AT24C256 2ECL IIC/I2C EEPROM Serial Interface Memory Module

AT24C256 2ECL IIC/I2C EEPROM Serial Interface Memory Module is a robust external non-volatile storage solution that easily integrates into any project requiring persistent data logging or configuration storage. This module features the popular AT24C256 chip, which provides 256 Kilobits (32 KB) of Electrically Erasable Programmable Read-Only Memory. Consequently, microcontrollers can quickly and reliably store critical data, such as calibration constants, system settings, or small datasets, even when the system loses power. Utilizing the widely adopted two-wire I2C serial interface, this module minimizes pin usage on your host microcontroller. Furthermore, its onboard circuitry and standard 4-pin interface simplify wiring and operation, making it an ideal choice for both prototyping and mass production of embedded systems.

Key Features:

• High-Density Storage: The module provides 32 KB (256 Kbits) of EEPROM, offering substantial non-volatile memory capacity for configuration parameters and system logs.
• I2C Serial Interface: It utilizes the two-wire I2C (or TWI) protocol, minimizing the required connections to the host microcontroller (SDA and SCL only).
• High Write Endurance: The AT24C256 chip guarantees a minimum of 1,000,000 erase/write cycles, ensuring long-term reliability for frequently updated data.
• Wide Operating Voltage: The module operates reliably across a wide voltage range, typically from 2.7 V to 5.5 V, supporting both 3.3 V and 5 V logic levels.
• Hardware Write Protect: Users can easily enable data security using the onboard write-protect pin (WP), safeguarding stored information from accidental corruption.

Technical Specifications:

• Memory Type: EEPROM (Electrically Erasable Programmable Read-Only Memory)
• Storage Capacity: 256 Kbits (32 KBytes)
• Interface Protocol: I2C (Two-Wire Interface)
• Maximum Clock Frequency: 400 kHz (Standard Mode) / 1 MHz (Fast Mode)
• Operating Voltage (V_CC): 2.7 V to 5.5 V
• Write Cycles: ≥ 1,000,000 Cycles
• Data Retention: ≥ 100 Years
• Operating Temperature Range: −40°C to +85°C (Industrial)

Mechanical Specifications:

• Module Dimensions: Small form factor PCB for easy embedding.
• Mounting: Fixed mounting holes available on the PCB.
• Connector Type: Standard 4-pin header (2.54 mm pitch).
• Chip Package: SOIC-8 or similar (mounted on the module PCB).

Dimensions:

• Module Length: ≈ 36.5 mm
• Module Width: ≈ 12.0 mm
• Module Height (w/ Header): ≈ 5.0 mm
• Weight: ≈ 2 g (Extremely lightweight)

Pinout and Wiring:

• VCC: Supply voltage input (2.7 V to 5.5 V).
• GND: Ground reference for the module.
• SCL: Serial Clock Input (Connect to the microcontroller’s SCL pin).
• SDA: Serial Data I/O (Connect to the microcontroller’s SDA pin).
• A0, A1, A2 (Optional): Address selection pins for utilizing multiple EEPROMs on the same I2C bus (Module typically configures these as default, however, check silkscreen for jumper options).
• WP (Write Protect – Optional): Tie this pin to VCC to disable all write operations. Leave unconnected or tied to GND for normal operation.

Datasheet Reference:

• Download AT24C256C Serial EEPROM Datasheet

Commonly Used in:

• Data Logging Systems: Essential for storing sensor readings and time-stamps in systems like weather stations or environmental monitors.
• Embedded System Configuration: Storing unique device IDs, boot parameters, and user preferences for microcontrollers.
• Robotics and Automation: Saving movement sequences, calibration data, and fault history in robotic arms and control units.

Applications:

• Calibration Parameter Storage: Permanently holds vital coefficients for sensors (e.g., pH, temperature, pressure).
• System Error Logging: Logs critical failure codes and timestamps, enabling easier device debugging and maintenance.
• Counter and Metering Devices: Retains total consumption values or usage counts, therefore preventing data loss during power outages.

Equivalent Models:

• CAT24C256 (ON Semi): A functionally equivalent 256 Kbit I2C EEPROM, often used as a direct replacement.
• 24LC256 (Microchip): Another industry-standard 256 Kbit EEPROM, offering nearly identical specifications and pinout.
• EEPROM Modules based on 24LC512: Higher capacity modules (512 Kbit) can replace this module provided that the software addresses the memory correctly.

Package Includes:

• 1 x AT24C256 2ECL IIC/I2C EEPROM Serial Interface Memory Module