Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual page 940

Reference Manual
LESENSE - Low Energy Sensor Interface
28.3.6.2 Sliding Window
In sliding window mode, the sensor data is compared against the upper and lower limits of a window range. The window is defined by a
base, given by CHx_EVAL_COMPTHRES, and a size configured in EVALCTRL_WINSIZE. The window size is constant and the same
for all LESENSE channels, while the base is specific to each channel and will be updated by LESENSE when the sensor data is outside
the current window range. If the sensor data is within the window range, the sensor evaluation will remain the same as it was for the
previous measurement. If the sensor data is below the window range, the measurement will be evaluated to false. If the sensor data is
above the window range, the measurement will be evaluated to true. In both cases, the window base in CHx_EVAL_COMPTHRES will
be updated to reflect the new window range. Figure 28.8 Sliding Window on page 940 shows how the sliding window evaluation mode
can be used to implement a system with two self calibrating thresholds.
Sensor data
SCANRES
Figure 28.8. Sliding Window
28.3.6.3 Step Detection
Step detection is used to detect steps in the sensor data compared to sensor data from the previous measurement. The size of the step
is configured in EVALCTRL_WINSIZE. In this mode, step up and step down are evaluated as described in Figure 28.9 Step Detection
on page 940:
STEP_UP = SENSORDATA >= SENSORDATA + EVALCTRL_WINSIZE
i i-1
STEP_DOWN = SENSORDATA < SENSORDATA - EVALCTRL_WINSIZE
i i-1
Figure 28.9. Step Detection
If either a step up or a step down is detected, the SCANRES bit for the active channel will be set. In addition, the STEPDIR bit for the
channel will be updated to indicate if a step up or a step down was detected. STEPDIR = 1 indicates a step up. In this mode, previous
sensor data is stored in CHx_EVAL_COMPTHRES.
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