gistfile1.ino

/************************************************************************
 * Arduino Due: Reading & Writing to I2C EEPROM           Version: 1.00 *
 * Function   : Reads and Writes to Atmel 24C64 Serial EEPROM           *
 * Exp. Level : Beginner/Elementary                                     *
 ************************************************************************
 * Arduino IDE v1.5.2 from http://arduino.cc/en/Main/Software           *
 * Configuration: Arduino Due (Programming Port) on /dev/ttyACM0        *
 * Operating System: Xubuntu Linux 13.10 Saucy Salamander (32-bit)      *
 * Created: June 13, 2013                Latest Revision: June 13, 2013 *
 ************************************************************************
 *                        The Main Ingredients                          *
 * Arduino Due (element14 Order #: 2250861)                             *
 * Atmel 24C64 Serial EEPROM 64K (element14 Order #: 1362657)           *
 ************************************************************************
 *                          Reference Pages                             *
 * Arduino DUE : http://goo.gl/4YRP8                                    *
 * Wire Library: http://goo.gl/6wKis                                    *
 * I2C EEPROM  : http://goo.gl/vlOR3                                    *
 ************************************************************************
 *-----------------------Wiring Configuration---------------------------*
 * Arduino DUE pin 20 (SDL) to EEPROM pin 5                             *
 * Arduino DUE pin 21 (SCL) to EEPROM pin 6                             *
 * Arduino DUE 3.3VDC (VCC) to EEPROM pin 8 <<< ADVISORY!!!             *
 * Arduino DUE Ground (GND) to EEPROM pins 1, 2, 3, and 4               *
 ************************************************************************
 *         MirandaSoft! - Pasig City, Metro Manila, Philippines         *
 *         http://www.element14.com/community/blogs/mirandasoft         *
 ************************************************************************/

#include <Wire.h>                          // I2C library

void i2c_eeprom_write_byte( int deviceaddress, unsigned int eeaddress, byte data ) {
  int rdata = data;
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));       // MSB
  Wire.write((int)(eeaddress & 0xFF));     // LSB
  Wire.write(rdata);
  Wire.endTransmission();
}

// WARNING: address is a page address, 6-bit end will wrap around
// also, data can be maximum of about 30 bytes, because the Wire library has a buffer of 32 bytes
void i2c_eeprom_write_page( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length ) {
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddresspage >> 8));   // MSB
  Wire.write((int)(eeaddresspage & 0xFF)); // LSB
  byte c;
  for ( c = 0; c < length; c++)
    Wire.write(data[c]);
  Wire.endTransmission();
}

byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress ) {
  byte rdata = 0xFF;
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));       // MSB
  Wire.write((int)(eeaddress & 0xFF));     // LSB
  Wire.endTransmission();
  Wire.requestFrom(deviceaddress,1);
  if (Wire.available()) rdata = Wire.read();
  return rdata;
}

// maybe let's not read more than 30 or 32 bytes at a time!
void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte *buffer, int length ) {
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));       // MSB
  Wire.write((int)(eeaddress & 0xFF));     // LSB
  Wire.endTransmission();
  Wire.requestFrom(deviceaddress,length);
  int c = 0;
  for ( c = 0; c < length; c++ )
    if (Wire.available()) buffer[c] = Wire.read();
}

void setup() {
  pinMode(13, OUTPUT);                    // DUE's Pin 13 LED is stuck HIGH
  digitalWrite(13, LOW);                  // Turn off Pin 13 LED
  char message[] = "Kuya Marc's Arduino DUE Life"; // data to write
  Wire.begin();                           // initialise the connection
  Serial.begin(9600);
  i2c_eeprom_write_page(0x50, 0, (byte *)message, sizeof(message)); // write to EEPROM 

  delay(10);                              // add a small delay

  Serial.println("Memory written");
}

void loop() {
  int addr=0;                             // first address
  byte b = i2c_eeprom_read_byte(0x50, 0); // access the first address from the memory

  while (b!=0) {
    Serial.print((char)b);                // print content to serial port
    addr++;                               // increase address
    b = i2c_eeprom_read_byte(0x50, addr); // access an address from the memory
  }
  Serial.println(" ");
  delay(2000);
}