MC3410 Datasheet, PDF (25/75 Pages) NXP Semiconductors – 10-Bit high-speed multiplying D/A converter

MC3410 3-Axis Accelerometer
Datasheet
9 ORIENTATION DETECTION
The MC3410 allows an application to determine the orientation of the device. The current
orientation of the device is reported as Left, Right, Up, Down, Front, and Back for each
sampling period. This information generates the Portrait/Landscape status bits in the TILT:
Status Register.
9.1 ORIENTATION HYSTERESIS
Hysteresis can be added to portrait/landscape and front/back detection by modifying the
default threshold offset values. See the specific sections below for more information.
9.2 PORTRAIT/LANDSCAPE EVENTS
Portrait/landscape detection is a combination of left, right, up, and down events, also partially
dependent upon Z sensor readings.
The default comparison angle for portrait/landscape is 45 degrees when evaluating differences
between LEFT, RIGHT, UP, and DOWN, as long as the magnitude of Z is < 0.8g (default). See
Figure 8.
By increasing the threshold values written to the UD_X_TH: Up/Down X Axis Threshold and
RL_Y_TH: Right/Left Y Axis Threshold, hysteresis can be introduced to the angle of
evaluation. These registers add a small offset to the default X and Y values and introduce
additional margin in the portrait/landscape detection logic.
For most applications, the same value should be written to both registers.
When the device orientation is in the hysteresis region, the device will report orientation as
“unknown”. When this reading is reported, in order to implement a hysteresis effect for
orientation, high-level software should use the last known portrait/landscape information.
In the example shown in Figure 9 the evaluation angle has been decreased to 40 degrees in
each threshold, such that there is a 10 degree “deadband” or hysteresis-area between
LEFT/RIGHT and DOWN/UP areas. The circle represents the acceleration in the Z axis, which
has a default of 0.8g, or about a 33 degree tilt relative to the Z axis.
mCube Proprietary.
APS-048-0010v2.2
© 2014 mCube Inc. All rights reserved.
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