chore: debloat (remove platformio), onewire improvements
Squashed commit of the following: commit 5f16309f629b9928d2134b85ae64af69bc3ebbcd Author: kuwoyuki <kuwoyuki@cock.li> Date: Sun Nov 24 22:55:15 2024 +0600 fix: Makefile, improve onewire retries commit 55496a3bda941b52ff349dc75c9c06eb5a37c07d Author: kuwoyuki <kuwoyuki@cock.li> Date: Mon Nov 18 00:41:18 2024 +0600 fix: make onewire validity less strict commit 3428a9bc9792508972ce3e7e4e35a64f047bca10 Author: kuwoyuki <kuwoyuki@cock.li> Date: Sun Nov 17 23:57:55 2024 +0600 chore: rm bins commit 1594e5ed430522b15466c8afa62ff7fb1b28947c Author: kuwoyuki <kuwoyuki@cock.li> Date: Sun Nov 17 23:32:01 2024 +0600 chore: unplatformiofy
This commit is contained in:
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onewire.c
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624
onewire.c
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/*
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Single-File One Wire Communication Functions for CH32V003
|
||||
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Relies on the CH32V003fun library from:
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https://github.com/cnlohr/ch32v003fun
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This is very heavily derived from the Arduino OneWire library,
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at https://github.com/PaulStoffregen/OneWire
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Original copyright notices follow:
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--------------------------------------------
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||||
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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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|
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OneWire has been maintained by Paul Stoffregen (paul@pjrc.com) since
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January 2010.
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DO NOT EMAIL for technical support, especially not for ESP chips!
|
||||
All project support questions must be posted on public forums
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relevant to the board or chips used. If using Arduino, post on
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Arduino's forum. If using ESP, post on the ESP community forums.
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||||
There is ABSOLUTELY NO TECH SUPPORT BY PRIVATE EMAIL!
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||||
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Github's issue tracker for OneWire should be used only to report
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||||
specific bugs. DO NOT request project support via Github. All
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project and tech support questions must be posted on forums, not
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github issues. If you experience a problem and you are not
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absolutely sure it's an issue with the library, ask on a forum
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first. Only use github to report issues after experts have
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confirmed the issue is with OneWire rather than your project.
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Back in 2010, OneWire 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,
|
||||
please contact Paul (this is pretty much the only reason to use
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private email about OneWire).
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OneWire is now very mature code. No changes other than adding
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definitions for newer hardware support are anticipated.
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ESP32 mods authored by stickbreaker:
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@stickbreaker 30APR2018 add IRAM_ATTR to read_bit() OneWireWriteBit() to solve
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ICache miss timing failure. thanks @everslick re:
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https://github.com/espressif/arduino-esp32/issues/1335 Altered by garyd9 for
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clean merge with Paul Stoffregen's source
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Version 2.3:
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Unknown 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
|
||||
"Software"), to deal in the Software without restriction, including
|
||||
without limitation the rights to use, copy, modify, merge, publish,
|
||||
distribute, sublicense, and/or sell copies of the Software, and to
|
||||
permit persons to whom the Software is furnished to do so, subject to
|
||||
the following conditions:
|
||||
|
||||
The above copyright notice and this permission notice shall be
|
||||
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,
|
||||
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
|
||||
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
|
||||
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
|
||||
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
|
||||
// copy of this software and associated documentation files (the "Software"),
|
||||
// to deal in the Software without restriction, including without limitation
|
||||
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
|
||||
// and/or sell copies of the Software, and to permit persons to whom the
|
||||
// Software is furnished to do so, subject to the following conditions:
|
||||
//
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||||
// The above copyright notice and this permission notice shall be 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, EXPRESS
|
||||
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
|
||||
// IN NO EVENT SHALL DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, DAMAGES
|
||||
// OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
|
||||
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
||||
// 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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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include "ch32v003fun.h"
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// global search state
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unsigned char ROM_NO[8];
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uint8_t LastDiscrepancy;
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uint8_t LastFamilyDiscrepancy;
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bool LastDeviceFlag;
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void OneWireBegin(void);
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// Perform a 1-Wire reset cycle. Returns 1 if a device responds
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// with a presence pulse. Returns 0 if there is no device or the
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// bus is shorted or otherwise held low for more than 250uS
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uint8_t OneWireReset(void);
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// Issue a 1-Wire rom select command, you do the reset first.
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void OneWireSelect(const uint8_t rom[8]);
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// Issue a 1-Wire rom skip command, to address all on bus.
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// void skip(void);
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// Write a byte. If 'power' is one then the wire is held high at
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// the end for parasitically powered devices. You are responsible
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// for eventually depowering it by calling depower() or doing
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// another read or write.
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void OneWireWrite(uint8_t v, uint8_t power);
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void OneWireWriteBytes(const uint8_t *buf, uint16_t count, bool power);
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// Read a byte.
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uint8_t OneWireRead(void);
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void OneWireReadBytes(uint8_t *buf, uint16_t count);
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// Write a bit. The bus is always left powered at the end, see
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// note in write() about that.
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void OneWireWriteBit(uint8_t v);
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// Read a bit.
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uint8_t OneWireReadBit(void);
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// Stop forcing power onto the bus. You only need to do this if
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// you used the 'power' flag to write() or used a write_bit() call
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// and aren't about to do another read or write. You would rather
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// not leave this powered if you don't have to, just in case
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// someone shorts your bus.
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void OneWireDepower(void);
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// Clear the search state so that if will start from the beginning again.
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void OneWireResetSearch();
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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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void OneWireTargetSearch(uint8_t family_code);
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// Look for the next device. Returns 1 if a new address has been
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// returned. A zero might mean that the bus is shorted, there are
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// no devices, or you have already retrieved all of them. It
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// might be a good idea to check the CRC to make sure you didn't
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// get garbage. The order is deterministic. You will always get
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// the same devices in the same order.
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bool OneWireSearch(uint8_t *newAddr, bool search_mode);
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// Compute a Dallas Semiconductor 8 bit CRC, these are used in the
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// ROM and scratchpad registers.
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uint8_t OneWireCrc8(const uint8_t *addr, uint8_t len);
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// Compute the 1-Wire CRC16 and compare it against the received CRC.
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// Example usage (reading a DS2408):
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// // Put everything in a buffer so we can compute the CRC easily.
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// uint8_t buf[13];
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// buf[0] = 0xF0; // Read PIO Registers
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// buf[1] = 0x88; // LSB address
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// buf[2] = 0x00; // MSB address
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// WriteBytes(net, buf, 3); // Write 3 cmd bytes
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// ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
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// if (!CheckCRC16(buf, 11, &buf[11])) {
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// // Handle error.
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// }
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//
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// @param input - Array of bytes to checksum.
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// @param len - How many bytes to use.
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// @param inverted_crc - The two CRC16 bytes in the received data.
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// This should just point into the received data,
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// *not* at a 16-bit integer.
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// @param crc - The crc starting value (optional)
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// @return True, iff the CRC matches.
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bool OneWireCheckCrc16(const uint8_t *input, uint16_t len,
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const uint8_t *inverted_crc, uint16_t crc);
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// Compute a Dallas Semiconductor 16 bit CRC. This is required to check
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// the integrity of data received from many 1-Wire devices. Note that the
|
||||
// CRC computed here is *not* what you'll get from the 1-Wire network,
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// for two reasons:
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// 1) The CRC is transmitted bitwise inverted.
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// 2) Depending on the endian-ness of your processor, the binary
|
||||
// representation of the two-byte return value may have a different
|
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// byte order than the two bytes you get from 1-Wire.
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// @param input - Array of bytes to checksum.
|
||||
// @param len - How many bytes to use.
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// @param crc - The crc starting value (optional)
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// @return The CRC16, as defined by Dallas Semiconductor.
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uint16_t OneWireCrc16(const uint8_t *input, uint16_t len, uint16_t crc);
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void OneWireBegin() {
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directModeInput();
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OneWireResetSearch();
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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 OneWireReset(void) {
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uint8_t r;
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uint8_t retries = 125;
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DIRECT_MODE_INPUT();
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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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Delay_Us(ONEWIRE_RESET_RETRY_TIME);
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} while (!DIRECT_READ());
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||||
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DIRECT_WRITE_LOW();
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DIRECT_MODE_OUTPUT(); // drive output low
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||||
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||||
Delay_Us(ONEWIRE_RESET_LOW_TIME);
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||||
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||||
DIRECT_MODE_INPUT(); // allow it to float
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Delay_Us(ONEWIRE_RESET_SAMPLE_TIME);
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||||
r = !DIRECT_READ();
|
||||
|
||||
Delay_Us(ONEWIRE_RESET_POST_TIME);
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||||
return r;
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||||
}
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||||
|
||||
//
|
||||
// Write a bit. Port and bit is used to cut lookup time and provide
|
||||
// more certain timing.
|
||||
//
|
||||
void OneWireWriteBit(uint8_t v) {
|
||||
if (v & 1) {
|
||||
DIRECT_WRITE_LOW();
|
||||
DIRECT_MODE_OUTPUT(); // drive output low
|
||||
Delay_Us(ONEWIRE_WRITE_1_LOW_TIME);
|
||||
DIRECT_WRITE_HIGH(); // drive output high
|
||||
|
||||
Delay_Us(ONEWIRE_WRITE_1_TOTAL_TIME - ONEWIRE_WRITE_1_LOW_TIME);
|
||||
} else {
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||||
DIRECT_WRITE_LOW();
|
||||
DIRECT_MODE_OUTPUT(); // drive output low
|
||||
Delay_Us(ONEWIRE_WRITE_0_LOW_TIME);
|
||||
DIRECT_WRITE_HIGH(); // drive output high
|
||||
|
||||
Delay_Us(ONEWIRE_WRITE_0_TOTAL_TIME - ONEWIRE_WRITE_0_LOW_TIME);
|
||||
}
|
||||
}
|
||||
|
||||
//
|
||||
// Read a bit. Port and bit is used to cut lookup time and provide
|
||||
// more certain timing.
|
||||
//
|
||||
uint8_t OneWireReadBit(void) {
|
||||
uint8_t r;
|
||||
|
||||
DIRECT_MODE_OUTPUT();
|
||||
DIRECT_WRITE_LOW();
|
||||
Delay_Us(ONEWIRE_READ_INIT_LOW_TIME); // 6us initial low pulse
|
||||
|
||||
DIRECT_MODE_INPUT(); // let pin float, pull up will raise
|
||||
Delay_Us(ONEWIRE_READ_SAMPLE_TIME); // 8us until sample point
|
||||
r = DIRECT_READ();
|
||||
|
||||
// Wait for remainder of the read timeslot
|
||||
// Total - init_low - sample = 64 - 6 - 8 = 50us
|
||||
Delay_Us(ONEWIRE_READ_TOTAL_TIME - ONEWIRE_READ_INIT_LOW_TIME -
|
||||
ONEWIRE_READ_SAMPLE_TIME);
|
||||
|
||||
return r;
|
||||
}
|
||||
|
||||
//
|
||||
// Write a byte. The writing code uses the active drivers to raise the
|
||||
// pin high, if you need power after the write (e.g. DS18S20 in
|
||||
// parasite power mode) then set 'power' to 1, otherwise the pin will
|
||||
// go tri-state at the end of the write to avoid heating in a short or
|
||||
// other mishap.
|
||||
//
|
||||
void OneWireWrite(uint8_t v, uint8_t power /* = 0 */) {
|
||||
uint8_t bitMask;
|
||||
|
||||
for (bitMask = 0x01; bitMask; bitMask <<= 1) {
|
||||
OneWireWriteBit((bitMask & v) ? 1 : 0);
|
||||
}
|
||||
if (!power) {
|
||||
DIRECT_MODE_INPUT();
|
||||
DIRECT_WRITE_LOW();
|
||||
}
|
||||
}
|
||||
|
||||
void OneWireWriteBytes(const uint8_t *buf, uint16_t count, bool power) {
|
||||
for (uint16_t i = 0; i < count; i++) OneWireWrite(buf[i], 0);
|
||||
if (!power) {
|
||||
DIRECT_MODE_INPUT();
|
||||
DIRECT_WRITE_LOW();
|
||||
}
|
||||
}
|
||||
|
||||
//
|
||||
// Read a byte
|
||||
//
|
||||
uint8_t OneWireRead() {
|
||||
uint8_t bitMask;
|
||||
uint8_t r = 0;
|
||||
|
||||
for (bitMask = 0x01; bitMask; bitMask <<= 1) {
|
||||
if (OneWireReadBit()) r |= bitMask;
|
||||
}
|
||||
return r;
|
||||
}
|
||||
|
||||
void OneWireReadBytes(uint8_t *buf, uint16_t count) {
|
||||
for (uint16_t i = 0; i < count; i++) buf[i] = OneWireRead();
|
||||
}
|
||||
|
||||
//
|
||||
// Do a ROM select
|
||||
//
|
||||
void OneWireSelect(const uint8_t rom[8]) {
|
||||
uint8_t i;
|
||||
|
||||
OneWireWrite(0x55, 0); // Choose ROM
|
||||
|
||||
for (i = 0; i < 8; i++) OneWireWrite(rom[i], 0);
|
||||
}
|
||||
|
||||
//
|
||||
// Do a ROM skip
|
||||
//
|
||||
void OneWireSkip() {
|
||||
OneWireWrite(0xCC, 0); // Skip ROM
|
||||
}
|
||||
|
||||
void OneWireDepower() { DIRECT_MODE_INPUT(); }
|
||||
|
||||
//
|
||||
// You need to use this function to start a search again from the beginning.
|
||||
// You do not need to do it for the first search, though you could.
|
||||
//
|
||||
void OneWireResetSearch() {
|
||||
// reset the search state
|
||||
LastDiscrepancy = 0;
|
||||
LastDeviceFlag = false;
|
||||
LastFamilyDiscrepancy = 0;
|
||||
for (int i = 7;; i--) {
|
||||
ROM_NO[i] = 0;
|
||||
if (i == 0) break;
|
||||
}
|
||||
}
|
||||
|
||||
// Setup the search to find the device type 'family_code' on the next call
|
||||
// to search(*newAddr) if it is present.
|
||||
//
|
||||
void OneWireTargetSearch(uint8_t family_code) {
|
||||
// set the search state to find SearchFamily type devices
|
||||
ROM_NO[0] = family_code;
|
||||
for (uint8_t i = 1; i < 8; i++) ROM_NO[i] = 0;
|
||||
LastDiscrepancy = 64;
|
||||
LastFamilyDiscrepancy = 0;
|
||||
LastDeviceFlag = false;
|
||||
}
|
||||
|
||||
//
|
||||
// Perform a search. If this function returns a '1' then it has
|
||||
// enumerated the next device and you may retrieve the ROM from the
|
||||
// OneWireAddress variable. If there are no devices, no further
|
||||
// devices, or something horrible happens in the middle of the
|
||||
// enumeration then a 0 is returned. If a new device is found then
|
||||
// its address is copied to newAddr. Use OneWireReset_search() to
|
||||
// start over.
|
||||
//
|
||||
// --- Replaced by the one from the Dallas Semiconductor web site ---
|
||||
//--------------------------------------------------------------------------
|
||||
// Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
|
||||
// search state.
|
||||
// Return TRUE : device found, ROM number in ROM_NO buffer
|
||||
// FALSE : device not found, end of search
|
||||
//
|
||||
bool OneWireSearch(uint8_t *newAddr, bool search_mode /* = true */) {
|
||||
uint8_t id_bit_number;
|
||||
uint8_t last_zero, rom_byte_number;
|
||||
bool search_result;
|
||||
uint8_t id_bit, cmp_id_bit;
|
||||
|
||||
unsigned char rom_byte_mask, search_direction;
|
||||
|
||||
// initialize for search
|
||||
id_bit_number = 1;
|
||||
last_zero = 0;
|
||||
rom_byte_number = 0;
|
||||
rom_byte_mask = 1;
|
||||
search_result = false;
|
||||
|
||||
// if the last call was not the last one
|
||||
if (!LastDeviceFlag) {
|
||||
// 1-Wire reset
|
||||
if (!OneWireReset()) {
|
||||
// reset the search
|
||||
LastDiscrepancy = 0;
|
||||
LastDeviceFlag = false;
|
||||
LastFamilyDiscrepancy = 0;
|
||||
return false;
|
||||
}
|
||||
|
||||
// issue the search command
|
||||
if (search_mode == true) {
|
||||
OneWireWrite(0xF0, 0); // NORMAL SEARCH
|
||||
} else {
|
||||
OneWireWrite(0xEC, 0); // CONDITIONAL SEARCH
|
||||
}
|
||||
|
||||
// loop to do the search
|
||||
do {
|
||||
// read a bit and its complement
|
||||
id_bit = OneWireReadBit();
|
||||
cmp_id_bit = OneWireReadBit();
|
||||
|
||||
// check for no devices on 1-wire
|
||||
if ((id_bit == 1) && (cmp_id_bit == 1)) {
|
||||
break;
|
||||
} else {
|
||||
// all devices coupled have 0 or 1
|
||||
if (id_bit != cmp_id_bit) {
|
||||
search_direction = id_bit; // bit write value for search
|
||||
} else {
|
||||
// if this discrepancy if before the Last Discrepancy
|
||||
// on a previous next then pick the same as last time
|
||||
if (id_bit_number < LastDiscrepancy) {
|
||||
search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
|
||||
} else {
|
||||
// if equal to last pick 1, if not then pick 0
|
||||
search_direction = (id_bit_number == LastDiscrepancy);
|
||||
}
|
||||
// if 0 was picked then record its position in LastZero
|
||||
if (search_direction == 0) {
|
||||
last_zero = id_bit_number;
|
||||
|
||||
// check for Last discrepancy in family
|
||||
if (last_zero < 9) LastFamilyDiscrepancy = last_zero;
|
||||
}
|
||||
}
|
||||
|
||||
// set or clear the bit in the ROM byte rom_byte_number
|
||||
// with mask rom_byte_mask
|
||||
if (search_direction == 1)
|
||||
ROM_NO[rom_byte_number] |= rom_byte_mask;
|
||||
else
|
||||
ROM_NO[rom_byte_number] &= ~rom_byte_mask;
|
||||
|
||||
// serial number search direction write bit
|
||||
OneWireWriteBit(search_direction);
|
||||
|
||||
// increment the byte counter id_bit_number
|
||||
// and shift the mask rom_byte_mask
|
||||
id_bit_number++;
|
||||
rom_byte_mask <<= 1;
|
||||
|
||||
// if the mask is 0 then go to new SerialNum byte rom_byte_number and
|
||||
// reset mask
|
||||
if (rom_byte_mask == 0) {
|
||||
rom_byte_number++;
|
||||
rom_byte_mask = 1;
|
||||
}
|
||||
}
|
||||
} while (rom_byte_number < 8); // loop until through all ROM bytes 0-7
|
||||
|
||||
// if the search was successful then
|
||||
if (!(id_bit_number < 65)) {
|
||||
// search successful so set LastDiscrepancy,LastDeviceFlag,search_result
|
||||
LastDiscrepancy = last_zero;
|
||||
|
||||
// check for last device
|
||||
if (LastDiscrepancy == 0) {
|
||||
LastDeviceFlag = true;
|
||||
}
|
||||
search_result = true;
|
||||
}
|
||||
}
|
||||
|
||||
// if no device found then reset counters so next 'search' will be like a
|
||||
// first
|
||||
if (!search_result || !ROM_NO[0]) {
|
||||
LastDiscrepancy = 0;
|
||||
LastDeviceFlag = false;
|
||||
LastFamilyDiscrepancy = 0;
|
||||
search_result = false;
|
||||
} else {
|
||||
for (int i = 0; i < 8; i++) newAddr[i] = ROM_NO[i];
|
||||
}
|
||||
return search_result;
|
||||
}
|
||||
|
||||
// The 1-Wire CRC scheme is described in Maxim Application Note 27:
|
||||
// "Understanding and Using Cyclic Redundancy Checks with Maxim iButton
|
||||
// Products"
|
||||
//
|
||||
|
||||
//
|
||||
// Compute a Dallas Semiconductor 8 bit CRC directly.
|
||||
// this is much slower, but a little smaller, than the lookup table.
|
||||
//
|
||||
uint8_t OneWireCrc8(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;
|
||||
}
|
||||
|
||||
bool OneWireCheckCrc16(const uint8_t *input, uint16_t len,
|
||||
const uint8_t *inverted_crc, uint16_t crc) {
|
||||
crc = ~OneWireCrc16(input, len, crc);
|
||||
return (crc & 0xFF) == inverted_crc[0] && (crc >> 8) == inverted_crc[1];
|
||||
}
|
||||
|
||||
uint16_t OneWireCrc16(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;
|
||||
}
|
||||
Reference in New Issue
Block a user