AT24C256 I2C Interface EEPROM Memory Module...
AT24C256 I2C Interface EEPROM Memory Module...
AT24C256 I2C Interface EEPROM Memory Module (256 Kbit)
AT24C256 I2C Interface EEPROM Memory Module (256 Kbit)

AT24C256 I2C Interface EEPROM Memory Module (256 Kbit)

Modules
DET641
Part.No: AT24C256
€4.95
In Stock
Immediate Dispatch
The AT24C256 I2C EEPROM Memory Module offers 256 Kbit (32 KB) of non-volatile storage via a simple 2-wire I2C interface. Address jumpers (A0, A1, A2) allow up to 8 modules on the same bus — ideal for Arduino, ESP32, and Raspberry Pi projects.

 

The AT24C256 EEPROM Memory Module (MPN: AT24C256) is a compact, non-volatile memory expansion board designed for microcontroller projects that need persistent data storage. With 256 Kbit (32 KB) of EEPROM capacity and a standard I2C (Two-Wire Interface) bus, it lets you store configuration settings, calibration data, log files, or user preferences that survive power cycles — all without occupying precious internal flash on your microcontroller.

Key Features

  • 256 Kbit (32 KB) Non-Volatile Storage: Data is retained when power is removed → perfect for settings, logs, and calibration tables.
  • I2C Interface (SDA + SCL only): Only two signal lines needed → minimal GPIO usage on any microcontroller.
  • Address Jumpers A0, A1, A2: Hardware address selection via on-board jumpers → stack up to 8 AT24C256 modules on the same I2C bus for up to 256 KB total.
  • Breadboard & Header Compatible: Standard 2.54 mm pin headers → easy integration into any prototype or PCB.

Pinout & Wiring

PINSymbolDescription
1A0I2C address bit 0 (jumper)
2A1I2C address bit 1 (jumper)
3A2I2C address bit 2 (jumper)
4GNDGround
5VCCPower supply
6SCLI2C clock line
7SDAI2C data line
8WPWrite Protect (connect to GND to enable writes)

Wiring note: Connect SDA → SDA and SCL → SCL on your microcontroller. Add 4.7 kΩ pull-up resistors on both lines if not already present on your board. Leave WP pin connected to GND to allow write operations.

Compatibility

  • Arduino UNO / Nano / Mega (5 V): Fully compatible — use the Wire library; I2C base address 0x50 (all jumpers open).
  • ESP32 / ESP8266 (3.3 V): Compatible — operates at 3.3 V logic; use the Wire library with defined SDA/SCL pins.
  • Raspberry Pi (3.3 V I2C): Compatible — enable I2C in raspi-config and use the smbus Python library.

Typical Applications

  • Storing device configuration: Save Wi-Fi credentials, PID tuning values, or user preferences that persist across reboots.
  • Data logging: Record sensor readings, event timestamps, or error codes without needing an SD card.
  • Calibration tables: Store factory or field calibration data for sensors and actuators.
  • Multi-module I2C bus expansion: Chain up to 8 modules for larger non-volatile storage needs in a single project.
  • Bootloader / firmware parameters: Keep critical parameters separate from the main MCU flash for safer OTA updates.

Technical Specifications

ParameterValue
InterfaceI2C (Two-Wire)
Memory Capacity256 Kbit (32 KB)
Address PinsA0, A1, A2 (up to 8 devices on one bus)
MPNAT24C256

Frequently Asked Questions

Q: How many AT24C256 modules can I connect to the same I2C bus?
A: Up to 8 modules, because the three address jumpers (A0, A1, A2) provide 2³ = 8 unique I2C addresses (0x50–0x57), giving a combined capacity of up to 256 KB.

Q: Do I need external pull-up resistors?
A: The module includes pull-up resistors on the SDA and SCL lines on the PCB. When connecting multiple modules on the same bus, you may need to remove redundant pull-ups to avoid too-low bus impedance.

Package Contents: 1× AT24C256 I2C EEPROM Memory Module

⚠ Note: Ensure your power supply voltage matches your microcontroller logic level. Always connect the WP (Write Protect) pin to GND when write operations are required; leaving it floating may prevent writes.
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