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MMA865xFC Sensor Toolbox User’s Guide, Rev. 0
58
Freescale Semiconductor, Inc.
Table 18. Full-System Evaluation – Pulse Detection screen
Screen
frame
Field or option
Description
Overall
settings
Default Single Tap
Sets the parameters for detecting single taps to the factory-defined values.
Default
Double Tap
Sets the threshold for detecting single and double taps to the factory-defined values.
LPF Enable
LPF = Low-Pass Filter
Sends accelerometer data through a low-pass filter before it (the data) is processed by the
tap application.
The low-pass filter treats higher frequency signals as noise, filtering out very fast shocks,
to prevent them (the fast shocks) 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.
• Disabling the high pass filter can cause non-tap events (such as tilting the device) to be
registered as taps.
Single Tap
Settings
• Enable X SP
• Enable Y SP
• Enable Z SP
(Enable Single Pulse)
Allows taps along these axes to trigger the “Event Detected” Indicator on the Tap Status
frame.
For example, to see only taps on the top of the device, clear the X and Y SP boxes.
Enable Latch
Causes any triggered event to remain until the Status register is read.
If the Enable Latch checkbox is not enabled, then the interrupt will only last as long as the
event, and the Status register will represent the most-recent event.
Pulse Time Limit
slider
Sets the maximum time that a tap can last before it is ignored (i.e., it is not considered a
tap).
Set Time Limit
Click Set to register the new
settings with the device.
• Before changing the Pulse Time Limit slider,
click Reset Time Limit.
• After changing the Pulse Time Limit slider
click Set Time Limit.
Reset Time Limit
Click Reset to enable a new
configuration.
• X Threshold
• Y Threshold
• Z Threshold
sliders
Sets the g threshold for a
tap to be detected along the
designated axis.
Pulses with a G value less
than the setting will be
ignored.
• Before using the axis threshold sliders,
click Reset XYZ Thresholds.
• After using the axis threshold sliders,
click Set XYZ Thresholds.
Set XYZ
Thresholds
Click Set to register the new
settings with the device.
Reset XYZ
Thresholds
Click Reset to enable a new
configuration.