BMP085-0330SBO008 BOSCH, BMP085-0330SBO008 Datasheet - Page 12

• Manufacturer Part Number: BMP085-0330SBO008
• Description: Daughter Board
• Manufacturer: BOSCH

Specifications of BMP085-0330SBO008

• Silicon Manufacturer: Bosch
• Application Sub Type: Accelerometer - Three-Axis
• Kit Application Type: Sensing - Motion / Vibration / Shock
• Silicon Core Number: BMP085
• Kit Contents: Board

The following figure shows the detailed algorithm for pressure and temperature measurement.
The algorithm is available as C source code (“
Rev. 1.0
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
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.
Calculation of pressure and temperature for BMP085
UT = MSB << 8 + LSB
UP = (MSB<<16 + LSB<<8 + XLSB) >> (8-oss)
X1 = (UT - AC6) * AC5 / 2
X2 = MC * 2
B5 = X1 + X2
T = (B5 + 8) / 2
B6 = B5 - 4000
X1 = (B2 * (B6 * B6 / 2
X2 = AC2 * B6 / 2
X3 = X1 + X2
B3 = ((AC1*4+X3) << oss + 2) / 4
X1 = AC3 * B6 / 2
X2 = (B1 * (B6 * B6 / 2
X3 = ((X1 + X2) + 2) / 2
B4 = AC4 * (unsigend long)(X3 + 32768) / 2
B7 = ((unsigned long)UP - B3) * (50000 >> oss)
if (B7 < 0x80000000) { p = (B7 * 2) / B4 }
X1 = (p / 2
X1 = (X1 * 3038) / 2
X2 = (-7357 * p) / 2
p = p + (X1 + X2 + 3791) / 2
else { p = (B7 / B4) * 2 }
read reg 0xF6 (MSB), 0xF7 (LSB), 0xF8 (XLSB)
read out E
read uncompensated temperature value
display temperature and pressure value
write 0x34+(oss<<6) into reg 0xF4, wait
read uncompensated pressure value
write 0x2E into reg 0xF4, wait 4.5ms
read reg 0xF6 (MSB), 0xF7 (LSB)
from the E
8
) * (p / 2
11
calculate true temperature
2
/ (X1 + MD)
calculate true pressure
PROM registers, 16 bit, MSB first
Read calibration data
4
AC2 (0xAC, 0xAD)
AC1 (0xAA, 0xAB)
AC3 (0xAE, 0xAF)
AC4 (0xB0, 0xB1)
AC5 (0xB2, 0xB3)
AC6 (0xB4, 0xB5)
11
13
MC (0xBC, 0xBD)
MB (0xBa, 0xBB)
MD (0xBE, 0xBF)
B1 (0xB6, 0xB7)
B2 (0xB8, 0xB9)
16
8
16
2
PROM of the BMP085
)
Start
12
12
2
)) / 2
)) / 2
15
4
16
11
15
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
(16 bit)
Data sheet
Page 12
BMP085
example:
AC1 =
AC2 =
AC3 =
AC4 =
AC5 =
AC6 =
B1 =
B2 =
MB =
MC =
MD =
UT =
oss =
= oversampling_setting
(ultra low power mode)
UP =
X1 =
X2 =
B5 =
T =
B6 =
X1 =
X2 =
X3 =
B3 =
X1 =
X2 =
X3 =
B4 =
B7 =
p =
X1 =
X1 =
X2 =
p =
BMP085_SMD500_API”)
1171050000
-14383
-32767
27898
23843
32741
32757
23153
33457
70003
74774
69965
-8711
-2344
-1601
-7859
6190
2868
4743
2399
2810
3466
408
150
422
717
-72
56
57
59
4
0
1
C code function:
bmp085_get_temperature
temp in 0.1°C
BMP085_calpressure
press. in Pa
bmp085_get_cal_param
bmp085_get_ut
bmp085_get_up
from Bosch Sensortec.
Bosch Sensortec
01 July 2008
type:
short
short
short
unsigned short
unsigned short
unsigned short
short
short
short
short
short
long
short (0 .. 3)
long
long
long
long
long
long
long
long
long
long
long
long
long
unsigned long
long
long
long
long
long
long
long