crc8 Library - Original copyright: Colin O'Flynn - Copyright (c) 2002
Diff: crc8.cpp
- Revision:
- 0:cc65a6cec1a1
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/crc8.cpp Thu Oct 21 17:11:49 2010 +0000 @@ -0,0 +1,64 @@ +/* please read copyright-notice at EOF */ + +#include "crc8.h" + +#define CRC8INIT 0x00 +#define CRC8POLY 0x18 //0X18 = X^8+X^5+X^4+X^0 + +char crc8 ( char *data_in, int number_of_bytes_to_read ) +{ + char crc; + int loop_count; + char bit_counter; + char data; + char feedback_bit; + + crc = CRC8INIT; + + for (loop_count = 0; loop_count != number_of_bytes_to_read; loop_count++) + { + data = data_in[loop_count]; + + bit_counter = 8; + do { + feedback_bit = (crc ^ data) & 0x01; + + if ( feedback_bit == 0x01 ) { + crc = crc ^ CRC8POLY; + } + crc = (crc >> 1) & 0x7F; + if ( feedback_bit == 0x01 ) { + crc = crc | 0x80; + } + + data = data >> 1; + bit_counter--; + + } while (bit_counter > 0); + } + + return crc; +} + +/* +This code is from Colin O'Flynn - Copyright (c) 2002 +only minor changes by M.Thomas 9/2004 +oonverted to mbed library by Erik van Wijk 10/2010 + +Permission is hereby granted, free of charge, to any person obtaining a copy of +this software and associated documentation files (the "Software"), to deal in +the Software without restriction, including without limitation the rights to +use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of +the Software, and to permit persons to whom the Software is furnished to do so, +subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS +FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR +COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER +IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +*/