root / freemodbus / modbus / include / mbutils.h @ 20e5429c
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1 | 20e5429c | Tom Mullins | /*
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2 | * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
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3 | * Copyright (c) 2006 Christian Walter <wolti@sil.at>
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4 | * All rights reserved.
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5 | *
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6 | * Redistribution and use in source and binary forms, with or without
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7 | * modification, are permitted provided that the following conditions
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8 | * are met:
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9 | * 1. Redistributions of source code must retain the above copyright
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10 | * notice, this list of conditions and the following disclaimer.
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11 | * 2. Redistributions in binary form must reproduce the above copyright
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12 | * notice, this list of conditions and the following disclaimer in the
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13 | * documentation and/or other materials provided with the distribution.
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14 | * 3. The name of the author may not be used to endorse or promote products
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15 | * derived from this software without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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27 | *
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28 | * File: $Id: mbutils.h,v 1.5 2006/12/07 22:10:34 wolti Exp $
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29 | */
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30 | |||
31 | #ifndef _MB_UTILS_H
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32 | #define _MB_UTILS_H
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33 | |||
34 | #ifdef __cplusplus
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35 | PR_BEGIN_EXTERN_C |
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36 | #endif
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37 | /*! \defgroup modbus_utils Utilities
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38 | *
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39 | * This module contains some utility functions which can be used by
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40 | * the application. It includes some special functions for working with
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41 | * bitfields backed by a character array buffer.
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42 | *
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43 | */
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44 | /*! \addtogroup modbus_utils
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45 | * @{
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46 | */
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47 | /*! \brief Function to set bits in a byte buffer.
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48 | *
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49 | * This function allows the efficient use of an array to implement bitfields.
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50 | * The array used for storing the bits must always be a multiple of two
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51 | * bytes. Up to eight bits can be set or cleared in one operation.
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52 | *
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53 | * \param ucByteBuf A buffer where the bit values are stored. Must be a
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54 | * multiple of 2 bytes. No length checking is performed and if
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55 | * usBitOffset / 8 is greater than the size of the buffer memory contents
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56 | * is overwritten.
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57 | * \param usBitOffset The starting address of the bits to set. The first
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58 | * bit has the offset 0.
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59 | * \param ucNBits Number of bits to modify. The value must always be smaller
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60 | * than 8.
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61 | * \param ucValues Thew new values for the bits. The value for the first bit
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62 | * starting at <code>usBitOffset</code> is the LSB of the value
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63 | * <code>ucValues</code>
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64 | *
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65 | * \code
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66 | * ucBits[2] = {0, 0};
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67 | *
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68 | * // Set bit 4 to 1 (read: set 1 bit starting at bit offset 4 to value 1)
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69 | * xMBUtilSetBits( ucBits, 4, 1, 1 );
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70 | *
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71 | * // Set bit 7 to 1 and bit 8 to 0.
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72 | * xMBUtilSetBits( ucBits, 7, 2, 0x01 );
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73 | *
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74 | * // Set bits 8 - 11 to 0x05 and bits 12 - 15 to 0x0A;
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75 | * xMBUtilSetBits( ucBits, 8, 8, 0x5A);
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76 | * \endcode
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77 | */
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78 | void xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset,
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79 | UCHAR ucNBits, UCHAR ucValues ); |
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80 | |||
81 | /*! \brief Function to read bits in a byte buffer.
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82 | *
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83 | * This function is used to extract up bit values from an array. Up to eight
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84 | * bit values can be extracted in one step.
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85 | *
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86 | * \param ucByteBuf A buffer where the bit values are stored.
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87 | * \param usBitOffset The starting address of the bits to set. The first
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88 | * bit has the offset 0.
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89 | * \param ucNBits Number of bits to modify. The value must always be smaller
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90 | * than 8.
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91 | *
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92 | * \code
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93 | * UCHAR ucBits[2] = {0, 0};
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94 | * UCHAR ucResult;
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95 | *
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96 | * // Extract the bits 3 - 10.
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97 | * ucResult = xMBUtilGetBits( ucBits, 3, 8 );
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98 | * \endcode
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99 | */
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100 | UCHAR xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, |
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101 | UCHAR ucNBits ); |
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102 | |||
103 | /*! @} */
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104 | |||
105 | #ifdef __cplusplus
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106 | PR_END_EXTERN_C |
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107 | #endif
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108 | #endif
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