Filipe Morais / Mbed 2 deprecated mini_project

Sensor with Web Server

Dependencies:   EthernetInterface mbed-rpc mbed-rtos mbed

OneWireThermometer.cpp@0:c385e589a779, 2014-04-08 (annotated)

Committer:
afilipem
Date:
Tue Apr 08 12:13:32 2014 +0000
Revision:
0:c385e589a779
1 version;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
afilipem 0:c385e589a779 1 /*
afilipem 0:c385e589a779 2 * OneWireThermometer. Base class for Maxim One-Wire Thermometers.
afilipem 0:c385e589a779 3 * Uses the OneWireCRC library.
afilipem 0:c385e589a779 4 *
afilipem 0:c385e589a779 5 * Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk>
afilipem 0:c385e589a779 6 *
afilipem 0:c385e589a779 7 * This file is part of OneWireThermometer.
afilipem 0:c385e589a779 8 *
afilipem 0:c385e589a779 9 * OneWireThermometer is free software: you can redistribute it and/or modify
afilipem 0:c385e589a779 10 * it under the terms of the GNU General Public License as published by
afilipem 0:c385e589a779 11 * the Free Software Foundation, either version 3 of the License, or
afilipem 0:c385e589a779 12 * (at your option) any later version.
afilipem 0:c385e589a779 13 *
afilipem 0:c385e589a779 14 * OneWireThermometer is distributed in the hope that it will be useful,
afilipem 0:c385e589a779 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
afilipem 0:c385e589a779 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
afilipem 0:c385e589a779 17 * GNU General Public License for more details.
afilipem 0:c385e589a779 18 *
afilipem 0:c385e589a779 19 * You should have received a copy of the GNU General Public License
afilipem 0:c385e589a779 20 * along with OneWireThermometer. If not, see <http://www.gnu.org/licenses/>.
afilipem 0:c385e589a779 21 */
afilipem 0:c385e589a779 22
afilipem 0:c385e589a779 23 #include "OneWireThermometer.h"
afilipem 0:c385e589a779 24 #include "OneWireDefs.h"
afilipem 0:c385e589a779 25 #include "DebugTrace.h"
afilipem 0:c385e589a779 26
afilipem 0:c385e589a779 27 DebugTrace pc(ON, TO_SERIAL);
afilipem 0:c385e589a779 28
afilipem 0:c385e589a779 29 // constructor specifies standard speed for the 1-Wire comms
afilipem 0:c385e589a779 30 OneWireThermometer::OneWireThermometer(bool crcOn, bool useAddr, bool parasitic, PinName pin, int device_id) :
afilipem 0:c385e589a779 31 useCRC(crcOn), useAddress(useAddr), useParasiticPower(parasitic),
afilipem 0:c385e589a779 32 oneWire(pin, STANDARD), deviceId(device_id), resolution(twelveBit)
afilipem 0:c385e589a779 33 {
afilipem 0:c385e589a779 34 // NOTE: the power-up resolution of a DS18B20 is 12 bits. The DS18S20's resolution is always
afilipem 0:c385e589a779 35 // 9 bits + enhancement, but we treat the DS18S20 as fixed to 12 bits for calculating the
afilipem 0:c385e589a779 36 // conversion time Tconv.
afilipem 0:c385e589a779 37 }
afilipem 0:c385e589a779 38
afilipem 0:c385e589a779 39 bool OneWireThermometer::initialize()
afilipem 0:c385e589a779 40 {
afilipem 0:c385e589a779 41 // get the device address for use in selectROM() when reading the temperature
afilipem 0:c385e589a779 42 // - not really needed except for device validation if using skipROM()
afilipem 0:c385e589a779 43 if (useAddress)
afilipem 0:c385e589a779 44 {
afilipem 0:c385e589a779 45 pc.traceOut("\r\n");
afilipem 0:c385e589a779 46 pc.traceOut("New Scan\r\n");
afilipem 0:c385e589a779 47
afilipem 0:c385e589a779 48 oneWire.resetSearch();
afilipem 0:c385e589a779 49 if (!oneWire.search(address)) // search for 1-wire device address
afilipem 0:c385e589a779 50 {
afilipem 0:c385e589a779 51 pc.traceOut("No more addresses.\r\n");
afilipem 0:c385e589a779 52 wait(2);
afilipem 0:c385e589a779 53 return false;
afilipem 0:c385e589a779 54 }
afilipem 0:c385e589a779 55
afilipem 0:c385e589a779 56 pc.traceOut("Address = ");
afilipem 0:c385e589a779 57 for (int i = 0; i < ADDRESS_SIZE; i++)
afilipem 0:c385e589a779 58 {
afilipem 0:c385e589a779 59 pc.traceOut("%x ", (int)address[i]);
afilipem 0:c385e589a779 60 }
afilipem 0:c385e589a779 61 pc.traceOut("\r\n");
afilipem 0:c385e589a779 62
afilipem 0:c385e589a779 63 if (OneWireCRC::crc8(address, ADDRESS_CRC_BYTE) != address[ADDRESS_CRC_BYTE]) // check address CRC is valid
afilipem 0:c385e589a779 64 {
afilipem 0:c385e589a779 65 pc.traceOut("CRC is not valid!\r\n");
afilipem 0:c385e589a779 66 wait(2);
afilipem 0:c385e589a779 67 return false;
afilipem 0:c385e589a779 68 }
afilipem 0:c385e589a779 69
afilipem 0:c385e589a779 70 if (address[0] != deviceId)
afilipem 0:c385e589a779 71 {
afilipem 0:c385e589a779 72 // Make sure it is a one-wire thermometer device
afilipem 0:c385e589a779 73 if (DS18B20_ID == deviceId)
afilipem 0:c385e589a779 74 pc.traceOut("You need to use a DS1820 or DS18S20 for correct results.\r\n");
afilipem 0:c385e589a779 75 else if (DS18S20_ID == deviceId)
afilipem 0:c385e589a779 76 pc.traceOut("You need to use a DS18B20 for correct results.\r\n");
afilipem 0:c385e589a779 77 else
afilipem 0:c385e589a779 78 pc.traceOut("Device is not a DS18B20/DS1820/DS18S20 device.\r\n");
afilipem 0:c385e589a779 79
afilipem 0:c385e589a779 80 wait(2);
afilipem 0:c385e589a779 81 return false;
afilipem 0:c385e589a779 82 }
afilipem 0:c385e589a779 83 else
afilipem 0:c385e589a779 84 {
afilipem 0:c385e589a779 85 if (DS18B20_ID == deviceId) pc.traceOut("DS18B20 present and correct.\r\n");
afilipem 0:c385e589a779 86 if (DS18S20_ID == deviceId) pc.traceOut("DS1820/DS18S20 present and correct.\r\n");
afilipem 0:c385e589a779 87 }
afilipem 0:c385e589a779 88 }
afilipem 0:c385e589a779 89
afilipem 0:c385e589a779 90 return true;
afilipem 0:c385e589a779 91 }
afilipem 0:c385e589a779 92
afilipem 0:c385e589a779 93 // NOTE ON USING SKIP ROM: ok to use before a Convert command to get all
afilipem 0:c385e589a779 94 // devices on the bus to do simultaneous temperature conversions. BUT can
afilipem 0:c385e589a779 95 // only use before a Read Scratchpad command if there is only one device on the
afilipem 0:c385e589a779 96 // bus. For purpose of this library it is assumed there is only one device
afilipem 0:c385e589a779 97 // on the bus.
afilipem 0:c385e589a779 98 void OneWireThermometer::resetAndAddress()
afilipem 0:c385e589a779 99 {
afilipem 0:c385e589a779 100 oneWire.reset(); // reset device
afilipem 0:c385e589a779 101 if (useAddress)
afilipem 0:c385e589a779 102 {
afilipem 0:c385e589a779 103 oneWire.matchROM(address); // select which device to talk to
afilipem 0:c385e589a779 104 }
afilipem 0:c385e589a779 105 else
afilipem 0:c385e589a779 106 {
afilipem 0:c385e589a779 107 oneWire.skipROM(); // broadcast
afilipem 0:c385e589a779 108 }
afilipem 0:c385e589a779 109 }
afilipem 0:c385e589a779 110
afilipem 0:c385e589a779 111 bool OneWireThermometer::readAndValidateData(BYTE* data)
afilipem 0:c385e589a779 112 {
afilipem 0:c385e589a779 113 bool dataOk = true;
afilipem 0:c385e589a779 114
afilipem 0:c385e589a779 115 resetAndAddress();
afilipem 0:c385e589a779 116 oneWire.writeByte(READSCRATCH); // read Scratchpad
afilipem 0:c385e589a779 117
afilipem 0:c385e589a779 118 pc.traceOut("read = ");
afilipem 0:c385e589a779 119 for (int i = 0; i < THERMOM_SCRATCHPAD_SIZE; i++)
afilipem 0:c385e589a779 120 {
afilipem 0:c385e589a779 121 // we need all bytes which includes CRC check byte
afilipem 0:c385e589a779 122 data[i] = oneWire.readByte();
afilipem 0:c385e589a779 123 pc.traceOut("%x ", (int)data[i]);
afilipem 0:c385e589a779 124 }
afilipem 0:c385e589a779 125 pc.traceOut("\r\n");
afilipem 0:c385e589a779 126
afilipem 0:c385e589a779 127 // Check CRC is valid if you want to
afilipem 0:c385e589a779 128 if (useCRC && !(OneWireCRC::crc8(data, THERMOM_CRC_BYTE) == data[THERMOM_CRC_BYTE]))
afilipem 0:c385e589a779 129 {
afilipem 0:c385e589a779 130 // CRC failed
afilipem 0:c385e589a779 131 pc.traceOut("CRC FAILED... \r\n");
afilipem 0:c385e589a779 132 dataOk = false;
afilipem 0:c385e589a779 133 }
afilipem 0:c385e589a779 134
afilipem 0:c385e589a779 135 return dataOk;
afilipem 0:c385e589a779 136 }
afilipem 0:c385e589a779 137
afilipem 0:c385e589a779 138 float OneWireThermometer::readTemperature()
afilipem 0:c385e589a779 139 {
afilipem 0:c385e589a779 140 BYTE data[THERMOM_SCRATCHPAD_SIZE];
afilipem 0:c385e589a779 141 float realTemp = -999;
afilipem 0:c385e589a779 142
afilipem 0:c385e589a779 143 resetAndAddress();
afilipem 0:c385e589a779 144 oneWire.writeByte(CONVERT); // issue Convert command
afilipem 0:c385e589a779 145
afilipem 0:c385e589a779 146 if (useParasiticPower)
afilipem 0:c385e589a779 147 {
afilipem 0:c385e589a779 148 // wait while converting - Tconv (according to resolution of reading)
afilipem 0:c385e589a779 149 wait_ms(CONVERSION_TIME[resolution]);
afilipem 0:c385e589a779 150 }
afilipem 0:c385e589a779 151 else
afilipem 0:c385e589a779 152 {
afilipem 0:c385e589a779 153 // TODO
afilipem 0:c385e589a779 154 // after the Convert command, the device should respond by transmitting 0
afilipem 0:c385e589a779 155 // while the temperature conversion is in progress and 1 when the conversion is done
afilipem 0:c385e589a779 156 // - as were are not checking this (TODO), we use Tconv, as we would do for
afilipem 0:c385e589a779 157 // parasitic power
afilipem 0:c385e589a779 158 wait_ms(CONVERSION_TIME[resolution]);
afilipem 0:c385e589a779 159 }
afilipem 0:c385e589a779 160
afilipem 0:c385e589a779 161 if (readAndValidateData(data)) // issue Read Scratchpad commmand and get data
afilipem 0:c385e589a779 162 {
afilipem 0:c385e589a779 163 realTemp = calculateTemperature(data);
afilipem 0:c385e589a779 164 }
afilipem 0:c385e589a779 165
afilipem 0:c385e589a779 166 return realTemp;
afilipem 0:c385e589a779 167 }