//
//    FILE: set2standby.pde
//  AUTHOR: Rob Tillaart
// PURPOSE: Reset HMC6352 to standby mode without library
//          (esp if it is struck in continuous mode - Arduino)


#include <Wire.h>

int HMC = 0x21;
int ledPin = 13;
boolean ledState = LOW;


void setup()
{
  Serial.begin(115200);
  Serial.print("HMC6352 : start - ");
  Serial.println(HMC, HEX);

  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, ledState);

  Wire.begin();

  delay(1000); // give all things time to start
}


void loop()
{
  // flashing means not blocking
  ledState = !ledState;
  digitalWrite(ledPin, ledState);

  // write stdby mode to RAM 0x74 and do an L command immediately after it
  // this is done to "break through" the continuous mode
  // pull out 5 volt if it reads back 0x50
  Wire.beginTransmission(HMC);
  Wire.write('G');
  Wire.write(0x74);
  Wire.write(0x50);
  Wire.write('L');
  // Wire.write('O');  optional reset
  Wire.endTransmission();
  delay(10);

  // Read the EEPROM value for feedback as this is the next startup value
  Wire.beginTransmission(HMC);
  Wire.write('r');
  Wire.write(0x07);
  Wire.endTransmission();
  delay(10);

  int cnt = Wire.requestFrom(HMC, 1);
  if (cnt == 1)
  {
    Serial.print("Current Mode: ");
    Serial.println((int)Wire.read(), BIN);
  }
  else
  {
    Serial.print("Error... : ");
    Serial.println(cnt);
  }
}


// -- END OF FILE --