AT24C256 I2C EEPROM module with ESP32

Supply 3.3-5 V Bus I2C I2C address 0x50 / 0x51 / 0x52 / 0x53 / 0x54 / 0x55 / 0x56 / 0x57

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VCC	Power	3V3
GND	Ground	GND
SDA	I2C data (SDA)	D21
SCL	I2C clock (SCL)	D22
WP	Not wired to the ESP32	—	Write protect: LOW (default) allows writing

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x50);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "AT24C256 I2C EEPROM module found at 0x50" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Microchip AT24C256C datasheet, Device address 1010 A2 A1 A0 (0x50 to 0x57)

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.

AT24C256 I2C EEPROM module with ESP32

Pins and ESP32 wiring

Starter code (Arduino)

Sources

Try it in 3D in BoardPilot

Related parts