564 lines
17 KiB
C++
564 lines
17 KiB
C++
/*
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Copyright (c) 2007, Jim Studt (original old version - many contributors since)
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The latest version of this library may be found at:
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http://www.pjrc.com/teensy/td_libs_OneWire.html
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OneWire has been maintained by Paul Stoffregen (paul@pjrc.com) since
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January 2010. At the time, it was in need of many bug fixes, but had
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been abandoned the original author (Jim Studt). None of the known
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contributors were interested in maintaining OneWire. Paul typically
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works on OneWire every 6 to 12 months. Patches usually wait that
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long. If anyone is interested in more actively maintaining OneWire,
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please contact Paul.
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Version 2.3:
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Unknonw chip fallback mode, Roger Clark
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Teensy-LC compatibility, Paul Stoffregen
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Search bug fix, Love Nystrom
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Version 2.2:
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Teensy 3.0 compatibility, Paul Stoffregen, paul@pjrc.com
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Arduino Due compatibility, http://arduino.cc/forum/index.php?topic=141030
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Fix DS18B20 example negative temperature
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Fix DS18B20 example's low res modes, Ken Butcher
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Improve reset timing, Mark Tillotson
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Add const qualifiers, Bertrik Sikken
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Add initial value input to crc16, Bertrik Sikken
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Add target_search() function, Scott Roberts
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Version 2.1:
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Arduino 1.0 compatibility, Paul Stoffregen
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Improve temperature example, Paul Stoffregen
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DS250x_PROM example, Guillermo Lovato
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PIC32 (chipKit) compatibility, Jason Dangel, dangel.jason AT gmail.com
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Improvements from Glenn Trewitt:
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- crc16() now works
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- check_crc16() does all of calculation/checking work.
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- Added read_bytes() and write_bytes(), to reduce tedious loops.
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- Added ds2408 example.
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Delete very old, out-of-date readme file (info is here)
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Version 2.0: Modifications by Paul Stoffregen, January 2010:
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http://www.pjrc.com/teensy/td_libs_OneWire.html
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Search fix from Robin James
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http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295/27#27
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Use direct optimized I/O in all cases
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Disable interrupts during timing critical sections
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(this solves many random communication errors)
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Disable interrupts during read-modify-write I/O
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Reduce RAM consumption by eliminating unnecessary
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variables and trimming many to 8 bits
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Optimize both crc8 - table version moved to flash
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Modified to work with larger numbers of devices - avoids loop.
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Tested in Arduino 11 alpha with 12 sensors.
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26 Sept 2008 -- Robin James
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http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295/27#27
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Updated to work with arduino-0008 and to include skip() as of
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2007/07/06. --RJL20
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Modified to calculate the 8-bit CRC directly, avoiding the need for
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the 256-byte lookup table to be loaded in RAM. Tested in arduino-0010
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-- Tom Pollard, Jan 23, 2008
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Jim Studt's original library was modified by Josh Larios.
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Tom Pollard, pollard@alum.mit.edu, contributed around May 20, 2008
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Much of the code was inspired by Derek Yerger's code, though I don't
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think much of that remains. In any event that was..
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(copyleft) 2006 by Derek Yerger - Free to distribute freely.
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The CRC code was excerpted and inspired by the Dallas Semiconductor
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sample code bearing this copyright.
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//---------------------------------------------------------------------------
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// Copyright (C) 2000 Dallas Semiconductor Corporation, All Rights Reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES
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// OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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// OTHER DEALINGS IN THE SOFTWARE.
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//
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// Except as contained in this notice, the name of Dallas Semiconductor
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// shall not be used except as stated in the Dallas Semiconductor
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// Branding Policy.
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//--------------------------------------------------------------------------
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*/
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#include "OneWire.h"
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OneWire::OneWire(uint8_t pin)
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{
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pinMode(pin, INPUT);
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bitmask = PIN_TO_BITMASK(pin);
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baseReg = PIN_TO_BASEREG(pin);
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#if ONEWIRE_SEARCH
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reset_search();
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#endif
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}
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// Perform the onewire reset function. We will wait up to 250uS for
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// the bus to come high, if it doesn't then it is broken or shorted
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// and we return a 0;
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//
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// Returns 1 if a device asserted a presence pulse, 0 otherwise.
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//
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uint8_t OneWire::reset(void)
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{
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IO_REG_TYPE mask = bitmask;
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volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg;
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uint8_t r;
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uint8_t retries = 125;
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noInterrupts();
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DIRECT_MODE_INPUT(reg, mask);
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interrupts();
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// wait until the wire is high... just in case
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do {
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if (--retries == 0) return 0;
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delayMicroseconds(2);
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} while ( !DIRECT_READ(reg, mask));
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noInterrupts();
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DIRECT_WRITE_LOW(reg, mask);
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DIRECT_MODE_OUTPUT(reg, mask); // drive output low
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interrupts();
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delayMicroseconds(480);
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noInterrupts();
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DIRECT_MODE_INPUT(reg, mask); // allow it to float
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delayMicroseconds(70);
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r = !DIRECT_READ(reg, mask);
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interrupts();
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delayMicroseconds(410);
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return r;
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}
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//
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// Write a bit. Port and bit is used to cut lookup time and provide
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// more certain timing.
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//
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void OneWire::write_bit(uint8_t v)
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{
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IO_REG_TYPE mask=bitmask;
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volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg;
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if (v & 1) {
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noInterrupts();
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DIRECT_WRITE_LOW(reg, mask);
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DIRECT_MODE_OUTPUT(reg, mask); // drive output low
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delayMicroseconds(10);
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DIRECT_WRITE_HIGH(reg, mask); // drive output high
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interrupts();
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delayMicroseconds(55);
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} else {
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noInterrupts();
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DIRECT_WRITE_LOW(reg, mask);
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DIRECT_MODE_OUTPUT(reg, mask); // drive output low
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delayMicroseconds(65);
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DIRECT_WRITE_HIGH(reg, mask); // drive output high
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interrupts();
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delayMicroseconds(5);
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}
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}
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//
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// Read a bit. Port and bit is used to cut lookup time and provide
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// more certain timing.
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//
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uint8_t OneWire::read_bit(void)
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{
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IO_REG_TYPE mask=bitmask;
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volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg;
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uint8_t r;
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noInterrupts();
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DIRECT_MODE_OUTPUT(reg, mask);
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DIRECT_WRITE_LOW(reg, mask);
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delayMicroseconds(3);
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DIRECT_MODE_INPUT(reg, mask); // let pin float, pull up will raise
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delayMicroseconds(10);
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r = DIRECT_READ(reg, mask);
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interrupts();
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delayMicroseconds(53);
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return r;
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}
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//
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// Write a byte. The writing code uses the active drivers to raise the
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// pin high, if you need power after the write (e.g. DS18S20 in
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// parasite power mode) then set 'power' to 1, otherwise the pin will
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// go tri-state at the end of the write to avoid heating in a short or
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// other mishap.
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//
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void OneWire::write(uint8_t v, uint8_t power /* = 0 */) {
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uint8_t bitMask;
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for (bitMask = 0x01; bitMask; bitMask <<= 1) {
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OneWire::write_bit( (bitMask & v)?1:0);
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}
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if ( !power) {
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noInterrupts();
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DIRECT_MODE_INPUT(baseReg, bitmask);
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DIRECT_WRITE_LOW(baseReg, bitmask);
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interrupts();
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}
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}
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void OneWire::write_bytes(const uint8_t *buf, uint16_t count, bool power /* = 0 */) {
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for (uint16_t i = 0 ; i < count ; i++)
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write(buf[i]);
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if (!power) {
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noInterrupts();
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DIRECT_MODE_INPUT(baseReg, bitmask);
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DIRECT_WRITE_LOW(baseReg, bitmask);
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interrupts();
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}
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}
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//
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// Read a byte
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//
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uint8_t OneWire::read() {
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uint8_t bitMask;
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uint8_t r = 0;
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for (bitMask = 0x01; bitMask; bitMask <<= 1) {
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if ( OneWire::read_bit()) r |= bitMask;
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}
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return r;
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}
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void OneWire::read_bytes(uint8_t *buf, uint16_t count) {
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for (uint16_t i = 0 ; i < count ; i++)
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buf[i] = read();
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}
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//
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// Do a ROM select
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//
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void OneWire::select(const uint8_t rom[8])
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{
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uint8_t i;
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write(0x55); // Choose ROM
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for (i = 0; i < 8; i++) write(rom[i]);
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}
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//
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// Do a ROM skip
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//
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void OneWire::skip()
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{
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write(0xCC); // Skip ROM
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}
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void OneWire::depower()
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{
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noInterrupts();
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DIRECT_MODE_INPUT(baseReg, bitmask);
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interrupts();
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}
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#if ONEWIRE_SEARCH
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//
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// You need to use this function to start a search again from the beginning.
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// You do not need to do it for the first search, though you could.
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//
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void OneWire::reset_search()
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{
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// reset the search state
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LastDiscrepancy = 0;
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LastDeviceFlag = FALSE;
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LastFamilyDiscrepancy = 0;
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for(int i = 7; ; i--) {
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ROM_NO[i] = 0;
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if ( i == 0) break;
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}
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}
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// Setup the search to find the device type 'family_code' on the next call
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// to search(*newAddr) if it is present.
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//
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void OneWire::target_search(uint8_t family_code)
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{
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// set the search state to find SearchFamily type devices
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ROM_NO[0] = family_code;
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for (uint8_t i = 1; i < 8; i++)
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ROM_NO[i] = 0;
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LastDiscrepancy = 64;
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LastFamilyDiscrepancy = 0;
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LastDeviceFlag = FALSE;
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}
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//
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// Perform a search. If this function returns a '1' then it has
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// enumerated the next device and you may retrieve the ROM from the
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// OneWire::address variable. If there are no devices, no further
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// devices, or something horrible happens in the middle of the
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// enumeration then a 0 is returned. If a new device is found then
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// its address is copied to newAddr. Use OneWire::reset_search() to
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// start over.
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//
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// --- Replaced by the one from the Dallas Semiconductor web site ---
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//--------------------------------------------------------------------------
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// Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
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// search state.
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// Return TRUE : device found, ROM number in ROM_NO buffer
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// FALSE : device not found, end of search
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//
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uint8_t OneWire::search(uint8_t *newAddr)
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{
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uint8_t id_bit_number;
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uint8_t last_zero, rom_byte_number, search_result;
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uint8_t id_bit, cmp_id_bit;
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unsigned char rom_byte_mask, search_direction;
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// initialize for search
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id_bit_number = 1;
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last_zero = 0;
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rom_byte_number = 0;
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rom_byte_mask = 1;
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search_result = 0;
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// if the last call was not the last one
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if (!LastDeviceFlag)
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{
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// 1-Wire reset
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if (!reset())
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{
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// reset the search
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LastDiscrepancy = 0;
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LastDeviceFlag = FALSE;
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LastFamilyDiscrepancy = 0;
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return FALSE;
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}
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// issue the search command
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write(0xF0);
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// loop to do the search
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do
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{
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// read a bit and its complement
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id_bit = read_bit();
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cmp_id_bit = read_bit();
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// check for no devices on 1-wire
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if ((id_bit == 1) && (cmp_id_bit == 1))
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break;
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else
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{
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// all devices coupled have 0 or 1
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if (id_bit != cmp_id_bit)
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search_direction = id_bit; // bit write value for search
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else
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{
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// if this discrepancy if before the Last Discrepancy
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// on a previous next then pick the same as last time
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if (id_bit_number < LastDiscrepancy)
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search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
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else
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// if equal to last pick 1, if not then pick 0
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search_direction = (id_bit_number == LastDiscrepancy);
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// if 0 was picked then record its position in LastZero
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if (search_direction == 0)
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{
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last_zero = id_bit_number;
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// check for Last discrepancy in family
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if (last_zero < 9)
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LastFamilyDiscrepancy = last_zero;
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}
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}
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// set or clear the bit in the ROM byte rom_byte_number
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// with mask rom_byte_mask
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if (search_direction == 1)
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ROM_NO[rom_byte_number] |= rom_byte_mask;
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else
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ROM_NO[rom_byte_number] &= ~rom_byte_mask;
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// serial number search direction write bit
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write_bit(search_direction);
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// increment the byte counter id_bit_number
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// and shift the mask rom_byte_mask
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id_bit_number++;
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rom_byte_mask <<= 1;
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// if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
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if (rom_byte_mask == 0)
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{
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rom_byte_number++;
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rom_byte_mask = 1;
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}
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}
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}
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while(rom_byte_number < 8); // loop until through all ROM bytes 0-7
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// if the search was successful then
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if (!(id_bit_number < 65))
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{
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// search successful so set LastDiscrepancy,LastDeviceFlag,search_result
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LastDiscrepancy = last_zero;
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// check for last device
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if (LastDiscrepancy == 0)
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LastDeviceFlag = TRUE;
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search_result = TRUE;
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}
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}
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// if no device found then reset counters so next 'search' will be like a first
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if (!search_result || !ROM_NO[0])
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{
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LastDiscrepancy = 0;
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LastDeviceFlag = FALSE;
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LastFamilyDiscrepancy = 0;
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search_result = FALSE;
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} else {
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for (int i = 0; i < 8; i++) newAddr[i] = ROM_NO[i];
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}
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return search_result;
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}
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#endif
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#if ONEWIRE_CRC
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// The 1-Wire CRC scheme is described in Maxim Application Note 27:
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// "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
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//
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#if ONEWIRE_CRC8_TABLE
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// This table comes from Dallas sample code where it is freely reusable,
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// though Copyright (C) 2000 Dallas Semiconductor Corporation
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static const uint8_t PROGMEM dscrc_table[] = {
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0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65,
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157,195, 33,127,252,162, 64, 30, 95, 1,227,189, 62, 96,130,220,
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35,125,159,193, 66, 28,254,160,225,191, 93, 3,128,222, 60, 98,
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190,224, 2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255,
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70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89, 7,
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219,133,103, 57,186,228, 6, 88, 25, 71,165,251,120, 38,196,154,
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101, 59,217,135, 4, 90,184,230,167,249, 27, 69,198,152,122, 36,
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248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91, 5,231,185,
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140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205,
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17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80,
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175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238,
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50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115,
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202,148,118, 40,171,245, 23, 73, 8, 86,180,234,105, 55,213,139,
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87, 9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22,
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233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168,
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116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53};
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//
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// Compute a Dallas Semiconductor 8 bit CRC. These show up in the ROM
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// and the registers. (note: this might better be done without to
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// table, it would probably be smaller and certainly fast enough
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// compared to all those delayMicrosecond() calls. But I got
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// confused, so I use this table from the examples.)
|
|
//
|
|
uint8_t OneWire::crc8(const uint8_t *addr, uint8_t len)
|
|
{
|
|
uint8_t crc = 0;
|
|
|
|
while (len--) {
|
|
crc = pgm_read_byte(dscrc_table + (crc ^ *addr++));
|
|
}
|
|
return crc;
|
|
}
|
|
#else
|
|
//
|
|
// Compute a Dallas Semiconductor 8 bit CRC directly.
|
|
// this is much slower, but much smaller, than the lookup table.
|
|
//
|
|
uint8_t OneWire::crc8(const uint8_t *addr, uint8_t len)
|
|
{
|
|
uint8_t crc = 0;
|
|
|
|
while (len--) {
|
|
uint8_t inbyte = *addr++;
|
|
for (uint8_t i = 8; i; i--) {
|
|
uint8_t mix = (crc ^ inbyte) & 0x01;
|
|
crc >>= 1;
|
|
if (mix) crc ^= 0x8C;
|
|
inbyte >>= 1;
|
|
}
|
|
}
|
|
return crc;
|
|
}
|
|
#endif
|
|
|
|
#if ONEWIRE_CRC16
|
|
bool OneWire::check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc)
|
|
{
|
|
crc = ~crc16(input, len, crc);
|
|
return (crc & 0xFF) == inverted_crc[0] && (crc >> 8) == inverted_crc[1];
|
|
}
|
|
|
|
uint16_t OneWire::crc16(const uint8_t* input, uint16_t len, uint16_t crc)
|
|
{
|
|
static const uint8_t oddparity[16] =
|
|
{ 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
|
|
|
|
for (uint16_t i = 0 ; i < len ; i++) {
|
|
// Even though we're just copying a byte from the input,
|
|
// we'll be doing 16-bit computation with it.
|
|
uint16_t cdata = input[i];
|
|
cdata = (cdata ^ crc) & 0xff;
|
|
crc >>= 8;
|
|
|
|
if (oddparity[cdata & 0x0F] ^ oddparity[cdata >> 4])
|
|
crc ^= 0xC001;
|
|
|
|
cdata <<= 6;
|
|
crc ^= cdata;
|
|
cdata <<= 1;
|
|
crc ^= cdata;
|
|
}
|
|
return crc;
|
|
}
|
|
#endif
|
|
|
|
#endif
|