ISL29011_14 Datasheet, PDF (8/19 Pages) Intersil Corporation – Digital Ambient Light Sensor and Proximity Sensor with Interrupt Function

ISL29011
“IR or Proximity Sensing” spectral response curve in Figure 8 is
converted into current. With ADC, the current is converted to an
unsigned n-bit (up to 16 bits) digital output. The output reading is
inversely proportional to the square of the distance between the
sensor and the object.
Interrupt Function
The active low interrupt pin is an open drain pull-down
configuration. There is also an interrupt bit in the I²C register. The
interrupt serves as an alarm or monitoring function to determine
whether the ambient light level or the proximity detection level
exceeds the upper threshold or goes below the lower threshold.
The user can also configure the persistency of the interrupt. This
reduces the possibility of false triggers, such as noise or sudden
spikes in ambient light conditions. An unexpected camera flash,
Example:
State 0: Ambient light
Operation Mode = ALS continuous
Interrupt Persist = 1
Resolution = 16 bits
Range = 1000 Lux
Scheme, Frequency & IRDR = X (DONT CARE)
Threshold High = 100 Lux
Threshold Low = 10 Lux
Command1 = 101x xx00
Command2 = xxxx 0000
Hi Threshold = 655
Lo Threshold = 66
State 1: Proximity - interrupt when NEAR
Operation Mode = Proximity continuous
Interrupt Persist = 4
Resolution = 12 bits
Range = 1
Scheme = 1
Frequency = 0
IRDR = 100mA
Threshold High =
NEAR
Threshold Low = OFF
Command1 = 111x xx01
Command2 = 1011 0100
Hi Threshold = 1535 (75% of 2047)
Lo Threshold = -2048 (OFF)
for example, can be ignored by setting the persistency to
8 integration cycles.
Changing States - Avoiding Unintentional
Interrupts
A common application for the ISL29011 is alternating between
ambient light and proximity measurements. The two states have
different command words and threshold settings. To avoid an
unintentional interrupt the device should be powered down before
the state change. The conversion should not be enabled until the
new command word and thresholds have been set. A safe sequence
is to set the operation mode to power-down, set the command word
and thresholds to the new state, then set the operation mode to
desired setting.
Sequence State 0 -> State 1
Off:
Write Byte Command1 = 0
State 1 setup:
Write Word (Command 1&2) = B401h
Write Word (Hi Threshold) = 05FFh
Write Word (Lo Threshold) = F800h
On:
Write Byte Command1 = E1h
Sequence State 1 -> State 0
Off:
Write Byte Command1 = 0
State 0 setup:
Write Word (Command 1&2) = B000h
Write Word (Hi Threshold) = 028Fh
Write Word (Lo Threshold) = 0042h
On:
Write Byte Command1 = A0h
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FIGURE 2. CHANGING STATES FLOW EXAMPLE
FN6467.6
May 1, 2014