TCS3772

COLOR LIGHT-TO-DIGITAL CONVERTER

with PROXIMITY SENSING

TAOS145B − SEPTEMBER 2012

13

The LUMENOLOGY

r Company

r

r

Copyright

E 2012, TAOS Inc.

www.taosinc.com

Interrupts

The interrupt feature simplifies and improves system efficiency by eliminating the need to poll the sensor for

light intensity or proximity values outside of a user-defined range. While the interrupt function is always enabled

and it’s status is available in the status register (0x13), the output of the interrupt state can be enabled using

the proximity interrupt enable (PIEN) or Clear interrupt enable (AIEN) fields in the enable register (0x00).

Four 16-bit interrupt threshold registers allow the user to set limits below and above a desired light level and

proximity range. An interrupt can be generated when the Clear data (CDATA) is less than the Clear interrupt

low threshold registers (AILTx) or greater than the Clear interrupt high threshold registers (AIHTx). Likewise,

an out-of-range proximity interrupt can be generated when the proximity data (PDATA) falls below the proximity

interrupt low threshold (PILTx) or exceeds the proximity interrupt high threshold (PIHTx).

It is important to note that the thresholds are evaluated in sequence, first the low threshold, then the high

threshold. As a result, if the low threshold is set above the high threshold, the high threshold is ignored and only

the low threshold is evaluated.

To further control when an interrupt occurs, the device provides a persistence filter. The persistence filter allows

the user to specify the number of consecutive out-of-range Clear or proximity occurrences before an interrupt

is generated. The persistence register (0x0C) allows the user to set the Clear persistence (APERS) and the

proximity persistence (PPERS) values. See the persistence register for details on the persistence filter values.

Once the persistence filter generates an interrupt, it will continue until a special function interrupt clear command

is received (see command register).

Prox

ADC

Prox

Data

Clear

ADC

Clear

Data

Prox

Integration

Clear

Upper Limit

Upper Limit

Lower Limit

Lower Limit

Prox Persistence

PILTH(r 0x09), PILTL(r0x 08)

AIHTH(r0x 07), AIHTL(r0x 06)

Clear Persistence

AILTH(r 0x05), AILTL(r0x 04)

PIHTH(r 0x0B), PIHTL(r 0x0A)

PPERS(r 0x0C, b7:4)

APERS(r 0x0C, b3:0)

Figure 13. Programmable Interrupt