Information

BMA280
Data sheet
Page 35
BST-BMA280-DS000-11 | Revision 1.8 | August 2014 Bosch Sensortec
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Note: Specifications within this document are subject to change without notice.
For each orientation mode the (0x0C) orient bits have a different meaning as shown in Table 14
to Table 16:
Table 14: Meaning of the (0x0C) orient bits in symmetrical mode
(0x0C)
orient
Name
Angle
Condition
x00
portrait upright
315° <  < 45°
|acc_y| < |acc_x| - ‘hyst’
and acc_x - ‘hyst’’ ≥ 0
x01
portrait upside down
135° <  < 225°
|acc_y| < |acc_x| - ‘hyst’
and acc_x + ‘hyst’ < 0
x10
landscape left
45° <  < 135°
|acc_y| ≥ |acc_x| + ‘hyst’
and acc_y < 0
x11
landscape right
225° <  < 315°
|acc_y| ≥ |acc_x| + ‘hyst’
and acc_y ≥ 0
Table 15: Meaning of the (0x0C) orient bits in high-asymmetrical mode
(0x0C)
orient
Name
Angle
Condition
x00
portrait upright
297° <  < 63°
|acc_y| < 2∙|acc_x| - ‘hyst’
and acc_x - ‘hyst’ ≥ 0
x01
portrait upside down
117° <  < 243°
|acc_y| < 2∙|acc_x| - ‘hyst’
and acc_x + ‘hyst’ < 0
x10
landscape left
63° <  < 117°
|acc_y| ≥ 2∙|acc_x| + ‘hyst’
and acc_y < 0
x11
landscape right
243° <  < 297°
|acc_y| ≥ 2∙|acc_x| + ‘hyst’
and acc_y ≥ 0
Table 16: Meaning of the (0x0C) orient bits in low-asymmetrical mode
(0x0C)
orient
Name
Angle
Condition
x00
portrait upright
333° <  < 27°
|acc_y| < 0.5∙|acc_x| - ‘hyst’
and acc_x - ‘hyst’ ≥ 0
x01
portrait upside down
153° <  < 207°
|acc_y| < 0.5∙|acc_x| - ‘hyst’
and acc_x + ‘hyst’ < 0
x10
landscape left
27° <  < 153°
|acc_y| ≥ 0.5∙|acc_x| + ‘hyst’
and acc_y < 0
x11
landscape right
207° <  < 333°
|acc_y| ≥ 0.5∙|acc_x| + ‘hyst’
and acc_y ≥ 0
In the preceding tables, the parameter ‘hyst’ stands for a hysteresis, which can be selected by
setting the (0x2C) orient_hyst bits. 1 LSB of (0x2C) 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).