BMA250 Bosch Sensortec, BMA250 Datasheet - Page 31

3-AXIS ACCELEROMETER DIGITAL I/F

BMA250

Manufacturer Part Number
BMA250
Description
3-AXIS ACCELEROMETER DIGITAL I/F
Manufacturer
Bosch Sensortec
Series
-r
Datasheets

Specifications of BMA250

Featured Product
BMA250 - Digital, Triaxial Acceleration Sensor
Axis
X, Y, Z
Acceleration Range
±2g, 4g, 8g, 16g
Sensitivity
256LSB/g, 128LSB/g, 64LSB/g, 16LSB/g
Voltage - Supply
1.62 V ~ 3.6 V
Output Type
I²C™, SPI™
Bandwidth
8Hz ~ 1kHz
Interface
I²C, SPI
Mounting Type
Surface Mount
Package / Case
12-VQFN
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
For Use With
828-1024 - BMA250 DAUGHTERCARD FOR DEV KIT
Other names
828-1023-2
In the preceding tables, the parameter
setting the (0x0C) orient_hyst bits. 1 LSB of (0x0C) orient_hyst always corresponds to 62.5 mg,
in any g-range (i.e. increment is independent from g-range setting). It is important to note that by
using a hysteresis ≠ 0 the actual switching angles become different from the angles given in the
tables since there is an overlap between the different orientations.
The most significant bit of the (0x0C) orient bits (which is displayed as an ´x´ in the above given
tables) contains information about the direction of the z-axis. It is set to ´0´ (´1´) if acc_z ≥ 0
(acc_z < 0).
Figure 9 shows the typical switching conditions between the four different orientations for the
symmetrical mode (i.e. without hysteresis):
The orientation interrupt is enabled (disabled) by writing ´1´ (´0´) to bit (0x16) orient_en. The
interrupt is generated if the value of (0x0C) orient has changed. It is automatically cleared after
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.
Note: Specifications within this document are subject to change without notice.
Table 20: Meaning of the (0x0C) orient bits in low-asymmetrical mode
(0x0C)
orient
x00
x01
x10
x11
Figure 9: Typical orientation switching conditions w/o hysteresis
portrait upside down
landscape right
portrait upright
landscape left
Name
Page 31 / not for publishing
‘hyst’
Data sheet
153° <  < 207°
207° <  < 333°
BMA250
333° <  < 27°
27° <  < 153°
stands for a hysteresis, which can be selected by
Angle
|acc_y| ≥ 0.5·|acc_x| +
|acc_y| ≥ 0.5·|acc_x| +
|acc_y| < 0.5·|acc_x| -
|acc_y| < 0.5·|acc_x| -
and acc_x +
and acc_x -
and acc_y < 0
and acc_y ≥ 0
Condition
‘hyst’
‘hyst’
Bosch Sensortec
03 March 2011
≥ 0
< 0
‘hyst’
‘hyst’
‘hyst’
‘hyst’

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