VEML6070
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Vishay Semiconductors
Rev. 1.7, 05-Dec-16
7
Document Number: 84277
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Note
(1)
Please refer to table 4, “Example of Refresh Time and R
SET
Value Relation”
Data Access
VEML6070 has 16-bit resolution to give high resolution for light intensity sensing. Examples of the application setting are shown
in table 3.
Notes
• Slave addresses (8 bits) for data read: 0x71 and 0x73
• Data reading sequence for the host:
-Set read command to 0x73, read MSB 8 bits of 16 bits light data (sequence 1)
-Set read command to 0x71, read LSB 8 bits of 16 bits light data for completing data structure (sequence 2)
Initialization
VEML6070 needs to be initialized while the system’s power is on. The initialization includes two major steps: (1) clear ACK state
of UVS and (2) fill the initial value, 06 (HEX), into the 0x70 addresses. After the initialization is completed, VEML6070 can be
programmable for operation by write command setting from the host. VEML6070 initialization is recommended to be completed
within 150 ms.
Acknowledge Activity
VEML6070 provides a function for sending an acknowledge signal (ACK) to the host when the value of sensed UV light is over
the programmed threshold (ACK_THD) value. The purpose of the ACK signal is similar to the interrupt feature which informs the
host once the sensed data level goes beyond the interrupt threshold setting. VEML6070 has two ACK threshold values,
102 steps and 145 steps.
There are two methods of driving acknowledge condition and read / write command to VEML6070:
(1) If the host implements the INT function, it performs a modified received byte operation to disengage VEML6070’s
acknowledge signal and acknowledge alert response address (ARA), 0x18 (Hex). A command format for responses to an
ARA is shown in figure 10.
Fig. 10 - Command Format for Responds to an ARA
(2) If the host does not implement this feature, it should periodically access the ARA or read ARA before setting each read /
write command.
The behavior of an ACK signal is similar to the INT definition in I
2
C specification. For the hardware circuit design, this pin
connects to an INT pin or GPIO pin of the MCU. The threshold ACK_THD definition is based on the sensitivity setting of
TABLE 2 - REGISTER TABLE SETTING
BITS SETTING DESCRIPTION BITS SETTING DESCRIPTION
Reserved Set initial value to (0 : 0) (IT1 : IT0)
(1)
(0 : 0) = ½T
(0 : 1) = 1T
(1 : 0) = 2T
(1 : 1) = 4T
ACK
0 = disable
Reserved Set initial value to 1
1 = enable
ACK_THD
0 = 102 steps
SD
0 = disable
1 = 145 steps 1 = enable
TABLE 3 - DATA ACCESS DESCRIPTION
VEML6070 16-BIT DATA BUFFER
Data bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Sequence 1
Sequence 2
S ARA (0x18) Rd A UVS Slave Address A P
