BME280 with Arduino Mega 2560 R3

Wiring for the GY-BME280 breakout on the Arduino Mega 2560 R3 (ATmega2560, 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: 3.3 V from the 3.3V pin.
• The BME280 is a 3.3 V part and the Arduino Mega 2560 R3 uses 5 V signals. Power it from 3.3 V and put a level shifter on the signal wires, or buy a 5 V version of the module.
• I2C uses the board’s default pins SDA 20 (SDA) and SCL 21 (SCL). Most modules include pull-up resistors; if the part is not found, check them and swap-test SDA/SCL.
• To make sure it is the real chip, read register 0xD0: a genuine part answers 0x60.

Test code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA = SDA 20, SCL = SCL 21 (the board's default I2C pins)
  Wire.beginTransmission(0x76);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "GY-BME280 breakout found at 0x76" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Arduino board: arduino:avr:mega.

Questions

Which Arduino Mega 2560 R3 pins do I use for the BME280?

VIN → 3.3V, GND → GND, SCL → SCL 21 (PD0), SDA → SDA 20 (PD1).

Does the BME280 work with the Arduino Mega 2560 R3 at 5 V?

The BME280 is a 3.3 V part and the Arduino Mega 2560 R3 uses 5 V signals. Power it from 3.3 V and put a level shifter on the signal wires, or buy a 5 V version of the module.

What is the I2C address of the BME280?

0x76 or 0x77. An I2C scan (BoardPilot does it for you) shows which one your module uses.

Full Arduino Mega 2560 R3 pinout · GY-BME280 breakout: all pins and data

The BME280 on other boards

ESP32 DevKit Arduino Nano Arduino Uno R3 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

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