBits( ucBits, 8, 8, 0x5A);
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* \endcode
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*/
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void xMBUtilSetBits( uint8_t * ucByteBuf, uint16_t usBitOffset,
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uint8_t ucNBits, uint8_t ucValues );
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/*! \brief Function to read bits in a byte buffer.
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*
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* This function is used to extract up bit values from an array. Up to eight
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* bit values can be extracted in one step.
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*
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* \param ucByteBuf A buffer where the bit values are stored.
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* \param usBitOffset The starting address of the bits to set. The first
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* bit has the offset 0.
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* \param ucNBits Number of bits to modify. The value must always be smaller
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* than 8.
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*
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* \code
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* uint8_t ucBits[2] = {0, 0};
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* uint8_t ucResult;
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*
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* // Extract the bits 3 - 10.
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* ucResult = xMBUtilGetBits( ucBits, 3, 8 );
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* \endcode
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*/
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uint8_t xMBUtilGetBits( uint8_t * ucByteBuf, uint16_t usBitOffset,
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uint8_t ucNBits );
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/*! @} */
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#ifdef __cplusplus
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PR_END_EXTERN_C
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#endif
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#endif
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