ISL29018_14 Datasheet, PDF (11/19 Pages) Intersil Corporation – Digital Ambient Light Sensor and Proximity Sensor with Interrupt Function

ISL29018
Command Register I 00(hex)
The first command register has the following functions:
1. Operation Mode: Bits 7, 6, and 5.These three bits determines
the operation mode of the device.
TABLE 2. OPERATION MODE
BITS 7 TO 5
OPERATION
000
Power-down the device
001
ALS once
010
IR once
011
Proximity once
100
Reserved (Do not use)
101
ALS continuous
110
IR continuous
111
Proximity continuous
2. Interrupt flag; Bit 2. This is the status bit of the interrupt. The bit
is set to logic high when the interrupt thresholds have been
triggered, and logic low when not yet triggered. Once triggered,
INT pin stays low and the status bit stays high. Both interrupt
pin and the status bit are automatically cleared at the end of
Command Register I transfer.
TABLE 3. INTERRUPT FLAG
BIT 2
OPERATION
0
Interrupt is cleared or not triggered yet
1
Interrupt is triggered
3. Interrupt persist; Bits 1 and 0. The interrupt pin and the
interrupt flag is triggered/set when the data sensor reading is
out of the interrupt threshold window after m consecutive
number of integration cycles. The interrupt persist bits
determine m.
TABLE 4. INTERRUPT PERSIST
BITS 1 TO 0
NUMBER OF INTEGRATION CYCLES
00
1
01
4
10
8
11
16
Command Register II 01(hex)
The second command register has the following functions:
1. Proximity Sensing Scheme: Bit 7. This bit programs the function
of the proximity detection. Logic 0 of this bit, Scheme 0, makes
full n (4, 8, 12, 16) bits (unsigned) proximity detection. The range
of Scheme 0 proximity count is from 0 to 2ⁿ. Logic 1 of this bit,
Scheme 1, makes n-1 (3, 7, 11, 15) bits (2’s complementary)
proximity_less_ambient detection. The range of Scheme 1
proximity count is from -2^(n-1) to 2^(n-1). The sign bit is extended
for resolutions less than 16. While Scheme 0 has wider dynamic
range, Scheme 1 proximity detection is less affected by the
ambient IR noise variation.
TABLE 5. PROXIMITY SENSING SCHEME
BIT 7
OPERATION
0
Sensing IR from LED and ambient
1
Sensing IR from LED with ambient IR rejection
2. Modulation Frequency: Bits 6. This bit sets the IR LED driver’s
modulation frequency.
TABLE 6. MODULATION FREQUENCY
BITS 6
MODULATION FREQUENCY
(kHz)
0
DC
1
360
3. Amplitude of IR driver current: Bits 5 and 4. This device
provides current source to drive an external IR LED. The drive
capability can be programmed through Bits 5 and 4. For
example, the device sources 12.5mA out of the IRDR pin if
Bits 5 and 4 are 0.
TABLE 7. CURRENT SOURCE CAPABILITY AT IRDR PIN
BITS 5 TO 4
IRDR PIN SOURCE CURRENT
00
12.5mA IR LED driver
01
25mA IR LED driver
10
50mA IR LED driver
11
100mA IR LED driver
4. Resolution: Bits 3 and 2. Bits 3 and 2 determine the ADC’s
resolution and the number of clock cycles per conversion in
Internal Timing Mode. Changing the number of clock cycles
does more than just change the resolution of the device. It also
changes the integration time, which is the period the device’s
analog-to-digital (A/D) converter samples the photodiode
current signal for a measurement.
BITS 3 TO 2
00
01
10
11
TABLE 8. RESOLUTION/WIDTH
NUMBER OF CLOCK CYCLES
2¹⁶ = 65,536
2¹² = 4,096
2⁸ = 256
2⁴ = 16
n-BIT ADC
16
12
8
4
5. Range: Bits 1 and 0. The Full Scale Range (FSR) can be
adjusted via I²C using Bits 1 and 0. Table 9 lists the possible
values of FSR for the 499kΩ R_{EXT resistor.}
11
FN6619.4
October 8, 2012