EVAL-ADP5588
Rev. 0 | Page 11 of 20
081
02-
026
Figure 25. Light Sensors Configuration
Light Sensor Comparator Trip Reference Programming
The ADP5588 is equipped to support two light sensor comparator
inputs. Both light sensors (D12 and D13) are mounted on the
motherboard (see the layout for the light sensor location in
Figure 32).
Use the
Light-Sensors
tab to program the light sensors and
comparator parameters. Column 8 and Column 9 are used as
the light sensor comparator inputs. When Column 8 and
Column 9 are programmed as light sensor comparator inputs,
LK1 and LK2 should be placed on the daughterboard. LK1
and LK2 connect C19 and C20 to the comparator inputs; these
capacitors are needed for the light sensor comparator operation
and should be placed only if Column 8 and/or Column 9 is
configured as a light sensor input.
To program Column 8 and Column 9 as light sensor inputs
1. Clear Bit 0 and Bit 1 in Register 0x1F.
2. Set Bit 0 and/or Bit 1 in Register 0x30 to enable
Comparator 1 and/or Comparator 2.
3. Set Bit 2 and/or Bit 3 of Register 0x30 to enable interrupt
for the comparators, if needed.
4. Set Bit 0 and Bit 1 of Register 0x31 and Register 0x32 to
enable the comparator trip points.
Use Register 0x33 through Register 0x3A to set individual
comparator trip references and hysteresis.
Trip point values are expressed in μA or lux. Ensure that the
right values are picked for the correct lighting environment; the
comparator does not trip if the values are not within the brightness
range of the lighting environment.
Use the filter time to increase the number of photo sensor readings
necessary to trip from one lighting environment to another.
The filter time register is programmable from 80 ms minimum
to 10.24 sec (see the
data sheet for more details on
sensor operation).
Comparator
L3 OUT
and Comparator
L2 OUT
are used in
conjunction with the force read bits in Register 0x31 and
Register 0x32 to determine the photo sensor readings during
a force read.
