64 lines
1.8 KiB
C
64 lines
1.8 KiB
C
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/* please read copyright-notice at EOF */
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#include <stdint.h>
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#define CRC8INIT 0x00
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#define CRC8POLY 0x18 //0X18 = X^8+X^5+X^4+X^0
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uint8_t crc8( uint8_t *data, uint16_t number_of_bytes_in_data )
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{
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uint8_t crc;
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uint16_t loop_count;
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uint8_t bit_counter;
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uint8_t b;
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uint8_t feedback_bit;
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crc = CRC8INIT;
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for (loop_count = 0; loop_count != number_of_bytes_in_data; loop_count++)
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{
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b = data[loop_count];
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bit_counter = 8;
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do {
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feedback_bit = (crc ^ b) & 0x01;
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if ( feedback_bit == 0x01 ) {
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crc = crc ^ CRC8POLY;
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}
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crc = (crc >> 1) & 0x7F;
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if ( feedback_bit == 0x01 ) {
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crc = crc | 0x80;
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}
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b = b >> 1;
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bit_counter--;
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} while (bit_counter > 0);
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}
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return crc;
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}
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/*
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This code is from Colin O'Flynn - Copyright (c) 2002
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only minor changes by M.Thomas 9/2004
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Permission is hereby granted, free of charge, to any person obtaining a copy of
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this software and associated documentation files (the "Software"), to deal in
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the Software without restriction, including without limitation the rights to
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use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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the Software, and to permit persons to whom the Software is furnished to do so,
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subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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