ALS-PDIC17-57B-TR8 Datasheet, PDF (8/19 Pages) Everlight Electronics Co., Ltd – Surface - Mount I2C Digital Ambient Light Sensor

Surface - Mount
I²C Digital Ambient Light Sensor
ALS-PDIC17-57B/TR8
Communication Protocol
ALS-PDIC17-57B 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 0101001 (0x29, MSB to LSB, A6 to A0). All the
Send Byte protocol, the Receive Byte protocol and Receive Word protocol are implemented in
ALS-PDIC17-57B.
The Send Byte protocol allows single bytes of data to be written to the device (see Figure
13-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 13-b). Two-byte data can be read by
following the Receive Word Protocol shown in Figure 13-c. In Figure 13, the clear area
represents data sent by the host (master) and the shaded area represents data returned by the
ambient light sensor (slave device).
17
1 18
11
S Slave Address WR A Command Byte A P
00
0
(a) Send byte protocol
17
1
S Slave Address RD
1
(b) Receive byte protocol
18
A Data
0
11
NA P
1
17
1 18
18
11
S Slave Address RD A LS byte of ADC A MS byte of ADC NA P
10
0
1
(c) Receive word (two bytes) protocol
S = start condition P = stop condition
Shaded = slave transmission
A = acknowledge NA = not acknowledge
WR = write RD= read
Figure 13 Communication Protocol
Everlight Electronics Co., Ltd.
Document No: DLS-00000xx Rev0.1
8
http://www.everlight.com
Jun. 22, 2011