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Test 1-wire , working wtih parasite power and few sensors with mixed power supply.
crc8.cpp
- Committer:
- macraj
- Date:
- 2010-05-10
- Revision:
- 0:1197076b78f4
File content as of revision 0:1197076b78f4:
#include <inttypes.h> #define CRC8INIT 0x00 #define CRC8POLY 0x18 //0X18 = X^8+X^5+X^4+X^0 uint8_t crc8 ( uint8_t *data_in, uint16_t number_of_bytes_to_read ) { uint8_t crc; uint16_t loop_count; uint8_t bit_counter; uint8_t data; uint8_t 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; }