Plamen Totev / Mbed 2 deprecated peltier

peltier with 2 fans

Dependencies:   mbed TextLCD

DS18B20Multiple/OneWireCRC.cpp@4:5213bee8158e, 2014-04-14 (annotated)

Committer:
redplam
Date:
Mon Apr 14 02:15:32 2014 +0000
Revision:
4:5213bee8158e
myproject;

Who changed what in which revision?

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redplam 4:5213bee8158e 1 /*
redplam 4:5213bee8158e 2 * OneWireCRC. This is a port to mbed of Jim Studt's Adruino One Wire
redplam 4:5213bee8158e 3 * library. Please see additional copyrights below this one, including
redplam 4:5213bee8158e 4 * references to other copyrights.
redplam 4:5213bee8158e 5 *
redplam 4:5213bee8158e 6 * Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
redplam 4:5213bee8158e 7 *
redplam 4:5213bee8158e 8 * This file is part of OneWireCRC.
redplam 4:5213bee8158e 9 *
redplam 4:5213bee8158e 10 * OneWireCRC is free software: you can redistribute it and/or modify
redplam 4:5213bee8158e 11 * it under the terms of the GNU General Public License as published by
redplam 4:5213bee8158e 12 * the Free Software Foundation, either version 3 of the License, or
redplam 4:5213bee8158e 13 * (at your option) any later version.
redplam 4:5213bee8158e 14 *
redplam 4:5213bee8158e 15 * OneWireCRC is distributed in the hope that it will be useful,
redplam 4:5213bee8158e 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
redplam 4:5213bee8158e 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
redplam 4:5213bee8158e 18 * GNU General Public License for more details.
redplam 4:5213bee8158e 19 *
redplam 4:5213bee8158e 20 * You should have received a copy of the GNU General Public License
redplam 4:5213bee8158e 21 * along with OneWireCRC. If not, see <http://www.gnu.org/licenses/>.
redplam 4:5213bee8158e 22 */
redplam 4:5213bee8158e 23 /*
redplam 4:5213bee8158e 24 Copyright (c) 2007, Jim Studt
redplam 4:5213bee8158e 25
redplam 4:5213bee8158e 26 Updated to work with arduino-0008 and to include skip() as of
redplam 4:5213bee8158e 27 2007/07/06. --RJL20
redplam 4:5213bee8158e 28
redplam 4:5213bee8158e 29 Modified to calculate the 8-bit CRC directly, avoiding the need for
redplam 4:5213bee8158e 30 the 256-byte lookup table to be loaded in RAM. Tested in arduino-0010
redplam 4:5213bee8158e 31 -- Tom Pollard, Jan 23, 2008
redplam 4:5213bee8158e 32
redplam 4:5213bee8158e 33 Permission is hereby granted, free of charge, to any person obtaining
redplam 4:5213bee8158e 34 a copy of this software and associated documentation files (the
redplam 4:5213bee8158e 35 "Software"), to deal in the Software without restriction, including
redplam 4:5213bee8158e 36 without limitation the rights to use, copy, modify, merge, publish,
redplam 4:5213bee8158e 37 distribute, sublicense, and/or sell copies of the Software, and to
redplam 4:5213bee8158e 38 permit persons to whom the Software is furnished to do so, subject to
redplam 4:5213bee8158e 39 the following conditions:
redplam 4:5213bee8158e 40
redplam 4:5213bee8158e 41 The above copyright notice and this permission notice shall be
redplam 4:5213bee8158e 42 included in all copies or substantial portions of the Software.
redplam 4:5213bee8158e 43
redplam 4:5213bee8158e 44 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
redplam 4:5213bee8158e 45 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
redplam 4:5213bee8158e 46 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
redplam 4:5213bee8158e 47 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
redplam 4:5213bee8158e 48 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
redplam 4:5213bee8158e 49 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
redplam 4:5213bee8158e 50 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
redplam 4:5213bee8158e 51
redplam 4:5213bee8158e 52 Much of the code was inspired by Derek Yerger's code, though I don't
redplam 4:5213bee8158e 53 think much of that remains. In any event that was..
redplam 4:5213bee8158e 54 (copyleft) 2006 by Derek Yerger - Free to distribute freely.
redplam 4:5213bee8158e 55
redplam 4:5213bee8158e 56 The CRC code was excerpted and inspired by the Dallas Semiconductor
redplam 4:5213bee8158e 57 sample code bearing this copyright.
redplam 4:5213bee8158e 58 //---------------------------------------------------------------------------
redplam 4:5213bee8158e 59 // Copyright (C) 2000 Dallas Semiconductor Corporation, All Rights Reserved.
redplam 4:5213bee8158e 60 //
redplam 4:5213bee8158e 61 // Permission is hereby granted, free of charge, to any person obtaining a
redplam 4:5213bee8158e 62 // copy of this software and associated documentation files (the "Software"),
redplam 4:5213bee8158e 63 // to deal in the Software without restriction, including without limitation
redplam 4:5213bee8158e 64 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
redplam 4:5213bee8158e 65 // and/or sell copies of the Software, and to permit persons to whom the
redplam 4:5213bee8158e 66 // Software is furnished to do so, subject to the following conditions:
redplam 4:5213bee8158e 67 //
redplam 4:5213bee8158e 68 // The above copyright notice and this permission notice shall be included
redplam 4:5213bee8158e 69 // in all copies or substantial portions of the Software.
redplam 4:5213bee8158e 70 //
redplam 4:5213bee8158e 71 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
redplam 4:5213bee8158e 72 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
redplam 4:5213bee8158e 73 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
redplam 4:5213bee8158e 74 // IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES
redplam 4:5213bee8158e 75 // OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
redplam 4:5213bee8158e 76 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
redplam 4:5213bee8158e 77 // OTHER DEALINGS IN THE SOFTWARE.
redplam 4:5213bee8158e 78 //
redplam 4:5213bee8158e 79 // Except as contained in this notice, the name of Dallas Semiconductor
redplam 4:5213bee8158e 80 // shall not be used except as stated in the Dallas Semiconductor
redplam 4:5213bee8158e 81 // Branding Policy.
redplam 4:5213bee8158e 82 //--------------------------------------------------------------------------
redplam 4:5213bee8158e 83 */
redplam 4:5213bee8158e 84
redplam 4:5213bee8158e 85 #include "OneWireCRC.h"
redplam 4:5213bee8158e 86 #include "OneWireDefs.h"
redplam 4:5213bee8158e 87
redplam 4:5213bee8158e 88 // recommended data sheet timings in micro seconds
redplam 4:5213bee8158e 89 const int standardT[] = {6, 64, 60, 10, 9, 55, 0, 480, 70, 410};
redplam 4:5213bee8158e 90 const int overdriveT[] = {1.5, 7.5, 7.5, 2.5, 0.75, 7, 2.5, 70, 8.5, 40};
redplam 4:5213bee8158e 91
redplam 4:5213bee8158e 92 OneWireCRC::OneWireCRC(PinName oneWire, eSpeed speed) : oneWirePort(oneWire)
redplam 4:5213bee8158e 93 {
redplam 4:5213bee8158e 94 if (STANDARD == speed) timing = standardT;
redplam 4:5213bee8158e 95 else timing = overdriveT; // overdrive
redplam 4:5213bee8158e 96
redplam 4:5213bee8158e 97 resetSearch(); // reset address search state
redplam 4:5213bee8158e 98 }
redplam 4:5213bee8158e 99
redplam 4:5213bee8158e 100 // Generate a 1-wire reset, return 1 if no presence detect was found,
redplam 4:5213bee8158e 101 // return 0 otherwise.
redplam 4:5213bee8158e 102 // (NOTE: does not handle alarm presence from DS2404/DS1994)
redplam 4:5213bee8158e 103 int OneWireCRC::reset()
redplam 4:5213bee8158e 104 {
redplam 4:5213bee8158e 105
redplam 4:5213bee8158e 106 BYTE result = 0; // sample presence pulse result
redplam 4:5213bee8158e 107
redplam 4:5213bee8158e 108 wait_us(timing[6]);
redplam 4:5213bee8158e 109 oneWirePort.output();
redplam 4:5213bee8158e 110 oneWirePort = 0;
redplam 4:5213bee8158e 111 wait_us(timing[7]);
redplam 4:5213bee8158e 112 oneWirePort.input();
redplam 4:5213bee8158e 113 wait_us(timing[8]);
redplam 4:5213bee8158e 114 result = !(oneWirePort & 0x01);
redplam 4:5213bee8158e 115 wait_us(timing[9]);
redplam 4:5213bee8158e 116
redplam 4:5213bee8158e 117 return result;
redplam 4:5213bee8158e 118 }
redplam 4:5213bee8158e 119
redplam 4:5213bee8158e 120 //
redplam 4:5213bee8158e 121 // Write a bit. Port and bit is used to cut lookup time and provide
redplam 4:5213bee8158e 122 // more certain timing.
redplam 4:5213bee8158e 123 //
redplam 4:5213bee8158e 124 void OneWireCRC::writeBit(int bit)
redplam 4:5213bee8158e 125 {
redplam 4:5213bee8158e 126 bit = bit & 0x01;
redplam 4:5213bee8158e 127
redplam 4:5213bee8158e 128 if (bit)
redplam 4:5213bee8158e 129 {
redplam 4:5213bee8158e 130 // Write '1' bit
redplam 4:5213bee8158e 131 oneWirePort.output();
redplam 4:5213bee8158e 132 oneWirePort = 0;
redplam 4:5213bee8158e 133 wait_us(timing[0]);
redplam 4:5213bee8158e 134 oneWirePort.input();
redplam 4:5213bee8158e 135 wait_us(timing[1]);
redplam 4:5213bee8158e 136 }
redplam 4:5213bee8158e 137 else
redplam 4:5213bee8158e 138 {
redplam 4:5213bee8158e 139 // Write '0' bit
redplam 4:5213bee8158e 140 oneWirePort.output();
redplam 4:5213bee8158e 141 oneWirePort = 0;
redplam 4:5213bee8158e 142 wait_us(timing[2]);
redplam 4:5213bee8158e 143 oneWirePort.input();
redplam 4:5213bee8158e 144 wait_us(timing[3]);
redplam 4:5213bee8158e 145 }
redplam 4:5213bee8158e 146 }
redplam 4:5213bee8158e 147
redplam 4:5213bee8158e 148 //
redplam 4:5213bee8158e 149 // Read a bit. Port and bit is used to cut lookup time and provide
redplam 4:5213bee8158e 150 // more certain timing.
redplam 4:5213bee8158e 151 //
redplam 4:5213bee8158e 152 int OneWireCRC::readBit()
redplam 4:5213bee8158e 153 {
redplam 4:5213bee8158e 154 BYTE result;
redplam 4:5213bee8158e 155
redplam 4:5213bee8158e 156 oneWirePort.output();
redplam 4:5213bee8158e 157 oneWirePort = 0;
redplam 4:5213bee8158e 158 wait_us(timing[0]);
redplam 4:5213bee8158e 159 oneWirePort.input();
redplam 4:5213bee8158e 160 wait_us(timing[4]);
redplam 4:5213bee8158e 161 result = oneWirePort & 0x01;
redplam 4:5213bee8158e 162 wait_us(timing[5]);
redplam 4:5213bee8158e 163
redplam 4:5213bee8158e 164 return result;
redplam 4:5213bee8158e 165 }
redplam 4:5213bee8158e 166
redplam 4:5213bee8158e 167 //
redplam 4:5213bee8158e 168 // Write a byte. The writing code uses the active drivers to raise the
redplam 4:5213bee8158e 169 // pin high, if you need power after the write (e.g. DS18S20 in
redplam 4:5213bee8158e 170 // parasite power mode) then set 'power' to 1, otherwise the pin will
redplam 4:5213bee8158e 171 // go tri-state at the end of the write to avoid heating in a short or
redplam 4:5213bee8158e 172 // other mishap.
redplam 4:5213bee8158e 173 //
redplam 4:5213bee8158e 174 void OneWireCRC::writeByte(int data)
redplam 4:5213bee8158e 175 {
redplam 4:5213bee8158e 176 // Loop to write each bit in the byte, LS-bit first
redplam 4:5213bee8158e 177 for (int loop = 0; loop < 8; loop++)
redplam 4:5213bee8158e 178 {
redplam 4:5213bee8158e 179 writeBit(data & 0x01);
redplam 4:5213bee8158e 180
redplam 4:5213bee8158e 181 // shift the data byte for the next bit
redplam 4:5213bee8158e 182 data >>= 1;
redplam 4:5213bee8158e 183 }
redplam 4:5213bee8158e 184 }
redplam 4:5213bee8158e 185
redplam 4:5213bee8158e 186 //
redplam 4:5213bee8158e 187 // Read a byte
redplam 4:5213bee8158e 188 //
redplam 4:5213bee8158e 189 int OneWireCRC::readByte()
redplam 4:5213bee8158e 190 {
redplam 4:5213bee8158e 191 int result = 0;
redplam 4:5213bee8158e 192
redplam 4:5213bee8158e 193 for (int loop = 0; loop < 8; loop++)
redplam 4:5213bee8158e 194 {
redplam 4:5213bee8158e 195 // shift the result to get it ready for the next bit
redplam 4:5213bee8158e 196 result >>= 1;
redplam 4:5213bee8158e 197
redplam 4:5213bee8158e 198 // if result is one, then set MS bit
redplam 4:5213bee8158e 199 if (readBit()) result |= 0x80;
redplam 4:5213bee8158e 200 }
redplam 4:5213bee8158e 201
redplam 4:5213bee8158e 202 return result;
redplam 4:5213bee8158e 203 }
redplam 4:5213bee8158e 204
redplam 4:5213bee8158e 205 int OneWireCRC::touchByte(int data)
redplam 4:5213bee8158e 206 {
redplam 4:5213bee8158e 207 int result = 0;
redplam 4:5213bee8158e 208
redplam 4:5213bee8158e 209 for (int loop = 0; loop < 8; loop++)
redplam 4:5213bee8158e 210 {
redplam 4:5213bee8158e 211 // shift the result to get it ready for the next bit
redplam 4:5213bee8158e 212 result >>= 1;
redplam 4:5213bee8158e 213
redplam 4:5213bee8158e 214 // If sending a '1' then read a bit else write a '0'
redplam 4:5213bee8158e 215 if (data & 0x01)
redplam 4:5213bee8158e 216 {
redplam 4:5213bee8158e 217 if (readBit()) result |= 0x80;
redplam 4:5213bee8158e 218 }
redplam 4:5213bee8158e 219 else writeBit(0);
redplam 4:5213bee8158e 220
redplam 4:5213bee8158e 221 // shift the data byte for the next bit
redplam 4:5213bee8158e 222 data >>= 1;
redplam 4:5213bee8158e 223 }
redplam 4:5213bee8158e 224
redplam 4:5213bee8158e 225 return result;
redplam 4:5213bee8158e 226 }
redplam 4:5213bee8158e 227
redplam 4:5213bee8158e 228 void OneWireCRC::block(BYTE* data, int data_len)
redplam 4:5213bee8158e 229 {
redplam 4:5213bee8158e 230 for (int loop = 0; loop < data_len; loop++)
redplam 4:5213bee8158e 231 {
redplam 4:5213bee8158e 232 data[loop] = touchByte(data[loop]);
redplam 4:5213bee8158e 233 }
redplam 4:5213bee8158e 234 }
redplam 4:5213bee8158e 235
redplam 4:5213bee8158e 236 int OneWireCRC::overdriveSkip(BYTE* data, int data_len)
redplam 4:5213bee8158e 237 {
redplam 4:5213bee8158e 238 // set the speed to 'standard'
redplam 4:5213bee8158e 239 timing = standardT;
redplam 4:5213bee8158e 240
redplam 4:5213bee8158e 241 // reset all devices
redplam 4:5213bee8158e 242 if (reset()) return 0; // if no devices found
redplam 4:5213bee8158e 243
redplam 4:5213bee8158e 244 // overdrive skip command
redplam 4:5213bee8158e 245 writeByte(OVERDRIVE_SKIP);
redplam 4:5213bee8158e 246
redplam 4:5213bee8158e 247 // set the speed to 'overdrive'
redplam 4:5213bee8158e 248 timing = overdriveT;
redplam 4:5213bee8158e 249
redplam 4:5213bee8158e 250 // do a 1-Wire reset in 'overdrive' and return presence result
redplam 4:5213bee8158e 251 return reset();
redplam 4:5213bee8158e 252 }
redplam 4:5213bee8158e 253
redplam 4:5213bee8158e 254 //
redplam 4:5213bee8158e 255 // Do a ROM select
redplam 4:5213bee8158e 256 //
redplam 4:5213bee8158e 257 void OneWireCRC::matchROM(BYTE rom[8])
redplam 4:5213bee8158e 258 {
redplam 4:5213bee8158e 259 writeByte(MATCH_ROM); // Choose ROM
redplam 4:5213bee8158e 260
redplam 4:5213bee8158e 261 for(int i = 0; i < 8; i++) writeByte(rom[i]);
redplam 4:5213bee8158e 262 }
redplam 4:5213bee8158e 263
redplam 4:5213bee8158e 264 //
redplam 4:5213bee8158e 265 // Do a ROM skip
redplam 4:5213bee8158e 266 //
redplam 4:5213bee8158e 267 void OneWireCRC::skipROM()
redplam 4:5213bee8158e 268 {
redplam 4:5213bee8158e 269 writeByte(SKIP_ROM); // Skip ROM
redplam 4:5213bee8158e 270 }
redplam 4:5213bee8158e 271
redplam 4:5213bee8158e 272 //
redplam 4:5213bee8158e 273 // You need to use this function to start a search again from the beginning.
redplam 4:5213bee8158e 274 // You do not need to do it for the first search, though you could.
redplam 4:5213bee8158e 275 //
redplam 4:5213bee8158e 276 void OneWireCRC::resetSearch()
redplam 4:5213bee8158e 277 {
redplam 4:5213bee8158e 278 searchJunction = -1;
redplam 4:5213bee8158e 279 searchExhausted = false;
redplam 4:5213bee8158e 280 for (int i = 0; i < 8; i++)
redplam 4:5213bee8158e 281 {
redplam 4:5213bee8158e 282 address[i] = 0;
redplam 4:5213bee8158e 283 }
redplam 4:5213bee8158e 284 }
redplam 4:5213bee8158e 285
redplam 4:5213bee8158e 286 //
redplam 4:5213bee8158e 287 // Perform a search. If this function returns a '1' then it has
redplam 4:5213bee8158e 288 // enumerated the next device and you may retrieve the ROM from the
redplam 4:5213bee8158e 289 // OneWire::address variable. If there are no devices, no further
redplam 4:5213bee8158e 290 // devices, or something horrible happens in the middle of the
redplam 4:5213bee8158e 291 // enumeration then a 0 is returned. If a new device is found then
redplam 4:5213bee8158e 292 // its address is copied to newAddr. Use OneWire::reset_search() to
redplam 4:5213bee8158e 293 // start over.
redplam 4:5213bee8158e 294 //
redplam 4:5213bee8158e 295 BYTE OneWireCRC::search(BYTE* newAddr)
redplam 4:5213bee8158e 296 {
redplam 4:5213bee8158e 297 BYTE i;
redplam 4:5213bee8158e 298 int lastJunction = -1;
redplam 4:5213bee8158e 299 BYTE done = 1;
redplam 4:5213bee8158e 300
redplam 4:5213bee8158e 301 if (searchExhausted) return 0;
redplam 4:5213bee8158e 302
redplam 4:5213bee8158e 303 if (!reset()) return 0;
redplam 4:5213bee8158e 304
redplam 4:5213bee8158e 305 writeByte(SEARCH_ROM);
redplam 4:5213bee8158e 306
redplam 4:5213bee8158e 307 for(i = 0; i < 64; i++)
redplam 4:5213bee8158e 308 {
redplam 4:5213bee8158e 309 BYTE a = readBit( );
redplam 4:5213bee8158e 310 BYTE nota = readBit( );
redplam 4:5213bee8158e 311 BYTE ibyte = i/8;
redplam 4:5213bee8158e 312 BYTE ibit = 1 << (i & 7);
redplam 4:5213bee8158e 313
redplam 4:5213bee8158e 314 // I don't think this should happen, this means nothing responded, but maybe if
redplam 4:5213bee8158e 315 // something vanishes during the search it will come up.
redplam 4:5213bee8158e 316 if (a && nota) return 0;
redplam 4:5213bee8158e 317
redplam 4:5213bee8158e 318 if (!a && !nota)
redplam 4:5213bee8158e 319 {
redplam 4:5213bee8158e 320 if (i == searchJunction)
redplam 4:5213bee8158e 321 {
redplam 4:5213bee8158e 322 // this is our time to decide differently, we went zero last time, go one.
redplam 4:5213bee8158e 323 a = 1;
redplam 4:5213bee8158e 324 searchJunction = lastJunction;
redplam 4:5213bee8158e 325 }
redplam 4:5213bee8158e 326 else if (i < searchJunction)
redplam 4:5213bee8158e 327 {
redplam 4:5213bee8158e 328 // take whatever we took last time, look in address
redplam 4:5213bee8158e 329 if (address[ibyte] & ibit) a = 1;
redplam 4:5213bee8158e 330 else
redplam 4:5213bee8158e 331 {
redplam 4:5213bee8158e 332 // Only 0s count as pending junctions, we've already exhasuted the 0 side of 1s
redplam 4:5213bee8158e 333 a = 0;
redplam 4:5213bee8158e 334 done = 0;
redplam 4:5213bee8158e 335 lastJunction = i;
redplam 4:5213bee8158e 336 }
redplam 4:5213bee8158e 337 }
redplam 4:5213bee8158e 338 else
redplam 4:5213bee8158e 339 {
redplam 4:5213bee8158e 340 // we are blazing new tree, take the 0
redplam 4:5213bee8158e 341 a = 0;
redplam 4:5213bee8158e 342 searchJunction = i;
redplam 4:5213bee8158e 343 done = 0;
redplam 4:5213bee8158e 344 }
redplam 4:5213bee8158e 345 lastJunction = i;
redplam 4:5213bee8158e 346 }
redplam 4:5213bee8158e 347
redplam 4:5213bee8158e 348 if (a) address[ibyte] |= ibit;
redplam 4:5213bee8158e 349 else address[ibyte] &= ~ibit;
redplam 4:5213bee8158e 350
redplam 4:5213bee8158e 351 writeBit(a);
redplam 4:5213bee8158e 352 }
redplam 4:5213bee8158e 353
redplam 4:5213bee8158e 354 if (done) searchExhausted = true;
redplam 4:5213bee8158e 355
redplam 4:5213bee8158e 356 for (i = 0; i < 8; i++) newAddr[i] = address[i];
redplam 4:5213bee8158e 357
redplam 4:5213bee8158e 358 return 1;
redplam 4:5213bee8158e 359 }
redplam 4:5213bee8158e 360
redplam 4:5213bee8158e 361 // The 1-Wire CRC scheme is described in Maxim Application Note 27:
redplam 4:5213bee8158e 362 // "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
redplam 4:5213bee8158e 363 //
redplam 4:5213bee8158e 364
redplam 4:5213bee8158e 365 #if ONEWIRE_CRC8_TABLE
redplam 4:5213bee8158e 366 // This table comes from Dallas sample code where it is freely reusable,
redplam 4:5213bee8158e 367 // though Copyright (C) 2000 Dallas Semiconductor Corporation
redplam 4:5213bee8158e 368 static BYTE dscrc_table[] =
redplam 4:5213bee8158e 369 {
redplam 4:5213bee8158e 370 0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65,
redplam 4:5213bee8158e 371 157,195, 33,127,252,162, 64, 30, 95, 1,227,189, 62, 96,130,220,
redplam 4:5213bee8158e 372 35,125,159,193, 66, 28,254,160,225,191, 93, 3,128,222, 60, 98,
redplam 4:5213bee8158e 373 190,224, 2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255,
redplam 4:5213bee8158e 374 70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89, 7,
redplam 4:5213bee8158e 375 219,133,103, 57,186,228, 6, 88, 25, 71,165,251,120, 38,196,154,
redplam 4:5213bee8158e 376 101, 59,217,135, 4, 90,184,230,167,249, 27, 69,198,152,122, 36,
redplam 4:5213bee8158e 377 248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91, 5,231,185,
redplam 4:5213bee8158e 378 140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205,
redplam 4:5213bee8158e 379 17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80,
redplam 4:5213bee8158e 380 175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238,
redplam 4:5213bee8158e 381 50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115,
redplam 4:5213bee8158e 382 202,148,118, 40,171,245, 23, 73, 8, 86,180,234,105, 55,213,139,
redplam 4:5213bee8158e 383 87, 9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22,
redplam 4:5213bee8158e 384 233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168,
redplam 4:5213bee8158e 385 116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53};
redplam 4:5213bee8158e 386
redplam 4:5213bee8158e 387 //
redplam 4:5213bee8158e 388 // Compute a Dallas Semiconductor 8 bit CRC. These show up in the ROM
redplam 4:5213bee8158e 389 // and the registers. (note: this might better be done without the
redplam 4:5213bee8158e 390 // table, it would probably be smaller and certainly fast enough
redplam 4:5213bee8158e 391 // compared to all those delayMicrosecond() calls. But I got
redplam 4:5213bee8158e 392 // confused, so I use this table from the examples.)
redplam 4:5213bee8158e 393 //
redplam 4:5213bee8158e 394 BYTE OneWireCRC::crc8(BYTE* addr, BYTE len)
redplam 4:5213bee8158e 395 {
redplam 4:5213bee8158e 396 BYTE i;
redplam 4:5213bee8158e 397 BYTE crc = 0;
redplam 4:5213bee8158e 398
redplam 4:5213bee8158e 399 for (i = 0; i < len; i++)
redplam 4:5213bee8158e 400 {
redplam 4:5213bee8158e 401 crc = dscrc_table[crc ^ addr[i] ];
redplam 4:5213bee8158e 402 }
redplam 4:5213bee8158e 403
redplam 4:5213bee8158e 404 return crc;
redplam 4:5213bee8158e 405 }
redplam 4:5213bee8158e 406 #else
redplam 4:5213bee8158e 407 //
redplam 4:5213bee8158e 408 // Compute a Dallas Semiconductor 8 bit CRC directly.
redplam 4:5213bee8158e 409 //
redplam 4:5213bee8158e 410 BYTE OneWireCRC::crc8(BYTE* addr, BYTE len)
redplam 4:5213bee8158e 411 {
redplam 4:5213bee8158e 412 BYTE i, j;
redplam 4:5213bee8158e 413 BYTE crc = 0;
redplam 4:5213bee8158e 414
redplam 4:5213bee8158e 415 for (i = 0; i < len; i++)
redplam 4:5213bee8158e 416 {
redplam 4:5213bee8158e 417 BYTE inbyte = addr[i];
redplam 4:5213bee8158e 418 for (j = 0; j < 8; j++)
redplam 4:5213bee8158e 419 {
redplam 4:5213bee8158e 420 BYTE mix = (crc ^ inbyte) & 0x01;
redplam 4:5213bee8158e 421 crc >>= 1;
redplam 4:5213bee8158e 422 if (mix) crc ^= 0x8C;
redplam 4:5213bee8158e 423 inbyte >>= 1;
redplam 4:5213bee8158e 424 }
redplam 4:5213bee8158e 425 }
redplam 4:5213bee8158e 426
redplam 4:5213bee8158e 427 return crc;
redplam 4:5213bee8158e 428 }
redplam 4:5213bee8158e 429 #endif
redplam 4:5213bee8158e 430
redplam 4:5213bee8158e 431 static short oddparity[16] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
redplam 4:5213bee8158e 432
redplam 4:5213bee8158e 433 //
redplam 4:5213bee8158e 434 // Compute a Dallas Semiconductor 16 bit CRC. I have never seen one of
redplam 4:5213bee8158e 435 // these, but here it is.
redplam 4:5213bee8158e 436 //
redplam 4:5213bee8158e 437 unsigned short OneWireCRC::crc16(unsigned short* data, unsigned short len)
redplam 4:5213bee8158e 438 {
redplam 4:5213bee8158e 439 unsigned short i;
redplam 4:5213bee8158e 440 unsigned short crc = 0;
redplam 4:5213bee8158e 441
redplam 4:5213bee8158e 442 for ( i = 0; i < len; i++)
redplam 4:5213bee8158e 443 {
redplam 4:5213bee8158e 444 unsigned short cdata = data[len];
redplam 4:5213bee8158e 445
redplam 4:5213bee8158e 446 cdata = (cdata ^ (crc & 0xff)) & 0xff;
redplam 4:5213bee8158e 447 crc >>= 8;
redplam 4:5213bee8158e 448
redplam 4:5213bee8158e 449 if (oddparity[cdata & 0xf] ^ oddparity[cdata >> 4]) crc ^= 0xc001;
redplam 4:5213bee8158e 450
redplam 4:5213bee8158e 451 cdata <<= 6;
redplam 4:5213bee8158e 452 crc ^= cdata;
redplam 4:5213bee8158e 453 cdata <<= 1;
redplam 4:5213bee8158e 454 crc ^= cdata;
redplam 4:5213bee8158e 455 }
redplam 4:5213bee8158e 456
redplam 4:5213bee8158e 457 return crc;
redplam 4:5213bee8158e 458 }
redplam 4:5213bee8158e 459