User manual
Xact Application User Manual
Xact Application User Manual Page 14
alert operates independently; if the MSB is 1, the motion alert operates with geo-
fences.
Accelerometer
The following three fields govern the GPS module specifically when it turns on
or off under the presence of acceleration. These settings are available to optimize
device power consumption, because GPS is the most power-hungry module on
the device.
Wake Threshold
A scalar motion threshold is set in this field and this represents a motion
threshold, when the detected motion level is exceeded (crosses the numeric
threshold, the GPS chip set is enabled. An internal algorithm generates this
accelerometer scalar motion level
root is taken of the resultant motion levels.
If sent directly to the device, the value is a hexadecimal ASCII number from 0x00
to 0xFF.
To learn more about acceleration thresholds, please consult the MMA7455L Data
Sheet, available from Freescale Semiconductor.
Example: .
Only values above 0x16 are legal.
Wake Duration
This is a value between o and 65535 that defines the duration in milliseconds
during which the acceleration must be present to trigger before waking the
GPS.
If sent directly to the device, the value is a hexadecimal ASCII number from
0x0000 to 0xFFFF.
Example: .
Sleep Duration
This is a value which defines GPS ON time-to-live. 3D Search time where the
GPS chip set is fully powered and searching the sky for four satellites minimum
-
between o and 65535 that defines the duration in seconds during which no
motion is to be detected before the GPS is back to sleep (slow-idle) mode.
If sent directly to the device, the value is a hexadecimal ASCII number from
0x0000 to 0xFFFF.
Example: seconds or 3 minutes.