Руслан Бредун / Mbed 2 deprecated stm32-sensor-base2

test

Dependencies:   mbed Watchdog

Dependents:   STM32-MC_node

DS1820/OneWire/OneWire.cpp@11:32eeb052cda5, 2020-08-26 (annotated)

Committer:
ommpy
Date:
Wed Aug 26 14:26:27 2020 +0530
Revision:
11:32eeb052cda5
added temp sensor in code

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ommpy 11:32eeb052cda5 1 /*
ommpy 11:32eeb052cda5 2 Copyright (c) 2007, Jim Studt (original old version - many contributors since)
ommpy 11:32eeb052cda5 3
ommpy 11:32eeb052cda5 4 The latest version of this library may be found at:
ommpy 11:32eeb052cda5 5 http://www.pjrc.com/teensy/td_libs_Onehtml
ommpy 11:32eeb052cda5 6
ommpy 11:32eeb052cda5 7 OneWire has been maintained by Paul Stoffregen (paul@pjrc.com) since
ommpy 11:32eeb052cda5 8 January 2010. At the time, it was in need of many bug fixes, but had
ommpy 11:32eeb052cda5 9 been abandoned the original author (Jim Studt). None of the known
ommpy 11:32eeb052cda5 10 contributors were interested in maintaining One Paul typically
ommpy 11:32eeb052cda5 11 works on OneWire every 6 to 12 months. Patches usually wait that
ommpy 11:32eeb052cda5 12 long. If anyone is interested in more actively maintaining OneWire,
ommpy 11:32eeb052cda5 13 please contact Paul.
ommpy 11:32eeb052cda5 14
ommpy 11:32eeb052cda5 15 Version 2.2:
ommpy 11:32eeb052cda5 16 Teensy 3.0 compatibility, Paul Stoffregen, paul@pjrc.com
ommpy 11:32eeb052cda5 17 Arduino Due compatibility, http://arduino.cc/forum/index.php?topic=141030
ommpy 11:32eeb052cda5 18 Fix DS18B20 example negative temperature
ommpy 11:32eeb052cda5 19 Fix DS18B20 example's low res modes, Ken Butcher
ommpy 11:32eeb052cda5 20 Improve reset timing, Mark Tillotson
ommpy 11:32eeb052cda5 21 Add const qualifiers, Bertrik Sikken
ommpy 11:32eeb052cda5 22 Add initial value input to crc16, Bertrik Sikken
ommpy 11:32eeb052cda5 23 Add target_search() function, Scott Roberts
ommpy 11:32eeb052cda5 24
ommpy 11:32eeb052cda5 25 Version 2.1:
ommpy 11:32eeb052cda5 26 Arduino 1.0 compatibility, Paul Stoffregen
ommpy 11:32eeb052cda5 27 Improve temperature example, Paul Stoffregen
ommpy 11:32eeb052cda5 28 DS250x_PROM example, Guillermo Lovato
ommpy 11:32eeb052cda5 29 PIC32 (chipKit) compatibility, Jason Dangel, dangel.jason AT gmail.com
ommpy 11:32eeb052cda5 30 Improvements from Glenn Trewitt:
ommpy 11:32eeb052cda5 31 - crc16() now works
ommpy 11:32eeb052cda5 32 - check_crc16() does all of calculation/checking work.
ommpy 11:32eeb052cda5 33 - Added read_bytes() and write_bytes(), to reduce tedious loops.
ommpy 11:32eeb052cda5 34 - Added ds2408 example.
ommpy 11:32eeb052cda5 35 Delete very old, out-of-date readme file (info is here)
ommpy 11:32eeb052cda5 36
ommpy 11:32eeb052cda5 37 Version 2.0: Modifications by Paul Stoffregen, January 2010:
ommpy 11:32eeb052cda5 38 http://www.pjrc.com/teensy/td_libs_Onehtml
ommpy 11:32eeb052cda5 39 Search fix from Robin James
ommpy 11:32eeb052cda5 40 http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295/27#27
ommpy 11:32eeb052cda5 41 Use direct optimized I/O in all cases
ommpy 11:32eeb052cda5 42 Disable interrupts during timing critical sections
ommpy 11:32eeb052cda5 43 (this solves many random communication errors)
ommpy 11:32eeb052cda5 44 Disable interrupts during read-modify-write I/O
ommpy 11:32eeb052cda5 45 Reduce RAM consumption by eliminating unnecessary
ommpy 11:32eeb052cda5 46 variables and trimming many to 8 bits
ommpy 11:32eeb052cda5 47 Optimize both crc8 - table version moved to flash
ommpy 11:32eeb052cda5 48
ommpy 11:32eeb052cda5 49 Modified to work with larger numbers of devices - avoids loop.
ommpy 11:32eeb052cda5 50 Tested in Arduino 11 alpha with 12 sensors.
ommpy 11:32eeb052cda5 51 26 Sept 2008 -- Robin James
ommpy 11:32eeb052cda5 52 http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295/27#27
ommpy 11:32eeb052cda5 53
ommpy 11:32eeb052cda5 54 Updated to work with arduino-0008 and to include skip() as of
ommpy 11:32eeb052cda5 55 2007/07/06. --RJL20
ommpy 11:32eeb052cda5 56
ommpy 11:32eeb052cda5 57 Modified to calculate the 8-bit CRC directly, avoiding the need for
ommpy 11:32eeb052cda5 58 the 256-byte lookup table to be loaded in RAM. Tested in arduino-0010
ommpy 11:32eeb052cda5 59 -- Tom Pollard, Jan 23, 2008
ommpy 11:32eeb052cda5 60
ommpy 11:32eeb052cda5 61 Jim Studt's original library was modified by Josh Larios.
ommpy 11:32eeb052cda5 62
ommpy 11:32eeb052cda5 63 Tom Pollard, pollard@alum.mit.edu, contributed around May 20, 2008
ommpy 11:32eeb052cda5 64
ommpy 11:32eeb052cda5 65 Permission is hereby granted, free of charge, to any person obtaining
ommpy 11:32eeb052cda5 66 a copy of this software and associated documentation files (the
ommpy 11:32eeb052cda5 67 "Software"), to deal in the Software without restriction, including
ommpy 11:32eeb052cda5 68 without limitation the rights to use, copy, modify, merge, publish,
ommpy 11:32eeb052cda5 69 distribute, sublicense, and/or sell copies of the Software, and to
ommpy 11:32eeb052cda5 70 permit persons to whom the Software is furnished to do so, subject to
ommpy 11:32eeb052cda5 71 the following conditions:
ommpy 11:32eeb052cda5 72
ommpy 11:32eeb052cda5 73 The above copyright notice and this permission notice shall be
ommpy 11:32eeb052cda5 74 included in all copies or substantial portions of the Software.
ommpy 11:32eeb052cda5 75
ommpy 11:32eeb052cda5 76 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
ommpy 11:32eeb052cda5 77 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
ommpy 11:32eeb052cda5 78 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
ommpy 11:32eeb052cda5 79 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
ommpy 11:32eeb052cda5 80 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
ommpy 11:32eeb052cda5 81 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
ommpy 11:32eeb052cda5 82 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
ommpy 11:32eeb052cda5 83
ommpy 11:32eeb052cda5 84 Much of the code was inspired by Derek Yerger's code, though I don't
ommpy 11:32eeb052cda5 85 think much of that remains. In any event that was..
ommpy 11:32eeb052cda5 86 (copyleft) 2006 by Derek Yerger - Free to distribute freely.
ommpy 11:32eeb052cda5 87
ommpy 11:32eeb052cda5 88 The CRC code was excerpted and inspired by the Dallas Semiconductor
ommpy 11:32eeb052cda5 89 sample code bearing this copyright.
ommpy 11:32eeb052cda5 90 //---------------------------------------------------------------------------
ommpy 11:32eeb052cda5 91 // Copyright (C) 2000 Dallas Semiconductor Corporation, All Rights Reserved.
ommpy 11:32eeb052cda5 92 //
ommpy 11:32eeb052cda5 93 // Permission is hereby granted, free of charge, to any person obtaining a
ommpy 11:32eeb052cda5 94 // copy of this software and associated documentation files (the "Software"),
ommpy 11:32eeb052cda5 95 // to deal in the Software without restriction, including without limitation
ommpy 11:32eeb052cda5 96 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
ommpy 11:32eeb052cda5 97 // and/or sell copies of the Software, and to permit persons to whom the
ommpy 11:32eeb052cda5 98 // Software is furnished to do so, subject to the following conditions:
ommpy 11:32eeb052cda5 99 //
ommpy 11:32eeb052cda5 100 // The above copyright notice and this permission notice shall be included
ommpy 11:32eeb052cda5 101 // in all copies or substantial portions of the Software.
ommpy 11:32eeb052cda5 102 //
ommpy 11:32eeb052cda5 103 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
ommpy 11:32eeb052cda5 104 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
ommpy 11:32eeb052cda5 105 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
ommpy 11:32eeb052cda5 106 // IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES
ommpy 11:32eeb052cda5 107 // OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ommpy 11:32eeb052cda5 108 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
ommpy 11:32eeb052cda5 109 // OTHER DEALINGS IN THE SOFTWARE.
ommpy 11:32eeb052cda5 110 //
ommpy 11:32eeb052cda5 111 // Except as contained in this notice, the name of Dallas Semiconductor
ommpy 11:32eeb052cda5 112 // shall not be used except as stated in the Dallas Semiconductor
ommpy 11:32eeb052cda5 113 // Branding Policy.
ommpy 11:32eeb052cda5 114 //--------------------------------------------------------------------------
ommpy 11:32eeb052cda5 115 */
ommpy 11:32eeb052cda5 116 #include "OneWire.h"
ommpy 11:32eeb052cda5 117
ommpy 11:32eeb052cda5 118
ommpy 11:32eeb052cda5 119 /**
ommpy 11:32eeb052cda5 120 * @brief Constructs a OneWire object.
ommpy 11:32eeb052cda5 121 * @note GPIO is configured as output and an internal pull up resistor is connected.
ommpy 11:32eeb052cda5 122 * But because for STM chips it takes very long time to change from output
ommpy 11:32eeb052cda5 123 * to input an open drain mode is used rather and the GPIO remains output forever.
ommpy 11:32eeb052cda5 124 * @param
ommpy 11:32eeb052cda5 125 * @retval
ommpy 11:32eeb052cda5 126 */
ommpy 11:32eeb052cda5 127 OneWire::OneWire(PinName pin, int sample_point_us /* = 13 */) :
ommpy 11:32eeb052cda5 128 DigitalInOut(pin),
ommpy 11:32eeb052cda5 129 _sample_point_us(sample_point_us)
ommpy 11:32eeb052cda5 130 {
ommpy 11:32eeb052cda5 131 Timer timer;
ommpy 11:32eeb052cda5 132
ommpy 11:32eeb052cda5 133 MODE(); // set mode to either OpenDrain for STM or PullUp for others
ommpy 11:32eeb052cda5 134
ommpy 11:32eeb052cda5 135 // Measure bus transition time from ouput to input
ommpy 11:32eeb052cda5 136 timer.reset();
ommpy 11:32eeb052cda5 137 OUTPUT(); // set as output
ommpy 11:32eeb052cda5 138 WRITE(0); // pull the line down
ommpy 11:32eeb052cda5 139 timer.start();
ommpy 11:32eeb052cda5 140 INPUT(); // set as input (and release the bus)
ommpy 11:32eeb052cda5 141 timer.stop();
ommpy 11:32eeb052cda5 142 _out_to_in_transition_us = timer.read_us();
ommpy 11:32eeb052cda5 143
ommpy 11:32eeb052cda5 144 MBED_ASSERT(_out_to_in_transition_us < _sample_point_us);
ommpy 11:32eeb052cda5 145
ommpy 11:32eeb052cda5 146 INIT_WAIT;
ommpy 11:32eeb052cda5 147 #if ONEWIRE_SEARCH
ommpy 11:32eeb052cda5 148 reset_search();
ommpy 11:32eeb052cda5 149 #endif
ommpy 11:32eeb052cda5 150 }
ommpy 11:32eeb052cda5 151
ommpy 11:32eeb052cda5 152 /**
ommpy 11:32eeb052cda5 153 * @brief Performs the onewire reset function.
ommpy 11:32eeb052cda5 154 * @note We will wait up to 250uS for the bus to come high,
ommpy 11:32eeb052cda5 155 * if it doesn't then it is broken or shorted and we return a 0;
ommpy 11:32eeb052cda5 156 * @param
ommpy 11:32eeb052cda5 157 * @retval 1 if a device asserted a presence pulse, 0 otherwise.
ommpy 11:32eeb052cda5 158 */
ommpy 11:32eeb052cda5 159 uint8_t OneWire::reset(void)
ommpy 11:32eeb052cda5 160 {
ommpy 11:32eeb052cda5 161 uint8_t present;
ommpy 11:32eeb052cda5 162
ommpy 11:32eeb052cda5 163 OUTPUT();
ommpy 11:32eeb052cda5 164 WRITE(0); // pull down the 1-wire bus do create reset pulse
ommpy 11:32eeb052cda5 165 WAIT_US(500); // wait at least 480 us
ommpy 11:32eeb052cda5 166 INPUT(); // release the 1-wire bus and go into receive mode
ommpy 11:32eeb052cda5 167 WAIT_US(90); // DS1820 waits about 15 to 60 us and generates a 60 to 240 us presence pulse
ommpy 11:32eeb052cda5 168 present = !READ(); // read the presence pulse
ommpy 11:32eeb052cda5 169 WAIT_US(420);
ommpy 11:32eeb052cda5 170
ommpy 11:32eeb052cda5 171 return present;
ommpy 11:32eeb052cda5 172 }
ommpy 11:32eeb052cda5 173
ommpy 11:32eeb052cda5 174 /**
ommpy 11:32eeb052cda5 175 * @brief Writes a bit.
ommpy 11:32eeb052cda5 176 * @note GPIO registers are used for STM chips to cut time.
ommpy 11:32eeb052cda5 177 * @param
ommpy 11:32eeb052cda5 178 * @retval
ommpy 11:32eeb052cda5 179 */
ommpy 11:32eeb052cda5 180 void OneWire::write_bit(uint8_t v)
ommpy 11:32eeb052cda5 181 {
ommpy 11:32eeb052cda5 182 OUTPUT();
ommpy 11:32eeb052cda5 183 if (v & 1) {
ommpy 11:32eeb052cda5 184 WRITE(0); // drive output low
ommpy 11:32eeb052cda5 185 WAIT_US(1);
ommpy 11:32eeb052cda5 186 WRITE(1); // drive output high
ommpy 11:32eeb052cda5 187 WAIT_US(60);
ommpy 11:32eeb052cda5 188 }
ommpy 11:32eeb052cda5 189 else {
ommpy 11:32eeb052cda5 190 WRITE(0); // drive output low
ommpy 11:32eeb052cda5 191 WAIT_US(60);
ommpy 11:32eeb052cda5 192 WRITE(1); // drive output high
ommpy 11:32eeb052cda5 193 WAIT_US(1);
ommpy 11:32eeb052cda5 194 }
ommpy 11:32eeb052cda5 195 }
ommpy 11:32eeb052cda5 196
ommpy 11:32eeb052cda5 197 /**
ommpy 11:32eeb052cda5 198 * @brief Reads a bit.
ommpy 11:32eeb052cda5 199 * @note GPIO registers are used for STM chips to cut time.
ommpy 11:32eeb052cda5 200 * @param
ommpy 11:32eeb052cda5 201 * @retval
ommpy 11:32eeb052cda5 202 */
ommpy 11:32eeb052cda5 203 uint8_t OneWire::read_bit(void)
ommpy 11:32eeb052cda5 204 {
ommpy 11:32eeb052cda5 205 uint8_t r;
ommpy 11:32eeb052cda5 206
ommpy 11:32eeb052cda5 207 OUTPUT();
ommpy 11:32eeb052cda5 208 WRITE(0);
ommpy 11:32eeb052cda5 209 INPUT();
ommpy 11:32eeb052cda5 210 wait_us(_sample_point_us - _out_to_in_transition_us); // wait till sample point
ommpy 11:32eeb052cda5 211 r = READ();
ommpy 11:32eeb052cda5 212 WAIT_US(55);
ommpy 11:32eeb052cda5 213 return r;
ommpy 11:32eeb052cda5 214 }
ommpy 11:32eeb052cda5 215
ommpy 11:32eeb052cda5 216 /**
ommpy 11:32eeb052cda5 217 * @brief Writes a byte.
ommpy 11:32eeb052cda5 218 * @note The writing code uses the active drivers to raise the
ommpy 11:32eeb052cda5 219 pin high, if you need power after the write (e.g. DS18S20 in
ommpy 11:32eeb052cda5 220 parasite power mode) then set 'power' to 1, otherwise the pin will
ommpy 11:32eeb052cda5 221 go tri-state at the end of the write to avoid heating in a short or
ommpy 11:32eeb052cda5 222 other mishap.
ommpy 11:32eeb052cda5 223 * @param
ommpy 11:32eeb052cda5 224 * @retval
ommpy 11:32eeb052cda5 225 */
ommpy 11:32eeb052cda5 226 void OneWire::write_byte(uint8_t v, uint8_t power /* = 0 */ )
ommpy 11:32eeb052cda5 227 {
ommpy 11:32eeb052cda5 228 uint8_t bitMask;
ommpy 11:32eeb052cda5 229
ommpy 11:32eeb052cda5 230 for (bitMask = 0x01; bitMask; bitMask <<= 1)
ommpy 11:32eeb052cda5 231 write_bit((bitMask & v) ? 1 : 0);
ommpy 11:32eeb052cda5 232 if (!power)
ommpy 11:32eeb052cda5 233 INPUT();
ommpy 11:32eeb052cda5 234 }
ommpy 11:32eeb052cda5 235
ommpy 11:32eeb052cda5 236 /**
ommpy 11:32eeb052cda5 237 * @brief Writes bytes.
ommpy 11:32eeb052cda5 238 * @note
ommpy 11:32eeb052cda5 239 * @param
ommpy 11:32eeb052cda5 240 * @retval
ommpy 11:32eeb052cda5 241 */
ommpy 11:32eeb052cda5 242 void OneWire::write_bytes(const uint8_t* buf, uint16_t count, bool power /* = 0 */ )
ommpy 11:32eeb052cda5 243 {
ommpy 11:32eeb052cda5 244 for (uint16_t i = 0; i < count; i++)
ommpy 11:32eeb052cda5 245 write_byte(buf[i]);
ommpy 11:32eeb052cda5 246 if (!power)
ommpy 11:32eeb052cda5 247 INPUT();
ommpy 11:32eeb052cda5 248 }
ommpy 11:32eeb052cda5 249
ommpy 11:32eeb052cda5 250 /**
ommpy 11:32eeb052cda5 251 * @brief Reads a byte.
ommpy 11:32eeb052cda5 252 * @note
ommpy 11:32eeb052cda5 253 * @param
ommpy 11:32eeb052cda5 254 * @retval
ommpy 11:32eeb052cda5 255 */
ommpy 11:32eeb052cda5 256 uint8_t OneWire::read_byte()
ommpy 11:32eeb052cda5 257 {
ommpy 11:32eeb052cda5 258 uint8_t bitMask;
ommpy 11:32eeb052cda5 259 uint8_t r = 0;
ommpy 11:32eeb052cda5 260
ommpy 11:32eeb052cda5 261 for (bitMask = 0x01; bitMask; bitMask <<= 1) {
ommpy 11:32eeb052cda5 262 if (read_bit())
ommpy 11:32eeb052cda5 263 r |= bitMask;
ommpy 11:32eeb052cda5 264 }
ommpy 11:32eeb052cda5 265
ommpy 11:32eeb052cda5 266 return r;
ommpy 11:32eeb052cda5 267 }
ommpy 11:32eeb052cda5 268
ommpy 11:32eeb052cda5 269 /**
ommpy 11:32eeb052cda5 270 * @brief Reads bytes.
ommpy 11:32eeb052cda5 271 * @note
ommpy 11:32eeb052cda5 272 * @param
ommpy 11:32eeb052cda5 273 * @retval
ommpy 11:32eeb052cda5 274 */
ommpy 11:32eeb052cda5 275 void OneWire::read_bytes(uint8_t* buf, uint16_t count)
ommpy 11:32eeb052cda5 276 {
ommpy 11:32eeb052cda5 277 for (uint16_t i = 0; i < count; i++)
ommpy 11:32eeb052cda5 278 buf[i] = read_byte();
ommpy 11:32eeb052cda5 279 }
ommpy 11:32eeb052cda5 280
ommpy 11:32eeb052cda5 281 /**
ommpy 11:32eeb052cda5 282 * @brief Selects ROM.
ommpy 11:32eeb052cda5 283 * @note
ommpy 11:32eeb052cda5 284 * @param
ommpy 11:32eeb052cda5 285 * @retval
ommpy 11:32eeb052cda5 286 */
ommpy 11:32eeb052cda5 287 void OneWire::select(const uint8_t rom[8])
ommpy 11:32eeb052cda5 288 {
ommpy 11:32eeb052cda5 289 uint8_t i;
ommpy 11:32eeb052cda5 290
ommpy 11:32eeb052cda5 291 write_byte(0x55); // Choose ROM
ommpy 11:32eeb052cda5 292 for (i = 0; i < 8; i++)
ommpy 11:32eeb052cda5 293 write_byte(rom[i]);
ommpy 11:32eeb052cda5 294 }
ommpy 11:32eeb052cda5 295
ommpy 11:32eeb052cda5 296 /**
ommpy 11:32eeb052cda5 297 * @brief Skips ROM select.
ommpy 11:32eeb052cda5 298 * @note
ommpy 11:32eeb052cda5 299 * @param
ommpy 11:32eeb052cda5 300 * @retval
ommpy 11:32eeb052cda5 301 */
ommpy 11:32eeb052cda5 302 void OneWire::skip()
ommpy 11:32eeb052cda5 303 {
ommpy 11:32eeb052cda5 304 write_byte(0xCC); // Skip ROM
ommpy 11:32eeb052cda5 305 }
ommpy 11:32eeb052cda5 306
ommpy 11:32eeb052cda5 307 /**
ommpy 11:32eeb052cda5 308 * @brief Unpowers the chip.
ommpy 11:32eeb052cda5 309 * @note
ommpy 11:32eeb052cda5 310 * @param
ommpy 11:32eeb052cda5 311 * @retval
ommpy 11:32eeb052cda5 312 */
ommpy 11:32eeb052cda5 313 void OneWire::depower()
ommpy 11:32eeb052cda5 314 {
ommpy 11:32eeb052cda5 315 INPUT();
ommpy 11:32eeb052cda5 316 }
ommpy 11:32eeb052cda5 317
ommpy 11:32eeb052cda5 318 #if ONEWIRE_SEARCH
ommpy 11:32eeb052cda5 319 //
ommpy 11:32eeb052cda5 320
ommpy 11:32eeb052cda5 321 /**
ommpy 11:32eeb052cda5 322 * @brief Resets the search state.
ommpy 11:32eeb052cda5 323 * @note We need to use this function to start a search again from the beginning.
ommpy 11:32eeb052cda5 324 * We do not need to do it for the first search, though we could.
ommpy 11:32eeb052cda5 325 * @param
ommpy 11:32eeb052cda5 326 * @retval
ommpy 11:32eeb052cda5 327 */
ommpy 11:32eeb052cda5 328 void OneWire::reset_search()
ommpy 11:32eeb052cda5 329 {
ommpy 11:32eeb052cda5 330 // reset the search state
ommpy 11:32eeb052cda5 331 LastDiscrepancy = 0;
ommpy 11:32eeb052cda5 332 LastDeviceFlag = false;
ommpy 11:32eeb052cda5 333 LastFamilyDiscrepancy = 0;
ommpy 11:32eeb052cda5 334 for (int i = 7;; i--) {
ommpy 11:32eeb052cda5 335 ROM_NO[i] = 0;
ommpy 11:32eeb052cda5 336 if (i == 0)
ommpy 11:32eeb052cda5 337 break;
ommpy 11:32eeb052cda5 338 }
ommpy 11:32eeb052cda5 339 }
ommpy 11:32eeb052cda5 340
ommpy 11:32eeb052cda5 341 /**
ommpy 11:32eeb052cda5 342 * @brief Sets the search state to find SearchFamily type devices.
ommpy 11:32eeb052cda5 343 * @note
ommpy 11:32eeb052cda5 344 * @param
ommpy 11:32eeb052cda5 345 * @retval
ommpy 11:32eeb052cda5 346 */
ommpy 11:32eeb052cda5 347 void OneWire::target_search(uint8_t family_code)
ommpy 11:32eeb052cda5 348 {
ommpy 11:32eeb052cda5 349 // set the search state to find SearchFamily type devices
ommpy 11:32eeb052cda5 350 ROM_NO[0] = family_code;
ommpy 11:32eeb052cda5 351 for (uint8_t i = 1; i < 8; i++)
ommpy 11:32eeb052cda5 352 ROM_NO[i] = 0;
ommpy 11:32eeb052cda5 353 LastDiscrepancy = 64;
ommpy 11:32eeb052cda5 354 LastFamilyDiscrepancy = 0;
ommpy 11:32eeb052cda5 355 LastDeviceFlag = false;
ommpy 11:32eeb052cda5 356 }
ommpy 11:32eeb052cda5 357
ommpy 11:32eeb052cda5 358 /**
ommpy 11:32eeb052cda5 359 * @brief Performs a search.
ommpy 11:32eeb052cda5 360 * @note Perform a search. If this function returns a '1' then it has
ommpy 11:32eeb052cda5 361 enumerated the next device and you may retrieve the ROM from the
ommpy 11:32eeb052cda5 362 OneWire::address variable. If there are no devices, no further
ommpy 11:32eeb052cda5 363 devices, or something horrible happens in the middle of the
ommpy 11:32eeb052cda5 364 enumeration then a 0 is returned. If a new device is found then
ommpy 11:32eeb052cda5 365 its address is copied to newAddr. Use OneWire::reset_search() to
ommpy 11:32eeb052cda5 366 start over.
ommpy 11:32eeb052cda5 367
ommpy 11:32eeb052cda5 368 --- Replaced by the one from the Dallas Semiconductor web site ---
ommpy 11:32eeb052cda5 369 -------------------------------------------------------------------------
ommpy 11:32eeb052cda5 370 Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
ommpy 11:32eeb052cda5 371 search state.
ommpy 11:32eeb052cda5 372 * @param
ommpy 11:32eeb052cda5 373 * @retval true : device found, ROM number in ROM_NO buffer
ommpy 11:32eeb052cda5 374 * false : device not found, end of search
ommpy 11:32eeb052cda5 375 */
ommpy 11:32eeb052cda5 376 uint8_t OneWire::search(uint8_t* newAddr)
ommpy 11:32eeb052cda5 377 {
ommpy 11:32eeb052cda5 378 uint8_t id_bit_number;
ommpy 11:32eeb052cda5 379 uint8_t last_zero, rom_byte_number, search_result;
ommpy 11:32eeb052cda5 380 uint8_t id_bit, cmp_id_bit;
ommpy 11:32eeb052cda5 381
ommpy 11:32eeb052cda5 382 unsigned char rom_byte_mask, search_direction;
ommpy 11:32eeb052cda5 383
ommpy 11:32eeb052cda5 384 // initialize for search
ommpy 11:32eeb052cda5 385 id_bit_number = 1;
ommpy 11:32eeb052cda5 386 last_zero = 0;
ommpy 11:32eeb052cda5 387 rom_byte_number = 0;
ommpy 11:32eeb052cda5 388 rom_byte_mask = 1;
ommpy 11:32eeb052cda5 389 search_result = 0;
ommpy 11:32eeb052cda5 390
ommpy 11:32eeb052cda5 391 // if the last call was not the last one
ommpy 11:32eeb052cda5 392 if (!LastDeviceFlag) {
ommpy 11:32eeb052cda5 393 // 1-Wire reset
ommpy 11:32eeb052cda5 394 if (!reset()) {
ommpy 11:32eeb052cda5 395 // reset the search
ommpy 11:32eeb052cda5 396 LastDiscrepancy = 0;
ommpy 11:32eeb052cda5 397 LastDeviceFlag = false;
ommpy 11:32eeb052cda5 398 LastFamilyDiscrepancy = 0;
ommpy 11:32eeb052cda5 399 return false;
ommpy 11:32eeb052cda5 400 }
ommpy 11:32eeb052cda5 401
ommpy 11:32eeb052cda5 402 // issue the search command
ommpy 11:32eeb052cda5 403 write_byte(0xF0);
ommpy 11:32eeb052cda5 404
ommpy 11:32eeb052cda5 405 // loop to do the search
ommpy 11:32eeb052cda5 406 do {
ommpy 11:32eeb052cda5 407 // read a bit and its complement
ommpy 11:32eeb052cda5 408 id_bit = read_bit();
ommpy 11:32eeb052cda5 409 cmp_id_bit = read_bit();
ommpy 11:32eeb052cda5 410
ommpy 11:32eeb052cda5 411 // check for no devices on 1-wire
ommpy 11:32eeb052cda5 412 if ((id_bit == 1) && (cmp_id_bit == 1))
ommpy 11:32eeb052cda5 413 break;
ommpy 11:32eeb052cda5 414 else {
ommpy 11:32eeb052cda5 415 // all devices coupled have 0 or 1
ommpy 11:32eeb052cda5 416 if (id_bit != cmp_id_bit)
ommpy 11:32eeb052cda5 417 search_direction = id_bit; // bit write value for search
ommpy 11:32eeb052cda5 418 else {
ommpy 11:32eeb052cda5 419 // if this discrepancy if before the Last Discrepancy
ommpy 11:32eeb052cda5 420 // on a previous next then pick the same as last time
ommpy 11:32eeb052cda5 421 if (id_bit_number < LastDiscrepancy)
ommpy 11:32eeb052cda5 422 search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
ommpy 11:32eeb052cda5 423 else
ommpy 11:32eeb052cda5 424 // if equal to last pick 1, if not then pick 0
ommpy 11:32eeb052cda5 425 search_direction = (id_bit_number == LastDiscrepancy);
ommpy 11:32eeb052cda5 426
ommpy 11:32eeb052cda5 427 // if 0 was picked then record its position in LastZero
ommpy 11:32eeb052cda5 428 if (search_direction == 0) {
ommpy 11:32eeb052cda5 429 last_zero = id_bit_number;
ommpy 11:32eeb052cda5 430
ommpy 11:32eeb052cda5 431 // check for Last discrepancy in family
ommpy 11:32eeb052cda5 432 if (last_zero < 9)
ommpy 11:32eeb052cda5 433 LastFamilyDiscrepancy = last_zero;
ommpy 11:32eeb052cda5 434 }
ommpy 11:32eeb052cda5 435 }
ommpy 11:32eeb052cda5 436
ommpy 11:32eeb052cda5 437 // set or clear the bit in the ROM byte rom_byte_number
ommpy 11:32eeb052cda5 438 // with mask rom_byte_mask
ommpy 11:32eeb052cda5 439 if (search_direction == 1)
ommpy 11:32eeb052cda5 440 ROM_NO[rom_byte_number] |= rom_byte_mask;
ommpy 11:32eeb052cda5 441 else
ommpy 11:32eeb052cda5 442 ROM_NO[rom_byte_number] &= ~rom_byte_mask;
ommpy 11:32eeb052cda5 443
ommpy 11:32eeb052cda5 444 // serial number search direction write bit
ommpy 11:32eeb052cda5 445 write_bit(search_direction);
ommpy 11:32eeb052cda5 446
ommpy 11:32eeb052cda5 447 // increment the byte counter id_bit_number
ommpy 11:32eeb052cda5 448 // and shift the mask rom_byte_mask
ommpy 11:32eeb052cda5 449 id_bit_number++;
ommpy 11:32eeb052cda5 450 rom_byte_mask <<= 1;
ommpy 11:32eeb052cda5 451
ommpy 11:32eeb052cda5 452 // if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
ommpy 11:32eeb052cda5 453 if (rom_byte_mask == 0) {
ommpy 11:32eeb052cda5 454 rom_byte_number++;
ommpy 11:32eeb052cda5 455 rom_byte_mask = 1;
ommpy 11:32eeb052cda5 456 }
ommpy 11:32eeb052cda5 457 }
ommpy 11:32eeb052cda5 458 } while (rom_byte_number < 8);
ommpy 11:32eeb052cda5 459 // loop until through all ROM bytes 0-7
ommpy 11:32eeb052cda5 460 // if the search was successful then
ommpy 11:32eeb052cda5 461 if (!(id_bit_number < 65)) {
ommpy 11:32eeb052cda5 462 // search successful so set LastDiscrepancy,LastDeviceFlag,search_result
ommpy 11:32eeb052cda5 463 LastDiscrepancy = last_zero;
ommpy 11:32eeb052cda5 464
ommpy 11:32eeb052cda5 465 // check for last device
ommpy 11:32eeb052cda5 466 if (LastDiscrepancy == 0)
ommpy 11:32eeb052cda5 467 LastDeviceFlag = true;
ommpy 11:32eeb052cda5 468
ommpy 11:32eeb052cda5 469 search_result = true;
ommpy 11:32eeb052cda5 470 }
ommpy 11:32eeb052cda5 471 }
ommpy 11:32eeb052cda5 472
ommpy 11:32eeb052cda5 473 // if no device found then reset counters so next 'search' will be like a first
ommpy 11:32eeb052cda5 474 if (!search_result || !ROM_NO[0]) {
ommpy 11:32eeb052cda5 475 LastDiscrepancy = 0;
ommpy 11:32eeb052cda5 476 LastDeviceFlag = false;
ommpy 11:32eeb052cda5 477 LastFamilyDiscrepancy = 0;
ommpy 11:32eeb052cda5 478 search_result = false;
ommpy 11:32eeb052cda5 479 }
ommpy 11:32eeb052cda5 480
ommpy 11:32eeb052cda5 481 for (int i = 0; i < 8; i++)
ommpy 11:32eeb052cda5 482 newAddr[i] = ROM_NO[i];
ommpy 11:32eeb052cda5 483 return search_result;
ommpy 11:32eeb052cda5 484 }
ommpy 11:32eeb052cda5 485 #endif
ommpy 11:32eeb052cda5 486 //
ommpy 11:32eeb052cda5 487 #if ONEWIRE_CRC
ommpy 11:32eeb052cda5 488 //
ommpy 11:32eeb052cda5 489 /**
ommpy 11:32eeb052cda5 490 * @brief Computes a Dallas Semiconductor 8 bit CRC directly.
ommpy 11:32eeb052cda5 491 * @note The 1-Wire CRC scheme is described in Maxim Application Note 27:
ommpy 11:32eeb052cda5 492 "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
ommpy 11:32eeb052cda5 493 * @param
ommpy 11:32eeb052cda5 494 * @retval
ommpy 11:32eeb052cda5 495 */
ommpy 11:32eeb052cda5 496 uint8_t OneWire::crc8(const uint8_t* addr, uint8_t len)
ommpy 11:32eeb052cda5 497 {
ommpy 11:32eeb052cda5 498 uint8_t crc = 0;
ommpy 11:32eeb052cda5 499
ommpy 11:32eeb052cda5 500 while (len--) {
ommpy 11:32eeb052cda5 501 uint8_t inbyte = *addr++;
ommpy 11:32eeb052cda5 502 for (uint8_t i = 8; i; i--) {
ommpy 11:32eeb052cda5 503 uint8_t mix = (crc ^ inbyte) & 0x01;
ommpy 11:32eeb052cda5 504 crc >>= 1;
ommpy 11:32eeb052cda5 505 if (mix)
ommpy 11:32eeb052cda5 506 crc ^= 0x8C;
ommpy 11:32eeb052cda5 507 inbyte >>= 1;
ommpy 11:32eeb052cda5 508 }
ommpy 11:32eeb052cda5 509 }
ommpy 11:32eeb052cda5 510
ommpy 11:32eeb052cda5 511 return crc;
ommpy 11:32eeb052cda5 512 }
ommpy 11:32eeb052cda5 513 #endif