FRAM-X Add-on

512 bytes of non-volatile, ultra-lower power memory via I2C, which directly replaces EEPROM and FLASH.

FRAM is short for Ferroelectric RAM. This module is non-volatile (retains data without power) and is a drop-in replacement for EEPROM and Flash on an I2C Bus.

We have a free Arduino Library, and ANSI C code examples available here: FRAM-X Code Examples

FRAM is backward compatible with EEPROM but with the following improvements:

• It's faster (1 ns read/write)
• Lower power (microamps at 3.3V)
• Orders of magnitude greater write-erase cycles
• Reference: http://en.wikipedia.org/wiki/Ferroelectric_RAM

Some project ideas include:

• Memory for robots to preserve previously acquired data
• Pre-computed look-up tables for complex mathematical functions
• Scratch memory to expand a processor's available RAM

This Add-on comes with 3 address selection switches as well as a write-disable switch. Pin compatible chips are also available in higher memory densities.

Hook up your AVR-X Add-on and FRAM-X and paste the following into the Arduino SDK to get started, or check out FRAM-X Code Examples for a more detailed step-by-step guide.

#include <Wire.h>
#include <FRAMX.h>

/*Initialize the FRAM and use the default 
  FRAM address that's provided */
FRAMX fram(FRAMX::FRAMX_I2C_DEFAULT_ADDRESS);

/* read and write buffers here are used to store incoming and outgoing data */
static unsigned char read_buffer[2] ={0x00,0x00};
static unsigned char write_buffer[2]={0x00,0x01};

void setup(){
/* we must call this before using any I2C functions! */
	Wire.begin();
	Serial.begin(9600);
}

void loop(){

	/* memory address to begin with on FRAM */
	unsigned char start_address = 0;

	/* do not exceed the length of your read and write buffers */
	unsigned char number_of_bytes_to_transfer = 2;

	/* Write some stuff! */
	unsigned int number_of_bytes_written = fram.write(start_address, write_buffer, number_of_bytes_to_transfer);

	/* Read some stuff! */
	unsigned int number_of_bytes_read = fram.read(start_address, read_buffer, number_of_bytes_to_transfer);


	/* Print what we got */
	for(int i=0; i<number_of_bytes_to_transfer; i++){
		Serial.print("Wrote: ");
		Serial.print(write_buffer[i], HEX);
		Serial.print(" Read back: ");
		Serial.print(read_buffer[i], HEX);
		Serial.println(" ");
	}

	/* Handle any I2C errors */
	unsigned int error = fram.errors();
	Serial.print("Error code: ");
	Serial.print(error,HEX);

	switch(error)
	{
		case 0: Serial.print(" [Success!] "); 
			break;
		case 1: Serial.print(" [Data too large for buffer] "); 
			break;
		case 2: Serial.print(" [I2C Address was not found] "); 
			break;
		case 3: Serial.print(" [Data was not acknowledged] "); 
			break;
		default:Serial.print(" [There was some other error] "); 
			break;
	}
	Serial.println(" ");

	delay(5000);
}