bmp280 datasheet

Bosch
Sensortec | BMP280 Data sheet
12 |
48
Modifications reserved | Data subject to change without notice
Document number: BST-BMP280-DS001-23 Revision_1.23_11202
0
Measure temperature
(oversampling set by osrs_t;
skip if osrs_t = 0)
Start
measurement cycle
Measure pressure
(oversampling set by osrs_p;
skip if osrs_p = 0)
IIR filter enabled?
End
measurement cycle
IIR filter initialised?
Copy ADC values
to filter memory
(initalises IIR filter)
No
Update filter memory using
filter memory, ADC value
and filter coefficient
No
Yes
Yes
Copy filter memory
to output registers
Figure 2: BMP280 measurement cycle
The individual blocks of the diagram above will be detailed in the following subchapters.
3.3.1 Pressure measurement
Pressure measurement can be enabled or skipped. Skipping the measurement could be useful if
BMP280 is used as temperature sensor. When enabled, several oversampling options exist. Each
oversampling step reduces noise and increases the output resolution by one bit, which is stored in the
XLSB data register 0xF9. Enabling/disabling the measurement and oversampling settings are selected
through the osrs_p[2:0] bits in control register 0xF4.
Table 4: osrs_p settings
Oversampling setting
Pressure
oversampling
Typical pressure
resolution
Recommended
temperature
oversampling
Pressure measurement
skipped
Skipped
(output set to 0x80000)
– As needed
Ultra low power ×1 16 bit / 2.62 Pa ×1
Low power ×2 17 bit / 1.31 Pa ×1
Standard resolution ×4 18 bit / 0.66 Pa ×1
High resolution ×8 19 bit / 0.33 Pa ×1
Ultra high resolution ×16 20 bit / 0.16 Pa ×2
In order to find a suitable setting for osrs_p, please consult chapter 3.4.