User's Manual

UMXXX
• VL531L1X_CHECKENABLE_SIGMA_FINAL_RANGE: standard deviation in mm,
default is 15mm. Decrease to reduce repeatability error, but maximum ranging
distance will be reduced.
• VL53L1X_CHECKENABLE_SIGNAL_RATE_FINAL_RANGE: rate of photons
reflected by target in Mcps, default is 1Mcps. Increase to reduce repeatability error,
but maximum ranging distance will be reduced as more photons need to be
reflected back and collected by the sensor before a measurement is reported.
POWER UP AND BOOT SEQUENCE
In the BlueNRG-2 sensor node the XSHUT pin is connected to the host BlueNRG-2. XSHUT
is used used to completely power off the sensor between measurements, and wake up only
when needed. Please note that when the sensor is powered off, the configuration is lost.
The sensor must be re-configured at each wake-up. The boot duration is max 1.2ms.
For minimal power consumption, after wake-up, the application firmware may skip the
configuration step and use the default; the application may also perform an early readout,
not waiting for the data ready flag, and immediately shut down the sensors. This will reduce
power consumption but will also limit the accuracy. Min ranging distance in this case is
observed to be around 70mm.
Figure 6. BlueNRG-2 sensor node (BCN002V1) on the top is connected to its
motherboard (BCN002V1D) in the middle, which in turn is connected to a NUCLEO ST-
Link on the bottom.