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Auto search for All DS18B20 sensors on data bus
DS18B20Multiple/DS18B20.cpp@0:a2a81f538133, 2014-04-13 (annotated)
- Committer:
- umairaftab
- Date:
- Sun Apr 13 10:06:52 2014 +0000
- Revision:
- 0:a2a81f538133
Multiple Sensors Functionality Added to Peter Sudensikis Library
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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umairaftab | 0:a2a81f538133 | 1 | /* |
umairaftab | 0:a2a81f538133 | 2 | * DS18B20. Maxim DS18B20 One-Wire Thermometer. |
umairaftab | 0:a2a81f538133 | 3 | * Uses the OneWireCRC library. |
umairaftab | 0:a2a81f538133 | 4 | * |
umairaftab | 0:a2a81f538133 | 5 | * Copyright (C) <2010> Petras Saduikis <petras@petras.co.uk> |
umairaftab | 0:a2a81f538133 | 6 | * |
umairaftab | 0:a2a81f538133 | 7 | * This file is part of OneWireThermometer. |
umairaftab | 0:a2a81f538133 | 8 | * |
umairaftab | 0:a2a81f538133 | 9 | * OneWireThermometer is free software: you can redistribute it and/or modify |
umairaftab | 0:a2a81f538133 | 10 | * it under the terms of the GNU General Public License as published by |
umairaftab | 0:a2a81f538133 | 11 | * the Free Software Foundation, either version 3 of the License, or |
umairaftab | 0:a2a81f538133 | 12 | * (at your option) any later version. |
umairaftab | 0:a2a81f538133 | 13 | * |
umairaftab | 0:a2a81f538133 | 14 | * OneWireThermometer is distributed in the hope that it will be useful, |
umairaftab | 0:a2a81f538133 | 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
umairaftab | 0:a2a81f538133 | 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
umairaftab | 0:a2a81f538133 | 17 | * GNU General Public License for more details. |
umairaftab | 0:a2a81f538133 | 18 | * |
umairaftab | 0:a2a81f538133 | 19 | * You should have received a copy of the GNU General Public License |
umairaftab | 0:a2a81f538133 | 20 | * along with OneWireThermometer. If not, see <http://www.gnu.org/licenses/>. |
umairaftab | 0:a2a81f538133 | 21 | */ |
umairaftab | 0:a2a81f538133 | 22 | |
umairaftab | 0:a2a81f538133 | 23 | #include "DS18B20.h" |
umairaftab | 0:a2a81f538133 | 24 | //#include "DebugTrace.h" |
umairaftab | 0:a2a81f538133 | 25 | |
umairaftab | 0:a2a81f538133 | 26 | //DebugTrace pc_ds18B20(OFF, TO_SERIAL); |
umairaftab | 0:a2a81f538133 | 27 | |
umairaftab | 0:a2a81f538133 | 28 | DS18B20::DS18B20( PinName pin) : |
umairaftab | 0:a2a81f538133 | 29 | OneWireThermometer(pin, DS18B20_ID) |
umairaftab | 0:a2a81f538133 | 30 | { |
umairaftab | 0:a2a81f538133 | 31 | } |
umairaftab | 0:a2a81f538133 | 32 | |
umairaftab | 0:a2a81f538133 | 33 | void DS18B20::setResolution(eResolution resln) |
umairaftab | 0:a2a81f538133 | 34 | { |
umairaftab | 0:a2a81f538133 | 35 | // as the write to the configuration register involves a write to the |
umairaftab | 0:a2a81f538133 | 36 | // high and low alarm bytes, need to read these registers first |
umairaftab | 0:a2a81f538133 | 37 | // and copy them back on the write |
umairaftab | 0:a2a81f538133 | 38 | |
umairaftab | 0:a2a81f538133 | 39 | BYTE read_data[THERMOM_SCRATCHPAD_SIZE]; |
umairaftab | 0:a2a81f538133 | 40 | BYTE write_data[ALARM_CONFIG_SIZE]; |
umairaftab | 0:a2a81f538133 | 41 | |
umairaftab | 0:a2a81f538133 | 42 | if (readAndValidateData(read_data)) |
umairaftab | 0:a2a81f538133 | 43 | { |
umairaftab | 0:a2a81f538133 | 44 | // copy alarm and config data to write data |
umairaftab | 0:a2a81f538133 | 45 | for (int k = 2; k < 5; k++) |
umairaftab | 0:a2a81f538133 | 46 | { |
umairaftab | 0:a2a81f538133 | 47 | write_data[k - 2] = read_data[k]; |
umairaftab | 0:a2a81f538133 | 48 | } |
umairaftab | 0:a2a81f538133 | 49 | int config = write_data[2]; |
umairaftab | 0:a2a81f538133 | 50 | config &= 0x9F; |
umairaftab | 0:a2a81f538133 | 51 | config ^= (resln << 5); |
umairaftab | 0:a2a81f538133 | 52 | write_data[2] = config; |
umairaftab | 0:a2a81f538133 | 53 | |
umairaftab | 0:a2a81f538133 | 54 | resetAndAddress(); |
umairaftab | 0:a2a81f538133 | 55 | oneWire.writeByte(WRITESCRATCH); |
umairaftab | 0:a2a81f538133 | 56 | for (int k = 0; k < 3; k++) |
umairaftab | 0:a2a81f538133 | 57 | { |
umairaftab | 0:a2a81f538133 | 58 | oneWire.writeByte(write_data[k]); |
umairaftab | 0:a2a81f538133 | 59 | } |
umairaftab | 0:a2a81f538133 | 60 | |
umairaftab | 0:a2a81f538133 | 61 | // remember it so we can use the correct delay in reading the temperature |
umairaftab | 0:a2a81f538133 | 62 | // for parasitic power |
umairaftab | 0:a2a81f538133 | 63 | resolution = resln; |
umairaftab | 0:a2a81f538133 | 64 | } |
umairaftab | 0:a2a81f538133 | 65 | } |
umairaftab | 0:a2a81f538133 | 66 | |
umairaftab | 0:a2a81f538133 | 67 | float DS18B20::calculateTemperature(BYTE* data) |
umairaftab | 0:a2a81f538133 | 68 | { |
umairaftab | 0:a2a81f538133 | 69 | bool signBit = false; |
umairaftab | 0:a2a81f538133 | 70 | if (data[TEMPERATURE_MSB] & 0x80) signBit = true; |
umairaftab | 0:a2a81f538133 | 71 | |
umairaftab | 0:a2a81f538133 | 72 | int read_temp = (data[TEMPERATURE_MSB] << 8) + data[TEMPERATURE_LSB]; |
umairaftab | 0:a2a81f538133 | 73 | if (signBit) |
umairaftab | 0:a2a81f538133 | 74 | { |
umairaftab | 0:a2a81f538133 | 75 | read_temp = (read_temp ^ 0xFFFF) + 1; // two's complement |
umairaftab | 0:a2a81f538133 | 76 | read_temp *= -1; |
umairaftab | 0:a2a81f538133 | 77 | } |
umairaftab | 0:a2a81f538133 | 78 | |
umairaftab | 0:a2a81f538133 | 79 | int resolution = (data[CONFIG_REG_BYTE] & 0x60) >> 5; // mask off bits 6,5 and move to 1,0 |
umairaftab | 0:a2a81f538133 | 80 | switch (resolution) |
umairaftab | 0:a2a81f538133 | 81 | { |
umairaftab | 0:a2a81f538133 | 82 | case nineBit: // 0.5 deg C increments |
umairaftab | 0:a2a81f538133 | 83 | read_temp &= 0xFFF8; // bits 2,1,0 are undefined |
umairaftab | 0:a2a81f538133 | 84 | //pc_ds18B20.traceOut("9 bit resolution ...\r\n"); |
umairaftab | 0:a2a81f538133 | 85 | break; |
umairaftab | 0:a2a81f538133 | 86 | case tenBit: // 0.25 deg C increments |
umairaftab | 0:a2a81f538133 | 87 | read_temp &= 0xFFFC; // bits 1,0 are undefined |
umairaftab | 0:a2a81f538133 | 88 | //pc_ds18B20.traceOut("10 bit resolution ...\r\n"); |
umairaftab | 0:a2a81f538133 | 89 | break; |
umairaftab | 0:a2a81f538133 | 90 | case elevenBit: // 0.125 deg C increments |
umairaftab | 0:a2a81f538133 | 91 | read_temp &= 0xFFFE; // bit 0 is undefined |
umairaftab | 0:a2a81f538133 | 92 | //pc_ds18B20.traceOut("11 bit resolution ...\r\n"); |
umairaftab | 0:a2a81f538133 | 93 | break; |
umairaftab | 0:a2a81f538133 | 94 | case twelveBit: // 0.0625 deg C increments |
umairaftab | 0:a2a81f538133 | 95 | //pc_ds18B20.traceOut("12 bit resolution ...\r\n"); |
umairaftab | 0:a2a81f538133 | 96 | break; |
umairaftab | 0:a2a81f538133 | 97 | } |
umairaftab | 0:a2a81f538133 | 98 | float realTemp = (float)read_temp/16 ; |
umairaftab | 0:a2a81f538133 | 99 | |
umairaftab | 0:a2a81f538133 | 100 | //pc_ds18B20.traceOut("TEMP_READ/REAL TEMP: %f \r\n", realTemp); |
umairaftab | 0:a2a81f538133 | 101 | |
umairaftab | 0:a2a81f538133 | 102 | return realTemp; |
umairaftab | 0:a2a81f538133 | 103 | } |