AT24C1024 I2C EEPROM Library

Overview

This is a library to support the AT24C1024 EEPROM. Up to 4 of these devices may be chained together to provide 128-512 kilobytes of EEPROM storage.

AT24C1024 Library Project Home at Google Code

The usage is based on the Arduino EEPROM library and two I2C EEPROM libraries. If you're familiar with how that works, using this library should be pretty straightforward. Basically just substitute EEPROM1024 where you were using EEPROM.

For example:

EEPROM.write(address, value);

becomes:

EEPROM1024.write(address, value);

Credits

This library is based on several projects:

The Arduino EEPROM library found here: http://arduino.cc/en/Reference/EEPROM

The 24C256 library found here: http://www.arduino.cc/playground/Code/I2CEEPROM

The 24C512 library found here: http://www.arduino.cc/playground/Code/I2CEEPROM24LC512

Download

http://code.google.com/p/arduino-at24c1024/downloads/list

Installing

Install like any other Arduino library. Unzip the download into your Arduino-00xx/hardware/libraries directory. If the Arduino IDE is already running then exit and restart the Arduino IDE. This will compile and build the library files.

Example

/*
  EEPROM1024.pde
  AT24C1024 EEPROM Benchmark Sketch 

  Our project page is here:
  http://www.arduino.cc/playground/Code/I2CEEPROM24C1024

  From the datasheet:

  The AT24C1024B provides 1,048,576 bits of serial electrically 
  erasable and programmable read only memory (EEPROM) organized 
  as 131,072 words of 8 bits each. The device’s cascadable 
  feature allows up to four devices to share a common two-wire 
  bus.

  http://www.atmel.com/dyn/resources/prod_documents/doc5194.pdf

*/
#include <WProgram.h>
#include <Wire.h>
#include <E24C1024.h>

unsigned long time;
unsigned long finishTime;
unsigned long errors = 0;
unsigned long address = 0;
byte loop_size;

// Set to a higher number if you want to start at a higher address. 
#define MIN_ADDRESS 0

// Upper boundary of the address space.  Choose one.
#define MAX_ADDRESS 131072 // 1 device
//#define MAX_ADDRESS 262144 // 2 devices
//#define MAX_ADDRESS 393216 // 3 devices
//#define MAX_ADDRESS 524288 // 4 devices

void setup()
{
  // Make sure we aren't reading old data
  randomSeed(analogRead(0));
  loop_size = random(1, 100);
  Serial.begin(9600);
  Serial.println();
  Serial.println("E24C1024 Library Benchmark Sketch");
  Serial.println();
  writeByByteTest();
  readByByteTest();
}

void loop()
{
}

void writeByByteTest()
{
  time = millis();
  errors = 0;
  Serial.println("--------------------------------");
  Serial.println("Write By Byte Test:");
  Serial.println();
  Serial.print("Writing data:");
  for (address = MIN_ADDRESS; address < MAX_ADDRESS; address++)
  {
    EEPROM1024.write(address, (uint8_t)(address % loop_size));
    if (!(address % 5000)) Serial.print(".");
  }
  finishTime = millis() - time;
  Serial.println("DONE");
  Serial.print("Total Time (seconds): "); 
  Serial.println((unsigned long)(finishTime / 1000));
  Serial.print("Write operations per second: "); 
  Serial.println((unsigned long)(MAX_ADDRESS / (finishTime / 1000))); 
  Serial.println("--------------------------------");   
  Serial.println();
}

void readByByteTest()
{
  time = millis();
  errors = 0;
  Serial.println("--------------------------------");
  Serial.println("Read By Byte Test:");
  Serial.println();
  Serial.print("Reading data:");
  for (address = MIN_ADDRESS; address < MAX_ADDRESS; address++)
  {
    uint8_t data;
    data = EEPROM1024.read(address);
    if (data != (uint8_t)(address % loop_size)) 
    {
      Serial.println();
      Serial.print("Address: ");
      Serial.print(address);
      Serial.print(" Should be: ");
      Serial.print((uint8_t)(address % loop_size), DEC);
      Serial.print(" Read val: ");
      Serial.println(data, DEC);
      errors++;
    }
    if (!(address % 5000)) Serial.print(".");
  }
  finishTime = millis() - time;
  Serial.println("DONE");
  Serial.println();
  Serial.print("Total Test Time (secs): "); 
  Serial.println((unsigned long)(finishTime / 1000));
  Serial.print("Read operations per second: "); 
  Serial.println((unsigned long)(MAX_ADDRESS / (finishTime / 1000))); 
  Serial.print("Total errors: "); 
  Serial.println(errors);   
  Serial.println("--------------------------------");
  Serial.println();
}