ST VL53L3CX - Additional Driver Functions Description; Timing Budget; Distance Mode; Tuning Parameters

5 Additional driver functions description
5.1 Timing budget
Timing budget is the time allocated by the user to perform one range measurement.
VL53LX_SetMeasurementTimingBudgetMicroSeconds() is the function to be used to set the timing budget.
The default timing budget value is 33 ms. Minimum is 8 ms, maximum is 500 ms.
For example, to set the timing budget to 66 ms:
status = VL53LX_SetMeasurementTimingBudgetMicroSeconds(&VL53L3Dev, 66000 );
The function VL53LX_GetMeasurementTimingBudgetMicroSeconds() allows to get the programmed timing
budget.
5.2 Distance mode
A function has been added to optimize the internal settings depending on the ranging distance requested by user.
The benefit of changing the distance mode is detailed in the following table.
Table 2. Distance modes
Possible distance mode Benefit / comments
Short Better ambient immunity
Medium (Default) Maximum distance
Long Lower power consumption
The function to use is called VL53LX_SetDistanceMode().
The driver can help the host to select the optimum distance mode. A specific value is returned at each ranging to
indicate the best choice, depending on the ambient conditions.
Possible values are:
• VL53LX_DISTANCE_SHORT
• VL53LX_DISTANCE_MEDIUM
• VL53LX_DISTANCE_LONG
5.3 Tuning parameters
Tuning parameters allow to find the best fit between the sensor and the host use case. For each use case, a set
of tuning parameters can be defined and loaded in the driver.
Most of the tuning parameters are tunable thresholds, used in the signal treatment algorithm. Modifying these
parameters allows the algorithm to make technical trade offs to the specific customer use case.
5.3.1 Set a tuning parameter
An extra function exists to load tuning parameters. For specific use cases, ST can recommend some specific
parameters composed of a key and a value.
The list of tuning parameters and their default values is given in the vl53lx_tuning_parm_defaults.h file. Either
change a tuning parameter value in this file and recompile the code, or use the VL53LX_SetTuningParameter()
function to load this tuning parameter.
Changing a tuning parameter can modify the device performances. ST recommends to use the default values for
optimal results.
UM2778
Additional driver functions description
UM2778 - Rev 1
page 12/25