VEML7700 Datasheet, PDF (4/12 Pages) Vishay Siliconix – High Accuracy Ambient Light Sensor with IC Interface

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VEML7700
Vishay Semiconductors
APPLICATION INFORMATION
VEML7700 is a cost effective solution of ambient light sensor with I²C bus interface. The standard serial digital interface is easy
to access “Ambient Light Signal” without complex calculation and programming by external controller.
1. Application Circuit
2.5 V to 3.6 V ^R3
10R
C1 C2
10 μF
100 nF
1.7 V to 3.6 V
R1
R2
V_DD (2)
C1 and R3
are optional
for very
disturbed
supply
VEML7700
SDA (4)
SCL (1)
GND (3)
Host
Micro Controller
I²C bus sata SDA
I²C bus clock SCL
Fig. 6 - Application Diagram
Notes
• Proposed values for the pull-up resistor R1 and R2 should be > 1 kΩ, e.g. 2.2 kΩ to 4.7 kΩ.
For detailed description about set-up and use as well as more application related information see AN: “Designing VEML7700 into an
Application”.
2. I²C Interface
The VEML7700 contains actual six 16 bit command codes for operation control, parameter setup, and result buffering. All
registers are accessible via I²C communication. Figure 7 shows the basic I²C communication with VEML7700.
The built in I²C interface is compatible with I²C modes “standard” and “fast”: 10 kHz to 400 kHz.
I²C H-level range = 1.3 V to 3.6 V.
Please refer to the I²C specification from NXP for details.
Send byte
Write command to VEML7700
S
Slave address
Wr A Command code
A
Data byte (LSB)
A
Data byte (MSB) A P
Receive byte
Read data from VEML7700
S
Slave address
Wr A Command code
AS
Slave address
Rd A
Data byte (LSB)
A
Data byte (MSB) N P
S = start condition
P = stop condition
A = acknowledge
N = no acknowledge
Host action
VEML7700 response
Fig. 7 - Send Byte / Receive Byte Protocol
Register Addresses
VEML7700 has actual six user accessible 16 bit command
codes.
The addresses are 00h to 06h (03h not defined / reserved).
Device Address
The VEML7700 has a fix slave address for the host
programming and accessing selection.
The slave address (7 bit) is set to 0010000 = 0x10.
The least significant bit (LSB) defines read or write mode.
According 8 bit the bus address is then 0010 0000 = 20h for
write and 0010 0001 = 21h for read.
Auto-Memorization
VEML7700 can memorize the last ambient data before
shutdown and keep this data before waking up.
When VEML7700 is in shutdown mode, the host can freely
read this data via read command directly.
When VEML7700 wakes up, the data will be refreshed by
new detection.
Rev. 1.0, 19-Nov-15
4
Document Number: 84286
For technical questions, contact: [e-mail]
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ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000