nuttx-apps/include/modbus/mbutils.h

111 lines
4.2 KiB
C

/****************************************************************************
* apps/include/modbus/mbutils.h
*
* FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
* Copyright (c) 2006 Christian Walter <wolti@sil.at>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __APPS_INCLUDE_MODBUS_MBUTILS_H
#define __APPS_INCLUDE_MODBUS_MBUTILS_H
#ifdef __cplusplus
PR_BEGIN_EXTERN_C
#endif
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* This module contains some utility functions which can be used by
* the application. It includes some special functions for working with
* bitfields backed by a character array buffer.
*/
/* Function to set bits in a byte buffer.
*
* This function allows the efficient use of an array to implement bitfields.
* The array used for storing the bits must always be a multiple of two
* bytes. Up to eight bits can be set or cleared in one operation.
*
* Input Parameters:
* ucByteBuf A buffer where the bit values are stored. Must be a
* multiple of 2 bytes. No length checking is performed and if
* usBitOffset / 8 is greater than the size of the buffer memory contents
* is overwritten.
* usBitOffset The starting address of the bits to set. The first
* bit has the offset 0.
* ucNBits Number of bits to modify. The value must always be smaller
* than 8.
* ucValues Thew new values for the bits. The value for the first bit
* starting at usBitOffset is the LSB of the value ucValues
*
* ucBits[2] = {0, 0};
*
* // Set bit 4 to 1 (read: set 1 bit starting at bit offset 4 to value 1)
*
* xMBUtilSetBits(ucBits, 4, 1, 1);
*
* // Set bit 7 to 1 and bit 8 to 0.
*
* xMBUtilSetBits(ucBits, 7, 2, 0x01);
*
* // Set bits 8 - 11 to 0x05 and bits 12 - 15 to 0x0A;
*
* xMBUtilSetBits(ucBits, 8, 8, 0x5A);
*/
void xMBUtilSetBits(uint8_t *ucByteBuf, uint16_t usBitOffset,
uint8_t ucNBits, uint8_t ucValues);
/* Function to read bits in a byte buffer.
*
* This function is used to extract up bit values from an array. Up to eight
* bit values can be extracted in one step.
*
* Input Parameters:
* ucByteBuf A buffer where the bit values are stored.
* usBitOffset The starting address of the bits to set. The first
* bit has the offset 0.
* ucNBits Number of bits to modify. The value must always be smaller
* than 8.
*
* uint8_t ucBits[2] = {0, 0};
* uint8_t ucResult;
*
* // Extract the bits 3 - 10.
*
* ucResult = xMBUtilGetBits(ucBits, 3, 8);
*/
uint8_t xMBUtilGetBits(uint8_t *ucByteBuf, uint16_t usBitOffset, uint8_t ucNBits);
#ifdef __cplusplus
PR_END_EXTERN_C
#endif
#endif /* __APPS_INCLUDE_MODBUS_MBUTILS_H */