BMP085

Data sheet

Bosch Sensortec

Rev. 1.2

Page 12

15 October 2009

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as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Specifications are subject to change without notice.

3.4 Calibration coefficients

The 176 bit E

coefficients. Every sensor module has individual coefficients. Before the first calculation of

temperature and pressure, the master reads out the E

The data communication can be checked by checking that none of the words has the value 0 or

0xFFFF.

BMP085 reg adr

Parameter

MSB

LSB

AC1

0xAA

0xAB

AC2

0xAC

0xAD

AC3

0xAE

0xAF

AC4

0xB0

0xB1

AC5

0xB2

0xB3

AC6

0xB4

0xB5

B1

0xB6

0xB7

B2

0xB8

0xB9

MB

0xBA

0xBB

MC

0xBC

0xBD

MD

0xBE

0xBF

3.5 Calculating pressure and temperature

The mode (ultra low power, standard, high, ultra high resolution) can be selected by the variable

oversampling_setting (0, 1, 2, 3) in the C code.

The universal code SMD500/BMP085 is fully upward compatible to SMD500 and recognizes

automatically the device ID. Thus, the SMD500 can be replaced "on the fly" by the BMP085

without changing hardware or software.

Calculation of true temperature and pressure in steps of 1Pa (= 0.01hPa = 0.01mbar) and

temperature in steps of 0.1°C.

The following figure shows the detailed algorithm for pressure and temperature measurement.

from Bosch Sensortec and via its sales and distribution partners. Please contact your Bosch

Sensortec representative for details.