How to Use 24C02 – 2 Kb I2C Serial EEPROM : Examples, Pinouts, and Specs

The 24C02 is a 2 Kb I2C serial EEPROM (Electrically Erasable Programmable Read-Only Memory) manufactured by STMicroelectronics. It is designed for non-volatile data storage, meaning it retains data even when power is removed. The component communicates with microcontrollers and other devices using the I2C protocol, making it a versatile and easy-to-use memory solution for a wide range of applications.

• Storing configuration data for embedded systems
• Data logging in IoT devices
• Calibration data storage for sensors
• Non-volatile memory for microcontroller-based projects
• Storing user preferences in consumer electronics

The following are the key technical details of the 24C02 – 2 Kb I2C Serial EEPROM:

The 24C02 comes in an 8-pin DIP (Dual In-line Package) configuration. Below is the pinout and description:

1. Power Supply: Connect the VCC pin to a power source (1.8 V to 5.5 V) and the GND pin to ground.
2. I2C Connections:
   • Connect the SDA pin to the microcontroller's I2C data line.
   • Connect the SCL pin to the microcontroller's I2C clock line.
   • Use pull-up resistors (typically 4.7 kΩ) on both the SDA and SCL lines.
3. Address Selection: Use the A0, A1, and A2 pins to set the I2C slave address. These pins can be connected to either VCC (logic HIGH) or GND (logic LOW).
4. Write Protection: If write protection is required, connect the WP pin to VCC. Leave it connected to GND or floating for normal read/write operations.

• Pull-Up Resistors: Ensure proper pull-up resistors are used on the I2C lines to maintain signal integrity.
• Write Cycle Time: Allow sufficient time (5 ms) for write operations to complete before initiating another write.
• Address Conflicts: Avoid address conflicts when using multiple I2C devices on the same bus by configuring unique addresses using the A0, A1, and A2 pins.
• Decoupling Capacitor: Place a 0.1 µF decoupling capacitor close to the VCC pin to filter out noise.

Below is an example of how to interface the 24C02 with an Arduino UNO to write and read data:

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

#define EEPROM_I2C_ADDRESS 0x50 // Base I2C address of 24C02 (A0, A1, A2 = GND)

void setup() {
  Wire.begin(); // Initialize I2C communication
  Serial.begin(9600); // Initialize serial communication for debugging

  // Write a byte to EEPROM
  writeEEPROM(0x00, 0x42); // Write 0x42 to memory address 0x00
  delay(10); // Wait for the write cycle to complete

  // Read the byte back from EEPROM
  byte data = readEEPROM(0x00);
  Serial.print("Read data: 0x");
  Serial.println(data, HEX); // Print the read data in hexadecimal format
}

void loop() {
  // Nothing to do here
}

// Function to write a byte to the 24C02 EEPROM
void writeEEPROM(byte address, byte data) {
  Wire.beginTransmission(EEPROM_I2C_ADDRESS); // Start I2C communication
  Wire.write(address); // Send memory address
  Wire.write(data); // Send data byte
  Wire.endTransmission(); // End I2C communication
}

// Function to read a byte from the 24C02 EEPROM
byte readEEPROM(byte address) {
  Wire.beginTransmission(EEPROM_I2C_ADDRESS); // Start I2C communication
  Wire.write(address); // Send memory address
  Wire.endTransmission(); // End transmission to set the address

  Wire.requestFrom(EEPROM_I2C_ADDRESS, 1); // Request 1 byte from EEPROM
  if (Wire.available()) {
    return Wire.read(); // Read and return the byte
  }
  return 0xFF; // Return 0xFF if no data is available
}

1. EEPROM Not Responding on I2C Bus:

   • Cause: Incorrect I2C address or wiring.
   • Solution: Verify the I2C address based on the A0, A1, and A2 pin configuration. Check the connections for SDA and SCL.

2. Data Not Written to EEPROM:

   • Cause: Write protection is enabled.
   • Solution: Ensure the WP pin is connected to GND or left floating for write operations.

3. Corrupted Data:

   • Cause: Insufficient delay after a write operation.
   • Solution: Add a delay of at least 5 ms after each write operation.

4. I2C Communication Errors:

   • Cause: Missing or incorrect pull-up resistors.
   • Solution: Use 4.7 kΩ pull-up resistors on the SDA and SCL lines.

• Q: Can I use the 24C02 with a 3.3 V microcontroller?
  A: Yes, the 24C02 operates within a voltage range of 1.8 V to 5.5 V, making it compatible with 3.3 V systems.

• Q: How many 24C02 devices can I connect on the same I2C bus?
  A: Up to 8 devices can be connected by configuring unique addresses using the A0, A1, and A2 pins.

• Q: What happens if the power is lost during a write operation?
  A: The data being written may be corrupted. Ensure a stable power supply during write operations.

• Q: Can I read from the EEPROM while writing?
  A: No, the EEPROM is busy during a write cycle and will not respond to read requests.

This concludes the documentation for the 24C02 – 2 Kb I2C Serial EEPROM.