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AT24C256
AT24C256
Memory
256Kb I2C serial EEPROM in the standard 8-pin layout (A0-A2 address, SDA/SCL, WP).
In stock
Specifications
0No specs listed.
Pinout
8| Pin | Name | Functions | Notes |
|---|---|---|---|
| 1 | A0 | GPIO | Address 0 |
| 2 | A1 | GPIO | Address 1 |
| 3 | A2 | GPIO | Address 2 |
| 4 | VSS | GND | Ground |
| 5 | SDA | I2C | I2C data |
| 6 | SCL | I2C | I2C clock |
| 7 | WP | GPIO | Write protect |
| 8 | VCC | POWER | Supply |
Interactive pinout
Highlight:
AT24C256
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Starter code
Community starter examples — minimal, unofficial, and provided to get you wiring fast. Verify against the manufacturer datasheet before relying on them.
Arduino (C++)
arduino
// AT24C256 I2C EEPROM (32 KB) — community starter example
// Identical protocol to AT24C32 (2-byte word address), just larger.
#include <Wire.h>
const byte EEPROM_ADDR = 0x50;
void writeByte(uint16_t addr, byte data) {
Wire.beginTransmission(EEPROM_ADDR);
Wire.write(addr >> 8); Wire.write(addr & 0xFF);
Wire.write(data);
Wire.endTransmission();
delay(5);
}
byte readByte(uint16_t addr) {
Wire.beginTransmission(EEPROM_ADDR);
Wire.write(addr >> 8); Wire.write(addr & 0xFF);
Wire.endTransmission();
Wire.requestFrom(EEPROM_ADDR, (byte)1);
return Wire.read();
}
void setup() {
Serial.begin(115200);
Wire.begin();
writeByte(100, 7);
Serial.println(readByte(100)); // -> 7
}
void loop() {}MicroPython
python
# AT24C256 I2C EEPROM (ESP32) — community starter example
from machine import Pin, I2C
import time
i2c = I2C(0, scl=Pin(22), sda=Pin(21))
ADDR = 0x50
i2c.writeto_mem(ADDR, 100, b"\x07", addrsize=16)
time.sleep_ms(5)
print(i2c.readfrom_mem(ADDR, 100, 1, addrsize=16))Wiring
| Pin | Arduino Uno R3 | ESP32 DevKitC (WROOM-32) | Notes |
|---|---|---|---|
| VCC | +5V | 3V3 | 1.7-5.5 V |
| GND | GND | GND | |
| SCL | A5/SCL | GPIO22 | I2C clock |
| SDA | A4/SDA | GPIO21 | I2C data |
| A0/A1/A2 | - | - | Address select -> 0x50-0x57 |
| WP | GND | GND | LOW = writable |
Typical uses
- 32 KB non-volatile storage
- Calibration data and logs