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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 74 | arune | 1 | /* please read copyright-notice at EOF */ |
| 2 | |||
| 3 | #include <inttypes.h> |
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| 4 | |||
| 5 | #define CRC8INIT 0x00 |
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| 6 | #define CRC8POLY 0x18 //0X18 = X^8+X^5+X^4+X^0 |
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| 7 | |||
| 8 | uint8_t crc8 ( uint8_t *data_in, uint16_t number_of_bytes_to_read ) |
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| 9 | { |
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| 10 | uint8_t crc; |
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| 11 | uint16_t loop_count; |
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| 12 | uint8_t bit_counter; |
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| 13 | uint8_t data; |
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| 14 | uint8_t feedback_bit; |
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| 15 | |||
| 16 | crc = CRC8INIT; |
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| 17 | |||
| 18 | for (loop_count = 0; loop_count != number_of_bytes_to_read; loop_count++) |
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| 19 | { |
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| 20 | data = data_in[loop_count]; |
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| 21 | |||
| 22 | bit_counter = 8; |
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| 23 | do { |
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| 24 | feedback_bit = (crc ^ data) & 0x01; |
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| 25 | |||
| 26 | if ( feedback_bit == 0x01 ) { |
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| 27 | crc = crc ^ CRC8POLY; |
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| 28 | } |
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| 29 | crc = (crc >> 1) & 0x7F; |
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| 30 | if ( feedback_bit == 0x01 ) { |
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| 31 | crc = crc | 0x80; |
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| 32 | } |
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| 33 | |||
| 34 | data = data >> 1; |
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| 35 | bit_counter--; |
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| 36 | |||
| 37 | } while (bit_counter > 0); |
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| 38 | } |
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| 39 | |||
| 40 | return crc; |
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| 41 | } |
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| 42 | |||
| 43 | /* |
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| 44 | This code is from Colin O'Flynn - Copyright (c) 2002 |
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| 45 | only minor changes by M.Thomas 9/2004 |
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| 46 | |||
| 47 | Permission is hereby granted, free of charge, to any person obtaining a copy of |
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| 48 | this software and associated documentation files (the "Software"), to deal in |
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| 49 | the Software without restriction, including without limitation the rights to |
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| 50 | use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of |
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| 51 | the Software, and to permit persons to whom the Software is furnished to do so, |
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| 52 | subject to the following conditions: |
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| 53 | |||
| 54 | The above copyright notice and this permission notice shall be included in all |
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| 55 | copies or substantial portions of the Software. |
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| 56 | |||
| 57 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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| 58 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS |
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| 59 | FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR |
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| 60 | COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER |
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| 61 | IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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| 62 | CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
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| 63 | */ |