ALS-PDIC17-79NB-TR8 Datasheet, PDF (8/21 Pages) Everlight Electronics Co., Ltd – I2 Digital Ambient Light Sensor

Surface - Mount
I²C Digital Ambient Light Sensor
ALS-PDIC17-79NB/TR8
Communication Protocol
ALS-PDIC17-79NB contains an 8-bit command register that can be written and read via the I²C bus.
The command register controls the overall operation of the device. There is a two-byte word read-only register
that contains the latest converted value of A/D converter. The I²C slave address is hardwired internally as
0111001 (0x39, MSB to LSB, A6 to A0). All the Send Byte protocol, the Receive Byte protocol and Receive
Word protocol are implemented in ALS-PDIC17-79NB.
The Send Byte protocol allows single bytes of data to be written to the device (see Figure 11-a). The
written byte is called the COMMAND byte. The Receive Byte protocol allows one-byte data to be read from the
device (see Figure 11-b). Two-byte data can be read by following the Receive Word Protocol shown in Figure
11-c. In Figure 11, the clear area represents data sent by the host (master) and the shaded area represents
data returned by the ambient light sensor (slave device).
1
7
11
8
11
S Slave Address WR A Command Byte A P
00
0
(a) send byte protocol
1
7
S Slave Address
(b) Receive byte protocol
11
RD A
10
8
Data
11
NA P
1
1
7
11
8
1
S Slave Address RD A LS byte of ADC A
10
0
(c) Receive word (two bytes) protocol
8
MS byte of ADC
S = start condition P = stop condition
Shaded = slave transmission
A = acknowledge
NA = not acknowledge
WR = write RD= read
Figure 11. Communication Protocol
11
NA P
1
Everlight Electronics Co., Ltd.
Document No: DLS-xxxxxxx Rev1
8
http://www.everlight.com
Oct. 12, 2010