Tony Mudd
Program to read the temperature from multiple DS18B20 sensors on the same pin. The original library/code came from Petras Saduikis (see http://mbed.org/users/snatch59/programs/OneWireCRC/gpdz56), but I've modified it to remember the address of multiple sensors all connected to the same data pin. My sample program displays the temperature of each device in turn. If you want to see more of what's going on behind the scenes turn on the debug by setting DebugTrace pc(OFF, TO_SERIAL); to ON (instead of OFF) in the couple of places it's used - it will log the device addresses as they are found etc. The addresses are set in the devices at the factory - I don't think they can be changed, the search always seems to find them in the same order, but this won't be anything to do with the way you've plugged them in. I've had a play with up to 7 sensors (the code has a limit of 10 hardwired in it, but this would be easy to change)
main.cpp@0:fb8b6da96a8b, 2011-07-17 (annotated)
- Committer:
- tonymudd
- Date:
- Sun Jul 17 15:56:49 2011 +0000
- Revision:
- 0:fb8b6da96a8b
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| tonymudd | 0:fb8b6da96a8b | 1 | /* |
| tonymudd | 0:fb8b6da96a8b | 2 | * OneWireCRC/OneWireThermometer demo. |
| tonymudd | 0:fb8b6da96a8b | 3 | * |
| tonymudd | 0:fb8b6da96a8b | 4 | * Copyright (C) <2009> Petras Saduikis <petras@petras.co.uk> |
| tonymudd | 0:fb8b6da96a8b | 5 | * |
| tonymudd | 0:fb8b6da96a8b | 6 | * This file is part of OneWireCRC/OneWireThermometer. |
| tonymudd | 0:fb8b6da96a8b | 7 | * |
| tonymudd | 0:fb8b6da96a8b | 8 | * OneWireCRC/OneWireThermometer is free software: you can redistribute it and/or modify |
| tonymudd | 0:fb8b6da96a8b | 9 | * it under the terms of the GNU General Public License as published by |
| tonymudd | 0:fb8b6da96a8b | 10 | * the Free Software Foundation, either version 3 of the License, or |
| tonymudd | 0:fb8b6da96a8b | 11 | * (at your option) any later version. |
| tonymudd | 0:fb8b6da96a8b | 12 | * |
| tonymudd | 0:fb8b6da96a8b | 13 | * OneWireCRC/OneWireThermometer is distributed in the hope that it will be useful, |
| tonymudd | 0:fb8b6da96a8b | 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| tonymudd | 0:fb8b6da96a8b | 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| tonymudd | 0:fb8b6da96a8b | 16 | * GNU General Public License for more details. |
| tonymudd | 0:fb8b6da96a8b | 17 | * |
| tonymudd | 0:fb8b6da96a8b | 18 | * You should have received a copy of the GNU General Public License |
| tonymudd | 0:fb8b6da96a8b | 19 | * along with OneWireCRC/OneWireThermometer0. If not, see <http://www.gnu.org/licenses/>. |
| tonymudd | 0:fb8b6da96a8b | 20 | */ |
| tonymudd | 0:fb8b6da96a8b | 21 | |
| tonymudd | 0:fb8b6da96a8b | 22 | //////////////////////////////////////////////////////////////////// |
| tonymudd | 0:fb8b6da96a8b | 23 | // Test code to read temperature from a Maxim DS18B20 or DS18S20 |
| tonymudd | 0:fb8b6da96a8b | 24 | // 1-wire device |
| tonymudd | 0:fb8b6da96a8b | 25 | //////////////////////////////////////////////////////////////////// |
| tonymudd | 0:fb8b6da96a8b | 26 | |
| tonymudd | 0:fb8b6da96a8b | 27 | #include <mbed.h> |
| tonymudd | 0:fb8b6da96a8b | 28 | #include "DS18B20.h" |
| tonymudd | 0:fb8b6da96a8b | 29 | #include "OneWireDefs.h" |
| tonymudd | 0:fb8b6da96a8b | 30 | |
| tonymudd | 0:fb8b6da96a8b | 31 | #define THERMOMETER DS18B20 |
| tonymudd | 0:fb8b6da96a8b | 32 | |
| tonymudd | 0:fb8b6da96a8b | 33 | float temp; |
| tonymudd | 0:fb8b6da96a8b | 34 | // device( mbed pin ) |
| tonymudd | 0:fb8b6da96a8b | 35 | THERMOMETER device(p21); |
| tonymudd | 0:fb8b6da96a8b | 36 | |
| tonymudd | 0:fb8b6da96a8b | 37 | void readTemp(int deviceNum) |
| tonymudd | 0:fb8b6da96a8b | 38 | { |
| tonymudd | 0:fb8b6da96a8b | 39 | temp = device.readTemperature(deviceNum); |
| tonymudd | 0:fb8b6da96a8b | 40 | printf("Device %d is %f\n\r",deviceNum, temp); |
| tonymudd | 0:fb8b6da96a8b | 41 | wait(0.5); |
| tonymudd | 0:fb8b6da96a8b | 42 | } |
| tonymudd | 0:fb8b6da96a8b | 43 | |
| tonymudd | 0:fb8b6da96a8b | 44 | int main() |
| tonymudd | 0:fb8b6da96a8b | 45 | { |
| tonymudd | 0:fb8b6da96a8b | 46 | |
| tonymudd | 0:fb8b6da96a8b | 47 | while (!device.initialize()); // keep calling until it works |
| tonymudd | 0:fb8b6da96a8b | 48 | // Say how many were found. |
| tonymudd | 0:fb8b6da96a8b | 49 | int deviceCount = device.getDeviceCount(); |
| tonymudd | 0:fb8b6da96a8b | 50 | printf("Found %d sensors\n\r",deviceCount); |
| tonymudd | 0:fb8b6da96a8b | 51 | |
| tonymudd | 0:fb8b6da96a8b | 52 | device.setResolution(twelveBit); |
| tonymudd | 0:fb8b6da96a8b | 53 | while (true) |
| tonymudd | 0:fb8b6da96a8b | 54 | { |
| tonymudd | 0:fb8b6da96a8b | 55 | for (int i = 0;i < deviceCount; i++) |
| tonymudd | 0:fb8b6da96a8b | 56 | readTemp(i); |
| tonymudd | 0:fb8b6da96a8b | 57 | } |
| tonymudd | 0:fb8b6da96a8b | 58 | |
| tonymudd | 0:fb8b6da96a8b | 59 | //return EXIT_SUCCESS; // Commented out to prevent the warning that this code is unreachable, due to the while(forever) above. |
| tonymudd | 0:fb8b6da96a8b | 60 | } |
| tonymudd | 0:fb8b6da96a8b | 61 |