103 lines
3.6 KiB
C
103 lines
3.6 KiB
C
/****************************************************************************
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* include/nuttx/1wire/1wire_crc.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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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, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __INCLUDE_NUTTX_1WIRE_1WIRE_CRC_H
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#define __INCLUDE_NUTTX_1WIRE_1WIRE_CRC_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: onewire_crc8
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*
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* Description:
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* Compute a Dallas Semiconductor 8 bit CRC.
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*
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* Input Parameters:
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* input - Input buffer for crc calculation
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* len - Buffer len
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*
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* Returned Value:
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* Calculated crc8
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*
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****************************************************************************/
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uint8_t onewire_crc8(FAR const uint8_t *input, uint8_t len);
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/****************************************************************************
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* Name: onewire_crc16
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*
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* Description:
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* Compute a Dallas Semiconductor 16 bit CRC. This is used to check
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* the integrity of received data from many 1-wire devices.
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*
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* Note: the CRC-16 computed here is not what you'll get from the 1-wire
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* network, because:
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* - The CRC-16 is transmitted bitwise inverted.
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* - The binary representation of the return value may have a different
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* byte order than the two bytes you get from 1-wire due to endian-ness.
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*
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* Input Parameters:
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* input - Input buffer for crc calculation
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* len - Buffer len
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* initial_crc - Initial crc for calculation
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*
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* Returned Value:
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* Calculated crc16
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*
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****************************************************************************/
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uint16_t onewire_crc16(FAR const uint8_t *input, uint16_t len,
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uint16_t initial_crc);
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/****************************************************************************
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* Name: onewire_check_crc16
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*
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* Description:
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* Check CRC-16 of received input
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*
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* Input Parameters:
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* input - Array of bytes to checksum
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* len - Length of input
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* inverted_crc - The two CRC16 bytes in the received data
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*
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* Returned Value:
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* true if CRC-16 matches
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*
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****************************************************************************/
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bool onewire_check_crc16(FAR const uint8_t *input, uint16_t len,
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FAR const uint8_t *inverted_crc);
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#endif /* __INCLUDE_NUTTX_1WIRE_1WIRE_CRC_H */
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