Felícito Manzano / Mbed 2 deprecated OneWireCRC

Custom

Dependencies:   mbed

Fork of OneWireCRC by Petras Saduikis

DS18B20.cpp@1:6af898f6c5e8, 2016-10-04 (annotated)

Committer:
fmanzano_dtk
Date:
Tue Oct 04 16:53:47 2016 +0000
Revision:
1:6af898f6c5e8
Parent:
0:01a6a40578c9 
Owned;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
snatch59 0:01a6a40578c9 1 /*
snatch59 0:01a6a40578c9 2 * DS18B20. Maxim DS18B20 One-Wire Thermometer.
snatch59 0:01a6a40578c9 3 * Uses the OneWireCRC library.
snatch59 0:01a6a40578c9 4 *
snatch59 0:01a6a40578c9 5 * Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk>
snatch59 0:01a6a40578c9 6 *
snatch59 0:01a6a40578c9 7 * This file is part of OneWireThermometer.
snatch59 0:01a6a40578c9 8 *
snatch59 0:01a6a40578c9 9 * OneWireThermometer is free software: you can redistribute it and/or modify
snatch59 0:01a6a40578c9 10 * it under the terms of the GNU General Public License as published by
snatch59 0:01a6a40578c9 11 * the Free Software Foundation, either version 3 of the License, or
snatch59 0:01a6a40578c9 12 * (at your option) any later version.
snatch59 0:01a6a40578c9 13 *
snatch59 0:01a6a40578c9 14 * OneWireThermometer is distributed in the hope that it will be useful,
snatch59 0:01a6a40578c9 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
snatch59 0:01a6a40578c9 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
snatch59 0:01a6a40578c9 17 * GNU General Public License for more details.
snatch59 0:01a6a40578c9 18 *
snatch59 0:01a6a40578c9 19 * You should have received a copy of the GNU General Public License
snatch59 0:01a6a40578c9 20 * along with OneWireThermometer. If not, see <http://www.gnu.org/licenses/>.
snatch59 0:01a6a40578c9 21 */
snatch59 0:01a6a40578c9 22
snatch59 0:01a6a40578c9 23 #include "DS18B20.h"
snatch59 0:01a6a40578c9 24 #include "DebugTrace.h"
snatch59 0:01a6a40578c9 25
snatch59 0:01a6a40578c9 26 DebugTrace pc_ds18B20(ON, TO_SERIAL);
snatch59 0:01a6a40578c9 27
snatch59 0:01a6a40578c9 28 DS18B20::DS18B20(bool crcOn, bool useAddr, bool parasitic, PinName pin) :
snatch59 0:01a6a40578c9 29 OneWireThermometer(crcOn, useAddr, parasitic, pin, DS18B20_ID)
snatch59 0:01a6a40578c9 30 {
snatch59 0:01a6a40578c9 31 }
snatch59 0:01a6a40578c9 32
snatch59 0:01a6a40578c9 33 void DS18B20::setResolution(eResolution resln)
snatch59 0:01a6a40578c9 34 {
snatch59 0:01a6a40578c9 35 // as the write to the configuration register involves a write to the
snatch59 0:01a6a40578c9 36 // high and low alarm bytes, need to read these registers first
snatch59 0:01a6a40578c9 37 // and copy them back on the write
snatch59 0:01a6a40578c9 38
snatch59 0:01a6a40578c9 39 BYTE read_data[THERMOM_SCRATCHPAD_SIZE];
snatch59 0:01a6a40578c9 40 BYTE write_data[ALARM_CONFIG_SIZE];
snatch59 0:01a6a40578c9 41
snatch59 0:01a6a40578c9 42 if (readAndValidateData(read_data))
snatch59 0:01a6a40578c9 43 {
snatch59 0:01a6a40578c9 44 // copy alarm and config data to write data
snatch59 0:01a6a40578c9 45 for (int k = 2; k < 5; k++)
snatch59 0:01a6a40578c9 46 {
snatch59 0:01a6a40578c9 47 write_data[k - 2] = read_data[k];
snatch59 0:01a6a40578c9 48 }
snatch59 0:01a6a40578c9 49 int config = write_data[2];
snatch59 0:01a6a40578c9 50 config &= 0x9F;
snatch59 0:01a6a40578c9 51 config ^= (resln << 5);
snatch59 0:01a6a40578c9 52 write_data[2] = config;
snatch59 0:01a6a40578c9 53
snatch59 0:01a6a40578c9 54 resetAndAddress();
snatch59 0:01a6a40578c9 55 oneWire.writeByte(WRITESCRATCH);
snatch59 0:01a6a40578c9 56 for (int k = 0; k < 3; k++)
snatch59 0:01a6a40578c9 57 {
snatch59 0:01a6a40578c9 58 oneWire.writeByte(write_data[k]);
snatch59 0:01a6a40578c9 59 }
snatch59 0:01a6a40578c9 60
snatch59 0:01a6a40578c9 61 // remember it so we can use the correct delay in reading the temperature
snatch59 0:01a6a40578c9 62 // for parasitic power
snatch59 0:01a6a40578c9 63 resolution = resln;
snatch59 0:01a6a40578c9 64 }
snatch59 0:01a6a40578c9 65 }
snatch59 0:01a6a40578c9 66
snatch59 0:01a6a40578c9 67 float DS18B20::calculateTemperature(BYTE* data)
snatch59 0:01a6a40578c9 68 {
snatch59 0:01a6a40578c9 69 bool signBit = false;
snatch59 0:01a6a40578c9 70 if (data[TEMPERATURE_MSB] & 0x80) signBit = true;
snatch59 0:01a6a40578c9 71
snatch59 0:01a6a40578c9 72 int read_temp = (data[TEMPERATURE_MSB] << 8) + data[TEMPERATURE_LSB];
snatch59 0:01a6a40578c9 73 if (signBit)
snatch59 0:01a6a40578c9 74 {
snatch59 0:01a6a40578c9 75 read_temp = (read_temp ^ 0xFFFF) + 1; // two's complement
snatch59 0:01a6a40578c9 76 read_temp *= -1;
snatch59 0:01a6a40578c9 77 }
snatch59 0:01a6a40578c9 78
snatch59 0:01a6a40578c9 79 int resolution = (data[CONFIG_REG_BYTE] & 0x60) >> 5; // mask off bits 6,5 and move to 1,0
snatch59 0:01a6a40578c9 80 switch (resolution)
snatch59 0:01a6a40578c9 81 {
snatch59 0:01a6a40578c9 82 case nineBit: // 0.5 deg C increments
snatch59 0:01a6a40578c9 83 read_temp &= 0xFFF8; // bits 2,1,0 are undefined
snatch59 0:01a6a40578c9 84 pc_ds18B20.traceOut("9 bit resolution ...\r\n");
snatch59 0:01a6a40578c9 85 break;
snatch59 0:01a6a40578c9 86 case tenBit: // 0.25 deg C increments
snatch59 0:01a6a40578c9 87 read_temp &= 0xFFFC; // bits 1,0 are undefined
snatch59 0:01a6a40578c9 88 pc_ds18B20.traceOut("10 bit resolution ...\r\n");
snatch59 0:01a6a40578c9 89 break;
snatch59 0:01a6a40578c9 90 case elevenBit: // 0.125 deg C increments
snatch59 0:01a6a40578c9 91 read_temp &= 0xFFFE; // bit 0 is undefined
snatch59 0:01a6a40578c9 92 pc_ds18B20.traceOut("11 bit resolution ...\r\n");
snatch59 0:01a6a40578c9 93 break;
snatch59 0:01a6a40578c9 94 case twelveBit: // 0.0625 deg C increments
snatch59 0:01a6a40578c9 95 pc_ds18B20.traceOut("12 bit resolution ...\r\n");
snatch59 0:01a6a40578c9 96 break;
snatch59 0:01a6a40578c9 97 }
snatch59 0:01a6a40578c9 98 float realTemp = (float)read_temp/16 ;
snatch59 0:01a6a40578c9 99
snatch59 0:01a6a40578c9 100 pc_ds18B20.traceOut("TEMP_READ/REAL TEMP: %f \r\n", realTemp);
snatch59 0:01a6a40578c9 101
snatch59 0:01a6a40578c9 102 return realTemp;
snatch59 0:01a6a40578c9 103 }