How to Use 24LC01: Examples, Pinouts, and Specs

The 24LC01 is a 1K-bit Electrically Erasable Programmable Read-Only Memory (EEPROM) integrated circuit, capable of storing data that must be preserved during power cycles. This component is commonly used in small-scale data storage applications where a limited amount of non-volatile memory is required. Typical use cases include storing device configurations, calibration data, or small user preferences.

• Memory Size: 1 Kbit (128 x 8 bits)
• Interface: I²C (Inter-Integrated Circuit)
• Operating Voltage Range: 2.5V to 5.5V
• Write Cycle Time: 5 ms (max)
• Endurance: 1 million write cycles
• Data Retention: >200 years
• Operating Temperature Range: -40°C to +85°C

To use the 24LC01 EEPROM in a circuit:

1. Connect Vcc to a 2.5V to 5.5V power supply.
2. Connect Vss to the ground of the power supply.
3. Connect SDA and SCL to the I²C data and clock lines, respectively.
4. Set the A0, A1, and A2 pins to either Vcc or Vss to determine the device's I²C address.
5. Optionally, connect the WP pin to Vcc to prevent accidental writes to the EEPROM.

• Use pull-up resistors on the SDA and SCL lines to ensure proper I²C communication.
• Avoid exposing the device to temperatures outside the specified operating range.
• Ensure that the WP pin is properly set when write protection is desired.
• Follow proper ESD precautions when handling the EEPROM to prevent damage.

#include <Wire.h>

// Define the I2C address for the EEPROM
const int EEPROM_ADDRESS = 0x50; // A2, A1, A0 are connected to GND

void setup() {
  Wire.begin(); // Initialize I2C
  Serial.begin(9600); // Start serial communication at 9600 baud
}

void loop() {
  // Write a single byte (0xAA) to address 0 of the EEPROM
  writeEEPROM(EEPROM_ADDRESS, 0, 0xAA);
  delay(10); // Short delay to ensure the write process is completed

  // Read the byte back from address 0 of the EEPROM
  byte readValue = readEEPROM(EEPROM_ADDRESS, 0);
  Serial.print("Read value: ");
  Serial.println(readValue, HEX); // Print the read value in hexadecimal format

  delay(1000); // Wait for a second before repeating the process
}

void writeEEPROM(int deviceAddress, unsigned int eeAddress, byte data) {
  Wire.beginTransmission(deviceAddress);
  Wire.write((int)(eeAddress >> 8));   // MSB
  Wire.write((int)(eeAddress & 0xFF)); // LSB
  Wire.write(data);
  Wire.endTransmission();

  delay(5); // Max write cycle time per datasheet
}

byte readEEPROM(int deviceAddress, unsigned int eeAddress) {
  byte rData = 0xFF;

  Wire.beginTransmission(deviceAddress);
  Wire.write((int)(eeAddress >> 8));   // MSB
  Wire.write((int)(eeAddress & 0xFF)); // LSB
  Wire.endTransmission();

  Wire.requestFrom(deviceAddress, 1);

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

  return rData;
}

• Data not persisting: Ensure that the WP pin is not set to write protect mode during a write operation.
• I²C communication failure: Check the pull-up resistors on the SDA and SCL lines and verify the connections.
• Incorrect data read: Confirm that the EEPROM address is set correctly and that there are no shorts or open circuits.

• If the EEPROM is not responding, check the power supply and ground connections.
• Ensure that the I²C bus is not being held by another device.
• Use an oscilloscope to check the integrity of the I²C signals if communication issues persist.

Q: How do I set the I²C address of the 24LC01? A: The I²C address is determined by the voltage applied to the A0, A1, and A2 pins. Connect these pins to either Vcc or Vss to set the address.

Q: Can I write to the EEPROM in a single operation? A: Yes, but the maximum amount of data that can be written in a single write cycle is limited by the page size of the EEPROM.

Q: How do I prevent accidental writes to the EEPROM? A: Connect the WP pin to Vcc to enable write protection. When WP is high, write operations are inhibited.

This documentation provides a comprehensive guide to using the 24LC01 EEPROM IC in your projects. For further information, consult the manufacturer's datasheet.