MyEEPROM

A class to manage TWI communication between the Arduino Due and the 24LC16B EEPROM chip. (Might work for other EEPROM chips too, but mileage will vary).

Getting started

Check out the examples folder, yo!

Basically, the 24LC16B has 8 blocks of 256 bytes each (for a total of 2 Kilobytes). Usually, these I2C devices have a way to dynamically address each slave, but for a variety of reasons the 24LC16B has a static address. Thus, you'll only be able to hang one of these bad boys off a given TWI.

You can address the EEPROM memory up to 16 bytes at a time. You want to use:

MyEEPROM.write(int memAddress, const byte * data, byte length);

Here, memAddress is the memory address you're writing to. It should be a 3-digit hex value, like 0x100 -- the first digit specifies which block you're addressing (therefore, should be limited from 0-7). The next two digits specify the address of the first byte you want to write. Thus, a memAddress of 0x120 would be addressing block 1, address 20.

Then, just pass in your data array, and the number of bytes you're writing (length). It will cut you off at 16 bytes if you try to write more than that at a time -- this is done to preserve the integrity of the data you did write; the EEPROM can only handle up to one page at a time (which I'm lead to believe is 16 bytes) -- doing more will cause the memory address pointer to loop around and overwrite the data you wrote at the beginning of this write cycle.

To read the data back out, simple use

MyEEPROM.read(int memAddress, byte * buffer, byte length);

Ie, give it an address to start from, a buffer to read the data into, and a length (in bytes) you want to read.

Hopefully the examples should clarify this useage. Don't forget to initialize the Arduino Wire communication line first!

#include <Wire.h>
#include <MyEEPROM.h>

void setup(){
    Wire.begin();
    byte data[] = {1, 2, 3};
    
    MyEEPROM.write(0x000, data, 3);
    // etc.
    
}