Revision 0:fb8b6da96a8b, committed 2011-07-17

Comitter:

tonymudd

Date:

Sun Jul 17 15:56:49 2011 +0000

Commit message:

Changed in this revision

diff -r 000000000000 -r fb8b6da96a8b DS18B20.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS18B20.cpp	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,103 @@
+/*
+* DS18B20. Maxim DS18B20 One-Wire Thermometer. 
+* Uses the OneWireCRC library.
+*
+* Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireThermometer.
+*
+* OneWireThermometer is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireThermometer is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireThermometer.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "DS18B20.h"
+#include "DebugTrace.h"
+
+DebugTrace pc_ds18B20(OFF, TO_SERIAL);
+
+DS18B20::DS18B20( PinName pin) : 
+    OneWireThermometer(pin, DS18B20_ID)
+{
+}
+
+void DS18B20::setResolution(eResolution resln)
+{
+    // as the write to the configuration register involves a write to the
+    // high and low alarm bytes, need to read these registers first
+    // and copy them back on the write
+    
+    BYTE read_data[THERMOM_SCRATCHPAD_SIZE];
+    BYTE write_data[ALARM_CONFIG_SIZE];
+    
+    if (readAndValidateData(read_data))
+    {
+        // copy alarm and config data to write data
+        for (int k = 2; k < 5; k++)
+        {
+            write_data[k - 2] = read_data[k];
+        }
+        int config = write_data[2];
+        config &= 0x9F;
+        config ^= (resln << 5);
+        write_data[2] = config;
+        
+        resetAndAddress();
+        oneWire.writeByte(WRITESCRATCH);
+        for (int k = 0; k < 3; k++)
+        {
+            oneWire.writeByte(write_data[k]);
+        }
+        
+        // remember it so we can use the correct delay in reading the temperature
+        // for parasitic power
+        resolution = resln; 
+    }
+}
+
+float DS18B20::calculateTemperature(BYTE* data)
+{
+    bool signBit = false;
+    if (data[TEMPERATURE_MSB] & 0x80) signBit = true;
+        
+    int read_temp = (data[TEMPERATURE_MSB] << 8) + data[TEMPERATURE_LSB];
+    if (signBit)
+    {
+        read_temp = (read_temp ^ 0xFFFF) + 1;    // two's complement
+        read_temp *= -1;
+    }
+    
+    int resolution = (data[CONFIG_REG_BYTE] & 0x60) >> 5; // mask off bits 6,5 and move to 1,0
+    switch (resolution)
+    {
+        case nineBit:    // 0.5 deg C increments
+            read_temp &= 0xFFF8;                // bits 2,1,0 are undefined
+            //pc_ds18B20.traceOut("9 bit resolution ...\r\n");
+            break;
+        case tenBit:     // 0.25 deg C increments
+            read_temp &= 0xFFFC;                // bits 1,0 are undefined
+            //pc_ds18B20.traceOut("10 bit resolution ...\r\n");
+            break;
+        case elevenBit:  // 0.125 deg C increments
+            read_temp &= 0xFFFE;                // bit 0 is undefined
+            //pc_ds18B20.traceOut("11 bit resolution ...\r\n");
+            break;
+        case twelveBit:  // 0.0625 deg C increments
+            //pc_ds18B20.traceOut("12 bit resolution ...\r\n");
+            break;
+    }
+    float realTemp = (float)read_temp/16 ;
+                 
+    pc_ds18B20.traceOut("TEMP_READ/REAL TEMP: %f \r\n", realTemp); 
+               
+    return realTemp;
+}
\ No newline at end of file

diff -r 000000000000 -r fb8b6da96a8b DS18B20.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS18B20.h	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,41 @@
+/*
+* DS18B20. Maxim DS18B20 One-Wire Thermometer. 
+* Uses the OneWireCRC library.
+*
+* Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireThermometer.
+*
+* OneWireThermometer is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireThermometer is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireThermometer.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef SNATCH59_DS18B20_H
+#define SNATCH59_DS18B20_H
+
+#include "OneWireThermometer.h"
+#include "OneWireDefs.h"
+
+class DS18B20 : public OneWireThermometer
+{
+public:
+    DS18B20( PinName pin);
+    
+    virtual void setResolution(eResolution resln);
+    
+protected:
+    virtual float calculateTemperature(BYTE* data);
+};
+
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r fb8b6da96a8b DebugTrace.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DebugTrace.cpp	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,143 @@
+/*
+* DebugTrace. Allows dumping debug messages/values to serial or
+* to file.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of DebugTrace.
+*
+* DebugTrace is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* DebugTrace is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with DebugTrace.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "DebugTrace.h"
+#include <mbed.h>
+#include <stdarg.h>
+#include <string.h>
+
+Serial logSerial(USBTX, USBRX);
+LocalFileSystem local("local");
+
+const char* FILE_PATH = "/local/";
+const char* EXTN = ".bak";
+
+DebugTrace::DebugTrace(eLog on, eLogTarget mode, const char* fileName, int maxSize) :
+    enabled(on), logMode(mode), maxFileSize(maxSize), currentFileSize(0),
+    logFileStatus(0)
+{
+    // allocate memory for file name strings
+    int str_size = (strlen(fileName) + strlen(FILE_PATH) + strlen(EXTN) + 1) * sizeof(char); 
+    logFile = (char*)malloc(str_size);
+    logFileBackup = (char*)malloc(str_size);
+    
+    // add path to log file name
+    strcpy(logFile, FILE_PATH);
+    strcat(logFile, fileName);
+    
+    // create backup file name
+    strcpy(logFileBackup, logFile);
+    strcpy(logFileBackup, strtok(logFileBackup, "."));
+    strcat(logFileBackup, EXTN);
+}
+
+DebugTrace::~DebugTrace()
+{
+    // dust to dust, ashes to ashes
+    if (logFile != NULL) free(logFile);
+    if (logFileBackup != NULL) free(logFileBackup);
+}
+
+void DebugTrace::clear()
+{
+    // don't care about whether these fail
+    remove(logFile);    
+    remove(logFileBackup);
+}
+
+void DebugTrace::backupLog()
+{
+    // delete previous backup file
+    if (remove(logFileBackup))
+    {
+        // standard copy stuff
+        char ch;
+        FILE* to = fopen(logFileBackup, "wb");
+        if (NULL != to)
+        {
+            FILE* from = fopen(logFile, "rb");   
+            if (NULL != from)
+            {
+                while(!feof(from))
+                {
+                    ch = fgetc(from);
+                    if (ferror(from)) break;
+                    
+                    if(!feof(from)) fputc(ch, to);
+                    if (ferror(to)) break;
+                }
+            }
+            
+            if (NULL != from) fclose(from);
+            if (NULL != to) fclose(to);
+        }
+    }
+
+    // now delete the log file, so we are ready to start again
+    // even if backup creation failed - the show must go on!
+    logFileStatus = remove(logFile);
+}
+
+void DebugTrace::traceOut(const char* fmt, ...)
+{
+    if (enabled)
+    {
+        va_list ap;            // argument list pointer
+        va_start(ap, fmt);
+        
+        if (TO_SERIAL == logMode)
+        {
+            vfprintf(logSerial, fmt, ap);
+        }
+        else    // TO_FILE
+        {
+            if (0 == logFileStatus)    // otherwise we failed to remove a full log file
+            {
+                // Write data to file. Note the file size may go over limit
+                // as we check total size afterwards, using the size written to file.
+                // This is not a big issue, as this mechanism is only here
+                // to stop the file growing unchecked. Just remember log file sizes may
+                // be some what over (as apposed to some what under), so don't push it 
+                // with the max file size.
+                FILE* fp = fopen(logFile, "a");
+                if (NULL == fp)
+                {
+                    va_end(ap);
+                    return;
+                }
+                int size_written = vfprintf(fp, fmt, ap);
+                fclose(fp);
+                
+                // check if we are over the max file size
+                // if so backup file and start again
+                currentFileSize += size_written;
+                if (currentFileSize >= maxFileSize)
+                {
+                    backupLog();
+                    currentFileSize = 0;
+                }
+            }
+        }
+        
+        va_end(ap);
+    }
+}

diff -r 000000000000 -r fb8b6da96a8b DebugTrace.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DebugTrace.h	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,50 @@
+/*
+* DebugTrace. Allows dumping debug messages/values to serial or
+* to file.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of DebugTrace.
+*
+* DebugTrace is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* DebugTrace is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with DebugTrace.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef SNATCH59_DEBUGTRACE_H
+#define SNATCH59_DEBUGTRACE_H
+
+enum eLog {OFF, ON};
+enum eLogTarget {TO_SERIAL, TO_FILE};
+
+class DebugTrace
+{
+public:
+    DebugTrace(eLog on, eLogTarget mode, const char* fileName = "log.txt", const int maxSize = 1024);
+    ~DebugTrace();
+    
+    void clear();
+    void traceOut(const char* fmt, ...);
+    
+private:
+    eLog enabled;
+    eLogTarget logMode;
+    int maxFileSize;
+    int currentFileSize;
+    char* logFile;
+    char* logFileBackup;
+    int logFileStatus;            // if things go wrong, don't write any more data to file
+    
+    void backupLog();
+};
+
+#endif

diff -r 000000000000 -r fb8b6da96a8b OneWireCRC.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWireCRC.cpp	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,459 @@
+/*
+* OneWireCRC. This is a port to mbed of Jim Studt's Adruino One Wire
+* library. Please see additional copyrights below this one, including
+* references to other copyrights.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireCRC.
+*
+* OneWireCRC is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireCRC is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireCRC.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/*
+Copyright (c) 2007, Jim Studt
+
+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
+
+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 "OneWireCRC.h"
+#include "OneWireDefs.h"
+
+// recommended data sheet timings in micro seconds
+const int standardT[] = {6, 64, 60, 10, 9, 55, 0, 480, 70, 410};
+const int overdriveT[] = {1.5, 7.5, 7.5, 2.5, 0.75, 7, 2.5, 70, 8.5, 40};
+
+OneWireCRC::OneWireCRC(PinName oneWire, eSpeed speed) : oneWirePort(oneWire)
+{
+    if (STANDARD == speed) timing = standardT;   
+    else  timing = overdriveT;  // overdrive
+    
+    resetSearch();    // reset address search state
+}
+
+// Generate a 1-wire reset, return 1 if no presence detect was found,
+// return 0 otherwise.
+// (NOTE: does not handle alarm presence from DS2404/DS1994)
+int OneWireCRC::reset() 
+{
+    
+    BYTE result = 0;    // sample presence pulse result
+        
+    wait_us(timing[6]);
+    oneWirePort.output();
+    oneWirePort = 0;
+    wait_us(timing[7]);
+    oneWirePort.input();
+    wait_us(timing[8]);
+    result = !(oneWirePort & 0x01);
+    wait_us(timing[9]);
+    
+    return result;
+}
+
+//
+// Write a bit. Port and bit is used to cut lookup time and provide
+// more certain timing.
+//
+void OneWireCRC::writeBit(int bit)
+{
+    bit = bit & 0x01;
+    
+    if (bit)
+    {
+        // Write '1' bit
+        oneWirePort.output();
+        oneWirePort = 0;
+        wait_us(timing[0]);
+        oneWirePort.input();
+        wait_us(timing[1]);
+    }
+    else
+    {
+        // Write '0' bit
+        oneWirePort.output();
+        oneWirePort = 0;
+        wait_us(timing[2]);
+        oneWirePort.input();
+        wait_us(timing[3]);
+    }
+}
+
+//
+// Read a bit. Port and bit is used to cut lookup time and provide
+// more certain timing.
+//
+int OneWireCRC::readBit() 
+{
+    BYTE result;
+    
+    oneWirePort.output();
+    oneWirePort = 0;
+    wait_us(timing[0]);
+    oneWirePort.input();
+    wait_us(timing[4]);
+    result = oneWirePort & 0x01;
+    wait_us(timing[5]);
+       
+    return result;
+}
+
+//
+// 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 OneWireCRC::writeByte(int data) 
+{
+    // Loop to write each bit in the byte, LS-bit first
+    for (int loop = 0; loop < 8; loop++)
+    {
+        writeBit(data & 0x01);
+        
+        // shift the data byte for the next bit
+        data >>= 1;
+    }
+}
+
+//
+// Read a byte
+//
+int OneWireCRC::readByte() 
+{
+    int result = 0;
+    
+    for (int loop = 0; loop < 8; loop++)
+    {
+        // shift the result to get it ready for the next bit
+        result >>= 1;
+        
+        // if result is one, then set MS bit
+        if (readBit()) result |= 0x80;
+    }
+    
+    return result;
+}
+
+int OneWireCRC::touchByte(int data)
+{
+    int result = 0;
+    
+    for (int loop = 0; loop < 8; loop++)
+    {
+        // shift the result to get it ready for the next bit
+        result >>= 1;
+        
+        // If sending a '1' then read a bit else write a '0'
+        if (data & 0x01)
+        {
+            if (readBit()) result |= 0x80;
+        }
+        else writeBit(0);
+        
+        // shift the data byte for the next bit
+        data >>= 1;
+    }
+    
+    return result;
+}
+
+void OneWireCRC::block(BYTE* data, int data_len)
+{
+    for (int loop = 0; loop < data_len; loop++)
+    {
+        data[loop] = touchByte(data[loop]);
+    }
+}
+
+int OneWireCRC::overdriveSkip(BYTE* data, int data_len)
+{
+    // set the speed to 'standard'
+    timing = standardT;
+    
+    // reset all devices
+    if (reset()) return 0;    // if no devices found
+    
+    // overdrive skip command
+    writeByte(OVERDRIVE_SKIP);
+    
+    // set the speed to 'overdrive'
+    timing = overdriveT;
+    
+    // do a 1-Wire reset in 'overdrive' and return presence result
+    return reset();
+}
+
+//
+// Do a ROM select
+//
+void OneWireCRC::matchROM(BYTE rom[8])
+{
+    writeByte(MATCH_ROM);         // Choose ROM
+
+    for(int i = 0; i < 8; i++) writeByte(rom[i]);
+}
+
+//
+// Do a ROM skip
+//
+void OneWireCRC::skipROM()
+{
+    writeByte(SKIP_ROM);         // Skip ROM
+}
+
+//
+// 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 OneWireCRC::resetSearch()
+{
+    searchJunction = -1;
+    searchExhausted = false;
+    for (int i = 0; i < 8; i++) 
+    {
+        address[i] = 0;
+    }
+}
+
+//
+// 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.
+// 
+BYTE OneWireCRC::search(BYTE* newAddr)
+{
+    BYTE i;
+    int lastJunction = -1;
+    BYTE done = 1;
+    
+    if (searchExhausted) return 0;
+    
+    if (!reset()) return 0;
+
+    writeByte(SEARCH_ROM);
+    
+    for(i = 0; i < 64; i++) 
+    {
+        BYTE a = readBit( );
+        BYTE nota = readBit( );
+        BYTE ibyte = i/8;
+        BYTE ibit = 1 << (i & 7);
+    
+        // I don't think this should happen, this means nothing responded, but maybe if
+        // something vanishes during the search it will come up.
+        if (a && nota) return 0;  
+        
+        if (!a && !nota)
+        {
+            if (i == searchJunction) 
+            {
+                // this is our time to decide differently, we went zero last time, go one.
+                a = 1;
+                searchJunction = lastJunction;
+            } 
+            else if (i < searchJunction) 
+            {
+                // take whatever we took last time, look in address
+                if (address[ibyte] & ibit) a = 1;
+                else 
+                {
+                    // Only 0s count as pending junctions, we've already exhasuted the 0 side of 1s
+                    a = 0;
+                    done = 0;
+                    lastJunction = i;
+                }
+            } 
+            else 
+            {
+                // we are blazing new tree, take the 0
+                a = 0;
+                searchJunction = i;
+                done = 0;
+            }
+            lastJunction = i;
+        }
+        
+        if (a) address[ibyte] |= ibit;
+        else address[ibyte] &= ~ibit;
+    
+        writeBit(a);
+    }
+    
+    if (done) searchExhausted = true;
+    
+    for (i = 0; i < 8; i++) newAddr[i] = address[i];
+    
+    return 1;  
+}
+
+// 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 BYTE 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 the
+// 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.)  
+//
+BYTE OneWireCRC::crc8(BYTE* addr, BYTE len)
+{
+    BYTE i;
+    BYTE crc = 0;
+    
+    for (i = 0; i < len; i++)
+    {
+        crc  = dscrc_table[crc ^ addr[i] ];
+    }
+    
+    return crc;
+}
+#else
+//
+// Compute a Dallas Semiconductor 8 bit CRC directly. 
+//
+BYTE OneWireCRC::crc8(BYTE* addr, BYTE len)
+{
+    BYTE i, j;
+    BYTE crc = 0;
+    
+    for (i = 0; i < len; i++) 
+    {
+        BYTE inbyte = addr[i];
+        for (j = 0; j < 8; j++) 
+        {
+            BYTE mix = (crc ^ inbyte) & 0x01;
+            crc >>= 1;
+            if (mix) crc ^= 0x8C;
+            inbyte >>= 1;
+        }
+    }
+    
+    return crc;
+}
+#endif
+
+static short oddparity[16] = { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
+
+//
+// Compute a Dallas Semiconductor 16 bit CRC. I have never seen one of
+// these, but here it is.
+//
+unsigned short OneWireCRC::crc16(unsigned short* data, unsigned short len)
+{
+    unsigned short i;
+    unsigned short crc = 0;
+    
+    for ( i = 0; i < len; i++) 
+    {
+        unsigned short cdata = data[len];
+    
+        cdata = (cdata ^ (crc & 0xff)) & 0xff;
+        crc >>= 8;
+    
+        if (oddparity[cdata & 0xf] ^ oddparity[cdata >> 4]) crc ^= 0xc001;
+    
+        cdata <<= 6;
+        crc ^= cdata;
+        cdata <<= 1;
+        crc ^= cdata;
+    }
+    
+    return crc;
+}
+

diff -r 000000000000 -r fb8b6da96a8b OneWireCRC.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWireCRC.h	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,138 @@
+/*
+* OneWireCRC. This is a port to mbed of Jim Studt's Adruino One Wire
+* library. Please see additional copyrights below this one, including
+* references to other copyrights.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireCRC.
+*
+* OneWireCRC is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireCRC is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireCRC.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/*
+Copyright (c) 2007, Jim Studt
+
+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
+
+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.
+//--------------------------------------------------------------------------
+
+#ifndef SNATCH59_ONEWIRECRC_H
+#define SNATCH59_ONEWIRECRC_H
+
+#include <mbed.h>
+
+// Select the table-lookup method of computing the 8-bit CRC by setting this to 1
+#ifndef ONEWIRE_CRC8_TABLE
+#define ONEWIRE_CRC8_TABLE 1
+#endif
+
+typedef unsigned char BYTE;    // used to be uint8_t : something a byte wide, whatever ....
+
+enum eSpeed {OVERDRIVE, STANDARD};
+
+class OneWireCRC
+{
+public:
+    OneWireCRC(PinName oneWire, eSpeed);
+    
+    // reset, read, write functions
+    int reset();
+    void writeByte(int data);
+    int readByte();
+    int touchByte(int data);
+    void block(BYTE* data, int data_len);
+    int overdriveSkip(BYTE* data, int data_len);
+    
+    // address functions
+    void matchROM(BYTE rom[8]);
+    void skipROM();
+
+    // address search functions
+    void resetSearch();
+    BYTE search(BYTE* newAddr);
+
+    // CRC check functions
+    static BYTE crc8(BYTE* addr, BYTE len);
+    static unsigned short crc16(unsigned short* data, unsigned short len);
+
+private:
+    const int* timing;
+    
+    BYTE address[8];
+    int searchJunction;        // so we can set to it -1 somewhere
+    bool searchExhausted;
+    
+    DigitalInOut oneWirePort;
+    
+    // read/write bit functions
+    void writeBit(int bit);
+    int readBit();
+};
+
+#endif

diff -r 000000000000 -r fb8b6da96a8b OneWireDefs.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWireDefs.h	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,66 @@
+/*
+* OneWireCRC. This is a port to mbed of Jim Studt's Adruino One Wire
+* library.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireCRC.
+*
+* OneWireCRC is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireCRC is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireCRC.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef SNATCH59_ONEWIREDEFS_H
+#define SNATCH59_ONEWIREDEFS_H
+
+// device ids
+#define DS18B20_ID        0x28
+#define DS18S20_ID        0x10
+
+#define ALARM_CONFIG_SIZE 3
+#define THERMOM_SCRATCHPAD_SIZE    9
+#define THERMOM_CRC_BYTE  8
+#define ADDRESS_SIZE      8
+#define ADDRESS_CRC_BYTE  7
+
+// One Wire command codes
+#define OVERDRIVE_SKIP    0x3C
+// ROM commands
+#define SEARCH_ROM        0xF0
+#define READ_ROM          0x33
+#define MATCH_ROM         0x55
+#define SKIP_ROM          0xCC
+#define ALARM_SEARCH      0xEC
+// Functions Commnds
+#define CONVERT           0x44
+#define WRITESCRATCH      0x4E
+#define READSCRATCH       0xBE
+#define COPYSCRATCH       0x48
+#define RECALLE2          0xB8
+#define READPOWERSUPPLY   0xB4
+
+// temperature read resolutions
+enum eResolution {nineBit = 0, tenBit, elevenBit, twelveBit};
+const int CONVERSION_TIME[] = {94, 188, 375, 750};    // milli-seconds
+
+// DS18B20/DS18S20 related
+#define TEMPERATURE_LSB    0
+#define TEMPERATURE_MSB    1
+#define HIGH_ALARM_BYTE    2
+#define LOW_ALARM_BYTE     3
+#define CONFIG_REG_BYTE    4
+#define CONFIG_READ_END    5
+#define COUNT_REMAIN_BYTE  6
+#define COUNT_PER_DEG_BYTE 7
+
+#endif

diff -r 000000000000 -r fb8b6da96a8b OneWireThermometer.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWireThermometer.cpp	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,154 @@
+/*
+* OneWireThermometer. Base class for Maxim One-Wire Thermometers. 
+* Uses the OneWireCRC library.
+*
+* Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireThermometer.
+*
+* OneWireThermometer is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireThermometer is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireThermometer.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "OneWireThermometer.h"
+#include "OneWireDefs.h"
+#include "DebugTrace.h"
+
+DebugTrace pc(OFF, TO_SERIAL);
+
+// constructor specifies standard speed for the 1-Wire comms
+// Used to have params for CRCon and useAddress, can't see why you wouldn't use CRC and you have to use address since there could be more than one.
+OneWireThermometer::OneWireThermometer(PinName pin, int device_id) :
+    oneWire(pin, STANDARD), deviceId(device_id), resolution(twelveBit)
+{
+    // NOTE: the power-up resolution of a DS18B20 is 12 bits. The DS18S20's resolution is always
+    // 9 bits + enhancement, but we treat the DS18S20 as fixed to 12 bits for calculating the
+    // conversion time Tconv.
+    deviceCount = 0;
+}
+
+bool OneWireThermometer::initialize()
+{
+    // get all the device addresses for use in selectROM() when reading the temperature
+    pc.traceOut("\r\n");
+    pc.traceOut("New Scan\r\n");
+
+    oneWire.resetSearch();    
+    while (oneWire.search(address))   // search for 1-wire device address
+    {
+        pc.traceOut("Address = ");
+        for (int i = 0; i < ADDRESS_SIZE; i++) 
+        {
+            pc.traceOut("%x ", (int)address[i]);
+            devices[deviceCount][i] = address[i];
+        }
+        pc.traceOut("\r\n");
+        deviceCount++;
+    }
+    
+    if (OneWireCRC::crc8(address, ADDRESS_CRC_BYTE) != address[ADDRESS_CRC_BYTE])   // check address CRC is valid
+    {
+        pc.traceOut("CRC is not valid!\r\n");
+        wait(2);
+        return false;
+    }
+
+    if (address[0] != deviceId)
+    {                    
+        // Make sure it is a one-wire thermometer device
+        if (DS18B20_ID == deviceId)
+            pc.traceOut("You need to use a DS1820 or DS18S20 for correct results.\r\n");
+        else if (DS18S20_ID == deviceId)
+            pc.traceOut("You need to use a DS18B20 for correct results.\r\n");
+        else
+          pc.traceOut("Device is not a DS18B20/DS1820/DS18S20 device.\r\n");
+        
+        wait(2);
+        return false;   
+    }
+    else
+    {
+        if (DS18B20_ID == deviceId) pc.traceOut("DS18B20 present and correct.\r\n");
+        if (DS18S20_ID == deviceId) pc.traceOut("DS1820/DS18S20 present and correct.\r\n");            
+    }
+    
+    return true;
+}
+
+// NOTE ON USING SKIP ROM: ok to use before a Convert command to get all
+// devices on the bus to do simultaneous temperature conversions. BUT can 
+// only use before a Read Scratchpad command if there is only one device on the
+// bus. For purpose of this library it is assumed there is only one device
+// on the bus.
+void OneWireThermometer::resetAndAddress()
+{
+    oneWire.reset();                // reset device 
+    oneWire.matchROM(address);  // select which device to talk to
+}
+
+bool OneWireThermometer::readAndValidateData(BYTE* data)
+{
+    bool dataOk = true;
+    
+    resetAndAddress();
+    oneWire.writeByte(READSCRATCH);    // read Scratchpad
+
+    pc.traceOut("read = ");
+    for (int i = 0; i < THERMOM_SCRATCHPAD_SIZE; i++) 
+    {               
+        // we need all bytes which includes CRC check byte
+        data[i] = oneWire.readByte();
+        pc.traceOut("%x ", (int)data[i]);
+    }
+    pc.traceOut("\r\n");
+
+    // Check CRC is valid
+    if (!(OneWireCRC::crc8(data, THERMOM_CRC_BYTE) == data[THERMOM_CRC_BYTE]))  
+    {  
+        // CRC failed
+        pc.traceOut("CRC FAILED... \r\n");
+        dataOk = false;
+    }
+    
+    return dataOk;
+}
+
+float OneWireThermometer::readTemperature(int device)
+{
+    BYTE data[THERMOM_SCRATCHPAD_SIZE];
+    float realTemp = -999;
+
+    // need to select which device here.
+    for (int i = 0; i < ADDRESS_SIZE; i++) 
+    {
+        address[i] = devices[device][i];
+    }
+
+    resetAndAddress();
+    oneWire.writeByte(CONVERT);     // issue Convert command
+    
+    // Removed the check for parasitic power, since we waited the same time anyway.
+    wait_ms(CONVERSION_TIME[resolution]);
+
+    if (readAndValidateData(data))    // issue Read Scratchpad commmand and get data
+    {
+        realTemp = calculateTemperature(data);
+    }
+    
+    return realTemp; 
+}
+
+int OneWireThermometer::getDeviceCount()
+{
+    return deviceCount;
+}
\ No newline at end of file

diff -r 000000000000 -r fb8b6da96a8b OneWireThermometer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OneWireThermometer.h	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,57 @@
+/*
+* OneWireThermometer. Base class for Maxim One-Wire Thermometers. 
+* Uses the OneWireCRC library.
+*
+* Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireThermometer.
+*
+* OneWireThermometer is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireThermometer is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireThermometer.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef SNATCH59_ONEWIRETHERMOMETER_H
+#define SNATCH59_ONEWIRETHERMOMETER_H
+
+#include <mbed.h>
+#include "OneWireCRC.h"
+#include "OneWireDefs.h"
+
+typedef unsigned char BYTE;    // something a byte wide
+typedef unsigned char DEVADDRESS[8];   // stores the address of one device
+
+class OneWireThermometer
+{
+public:
+    OneWireThermometer(PinName pin, int device_id);
+    
+    bool initialize();
+    float readTemperature(int device);
+    virtual void setResolution(eResolution resln) = 0; 
+    int getDeviceCount();
+
+protected:
+    OneWireCRC oneWire;
+    const int deviceId;
+    
+    eResolution resolution; 
+    BYTE address[8];
+    DEVADDRESS devices[10];
+    int deviceCount;
+   
+    void resetAndAddress();
+    bool readAndValidateData(BYTE* data);
+    virtual float calculateTemperature(BYTE* data) = 0;    // device specific
+};
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r fb8b6da96a8b main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,61 @@
+/*
+* OneWireCRC/OneWireThermometer demo.
+*
+* Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk>
+*
+* This file is part of OneWireCRC/OneWireThermometer.
+*
+* OneWireCRC/OneWireThermometer is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+* 
+* OneWireCRC/OneWireThermometer is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with OneWireCRC/OneWireThermometer0.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+////////////////////////////////////////////////////////////////////
+// Test code to read temperature from a Maxim DS18B20 or DS18S20
+// 1-wire device 
+////////////////////////////////////////////////////////////////////
+
+#include <mbed.h>
+#include "DS18B20.h"
+#include "OneWireDefs.h"
+
+#define THERMOMETER DS18B20
+
+float temp;
+// device( mbed pin )
+THERMOMETER device(p21);
+
+void readTemp(int deviceNum)
+{
+    temp = device.readTemperature(deviceNum);
+    printf("Device %d is %f\n\r",deviceNum, temp);
+    wait(0.5);
+}
+
+int main()
+{
+    
+    while (!device.initialize());    // keep calling until it works
+    // Say how many were found.
+    int deviceCount = device.getDeviceCount();
+    printf("Found %d sensors\n\r",deviceCount);
+
+    device.setResolution(twelveBit);
+    while (true)
+    {
+        for (int i = 0;i < deviceCount; i++)
+            readTemp(i);
+    }
+     
+    //return EXIT_SUCCESS;  // Commented out to prevent the warning that this code is unreachable, due to the while(forever) above.
+}
+

diff -r 000000000000 -r fb8b6da96a8b mbed.bld
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Sun Jul 17 15:56:49 2011 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/49a220cc26e0