Mike Fruge / OneWire

Implementation of 1-Wire with added Alarm Search Functionality

Dependents:   Max32630_One_Wire_Interface

Utilities/crc.cpp@142:85b71cfd617e, 2019-08-13 (annotated)

Committer:
mfruge
Date:
Tue Aug 13 14:42:37 2019 +0000
Revision:
142:85b71cfd617e
Parent:
139:f0e0a7976846 
Added functions to ROMCommands to add Alarm Search functionality

Who changed what in which revision?

UserRevisionLine numberNew contents of line
j3 104:3f48daed532b 1 /******************************************************************//**
j3 104:3f48daed532b 2 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
j3 104:3f48daed532b 3 *
j3 104:3f48daed532b 4 * Permission is hereby granted, free of charge, to any person obtaining a
j3 104:3f48daed532b 5 * copy of this software and associated documentation files (the "Software"),
j3 104:3f48daed532b 6 * to deal in the Software without restriction, including without limitation
j3 104:3f48daed532b 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
j3 104:3f48daed532b 8 * and/or sell copies of the Software, and to permit persons to whom the
j3 104:3f48daed532b 9 * Software is furnished to do so, subject to the following conditions:
j3 104:3f48daed532b 10 *
j3 104:3f48daed532b 11 * The above copyright notice and this permission notice shall be included
j3 104:3f48daed532b 12 * in all copies or substantial portions of the Software.
j3 104:3f48daed532b 13 *
j3 104:3f48daed532b 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
j3 104:3f48daed532b 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
j3 104:3f48daed532b 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
j3 104:3f48daed532b 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
j3 104:3f48daed532b 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
j3 104:3f48daed532b 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
j3 104:3f48daed532b 20 * OTHER DEALINGS IN THE SOFTWARE.
j3 104:3f48daed532b 21 *
j3 104:3f48daed532b 22 * Except as contained in this notice, the name of Maxim Integrated
j3 104:3f48daed532b 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
j3 104:3f48daed532b 24 * Products, Inc. Branding Policy.
j3 104:3f48daed532b 25 *
j3 104:3f48daed532b 26 * The mere transfer of this software does not imply any licenses
j3 104:3f48daed532b 27 * of trade secrets, proprietary technology, copyrights, patents,
j3 104:3f48daed532b 28 * trademarks, maskwork rights, or any other form of intellectual
j3 104:3f48daed532b 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
j3 104:3f48daed532b 30 * ownership rights.
j3 104:3f48daed532b 31 **********************************************************************/
j3 104:3f48daed532b 32
j3 104:3f48daed532b 33 #include "Utilities/crc.h"
IanBenzMaxim 78:0cbbac7f2016 34
IanBenzMaxim 90:c233d1c265ff 35 namespace OneWire
j3 80:83b0d879cc32 36 {
IanBenzMaxim 90:c233d1c265ff 37 namespace crc
j3 80:83b0d879cc32 38 {
IanBenzMaxim 90:c233d1c265ff 39 uint8_t calculateCrc8(uint8_t crc8, uint8_t data)
j3 80:83b0d879cc32 40 {
IanBenzMaxim 90:c233d1c265ff 41 // See Application Note 27
IanBenzMaxim 90:c233d1c265ff 42 crc8 = crc8 ^ data;
IanBenzMaxim 90:c233d1c265ff 43 for (int i = 0; i < 8; i++)
IanBenzMaxim 90:c233d1c265ff 44 {
IanBenzMaxim 90:c233d1c265ff 45 if (crc8 & 1)
IanBenzMaxim 90:c233d1c265ff 46 {
IanBenzMaxim 90:c233d1c265ff 47 crc8 = (crc8 >> 1) ^ 0x8c;
IanBenzMaxim 90:c233d1c265ff 48 }
IanBenzMaxim 90:c233d1c265ff 49 else
IanBenzMaxim 90:c233d1c265ff 50 {
IanBenzMaxim 90:c233d1c265ff 51 crc8 = (crc8 >> 1);
IanBenzMaxim 90:c233d1c265ff 52 }
IanBenzMaxim 90:c233d1c265ff 53 }
IanBenzMaxim 90:c233d1c265ff 54
IanBenzMaxim 90:c233d1c265ff 55 return crc8;
IanBenzMaxim 90:c233d1c265ff 56 }
IanBenzMaxim 90:c233d1c265ff 57
IanBenzMaxim 90:c233d1c265ff 58 uint8_t calculateCrc8(const uint8_t * data, size_t dataLen, uint8_t crc)
IanBenzMaxim 90:c233d1c265ff 59 {
IanBenzMaxim 90:c233d1c265ff 60 for (size_t i = 0; i < dataLen; i++)
IanBenzMaxim 90:c233d1c265ff 61 {
IanBenzMaxim 90:c233d1c265ff 62 crc = calculateCrc8(crc, data[i]);
IanBenzMaxim 90:c233d1c265ff 63 }
IanBenzMaxim 90:c233d1c265ff 64 return crc;
j3 80:83b0d879cc32 65 }
IanBenzMaxim 90:c233d1c265ff 66
IanBenzMaxim 90:c233d1c265ff 67 uint16_t calculateCrc16(uint16_t crc16, uint16_t data)
j3 80:83b0d879cc32 68 {
IanBenzMaxim 90:c233d1c265ff 69 const uint16_t oddparity[] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
IanBenzMaxim 90:c233d1c265ff 70
IanBenzMaxim 90:c233d1c265ff 71 data = (data ^ (crc16 & 0xff)) & 0xff;
IanBenzMaxim 90:c233d1c265ff 72 crc16 >>= 8;
IanBenzMaxim 90:c233d1c265ff 73
IanBenzMaxim 90:c233d1c265ff 74 if (oddparity[data & 0xf] ^ oddparity[data >> 4])
IanBenzMaxim 90:c233d1c265ff 75 {
IanBenzMaxim 90:c233d1c265ff 76 crc16 ^= 0xc001;
IanBenzMaxim 90:c233d1c265ff 77 }
IanBenzMaxim 90:c233d1c265ff 78
IanBenzMaxim 90:c233d1c265ff 79 data <<= 6;
IanBenzMaxim 90:c233d1c265ff 80 crc16 ^= data;
IanBenzMaxim 90:c233d1c265ff 81 data <<= 1;
IanBenzMaxim 90:c233d1c265ff 82 crc16 ^= data;
IanBenzMaxim 90:c233d1c265ff 83
IanBenzMaxim 90:c233d1c265ff 84 return crc16;
IanBenzMaxim 90:c233d1c265ff 85 }
IanBenzMaxim 90:c233d1c265ff 86
j3 139:f0e0a7976846 87 uint16_t calculateCrc16(const uint8_t * data, size_t dataLen, uint16_t crc)
IanBenzMaxim 90:c233d1c265ff 88 {
j3 139:f0e0a7976846 89 for (size_t i = 0; i < dataLen; i++)
IanBenzMaxim 90:c233d1c265ff 90 {
IanBenzMaxim 90:c233d1c265ff 91 crc = calculateCrc16(crc, data[i]);
IanBenzMaxim 90:c233d1c265ff 92 }
IanBenzMaxim 90:c233d1c265ff 93 return crc;
j3 80:83b0d879cc32 94 }
j3 80:83b0d879cc32 95 }
j3 80:83b0d879cc32 96 }