Multiple Dallas onewire busses on one Arduino

Forum 2005-2010 (read only) Software Syntax & Programs
1

I am trying to setup an Arduino with two onewire busses attached to it using the DallasTemperature library. Below is some sample code from the Dallastemperature library of setting up 2 ds18b20 sensors on one bus. I cannot figure out how to modify this code to add another onewire bus . Everything I try to add another bus will not compile.
I cannot find an example on the internet . Can some kind soul help me with this perplexing(to me) problem? Maybe what I am trying to do isnt even possible?

Thanks
Frank

#include <OneWire.h>
#include <DallasTemperature.h>

// Data wire is plugged into port 2 on the Arduino
#define ONE_WIRE_BUS 2

// Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);

// Pass our oneWire reference to Dallas Temperature. 
DallasTemperature sensors(&oneWire);

void setup(void)
{
  // start serial port
  Serial.begin(9600);
  Serial.println("Dallas Temperature IC Control Library Demo");

  // Start up the library
  sensors.begin();
}

void loop(void)
{ 
  // call sensors.requestTemperatures() to issue a global temperature 
  // request to all devices on the bus
  Serial.print("Requesting temperatures...");
  sensors.requestTemperatures(); // Send the command to get temperatures
  Serial.println("DONE");
  
  Serial.print("Temperature for the device 1 (index 0) is: ");
  Serial.println(sensors.getTempFByIndex(0));
  delay(2000);

  Serial.print("Temperature for the device 2 (index 1) is: ");
  Serial.println(sensors.getTempFByIndex(1));
delay(2000);  
}
2

Add another OneWire instance?

OneWire oneWireA (2) ;
OneWire oneWireB (3) ;

DallasTemperature sensorsA (&oneWireA) ;
DallasTemperature sensorsB (&oneWireB) ;

BTW best not to say 'port' when you mean 'pin' - a port is an 8 bit thing in the AVR world, you'll cause confusion!

3

Well...you did it once again MarkT. Thanks I googled for hours looking for some sample code of using multiple onewire busses with Dallastemperature.

Frank

4

You do realize that you can put two (or many more) DS1820's on one 1-Wire line, I hope?

Best to avoid star topographies, though... that might be a reason for needing two 1-Wire busses.