Introduction

The AT24C02B is a 2-kilobit serial EEPROM designed for storing small amounts of non-volatile data. Its compact size and efficient I²C communication protocol make it ideal for embedded systems, IoT devices, and consumer electronics.

Features

• Memory Size: 2KB (2048 bits) of EEPROM memory.
• I²C Interface: Utilizes the I²C, a two-wire communication protocol (SDA for data, SCL for clock).
• Write Endurance: Up to 1 million write cycles per memory location.
• Low Power Consumption: Perfect for battery-powered applications.
• Write Protection: Prevents accidental overwriting of important data.
• Operating Voltage: Compatible with systems operating between 1.8V to 5.5V.

Specifications

Applications

The AT24C02B EEPROM is widely used in various applications, including:

• Data Storage: Stores configuration settings, calibration data, or small user data.
• Microcontroller Projects: Frequently used with microcontrollers like Arduino for storing preferences and sensor data.
• Portable Devices: Ideal for battery-operated devices where data needs to persist across power cycles.
• Embedded Systems: Essential for storing state or parameters in embedded systems.
• Security Applications: Used to store security data like keys, passwords, or encryption information.

How It Works

The AT24C02B uses the I²C protocol for communication between the EEPROM and a microcontroller or host device. Data is written and read in blocks, with support for random access to any byte. The chip uses 7-bit addressing for memory locations, making it easy to integrate into various systems.

Thanks to its small size and low power consumption, the AT24C02B is an excellent choice for embedded systems where space and power efficiency are crucial. Data is written in 8-bit blocks and can be retrieved at any time by addressing the memory location directly.

I²C Interface

The AT24C02B communicates over the I²C protocol, which uses two lines for communication:

• SDA (Serial Data Line): Transfers data between the EEPROM and the microcontroller.
• SCL (Serial Clock Line): Provides the clock signal for synchronization.

Devices on the I²C bus are assigned unique addresses. The AT24C02B typically uses a 7-bit address.

Pin Configuration

The AT24C02B comes in an 8-pin DIP or SOIC configuration. The pinout is as follows:

• Pin 1 (A0): I²C address pin for device selection (used when multiple devices share the same I²C bus).
• Pin 2 (A1): I²C address pin.
• Pin 3 (A2): I²C address pin.
• Pin 4 (SDA): Serial Data Line (I²C data).
• Pin 5 (SCL): Serial Clock Line (I²C clock).
• Pin 6 (WP): Write Protect pin (optional to prevent data overwriting).
• Pin 7 (GND): Ground connection.
• Pin 8 (VCC): Power supply voltage (1.8V to 5.5V).

Code Example

Here's an example of using the AT24C02B with an Arduino to write and read data:

// Include the Wire library for I²C
#include <Wire.h>

#define EEPROM_ADDRESS 0x50  // I²C address of AT24C02B

void setup() {
    Wire.begin();
    Serial.begin(9600);

    // Write a byte to address 0x00
    Wire.beginTransmission(EEPROM_ADDRESS);
    Wire.write(0x00);       // Memory address
    Wire.write(0x42);       // Data to write
    Wire.endTransmission();
    delay(5);               // Allow write cycle to complete

    // Read a byte from address 0x00
    Wire.beginTransmission(EEPROM_ADDRESS);
    Wire.write(0x00);       // Memory address
    Wire.endTransmission();
    Wire.requestFrom(EEPROM_ADDRESS, 1);

    if (Wire.available()) {
        byte data = Wire.read();
        Serial.print("Read data: ");
        Serial.println(data, HEX);
    }
}

void loop() {
    // Do nothing
}

    

Advantages

• Non-volatile: Retains data even without power.
• Low Power: Ideal for power-efficient applications.
• High-Endurance: Supports over 1 million write cycles per byte.
• Easy Integration: Compatible with a wide range of microcontrollers using I²C.

Conclusion

The AT24C02B EEPROM is a reliable and compact solution for non-volatile data storage in embedded systems. With its low power consumption, I²C interface, and high endurance, it is well-suited for a wide variety of applications—from simple data logging to complex microcontroller-based projects. By integrating the AT24C02B into your designs, you ensure reliable data retention for your electronics projects.