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2.1.5.1
ALS Controls
The top left corner of the ALS tab contains two controls; one to set the ALS integration time and
another to control the ALS gain.
The ITIME control sets the time of the ALS integration. ITIME can be adjusted in 2.72ms steps. This
register functions as a count-down value so ITIME=255 is the minimum integration time (2.72ms)
and ITIME=1 is the maximum integration time (693.6ms). Note that ITIME=0 is a special manual
mode which uses specific I2C commands to start and stop the integration cycle. Because of the
high timing accuracy required to execute in this mode, it cannot be supported in the AOS_EVM
software. The actual integration time, in milliseconds, is displayed next to this control. If 0 is
selected, the time display will be shown as “Manual Mode”.
The Gain control is a pulldown menu which lets you select the analog gain of the device. The
values that can be chosen are 1x, 8x, 16x, and 111x.
2.1.5.2
Interrupt Controls
The lower left corner of the ALS tab contains controls for the interrupt functionality of the device.
The ADC_INTR signal can be triggered when the CH0 data values are higher than a programmed
low threshold or higher than a programmed high threshold.
The Enable checkbox is checked to enable the ADC_INTR signal. Checking this box, allows the
interrupt signal to be generated.
The ADC_INTR indicator indicates whether the interrupt is active. When the interrupt is NOT
active, this will display an empty box. When the interrupt is active, this box will be marked. Clicking
on this box will clear the interrupt signal. (Note, depending on the remaining register settings the
interrupt may be raised again immediately.)
The Low and High controls allow you to set thresholds for the CH0 data value. If the CH0 value is
less than the low threshold or more than the high threshold for more times that specified in the
persistence register, the interrupt will be activated.
The Pers control sets the persistence value. It controls how many consecutive times that a
threshold must be exceeded before the interrupt is raised. A setting of 0 for this register will cause
the interrupt to be raised after every ALS cycle, regardless of the threshold settings. Setting this
value from 1 through 15 requires that the threshold must be exceeded for 1 to 15 consecutive
cycles before the interrupt is raised.
Checking the Stop On Interrupt checkbox causes the device to stop processing ALS data
whenever the interrupt is raised. To continue processing ALS data, the interrupt must be cleared
either by clicking on the ADC_INTR indicator or by disabling and enabling the interrupt.
2.1.5.3
ALS Output Data
The top right corner of the ALS tab displays the data which is output by the device.
CH0 displays the raw Channel 0 ADC count.
CH1 displays the raw Channel 1 count.
Ratio displays the ratio of CH1 to CH0.
Lux displays the calculated lux value which is a function of CH0, CH1, ITIME, and Gain.
