BMP280Digital barometric pressure sensor

BMP280 is a miniature digital sensor that measures barometric pressure and temperature. Its sensing elements and mixed-signal electronics share an eight-contact metal-lid LGA package. I²C and SPI provide the interface to a microcontroller; the IC itself has no display or regulator. The BMP280 has no humidity channel; a similar-looking BME280 is a different device. Raw conversion data must be compensated with calibration coefficients read from that individual sensor. Temperature compensation is performed first because the pressure calculation depends on its intermediate result. The example uses both supplies at 3.3 V, two local bypass capacitors and an I²C address of 0x76. Pin numbering runs clockwise in the top view, so pad 1 is at the upper right. The illustrated 25°C and 1000 hPa readings explain units; they are not measurements from a connected sensor.