Learning to find I2C addresses of sensors for Arduino Due

Rahim;

There are a couple of excellent tutorials on tronixstuff.com specifically about using I2C and Arduino.  It looks like you've already been to Adafruit, so no need to mention that.

http://tronixstuff.com/2010/10/20/tutorial-arduino-and-the-i2c-bus/

Here is a more general one on SparkFun: https://learn.sparkfun.com/tutorials/i2c

And the I2C/Wire library reference on the Arduino site: https://www.arduino.cc/en/Reference/Wire

When you're reading, the "Two-Wire" or "TWI" protocol is I2C.  Some refer to it as Two-Wire, understandably, as connections just require two wires: SDA (Data) and SCL (Clock).  A couple of gotcha's that you may or may not be aware of.  The Due is a 3V3 uC, unlike most Arduinos, which are 5VDC.  You'll need to reference (Include) the "Wire" library in your programming.  If you're using an IDE besides Arduino (Keil, Atmel Studio, etc.) then check Atmel's website for additional libraries required.

Arduino pins can sink 20mA of sustained current, or 40mA max.  Not a problem using I2C, but if you use other pins be aware of those limitations. 

Use a 9-12VDC/2A power source on the DC jack, when not using the USB port for power.  Any lower voltage and your uC may destabilize.  Much higher and the on-board voltage regulator will get too hot.  You can't really attach a heatsink as the VR is flush-mounted on the PCB.

Best of luck!

Thank you Brian Edwards!!! The link to tronixstuff is really putting things into a better prospective. Right now our team is doing its best to set up code to get the I2C sensors to Read and Write to the Arduino Due one at a time, but we are running into some issues that are holding us back from even getting one sensor to work. We know that there is a issue with the code, but we can not seem to pen-point what the issue is exactly.

So far, here is the code that we put together in bits and pieces down bellow...If you or someone else can help figure out what's wrong with the code it would be very much appreciated.

Thanks again.

Rahim M.

#include <Wire.h>

void setup()

{

   Serial.begin(57600);

   Wire.begin();

}

#define MPL3115A2_ADDRESS 0x60

void loop()

{

   Serial.println(IIC_Read(0x0C));

}

z

byte IIC_Read(byte regAddr)

{

  // This function reads one byte over IIC

  Wire.beginTransmission(MPL3115A2_ADDRESS);

  Wire.write(regAddr);  // Address of CTRL_REG1

  Wire.endTransmission(false); // Send data to I2C dev with option for a repeated start. THIS IS NECESSARY and not supported before Arduino V1.0.1!

  Wire.requestFrom(MPL3115A2_ADDRESS, 1); // Request the data...

  return Wire.read();

}

uint8_t I2CReadRegister(uint8_t I2CDestinationAddress, uint8_t Register)

{

   Wire.beginTransmission(I2CDestinationAddress);

   Wire.write(Register);

   Wire.endTransmission(false);

   Wire.requestFrom(I2CDestinationAddress, 1 );

   delay(200);

   return Wire.read();

}

void I2CWriteRegister(uint8_t I2CDestinationAddress, uint8_t Register, uint8_t Data)

{

   Wire.beginTransmission(I2CDestinationAddress);

   Wire.write(Register);

   Wire.write(Data);

   Wire.endTransmission();

}

You're welcome Rahim.

First question/observation - In your code what is 'z' in your loop?

void loop()

{

   Serial.println(IIC_Read(0x0C));

}

z      // What is this referencing?

byte IIC_Read(byte regAddr)

You're welcome Rahim.

First question/observation - In your code what is 'z' in your loop?

void loop()

{

   Serial.println(IIC_Read(0x0C));

}

z      // What is this referencing?

byte IIC_Read(byte regAddr)