/*
  MAG3110 Breakout Example Code
  
  by: Aaron Weiss, aaron at sparkfun dot com
      SparkFun Electronics 2011
  date: 9/6/11
  license: beerware, if you use this code and happen to meet me, you
           can by me a beer

  The code reads the raw 16-bit x, y, and z values and prints them 
  out. This sketch does not use the INT1 pin, nor does it poll for
  new data.

*/

#include <Wire.h>

#define MAG_ADDR  0x0E //7-bit address for the MAG3110, doesn't change

void setup()
{
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output
  config();            // turn the MAG3110 on
}

void loop()
{
  print_values();
  delay(5);
}

void config(void)
{
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x11);              // cntrl register2
  Wire.send(0x80);              // send 0x80, enable auto resets
  Wire.endTransmission();       // stop transmitting
  
  delay(15);
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x10);              // cntrl register1
  Wire.send(1);                 // send 0x01, active mode
  Wire.endTransmission();       // stop transmitting
}

void print_values(void)
{
  Serial.print("x=");
  Serial.print(readx()); 
  Serial.print(",");  
  Serial.print("y=");    
  Serial.print(ready());
  Serial.print(",");       
  Serial.print("z=");    
  Serial.println(readz());      
}

int readx(void)
{
  int xl, xh;  //define the MSB and LSB
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x01);              // x MSB reg
  Wire.endTransmission();       // stop transmitting
 
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.requestFrom(MAG_ADDR, 1); // request 1 byte
  while(Wire.available())    // slave may send less than requested
  { 
    xh = Wire.receive(); // receive the byte
  }
  
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x02);              // x LSB reg
  Wire.endTransmission();       // stop transmitting
 
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.requestFrom(MAG_ADDR, 1); // request 1 byte
  while(Wire.available())    // slave may send less than requested
  { 
    xl = Wire.receive(); // receive the byte
  }
  
  int xout = (xl|(xh << 8)); //concatenate the MSB and LSB
  return xout;
}

int ready(void)
{
  int yl, yh;  //define the MSB and LSB
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x03);              // y MSB reg
  Wire.endTransmission();       // stop transmitting
 
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.requestFrom(MAG_ADDR, 1); // request 1 byte
  while(Wire.available())    // slave may send less than requested
  { 
    yh = Wire.receive(); // receive the byte
  }
  
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x04);              // y LSB reg
  Wire.endTransmission();       // stop transmitting
 
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.requestFrom(MAG_ADDR, 1); // request 1 byte
  while(Wire.available())    // slave may send less than requested
  { 
    yl = Wire.receive(); // receive the byte
  }
  
  int yout = (yl|(yh << 8)); //concatenate the MSB and LSB
  return yout;
}

int readz(void)
{
  int zl, zh;  //define the MSB and LSB
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x05);              // z MSB reg
  Wire.endTransmission();       // stop transmitting
 
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.requestFrom(MAG_ADDR, 1); // request 1 byte
  while(Wire.available())    // slave may send less than requested
  { 
    zh = Wire.receive(); // receive the byte
  }
  
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.beginTransmission(MAG_ADDR); // transmit to device 0x0E
  Wire.send(0x06);              // z LSB reg
  Wire.endTransmission();       // stop transmitting
 
  delayMicroseconds(2); //needs at least 1.3us free time between start and stop
  
  Wire.requestFrom(MAG_ADDR, 1); // request 1 byte
  while(Wire.available())    // slave may send less than requested
  { 
    zl = Wire.receive(); // receive the byte
  }
  
  int zout = (zl|(zh << 8)); //concatenate the MSB and LSB
  return zout;
}