TSL2561 datasheet(23/37 Pages) OSRAM

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ams Datasheet

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[v1-01] 2018-Apr-23

TSL2561 − Device Operation

Basic Operation

After applying VDD, the device will initially be in the

power-down state. To operate the device, issue a command to

access the Control Register followed by the data value 03h to

power up the device. At this point, both ADC channels will begin

a conversion at the default integration time of 400ms. After

400ms, the conversion results will be available in the DATA0 and

DATA1 registers.

Configuring the Timing Register

The command, timing, and control registers are initialized to

default values on power up. Setting these registers to the

desired values would be part of a normal initialization or setup

procedure. In addition, to maximize the performance of the

device under various conditions, the integration time and gain

may be changed often during operation.

Interrupts

The interrupt feature of the TSL2561 device simplifies and

improves system efficiency by eliminating the need to poll the

sensor for a light intensity value. Interrupt styles are

determined by the INTR field in the Interrupt Register. The

interrupt feature may be disabled by writing a field value of 00h

to the Interrupt Control Register so that polling can be

performed.

The versatility of the interrupt feature provides many options

for interrupt configuration and usage. The primary purpose of

the interrupt function is to provide a meaningful change in light

intensity. However, it also be used as an end-of-conversion

signal. The concept of a meaningful change can be defined by

the user both in terms of light intensity and time, or persistence,

of that change in intensity. The TSL2561 device implements two

16-bit-wide interrupt threshold registers that allow the user to

define a threshold above and below the current light level. An

interrupt will then be generated when the value of a conversion

exceeds either of these limits. For simplicity of programming,

the threshold comparison is accomplished only with Channel

0. This simplifies calculation of thresholds that are based, for

example, on a percent of the current light level. It is adequate

to use only one channel when calculating light intensity

differences since, for a given light source, the channel 0 and

channel 1 values are linearly proportional to each other and

thus both values scale linearly with light intensity.

To further control when an interrupt occurs, the TSL2561 device

provides an interrupt persistence feature. This feature allows

the user to specify a number of conversion cycles for which a

light intensity exceeding either interrupt threshold must persist

before actually generating an interrupt. This can be used to

Device Operation

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