TCS3771

COLOR LIGHT-TO-DIGITAL CONVERTER

with PROXIMITY SENSING

TAOS110A − MARCH 2011

13

The LUMENOLOGY

r Company

r

r

Copyright

E 2011, 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 RGBC 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 RGBC Clear data (CDATA) falls outside of the desired

light level range, as determined by the values in the RGBC interrupt low threshold registers (AILTx) and RGBC

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 low threshold value must be less than the high

threshold value for proper operation.

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 RGBC or proximity occurrences before an interrupt

is generated. The persistence register (0x0C) allows the user to set the RGBC 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

Red

Upper Limit

Upper Limit

Lower Limit

Lower Limit

Prox Persistence

PILTH(r 09), PILTL(r 08)

AIHTH(r 07), AIHTL(r 06)

RGBC Persistence

AILTH(r 05), AILTL(r 04)

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

PPERS(r 0x0C, b7:4)

APERS(r 0x0C, b3:0)

Figure 13. Programmable Interrupt