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Diffstat (limited to 'lib/OneWire/OneWire.cpp')
| -rw-r--r-- | lib/OneWire/OneWire.cpp | 557 |
1 files changed, 557 insertions, 0 deletions
diff --git a/lib/OneWire/OneWire.cpp b/lib/OneWire/OneWire.cpp new file mode 100644 index 0000000..631813f --- /dev/null +++ b/lib/OneWire/OneWire.cpp @@ -0,0 +1,557 @@ +/* +Copyright (c) 2007, Jim Studt (original old version - many contributors since) + +The latest version of this library may be found at: + http://www.pjrc.com/teensy/td_libs_OneWire.html + +OneWire has been maintained by Paul Stoffregen (paul@pjrc.com) since +January 2010. At the time, it was in need of many bug fixes, but had +been abandoned the original author (Jim Studt). None of the known +contributors were interested in maintaining OneWire. Paul typically +works on OneWire every 6 to 12 months. Patches usually wait that +long. If anyone is interested in more actively maintaining OneWire, +please contact Paul. + +Version 2.2: + Teensy 3.0 compatibility, Paul Stoffregen, paul@pjrc.com + Arduino Due compatibility, http://arduino.cc/forum/index.php?topic=141030 + Fix DS18B20 example negative temperature + Fix DS18B20 example's low res modes, Ken Butcher + Improve reset timing, Mark Tillotson + Add const qualifiers, Bertrik Sikken + Add initial value input to crc16, Bertrik Sikken + Add target_search() function, Scott Roberts + +Version 2.1: + Arduino 1.0 compatibility, Paul Stoffregen + Improve temperature example, Paul Stoffregen + DS250x_PROM example, Guillermo Lovato + PIC32 (chipKit) compatibility, Jason Dangel, dangel.jason AT gmail.com + Improvements from Glenn Trewitt: + - crc16() now works + - check_crc16() does all of calculation/checking work. + - Added read_bytes() and write_bytes(), to reduce tedious loops. + - Added ds2408 example. + Delete very old, out-of-date readme file (info is here) + +Version 2.0: Modifications by Paul Stoffregen, January 2010: +http://www.pjrc.com/teensy/td_libs_OneWire.html + Search fix from Robin James + http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295/27#27 + Use direct optimized I/O in all cases + Disable interrupts during timing critical sections + (this solves many random communication errors) + Disable interrupts during read-modify-write I/O + Reduce RAM consumption by eliminating unnecessary + variables and trimming many to 8 bits + Optimize both crc8 - table version moved to flash + +Modified to work with larger numbers of devices - avoids loop. +Tested in Arduino 11 alpha with 12 sensors. +26 Sept 2008 -- Robin James +http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1238032295/27#27 + +Updated to work with arduino-0008 and to include skip() as of +2007/07/06. --RJL20 + +Modified to calculate the 8-bit CRC directly, avoiding the need for +the 256-byte lookup table to be loaded in RAM. Tested in arduino-0010 +-- Tom Pollard, Jan 23, 2008 + +Jim Studt's original library was modified by Josh Larios. + +Tom Pollard, pollard@alum.mit.edu, contributed around May 20, 2008 + +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: + +The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software. + +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. + +Much of the code was inspired by Derek Yerger's code, though I don't +think much of that remains. In any event that was.. + (copyleft) 2006 by Derek Yerger - Free to distribute freely. + +The CRC code was excerpted and inspired by the Dallas Semiconductor +sample code bearing this copyright. +//--------------------------------------------------------------------------- +// Copyright (C) 2000 Dallas Semiconductor Corporation, All Rights Reserved. +// +// 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: +// +// The above copyright notice and this permission notice shall be included +// in all copies or substantial portions of the Software. +// +// 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. +// +// Except as contained in this notice, the name of Dallas Semiconductor +// shall not be used except as stated in the Dallas Semiconductor +// Branding Policy. +//-------------------------------------------------------------------------- +*/ + +#include "OneWire.h" + + +OneWire::OneWire(uint8_t pin) +{ + pinMode(pin, INPUT); + bitmask = PIN_TO_BITMASK(pin); + baseReg = PIN_TO_BASEREG(pin); +#if ONEWIRE_SEARCH + reset_search(); +#endif +} + + +// Perform the onewire reset function. We will wait up to 250uS for +// the bus to come high, if it doesn't then it is broken or shorted +// and we return a 0; +// +// Returns 1 if a device asserted a presence pulse, 0 otherwise. +// +uint8_t OneWire::reset(void) +{ + IO_REG_TYPE mask = bitmask; + volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg; + uint8_t r; + uint8_t retries = 125; + + noInterrupts(); + DIRECT_MODE_INPUT(reg, mask); + interrupts(); + // wait until the wire is high... just in case + do { + if (--retries == 0) return 0; + delayMicroseconds(2); + } while ( !DIRECT_READ(reg, mask)); + + noInterrupts(); + DIRECT_WRITE_LOW(reg, mask); + DIRECT_MODE_OUTPUT(reg, mask); // drive output low + interrupts(); + delayMicroseconds(480); + noInterrupts(); + DIRECT_MODE_INPUT(reg, mask); // allow it to float + delayMicroseconds(70); + r = !DIRECT_READ(reg, mask); + interrupts(); + delayMicroseconds(410); + return r; +} + +// +// Write a bit. Port and bit is used to cut lookup time and provide +// more certain timing. +// +void OneWire::write_bit(uint8_t v) +{ + IO_REG_TYPE mask=bitmask; + volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg; + + if (v & 1) { + noInterrupts(); + DIRECT_WRITE_LOW(reg, mask); + DIRECT_MODE_OUTPUT(reg, mask); // drive output low + delayMicroseconds(10); + DIRECT_WRITE_HIGH(reg, mask); // drive output high + interrupts(); + delayMicroseconds(55); + } else { + noInterrupts(); + DIRECT_WRITE_LOW(reg, mask); + DIRECT_MODE_OUTPUT(reg, mask); // drive output low + delayMicroseconds(65); + DIRECT_WRITE_HIGH(reg, mask); // drive output high + interrupts(); + delayMicroseconds(5); + } +} + +// +// Read a bit. Port and bit is used to cut lookup time and provide +// more certain timing. +// +uint8_t OneWire::read_bit(void) +{ + IO_REG_TYPE mask=bitmask; + volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg; + uint8_t r; + + noInterrupts(); + DIRECT_MODE_OUTPUT(reg, mask); + DIRECT_WRITE_LOW(reg, mask); + delayMicroseconds(3); + DIRECT_MODE_INPUT(reg, mask); // let pin float, pull up will raise + delayMicroseconds(10); + r = DIRECT_READ(reg, mask); + interrupts(); + delayMicroseconds(53); + 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 OneWire::write(uint8_t v, uint8_t power /* = 0 */) { + uint8_t bitMask; + + for (bitMask = 0x01; bitMask; bitMask <<= 1) { + OneWire::write_bit( (bitMask & v)?1:0); + } + if ( !power) { + noInterrupts(); + DIRECT_MODE_INPUT(baseReg, bitmask); + DIRECT_WRITE_LOW(baseReg, bitmask); + interrupts(); + } +} + +void OneWire::write_bytes(const uint8_t *buf, uint16_t count, bool power /* = 0 */) { + for (uint16_t i = 0 ; i < count ; i++) + write(buf[i]); + if (!power) { + noInterrupts(); + DIRECT_MODE_INPUT(baseReg, bitmask); + DIRECT_WRITE_LOW(baseReg, bitmask); + interrupts(); + } +} + +// +// Read a byte +// +uint8_t OneWire::read() { + uint8_t bitMask; + uint8_t r = 0; + + for (bitMask = 0x01; bitMask; bitMask <<= 1) { + if ( OneWire::read_bit()) r |= bitMask; + } + return r; +} + +void OneWire::read_bytes(uint8_t *buf, uint16_t count) { + for (uint16_t i = 0 ; i < count ; i++) + buf[i] = read(); +} + +// +// Do a ROM select +// +void OneWire::select(const uint8_t rom[8]) +{ + uint8_t i; + + write(0x55); // Choose ROM + + for (i = 0; i < 8; i++) write(rom[i]); +} + +// +// Do a ROM skip +// +void OneWire::skip() +{ + write(0xCC); // Skip ROM +} + +void OneWire::depower() +{ + noInterrupts(); + DIRECT_MODE_INPUT(baseReg, bitmask); + interrupts(); +} + +#if ONEWIRE_SEARCH + +// +// 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 OneWire::reset_search() +{ + // 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 OneWire::target_search(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 +// OneWire::address 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 OneWire::reset_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 +// +uint8_t OneWire::search(uint8_t *newAddr) +{ + uint8_t id_bit_number; + uint8_t last_zero, rom_byte_number, 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 = 0; + + // if the last call was not the last one + if (!LastDeviceFlag) + { + // 1-Wire reset + if (!reset()) + { + // reset the search + LastDiscrepancy = 0; + LastDeviceFlag = FALSE; + LastFamilyDiscrepancy = 0; + return FALSE; + } + + // issue the search command + write(0xF0); + + // loop to do the search + do + { + // read a bit and its complement + id_bit = read_bit(); + cmp_id_bit = read_bit(); + + // 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 + write_bit(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; + } + for (int i = 0; i < 8; i++) newAddr[i] = ROM_NO[i]; + return search_result; + } + +#endif + +#if ONEWIRE_CRC +// The 1-Wire CRC scheme is described in Maxim Application Note 27: +// "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products" +// + +#if ONEWIRE_CRC8_TABLE +// This table comes from Dallas sample code where it is freely reusable, +// though Copyright (C) 2000 Dallas Semiconductor Corporation +static const uint8_t PROGMEM dscrc_table[] = { + 0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65, + 157,195, 33,127,252,162, 64, 30, 95, 1,227,189, 62, 96,130,220, + 35,125,159,193, 66, 28,254,160,225,191, 93, 3,128,222, 60, 98, + 190,224, 2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255, + 70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89, 7, + 219,133,103, 57,186,228, 6, 88, 25, 71,165,251,120, 38,196,154, + 101, 59,217,135, 4, 90,184,230,167,249, 27, 69,198,152,122, 36, + 248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91, 5,231,185, + 140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205, + 17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80, + 175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238, + 50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115, + 202,148,118, 40,171,245, 23, 73, 8, 86,180,234,105, 55,213,139, + 87, 9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22, + 233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168, + 116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53}; + +// +// Compute a Dallas Semiconductor 8 bit CRC. These show up in the ROM +// and the registers. (note: this might better be done without to +// table, it would probably be smaller and certainly fast enough +// compared to all those delayMicrosecond() calls. But I got +// 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 |