SG-7100 - Hardware Guide
© SkyWave Proprietary 27 T300, Version 01
The accelerometer thresholds to detect motion vary depending on the environment. In
order to avoid false motion detects, extensive testing is required to ensure that adequate
acceleration magnitude thresholds and time durations are used.
Parameter
Condition
Min
Typ
Max
Units
Resolution
2 g
-
3.91
-
mg
Acceleration Range
software selectable
-
±2
-
g
-
±4
-
g
-
±8
-
g
-
±16
-
g
Bandwidth Filtering
Selectable via digital interface
8
-
1000
Hz
Sensitivity
2 g
-
256
-
LSB/g
4 g
-
128
-
LSB/g
8 g
-
64
-
LSB/g
16 g
-
32
-
LSB/g
Sensitivity
Temperature Drift
3V supply
-
±0.02
-
%/K
Zero-g Offset
Ta = 25°C
-
±80
-
mg
Zero-g Offset
Temperature Drift
3V supply
-
±1
-
mg/K
Wake up time
From low power or suspend
modes
-
0.8
-
mS
Start Up Time
Power-on reset
-
2
-
mS
2.14.1.1
Accelerometer Operating Modes
The accelerometer hardware can be in one of three possible modes. The accelerometer
switches between these modes without any explicit control by the user.
Table 20
Accelerometer Power Modes
Operating Mode
Description
Suspended Mode
Suspended mode is the default mode when the accelerometer
hardware has nothing to do and no data acquisition is taking place.
All event detection is disabled and it consumes the least amount of
current. Suspended mode is automatically entered when no event
detectors are enabled and no sample capturing is taking place.
Low Power Mode
In low power mode, the accelerometer is periodically switching
between a sleep phase and a wake-up phase to conserve power. The
sleep phase is controlled by the sleepDuration property (PIN 3)
To enable low power mode, the sleep duration must be set to a non-
zero value. The accelerometer API uses low-power mode unless
sample capture is enabled.
NOTE: Low power mode adds up to sleepDuration milli-seconds to
event detection timing and sample acquisition.
Active Mode
In active mode (normal mode), the accelerometer hardware is fully
powered up and performing continuous data acquisition at the
