isl29028a Intersil Corporation, isl29028a Datasheet - Page 8

• Manufacturer Part Number: isl29028a
• Description: Low Power Ambient Light And Proximity Sensor With Intelligent Interrupt And Sleep Modes
• Manufacturer: Intersil Corporation

Principles of Operation
I
The ISL29028A’s I
as 0b100010<x>, where “0b” signifies binary notation and x
represents the logic level on pin ADDR0.
Figure 2 shows a sample one-byte read. The I
always drives the SCL (clock) line, while either the master or the
slave can drive the SDA (data) line. Every I
with the master asserting a start condition (SDA falling while SCL
remains high). The first transmitted byte is initiated by the
master and includes 7 address bits and a R/W bit. The slave is
responsible for pulling SDA low during the ACK bit after every
transmitted byte.
Each I
condition (SDA rising while SCL remains high).
For more information about the I
Philips™ I
I
SLAVE
2
I
I
MASTER
I
2
2
2
2
C SDA
C DATA
C SDA
C CLK
C Interface
BIT #
BIT #
BIT #
BIT #
7:0
7:4
3:0
7:0
7:0
2
(ISL29028A)
C transaction ends with the master asserting a stop
2
START
C specification documents.
ACCESS
ACCESS
ACCESS
ACCESS
2
RW
RW
A6 A5 A4 A3 A2 A1 A0 W A R7 R6 R5 R4 R3 R2 R1 R0 A
RO
RO
RO
1
C interface slave address is internally hardwired
SDA DRIVEN BY MASTER
FIGURE 2. I
DEVICE ADDRESS
2
3
4
DEFAULT
DEFAULT
DEFAULT
DEFAULT
0x00
0x00
0x00
0x00
0x00
5
8
TABLE 11. REGISTER 0x09 (ALSIR_DT1) - ALS/IR SENSOR DATA (LOWER 8 BITS)
TABLE 12. REGISTER 0x0A (ALSIR_DT2) - ALS/IR SENSOR DATA (UPPER 4 BITS)
2
2
6
C DRIVER TIMING DIAGRAM FOR MASTER AND SLAVE CONNECTED TO COMMON BUS
C standard, please consult the
7
W A
8
A
9
2
C transaction begins
(Write as 0x00)
(Write as 0x00)
(ALS/IR Data)
(ALS/IR Data)
1
ALSIR_DATA
ALSIR_DATA
TABLE 14. REGISTER 0x0F (TEST2) - TEST MODE 2
2
TABLE 13. REGISTER 0x0E (TEST1) - TEST MODE
BIT NAME
BIT NAME
BIT NAME
BIT NAME
REGISTER ADDRESS
(Unused)
C bus master
SDA DRIVEN BY MASTER
2
3
4
5
ISL29028A
6
Lower 8 bits (of 12 bits) from result of ALS/IR sensor conversion
Unused bits
Upper 4 bits (of 12 bits) from result of ALS/IR sensor conversion
Test mode register. When 0x00, in normal operation
Test mode register. When 0x00, in normal operation
7
8
9
A
STOP START
Photodiodes and ADCs
The ISL29028A contains two photodiode arrays which convert
photons (light) into current. The ALS photodiodes are constructed to
mimic the human eye’s wavelength response curve to visible light
(see Figure 6). The ALS photodiodes’ current output is digitized by a
12-bit ADC in 100ms. These 12 bits can be accessed by reading
from I
completed.
The ALS converter is a charge-balancing integrating 12-bit ADC.
Charge-balancing is best for converting small current signals in the
presence of periodic AC noise. Integrating over 100ms highly rejects
both 50Hz and 60Hz light flicker by picking the lowest integer
number of cycles for both 50Hz/60Hz frequencies.
2
SDA DRIVEN BY MASTER
C registers 0x9 and 0xA when the ADC conversion is
A6 A5 A4 A3 A2 A1 A0 W A
1
2
DEVICE ADDRESS
3
FUNCTION/OPERATION
FUNCTION/OPERATION
FUNCTION/OPERATION
FUNCTION/OPERATION
4
5
6
7
8
A
A D7 D6 D5 D4 D3 D2 D1 D0
9
1
2
SDA DRIVEN BY ISL29028A
3
DATA BYTE0
4
5
6
March 24, 2011
7
8
FN7721.2
9