This library uses I2C communication with Arduino/ESP8266 and read the Temperature( degC) , Pressure (mBar) and Altitude (m).
BMP280-----Arduino
VDD ----> 3.3V
GND ----> GND
SDA ----> PIN20 (arduino mega, changeable in begin)
SCL ----> PIN21 (arduino mega, changeable in begin)
SDO ----> GND (slave address 0x76)
CS ----> VDD (HIGH for I2C)
VDDIO ----> VDD
Copy the BMP280 folder to Arduino/libraries
Restart Arduino and Upload "measurments" sketch in Arduino.