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/*
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
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Delete very old, out-of-date readme file (info is here)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(500);
noInterrupts();
DIRECT_MODE_INPUT(reg, mask); // allow it to float
delayMicroseconds(80);
r = !DIRECT_READ(reg, mask);
interrupts();
delayMicroseconds(420);
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( uint8_t rom[8])
{
int 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;
}
}
//
// 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( 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( 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(uint8_t* input, uint16_t len, uint8_t* inverted_crc)
{
uint16_t crc = ~crc16(input, len);
return (crc & 0xFF) == inverted_crc[0] && (crc >> 8) == inverted_crc[1];
}
uint16_t OneWire::crc16(uint8_t* input, uint16_t len)
{
static const uint8_t oddparity[16] =
{ 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
uint16_t crc = 0; // Starting seed is zero.
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)) & 0xff;
crc >>= 8;
if (oddparity[cdata & 0x0F] ^ oddparity[cdata >> 4])
crc ^= 0xC001;
cdata <<= 6;
crc ^= cdata;
cdata <<= 1;
crc ^= cdata;
}
return crc;
}
#endif
#endif