4.5 Ranging data structures
The structure named VL53LX_MultiRangingData_t contains the following data applicable to all targets detected:
• TimeStamp: not implemented.
• StreamCount: this 8-bit integer gives a counter incremented at each range. The value starts at 0,
incrementing 1 by 1 up to 255. When it reaches 255, it starts again from 128 to 255.
• NumberOfObjectsFound: 8 bit integer value that gives the number of objects found.
• RangeData[VL53LX_MAX_RANGE_RESULTS]: a table of structure of type VL53LX_TargetRangeData_t.
The maximum number of targets is given by VL53LX_MAX_RANGE_RESULTS, and is by default equal to 4.
• HasXtalkValueChanged: 8 bit integer value that indicates if the crosstalk value has been changed.
• EffectiveSpadRtnCount: 16 bit integer that returns the effective Single photon avalanche diode (SPAD) count
for the current ranging. To obtain real value it should be divided by 256.
One structure per target detected (up to 4 by default) called VL53LX_TargetRangeData_t which contains the
following specific results for each target detected.
• RangeMaxMilliMeter: is a 16 bit integer, indicating the larger detected distance.
• RangeMinMilliMeter: is a 16 bit integer, indicating the smaller detected distance.
• SignalRateRtnMegaCps: this value is the return signal rate in MegaCountPer Second (MCPS), this is a
16.16 fix point value. To obtain the real value it should be divided by 65536.
• AmbientRateRtnMegaCps: this value is the return ambient rate (in MCPS), this is a 16.16 fix point value,
which is effectively a measure of the amount of ambient light measured by the sensor. To obtain the real
value it should be divided by 65536.
• SigmaMilliMeter: this 16.16 fix point value is an estimation of the standard deviation of the current ranging,
expressed in millimeter. To obtain the real value it should be divided by 65536.
• RangeMilliMeter: is a 16 bit integer indicating the range distance in millimeter.
• RangeStatus: this is a 8 bit integer indicating the range Status for the current measurement. Value = 0
means ranging is valid. See Table 1. Range Status.
• ExtendedRange: this is a 8 bit integer indicating if the range has been unwrapped (only for long distances)
A particular behavior is implemented when the target is not detected. If the target is not detected, and the
measurement is valid, the following values are reported in the VL53LX_TargetRangeData_t structure:
• RangeMaxMilliMeter: forced to 8191.
• RangeMinMilliMeter: forced to 8191.
• SignalRateRtnMegaCps: forced to 0.
• AmbientRateRtnMegaCps: the ambient rate value is normally computed.
• SigmaMilliMeter: forced to 0.
• RangeMilliMeter: forced to 8191.
• RangeStatus: forced to 255.
• ExtendedRange: forced to 0.
UM2778
Ranging data structures
UM2778 - Rev 1
page 10/25
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