BMP280 Barometric Pressure & Temperature Sensor

I2C address: 0x76

The BMP280 is a precision digital barometric pressure and temperature sensor from Bosch. It is widely used for altitude estimation, weather monitoring, and indoor navigation.

Datasheet

The full BMP280 datasheet is available here.

Registers

Register	Address	Description
calib00–calib25	0x88–0xA1	Factory calibration coefficients (read-only)
id	0xD0	Chip ID — always 0x60
reset	0xE0	Write 0xB6 to soft-reset
status	0xF3	Measuring / im_update flags
ctrl_meas	0xF4	Oversampling settings + power mode
config	0xF5	Standby time, IIR filter, SPI mode
press_msb/lsb/xlsb	0xF7–0xF9	Raw pressure output (20-bit)
temp_msb/lsb/xlsb	0xFA–0xFC	Raw temperature output (20-bit)

Power Modes

Mode (ctrl_meas bits [1:0])	Description
00	Sleep — no measurements
01 / 10	Forced — one measurement then back to sleep
11	Normal — continuous measurements at configured standby rate

Compensation

The BMP280 stores unique factory calibration coefficients at power-on. All raw ADC values must be passed through the Bosch compensation formulas (detailed in datasheet §4.2.3) to obtain physical units:

• Temperature: returns value in 0.01 °C units
• Pressure: returns value in Pa (divide by 256 for float Pa)

The simulator applies these compensation formulas internally and exposes the calibrated values directly.

Simulation Controls

Control	Range	Description
Temperature slider	−40 to +85 °C	Sets ambient temperature
Pressure slider	300 to 1100 hPa	Sets ambient pressure

Thermal lag (τ ≈ 2 s) and Gaussian measurement noise matching the datasheet specs are applied to every reading.

Altitude Estimation

Altitude can be derived from pressure using the barometric formula:

altitude = 44330 × (1 − (P / P0)^(1/5.255))

Where P0 is sea-level reference pressure (typically 1013.25 hPa).

Limitations

• IIR filter coefficients are stored but do not affect the simulated output
• Standby time in normal mode is not simulated — data updates on each read