Implementation of 1-Wire with added Alarm Search Functionality
Dependents: Max32630_One_Wire_Interface
Diff: Utilities/crc.cpp
- Revision:
- 90:c233d1c265ff
- Parent:
- 86:2ce08ca58b9e
- Child:
- 104:3f48daed532b
--- a/Utilities/crc.cpp Thu Jun 16 10:45:24 2016 -0500 +++ b/Utilities/crc.cpp Fri Jun 17 15:24:37 2016 -0500 @@ -1,61 +1,64 @@ - - #include "crc.h" - -uint8_t OneWire::crc::calculateCrc8(uint8_t crc8, uint8_t data) +namespace OneWire { - // See Application Note 27 - crc8 = crc8 ^ data; - for (int i = 0; i < 8; i++) + namespace crc { - if (crc8 & 1) + uint8_t calculateCrc8(uint8_t crc8, uint8_t data) { - crc8 = (crc8 >> 1) ^ 0x8c; + // See Application Note 27 + crc8 = crc8 ^ data; + for (int i = 0; i < 8; i++) + { + if (crc8 & 1) + { + crc8 = (crc8 >> 1) ^ 0x8c; + } + else + { + crc8 = (crc8 >> 1); + } + } + + return crc8; + } + + uint8_t calculateCrc8(const uint8_t * data, size_t dataLen, uint8_t crc) + { + for (size_t i = 0; i < dataLen; i++) + { + crc = calculateCrc8(crc, data[i]); + } + return crc; } - else + + uint16_t calculateCrc16(uint16_t crc16, uint16_t data) { - crc8 = (crc8 >> 1); + const uint16_t oddparity[] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 }; + + data = (data ^ (crc16 & 0xff)) & 0xff; + crc16 >>= 8; + + if (oddparity[data & 0xf] ^ oddparity[data >> 4]) + { + crc16 ^= 0xc001; + } + + data <<= 6; + crc16 ^= data; + data <<= 1; + crc16 ^= data; + + return crc16; + } + + uint16_t calculateCrc16(const uint8_t * data, size_t dataOffset, size_t dataLen, uint16_t crc) + { + for (size_t i = dataOffset; i < (dataLen + dataOffset); i++) + { + crc = calculateCrc16(crc, data[i]); + } + return crc; } } - - return crc8; } - -uint8_t OneWire::crc::calculateCrc8(const uint8_t * data, size_t dataLen, uint8_t crc) -{ - for (size_t i = 0; i < dataLen; i++) - { - crc = calculateCrc8(crc, data[i]); - } - return crc; -} - -uint16_t OneWire::crc::calculateCrc16(uint16_t crc16, uint16_t data) -{ - const uint16_t oddparity[] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 }; - - data = (data ^ (crc16 & 0xff)) & 0xff; - crc16 >>= 8; - - if (oddparity[data & 0xf] ^ oddparity[data >> 4]) - { - crc16 ^= 0xc001; - } - - data <<= 6; - crc16 ^= data; - data <<= 1; - crc16 ^= data; - - return crc16; -} - -uint16_t OneWire::crc::calculateCrc16(const uint8_t * data, size_t dataOffset, size_t dataLen, uint16_t crc) -{ - for (size_t i = dataOffset; i < (dataLen + dataOffset); i++) - { - crc = calculateCrc16(crc, data[i]); - } - return crc; -}