271 lines
10 KiB
C
271 lines
10 KiB
C
/*
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* Copyright (c) 2015, Freescale Semiconductor, Inc.
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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 modification,
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* are permitted provided that the following conditions are met:
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*
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* o Redistributions of source code must retain the above copyright notice, this list
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* of conditions and the following disclaimer.
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*
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* o Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* o Neither the name of Freescale Semiconductor, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY 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 THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "fsl_crc.h"
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/*******************************************************************************
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* Definitions
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******************************************************************************/
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#if defined(CRC_DRIVER_USE_CRC16_CCIT_FALSE_AS_DEFAULT) && CRC_DRIVER_USE_CRC16_CCIT_FALSE_AS_DEFAULT
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/* @brief Default user configuration structure for CRC-16-CCITT */
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#define CRC_DRIVER_DEFAULT_POLYNOMIAL 0x1021U
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/*< CRC-16-CCIT polynomial x**16 + x**12 + x**5 + x**0 */
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#define CRC_DRIVER_DEFAULT_SEED 0xFFFFU
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/*< Default initial checksum */
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#define CRC_DRIVER_DEFAULT_REFLECT_IN false
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/*< Default is no transpose */
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#define CRC_DRIVER_DEFAULT_REFLECT_OUT false
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/*< Default is transpose bytes */
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#define CRC_DRIVER_DEFAULT_COMPLEMENT_CHECKSUM false
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/*< Default is without complement of CRC data register read data */
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#define CRC_DRIVER_DEFAULT_CRC_BITS kCrcBits16
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/*< Default is 16-bit CRC protocol */
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#define CRC_DRIVER_DEFAULT_CRC_RESULT kCrcFinalChecksum
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/*< Default is resutl type is final checksum */
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#endif /* CRC_DRIVER_USE_CRC16_CCIT_FALSE_AS_DEFAULT */
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/*! @brief CRC type of transpose of read write data */
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typedef enum _crc_transpose_type
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{
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kCrcTransposeNone = 0U, /*! No transpose */
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kCrcTransposeBits = 1U, /*! Tranpose bits in bytes */
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kCrcTransposeBitsAndBytes = 2U, /*! Transpose bytes and bits in bytes */
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kCrcTransposeBytes = 3U, /*! Transpose bytes */
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} crc_transpose_type_t;
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/*!
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* @brief CRC module configuration.
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*
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* This structure holds the configuration for the CRC module.
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*/
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typedef struct _crc_module_config
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{
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uint32_t polynomial; /*!< CRC Polynomial, MSBit first.@n
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Example polynomial: 0x1021 = 1_0000_0010_0001 = x^12+x^5+1 */
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uint32_t seed; /*!< Starting checksum value */
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crc_transpose_type_t readTranspose; /*!< Type of transpose when reading CRC result. */
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crc_transpose_type_t writeTranspose; /*!< Type of transpose when writing CRC input data. */
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bool complementChecksum; /*!< True if the result shall be complement of the actual checksum. */
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crc_bits_t crcBits; /*!< Selects 16- or 32- bit CRC protocol. */
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} crc_module_config_t;
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/*******************************************************************************
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* Code
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******************************************************************************/
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/*!
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* @brief Returns transpose type for CRC protocol reflect in parameter.
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*
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* This functions helps to set writeTranspose member of crc_config_t structure. Reflect in is CRC protocol parameter.
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*
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* @param enable True or false for the selected CRC protocol Reflect In (refin) parameter.
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*/
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static inline crc_transpose_type_t crc_GetTransposeTypeFromReflectIn(bool enable)
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{
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return ((enable) ? kCrcTransposeBitsAndBytes : kCrcTransposeBytes);
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}
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/*!
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* @brief Returns transpose type for CRC protocol reflect out parameter.
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*
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* This functions helps to set readTranspose member of crc_config_t structure. Reflect out is CRC protocol parameter.
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*
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* @param enable True or false for the selected CRC protocol Reflect Out (refout) parameter.
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*/
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static inline crc_transpose_type_t crc_GetTransposeTypeFromReflectOut(bool enable)
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{
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return ((enable) ? kCrcTransposeBitsAndBytes : kCrcTransposeNone);
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}
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/*!
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* @brief Starts checksum computation.
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*
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* Configures the CRC module for the specified CRC protocol. @n
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* Starts the checksum computation by writing the seed value
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*
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* @param base CRC peripheral address.
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* @param config Pointer to protocol configuration structure.
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*/
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static void crc_ConfigureAndStart(CRC_Type *base, const crc_module_config_t *config)
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{
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uint32_t crcControl;
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/* pre-compute value for CRC control registger based on user configuraton without WAS field */
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crcControl = 0 | CRC_CTRL_TOT(config->writeTranspose) | CRC_CTRL_TOTR(config->readTranspose) |
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CRC_CTRL_FXOR(config->complementChecksum) | CRC_CTRL_TCRC(config->crcBits);
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/* make sure the control register is clear - WAS is deasserted, and protocol is set */
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base->CTRL = crcControl;
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/* write polynomial register */
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base->GPOLY = config->polynomial;
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/* write pre-computed control register value along with WAS to start checksum computation */
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base->CTRL = crcControl | CRC_CTRL_WAS(true);
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/* write seed (initial checksum) */
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base->DATA = config->seed;
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/* deassert WAS by writing pre-computed CRC control register value */
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base->CTRL = crcControl;
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}
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/*!
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* @brief Starts final checksum computation.
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*
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* Configures the CRC module for the specified CRC protocol. @n
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* Starts final checksum computation by writing the seed value.
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* @note CRC_Get16bitResult() or CRC_Get32bitResult() return final checksum
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* (output reflection and xor functions are applied).
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*
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* @param base CRC peripheral address.
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* @param protocolConfig Pointer to protocol configuration structure.
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*/
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static void crc_SetProtocolConfig(CRC_Type *base, const crc_config_t *protocolConfig)
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{
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crc_module_config_t moduleConfig;
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/* convert protocol to CRC peripheral module configuration, prepare for final checksum */
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moduleConfig.polynomial = protocolConfig->polynomial;
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moduleConfig.seed = protocolConfig->seed;
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moduleConfig.readTranspose = crc_GetTransposeTypeFromReflectOut(protocolConfig->reflectOut);
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moduleConfig.writeTranspose = crc_GetTransposeTypeFromReflectIn(protocolConfig->reflectIn);
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moduleConfig.complementChecksum = protocolConfig->complementChecksum;
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moduleConfig.crcBits = protocolConfig->crcBits;
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crc_ConfigureAndStart(base, &moduleConfig);
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}
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/*!
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* @brief Starts intermediate checksum computation.
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*
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* Configures the CRC module for the specified CRC protocol. @n
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* Starts intermediate checksum computation by writing the seed value.
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* @note CRC_Get16bitResult() or CRC_Get32bitResult() return intermediate checksum (raw data register value).
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*
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* @param base CRC peripheral address.
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* @param protocolConfig Pointer to protocol configuration structure.
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*/
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static void crc_SetRawProtocolConfig(CRC_Type *base, const crc_config_t *protocolConfig)
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{
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crc_module_config_t moduleConfig;
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/* convert protocol to CRC peripheral module configuration, prepare for intermediate checksum */
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moduleConfig.polynomial = protocolConfig->polynomial;
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moduleConfig.seed = protocolConfig->seed;
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moduleConfig.readTranspose =
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kCrcTransposeNone; /* intermediate checksum does no transpose of data register read value */
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moduleConfig.writeTranspose = crc_GetTransposeTypeFromReflectIn(protocolConfig->reflectIn);
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moduleConfig.complementChecksum = false; /* intermediate checksum does no xor of data register read value */
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moduleConfig.crcBits = protocolConfig->crcBits;
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crc_ConfigureAndStart(base, &moduleConfig);
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}
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void CRC_Init(CRC_Type *base, const crc_config_t *config)
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{
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/* ungate clock */
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CLOCK_EnableClock(kCLOCK_Crc0);
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/* configure CRC module and write the seed */
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if (config->crcResult == kCrcFinalChecksum)
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{
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crc_SetProtocolConfig(base, config);
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}
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else
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{
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crc_SetRawProtocolConfig(base, config);
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}
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}
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void CRC_GetDefaultConfig(crc_config_t *config)
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{
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static const crc_config_t crc16ccit = {
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CRC_DRIVER_DEFAULT_POLYNOMIAL, CRC_DRIVER_DEFAULT_SEED,
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CRC_DRIVER_DEFAULT_REFLECT_IN, CRC_DRIVER_DEFAULT_REFLECT_OUT,
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CRC_DRIVER_DEFAULT_COMPLEMENT_CHECKSUM, CRC_DRIVER_DEFAULT_CRC_BITS,
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CRC_DRIVER_DEFAULT_CRC_RESULT,
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};
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*config = crc16ccit;
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}
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void CRC_WriteData(CRC_Type *base, const uint8_t *data, size_t dataSize)
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{
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const uint32_t *data32;
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/* 8-bit reads and writes till source address is aligned 4 bytes */
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while ((dataSize) && ((uint32_t)data & 3U))
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{
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base->ACCESS8BIT.DATALL = *data;
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data++;
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dataSize--;
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}
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/* use 32-bit reads and writes as long as possible */
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data32 = (const uint32_t *)data;
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while (dataSize >= sizeof(uint32_t))
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{
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base->DATA = *data32;
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data32++;
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dataSize -= sizeof(uint32_t);
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}
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data = (const uint8_t *)data32;
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/* 8-bit reads and writes till end of data buffer */
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while (dataSize)
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{
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base->ACCESS8BIT.DATALL = *data;
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data++;
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dataSize--;
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}
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}
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uint16_t CRC_Get16bitResult(CRC_Type *base)
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{
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uint32_t retval;
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uint32_t totr; /* type of transpose read bitfield */
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retval = base->DATA;
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totr = (base->CTRL & CRC_CTRL_TOTR_MASK) >> CRC_CTRL_TOTR_SHIFT;
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/* check transpose type to get 16-bit out of 32-bit register */
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if (totr >= 2U)
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{
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/* transpose of bytes for read is set, the result CRC is in CRC_DATA[HU:HL] */
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retval &= 0xFFFF0000U;
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retval = retval >> 16U;
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}
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else
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{
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/* no transpose of bytes for read, the result CRC is in CRC_DATA[LU:LL] */
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retval &= 0x0000FFFFU;
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}
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return (uint16_t)retval;
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}
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