BMA222 Bosch Sensortec, BMA222 Datasheet - Page 29

• Manufacturer Part Number: BMA222
• Description: 3-AXIS ACCELEROMETER DIGITAL SMD
• Manufacturer: Bosch Sensortec

Specifications of BMA222

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 828-1025-2

4.8.7 Orientation recognition
The orientation recognition feature informs on an orientation change of the sensor with respect
to the gravitational field vector ‘g’. The measured acceleration vector components with respect
to the gravitational field are defined as shown in figure 8.
Therefore, the magnitudes of the acceleration vectors are calculated as follows:
Depending on the magnitudes of the acceleration vectors the orientation of the device in the
space is determined and stored in the three (0x0C) orient bits. These bits may not be reset in
the sleep phase of low-power mode. There are three orientation calculation modes with different
thresholds for switching between different orientations: symmetrical, high-asymmetrical, and
low-asymmetrical. The mode is selected by setting the (0x2C) orient_mode bits as given in table
17.
Rev. 1.0
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Note: Specifications within this document are subject to change without notice.
orient_mode
(0x2C)
Figure 8: Definition of vector components
acc_x = 1g·sin·cos
acc_y = −1g·sin·sin
acc_z = 1g·cos
→ acc_y/acc_x = −tan
Table 17: Orientation mode settings
00b
01b
10b
11b
Data sheet
BMA222
Page 29
Orientation Mode
high-asymmetrical
low-asymmetrical
symmetrical
symmetrical
Bosch Sensortec
07 March 2011