ST VL6180X - Reference Convergence Time; Reference Signal Count; Reference Ambient Count

Other ranging outputs AN4545
10/27 DocID026571 Rev 1
3.3.2 Reference convergence time
Register RESULT__RANGE_REFERENCE_CONV_TIME {0x80} contains the time in µs it
took for the reference array to settle or converged on a target distance during the range
measurement.
Note: {0x7c} is a 32-bit register.
3.3.3 Reference signal count
Register RESULT__RANGE_REFERENCE_SIGNAL_COUNT {0x70} contains the number
of counts recorded during the convergence time
(1)
from the reference array during each
range measurement.
The following equation show the relationship between count, signal rate and convergence
time.
Note: {0x70} is a 32-bit register.
3.3.4 Reference ambient count
Register RESULT__RANGE_REFERENCE_AMB_COUNT {0x78} contains the number of
ambient counts recorded during the convergence time
(1)
from the reference array. The
ambient counter is only active for 1/6 of the convergence time, hence the count value must
be multiplied by 6.
See the following equation of how to convert the ambient count into Mcps.
Note: {0x78} is a 32-bit register
Reference Signal Rate [Mcps]
Reference Signal Count
Convergence Time [µs]
---------------------------------------------------------------=
Reference Ambient Rate [Mcps]
Reference Ambient Count 6×
Convergence Time [µs]
------------------------------------------------------------------------------=