AT24C256 EEPROM Memory
Overview
An AT24C256 EEPROM memory module that allows reading and writing data. It is non-volatile memory where recorded data is not lost even when power is disconnected. It uses an I2C interface.
– AT24C128: 256 pages x 64 bytes = 16384 bytes
– AT24C256: 512 pages x 64 bytes = 32768 bytes
Specifications
- Supply Voltage : 5V
- Current : < 10mA
- Interface: I2C / TWI
- EEPROM : AT24C256
Supported GPIO
- Raspberry Pi 0~4
- Raspberry Pi 5
- BeagleBone Black/Green
- Jetson Nano
- FT232H, FT2232H, FT4232H
- MCP2221
I2C Address
The I2C address can be changed by modifying the A0, A1, A2 jumpers. (May vary by module manufacturer)
| A0 | A1 | A2 | I2C Address |
|---|---|---|---|
| ON | ON | ON | 0x50 |
| OFF | ON | ON | 0x51 |
| ON | OFF | ON | 0x52 |
| OFF | OFF | ON | 0x53 |
| ON | ON | OFF | 0x54 |
| OFF | ON | OFF | 0x55 |
| ON | OFF | OFF | 0x56 |
| OFF | OFF | OFF | 0x57 |
Commands
[READ_DATA]
Reads data of the specified size from the starting address. If a page boundary is reached during reading, it continues reading from the next page sequentially. However, if the memory address limit is reached, it wraps around to the beginning of the first page (address 0) and continues reading.
| Item | Type | Description |
|---|---|---|
| Start Address | WRITE | Enter the starting address to read from EEPROM. (0~32767) |
| Read Size | WRITE | Size of bytes to read. |
| Data | READ | Data read from EEPROM. |
[WRITE_DATA]
Writes data starting from the specified address. If the end of a page is reached during writing, it wraps around to the beginning of that page and overwrites existing data.
| Item | Type | Description |
|---|---|---|
| Start Address | WRITE | Enter the EEPROM address to write data to. (0~32767) |
| Data | WRITE | Enter the byte array data to write to EEPROM. |
Example
Objective
Every second, write a random integer between 0 and 100 to EEPROM memory, then read the data back from memory and display it on dashboard widgets.
Parts
| Part | Quantity |
|---|---|
| Raspberry Pi 4 * | 1 |
| AT24C256 | 1 |
Wiring
Connect each component to the corresponding connection as listed in each row below.
| AT24C256 | GPIO |
|---|---|
| VCC | 5V |
| GND | GND |
| SCL | 3 (I2C1 SCL) |
| SDA | 2 (I2C1 SDA) |
Project Link
