I2C Arduino Port (Wii MotionPlus)

[kylelanman]

I'll start off by saying prior to this season our team has had no prior knowledge of I2C.

We successfully were able to talk to a LSM303D using the standard calls in the WPILib I2C class.

We are now trying to integrate with a Wii MotionPlus. We have a working setup with an Arduino. In hopes of eliminating the Arduino we tried to port the Arduino sketch to C++. Our limited knowledge of I2C has made this a little bit of a challenge.

/* Arduino */
void receiveData(){
  Wire.beginTransmission(0x52);    //now at address 0x52
  Wire.send(0x00);		     //send zero to signal we want info
  Wire.endTransmission();
  nunchuck)
  Wire.requestFrom(0x52,6);	  //request the six bytes from the WM+
  for (int i=0;i<6;i++){
    data[i]=Wire.receive();
  }
}

I realize there is additional initialization that needs to happen. But that is straight forward. The 2 new concepts that the LSM303D did not require but that the Wii MotionPlus does are:
1. Sending data over I2C with no register as a target.
2. Receiving data over I2C with out a particular register as a source.

/* WPILib */
        // _wmp is an instance of I2C
	uint8_t buffer[6];
	_wmp->Transaction(0x00, 1, buffer, sizeof(buffer);

Are these code snippets functionally equivalent? If not what are the equivalent of requestFrom() and read() in the WPILib?

Thanks in advance to anyone that can assist us.

Kyle