SSD1306 OLED with Arduino Uno R3

Wiring for the SSD1306 OLED 128x64 (I2C) on the Arduino Uno R3 (ATmega328P, 5 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

Check before you power it on

• Supply: 5 V from the 5V pin.
• I2C uses the board’s default pins A4 (SDA) and A5 (SCL). Most modules include pull-up resistors; if the part is not found, check them and swap-test SDA/SCL.

Test code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA = A4, SCL = A5 (the board's default I2C pins)
  Wire.beginTransmission(0x3C);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "SSD1306 OLED 128x64 (I2C) found at 0x3C" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Arduino board: arduino:avr:uno.

Questions

Which Arduino Uno R3 pins do I use for the SSD1306 OLED?

GND → GND, VCC → 5V, SCL → A5 (PC5), SDA → A4 (PC4).

Does the SSD1306 OLED work with the Arduino Uno R3 at 5 V?

Yes: the SSD1306 OLED runs at 3.3-5 V and the Arduino Uno R3 uses 5 V signals, so no level shifting is needed.

What is the I2C address of the SSD1306 OLED?

0x3C or 0x3D. An I2C scan (BoardPilot does it for you) shows which one your module uses.

Full Arduino Uno R3 pinout · SSD1306 OLED 128x64 (I2C): all pins and data

The SSD1306 OLED on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 Nordic nRF52840 DK NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico Teensy 4.1

Other parts on the Arduino Uno R3

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