/*

* Use the I2C bus with EEPROM 24LC64

* Sketch: eeprom.pde

*

* Author: hkhijhe

* Date: 01/10/2010

*

*

*/

#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 ) {

#include <Wire.h>

Wire.beginTransmission(deviceaddress);

Wire.write((int)(eeaddresspage >> 8)); // MSB

#define EEPROM_ADDR 0x50 // I2C Buss address of 24LC256 256K EEPROM

Wire.write((int)(eeaddresspage & 0xFF)); // LSB

/*

byte c;

* Read and Write Buffer Page MAX is 28byte / Page

for ( c = 0; c < length; c++)

*

Wire.write(data[c]);

*/

Wire.endTransmission();

}

void i2c_eeprom_write_byte( int deviceaddress, unsigned int eeaddress, byte data )

byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress ) {

{

byte rdata = 0xFF;

int rdata = data;

Wire.beginTransmission(deviceaddress);

Wire.beginTransmission(deviceaddress);

Wire.write((int)(eeaddress >> 8)); // MSB

Wire.write((int)(eeaddress >> 8)); // Address High Byte

Wire.write((int)(eeaddress & 0xFF)); // LSB

Wire.write((int)(eeaddress & 0xFF)); // Address Low Byte

Wire.endTransmission();

Wire.write(rdata);

Wire.requestFrom(deviceaddress,1);

Wire.endTransmission();

if (Wire.available()) rdata = Wire.read();

}

return rdata;

}

// Address is a page address, 6-bit (63). More and end will wrap around

// But data can be maximum of 28 bytes, because the Wire library has a buffer of 32 bytes

// maybe let's not read more than 30 or 32 bytes at a time!

void i2c_eeprom_write_page

void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte *buffer, int length ) {

( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length )

{

Wire.beginTransmission(deviceaddress);

Wire.beginTransmission(deviceaddress);

Wire.write((int)(eeaddress >> 8)); // MSB

Wire.write((int)(eeaddresspage >> 8)); // Address High Byte

Wire.write((int)(eeaddress & 0xFF)); // LSB

Wire.write((int)(eeaddresspage & 0xFF)); // Address Low Byte

Wire.endTransmission();

byte c;

Wire.requestFrom(deviceaddress,length);

for ( c = 0; c < length; c++)

int c = 0;

Wire.write(data[c]);

for ( c = 0; c < length; c++ )

Wire.endTransmission();

if (Wire.available()) buffer[c] = Wire.read();

delay(10); // need some delay

}

}

byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress )

{

byte rdata = 0xFF;

void setup()

Wire.beginTransmission(deviceaddress);

{

Wire.write((int)(eeaddress >> 8)); // Address High Byte

char somedata[] = "this is data from the eeprom"; // data to write

Wire.write((int)(eeaddress & 0xFF)); // Address Low Byte

Wire.begin(); // initialise the connection

Wire.endTransmission();

Serial.begin(9600);

Wire.requestFrom(deviceaddress,1);

i2c_eeprom_write_page(0x50, 0, (byte *)somedata, sizeof(somedata)); // write to EEPROM

if (Wire.available()) rdata = Wire.read();

return rdata;

}

delay(10); //add a small delay

// should not read more than 28 bytes at a time!

Serial.println("Memory written");

void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte *buffer, int length )

}

{

void loop()

Wire.beginTransmission(deviceaddress);

{

Wire.write((int)(eeaddress >> 8)); // Address High Byte

int addr=0; //first address

Wire.write((int)(eeaddress & 0xFF)); // Address Low Byte

byte b = i2c_eeprom_read_byte(0x50, 0); // access the first address from the memory

Wire.endTransmission();

Wire.requestFrom(deviceaddress,length);

while (b!=0)

//int c = 0;

{

for ( int c = 0; c < length; c++ )

Serial.print(addr, HEX); //print content to serial port

if (Wire.available()) buffer[c] = Wire.read();

Serial.print(" : "); //print content to serial port

}

Serial.print(b); //print content to serial port

Serial.print(" : "); //print content to serial port

void setup()

Serial.println((char)b); //print content to serial port

{

addr++; //increase address

Wire.begin(); // join I2C bus (address optional for master)

b = i2c_eeprom_read_byte(0x50, addr); //access an address from the memory

Serial.begin(9600);

}

Serial.println(" ");

// TESTS FOR EACH FUNCTION BEGIN HERE

delay(2000);

Serial.print("Writing Test:");

for (int i=0; i<20; i++){ // loop for first 20 slots

}

i2c_eeprom_write_byte(EEPROM_ADDR,i,i+65); // write address + 65 A or 97 a

Serial.print((char)(i+65));

Serial.print(" ");

delay(10); // NEED THIS DELAY!

}

Serial.println("");

delay(500);

Serial.print("Reading Test:");

for (int i=0; i<20; i++){ // loop for first 20 slots

Serial.write(i2c_eeprom_read_byte(EEPROM_ADDR, i));

Serial.print(" ");

}

// setup for page tests . . .

byte PageData[30]; // array that will hold test data for a page

byte PageRead[30]; // array that will hold result of data for a page

for (int i=0; i<30; i++){ // zero both arrays for next test

PageData[i] = 0;

PageRead[i] = 0;

}

Serial.println("\n");

for (int i=0; i<30; i++) PageData[i] = i+33; // fill up array for next test char 33 = !

Serial.print("Writing Page Test:");

for (int i=0; i<28; i++){ // zero both arrays for next test

Serial.print((char)PageData[i]);

Serial.print(" ");

}

Serial.println("\n");

i2c_eeprom_write_page(EEPROM_ADDR, 100, PageData, 28 ); // 28 bytes/page is max

Serial.print("Reading Page Test:");

i2c_eeprom_read_buffer( EEPROM_ADDR, 100, PageRead, 28);

for (int i=0; i<28; i++){

Serial.write(PageRead[i]); // display the array read

Serial.print(" ");

}

}

void loop()

{

}