ISL29015 데이터 시트보기 (PDF) - Renesas Electronics
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ISL29015 Datasheet PDF : 13 Pages
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ISL29015
ISL29015
programmed in series to fulfill the application needs. The detailed
program configuration is listed in “Register Set” on page 6.
When the part is programmed for ambient light sensing, the
ambient light with wavelength within the “Ambient Light
Sensing” spectral response curve in Figure 6 is converted into
current. With ADC, the current is converted to an unsigned n-
bit (up to 16 bits) digital output.
When the part is programmed for infrared (IR) sensing, the IR
light with wavelength within the “IR or Proximity Sensing”
spectral response curve on Figure 6 is converted into current.
With ADC, the current is converted to an unsigned n-bit (up to
16 bits) digital output.
When the part is programmed for proximity sensing, the
external IR LED is turned on by the built-in IR LED driver
through the IRDR pin. The amplitude of the IR LED current and
the IR LED modulation frequency can be programmed through
Command Register II. When the IR from the LED reaches an
object and gets reflected back, the reflected IR light with
wavelength within the “IR or Proximity Sensing” spectral
response curve in Figure 6 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. When there is significant background IR noise like
direct sunlight, both IR and proximity sensing can be
implemented for background noise cancellation. The
differential output reading from the ADC decreases with
distance.
I2C Interface
There are four 8-bit registers available inside the ISL29015. The
two command registers define the operation of the device. The
command registers do not change until the registers are
overwritten. The two 8-bit data Read Only registers are for the
ADC output. The data registers contain the ADC's latest digital
output, or the number of clock cycles in the previous integration
period.
The ISL29015’s I2C interface slave address is internally
hardwired as 1000100. When 1000100x with x as R or W is sent
after the Start condition, this device compares the first seven bits
of this byte to its address and matches.
Figure 1 shows a sample one-byte read. Figure 2 shows a
sample one-byte write. The I2C bus master always drives the
SCL (clock) line, while either the master or the slave can drive
the SDA (data) line. Figure 2 shows a sample write. Every I2C
transaction begins with the master asserting a start condition
(SDA falling while SCL remains high). The following byte is
driven by the master, and includes the slave address and
read/write bit. The receiving device is responsible for pulling
SDA low during the acknowledgement period. Every I2C
transaction ends with the master asserting a stop condition
(SDA rising while SCL remains high).
For more information about the I2C standard, please consult
the Philips™ I2C specification documents.
I2C DATA START
DEVICE ADDRESS W A REGISTER ADDRESS
STOP START DEVICE ADDRESS
A
DATA BYTE0
I2C SDA
IN
I2C SDA
OUT
A6 A5 A4 A3 A2 A1 A0 W A R7 R6 R5 R4 R3 R2 R1 R0 A
SDA DRIVEN BY MASTER
A SDA DRIVEN BY MASTER A
A6 A5 A4 A3 A2 A1 A0 W A
SDA DRIVEN BY ISL29015
SDA DRIVEN BY MASTER
A D7 D6 D5 D4 D3 D2 D1 D0
I2C CLK
12 3456 789123456 789
123 45 67 89123456789
FIGURE 1. I2C READ TIMING DIAGRAM SAMPLE
FN6522 Rev 0.00
October 31, 2008
Page 5 of 13
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