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117 lines
3.3 KiB
117 lines
3.3 KiB
2 months ago
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/** @addtogroup crc_file CRC peripheral API
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@ingroup peripheral_apis
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@author @htmlonly © @endhtmlonly 2016 Cem Basoglu <cem.basoglu@web.de>
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*/
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/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2016 Cem Basoglu <cem.basoglu@web.de>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**@{*/
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#include <libopencm3/stm32/crc.h>
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/*---------------------------------------------------------------------------*/
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/** @brief Enable reverse output data.
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Enables the reversal of the bit order of the output data.
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*/
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void crc_reverse_output_enable()
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{
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CRC_CR |= CRC_CR_REV_OUT;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief Disable reverse output data.
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Disables the reversal of the bit order of the output data.
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*/
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void crc_reverse_output_disable()
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{
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CRC_CR &= ~CRC_CR_REV_OUT;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief Reverse input data.
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Controls the reversal of the bit order of the input data
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@param[in] reverse_in Unsigned int32. Reversal bit order @ref crc_rev_in.
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*/
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void crc_set_reverse_input(uint32_t reverse_in)
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{
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uint32_t reg32 = CRC_CR;
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reg32 = (reg32 & ~CRC_CR_REV_IN) | reverse_in;
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CRC_CR = reg32;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief Polynomial size
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Set the size of the polynomial.
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@param[in] polysize Unsigned int32. Size of polynomial @ref crc_polysize.
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*/
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void crc_set_polysize(uint32_t polysize)
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{
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uint32_t reg32 = CRC_CR;
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reg32 = (reg32 & ~CRC_CR_POLYSIZE) | polysize;
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CRC_CR = reg32;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief Polynomial coefficient
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Set the coefficients of the polynomial to be used for CRC calculation.
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If the polynomial size is less than 32-bits, the least significant bits
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have to be used to program the correct value.
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@note To obtain a reliable CRC calculation, any changes to the polynomial
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value or size can not be performed during a CRC calculation.
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As a result, if a CRC calculation is ongoing, the application must either
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reset the crc unit it or perform a CRC_DR read before changing the polynomial.
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@note The default polynomial value is the CRC-32 (Ethernet) polynomial: 0x4C11DB7.
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@param[in] polynomial Unsigned int32. Polynomial coefficient.
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*/
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void crc_set_polynomial(uint32_t polynomial)
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{
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CRC_POL = polynomial;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief CRC Initial value.
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Sets the crc initial value.
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@param[in] initial Unsigned int32. CRC initial value.
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*/
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void crc_set_initial(uint32_t initial)
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{
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CRC_INIT = initial;
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}
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/**@}*/
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