Implementation of 1-Wire with added Alarm Search Functionality
Dependents: Max32630_One_Wire_Interface
crc.cpp@78:0cbbac7f2016, 2016-05-16 (annotated)
- Committer:
- IanBenzMaxim
- Date:
- Mon May 16 15:18:09 2016 -0500
- Revision:
- 78:0cbbac7f2016
- Child:
- 80:83b0d879cc32
Code cleanup.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
IanBenzMaxim | 78:0cbbac7f2016 | 1 | #include "crc.h" |
IanBenzMaxim | 78:0cbbac7f2016 | 2 | |
IanBenzMaxim | 78:0cbbac7f2016 | 3 | uint16_t OneWire::crc::calculateCrc16(uint16_t crc16, uint16_t data) |
IanBenzMaxim | 78:0cbbac7f2016 | 4 | { |
IanBenzMaxim | 78:0cbbac7f2016 | 5 | const uint16_t oddparity[] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 }; |
IanBenzMaxim | 78:0cbbac7f2016 | 6 | |
IanBenzMaxim | 78:0cbbac7f2016 | 7 | data = (data ^ (crc16 & 0xff)) & 0xff; |
IanBenzMaxim | 78:0cbbac7f2016 | 8 | crc16 >>= 8; |
IanBenzMaxim | 78:0cbbac7f2016 | 9 | |
IanBenzMaxim | 78:0cbbac7f2016 | 10 | if (oddparity[data & 0xf] ^ oddparity[data >> 4]) |
IanBenzMaxim | 78:0cbbac7f2016 | 11 | { |
IanBenzMaxim | 78:0cbbac7f2016 | 12 | crc16 ^= 0xc001; |
IanBenzMaxim | 78:0cbbac7f2016 | 13 | } |
IanBenzMaxim | 78:0cbbac7f2016 | 14 | |
IanBenzMaxim | 78:0cbbac7f2016 | 15 | data <<= 6; |
IanBenzMaxim | 78:0cbbac7f2016 | 16 | crc16 ^= data; |
IanBenzMaxim | 78:0cbbac7f2016 | 17 | data <<= 1; |
IanBenzMaxim | 78:0cbbac7f2016 | 18 | crc16 ^= data; |
IanBenzMaxim | 78:0cbbac7f2016 | 19 | |
IanBenzMaxim | 78:0cbbac7f2016 | 20 | return crc16; |
IanBenzMaxim | 78:0cbbac7f2016 | 21 | } |
IanBenzMaxim | 78:0cbbac7f2016 | 22 | |
IanBenzMaxim | 78:0cbbac7f2016 | 23 | uint16_t OneWire::crc::calculateCrc16(const uint8_t * data, size_t dataOffset, size_t dataLen, uint16_t crc) |
IanBenzMaxim | 78:0cbbac7f2016 | 24 | { |
IanBenzMaxim | 78:0cbbac7f2016 | 25 | for (size_t i = dataOffset; i < (dataLen + dataOffset); i++) |
IanBenzMaxim | 78:0cbbac7f2016 | 26 | { |
IanBenzMaxim | 78:0cbbac7f2016 | 27 | crc = calculateCrc16(crc, data[i]); |
IanBenzMaxim | 78:0cbbac7f2016 | 28 | } |
IanBenzMaxim | 78:0cbbac7f2016 | 29 | return crc; |
IanBenzMaxim | 78:0cbbac7f2016 | 30 | } |