mirror of
https://github.com/DarkFlippers/unleashed-firmware
synced 2024-11-27 15:00:46 +00:00
86 lines
2.5 KiB
C
Executable file
86 lines
2.5 KiB
C
Executable file
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/******************************************************************************
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* \attention
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*
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* <h2><center>© COPYRIGHT 2020 STMicroelectronics</center></h2>
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*
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* Licensed under ST MYLIBERTY SOFTWARE LICENSE AGREEMENT (the "License");
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* You may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* www.st.com/myliberty
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied,
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* AND SPECIFICALLY DISCLAIMING THE IMPLIED WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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/*
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* PROJECT: ST25R391x firmware
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* Revision:
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* LANGUAGE: ISO C99
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*/
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/*! \file rfal_crc.c
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*
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* \author Oliver Regenfelder
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*
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* \brief CRC calculation implementation
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*
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*/
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/*
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******************************************************************************
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* INCLUDES
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******************************************************************************
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*/
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#include "rfal_crc.h"
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/*
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******************************************************************************
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* LOCAL FUNCTION PROTOTYPES
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******************************************************************************
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*/
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static uint16_t rfalCrcUpdateCcitt(uint16_t crcSeed, uint8_t dataByte);
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/*
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******************************************************************************
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* GLOBAL FUNCTIONS
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******************************************************************************
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*/
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uint16_t rfalCrcCalculateCcitt(uint16_t preloadValue, const uint8_t* buf, uint16_t length)
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{
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uint16_t crc = preloadValue;
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uint16_t index;
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for (index = 0; index < length; index++)
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{
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crc = rfalCrcUpdateCcitt(crc, buf[index]);
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}
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return crc;
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}
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/*
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******************************************************************************
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* LOCAL FUNCTIONS
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******************************************************************************
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*/
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static uint16_t rfalCrcUpdateCcitt(uint16_t crcSeed, uint8_t dataByte)
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{
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uint16_t crc = crcSeed;
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uint8_t dat = dataByte;
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dat ^= (uint8_t)(crc & 0xFFU);
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dat ^= (dat << 4);
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crc = (crc >> 8)^(((uint16_t) dat) << 8)^(((uint16_t) dat) << 3)^(((uint16_t) dat) >> 4);
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return crc;
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}
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