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MMA865xFC Sensor Toolbox User’s Guide, Rev. 0
34
Freescale Semiconductor, Inc.
Table 9. Directional Tap – Active/Standby screens
Screen
frame
Field or option
Description
Operation
Mode
Sample Rate
Enables you to change the rate at which the device acquires data.
Over-Sampling
Options for Data
Normal Mode
Normal operation.
Hi Res Mode
The device gives more accurate readings, but draws more
current.
Low Power Mode
The device draws less current than Normal mode does, but at
the expense of accuracy.
Low Noise Low Power
The device draws more current than Normal mode does, but
less current than Low Power mode does, and reduces noise.
Note:
In Low Noise mode, any g-force greater than ±4g will not
be read.
Auto Calibrate
Directs the device to calculate the offsets for each axis (accounting for any error in
measurements). For maximum resolution, the calibration is done with a dynamic range of
8g and a sample rate of 1.563 Hz.
Note:
Before enabling Auto Calibrate mode, place the device on a flat and stationary
surface.
Dynamic
Range
• 2g
• 4g
• 8g
Sets the range over which the accelerometer acquires data.
Standby
Active
Standby
Sets the device to Standby mode.
Active
Sets the device to Active mode.
• Standby Mode
• Wake Mode
• Sleep Mode
Indicates the device’s status.
Note:
The device will never enter Sleep mode during this demo.
Tap choice:
Choose
Single or
Double tap
LPF Enable
LPF = Low-Pass Filter
Sends accelerometer data through a low-pass filter before it is processed by the tap
application.
This filter treats higher frequency signals as noise, filtering out very fast shocks (to prevent
them from being detected as taps).
HPF Bypass
HPF = High-Pass Filter
Sends the raw accelerometer data to the tap application, bypassing the high-pass filter.
• The HPF Bypass option button normally should be cleared.
• Enabling the HPF Bypass can cause non-tap events (such as tilting the device) to be
registered as taps.