VD6283TX datasheet(6/59 Pages) STMICROELECTRONICS

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System description

3.1

Functional description

The figure below shows the system level functional description. The host customer application controls the

VD6283 device using a software (SW) driver API (application programming interface).

This software driver provides a set of high-level functions that allow the user to control the VD6283 without

worrying about I2C register control. Such control includes: start/stop ALS sensing, color channel selection,

activate AC flicker sensing and/or ALS sensing, set the exposure time or set the analog gain. This helps customer

evaluation, software development, and prototype building.

Figure 5. System functional description

driver

Customer

Application

VD6283

Driver/API

VD6283

DIGITAL &

I2C regs

I2C

3.2

Sensing operation

The color channels can be individually enabled to optimize power consumption through the I2C (or SW API):

•

Up to 6 ALS channels can be read in parallel (ALS mode): red, visible, blue, green, IR, and clear channels

can be enabled individually.

•

Up to 5 ALS channels can be read in parallel, together with 1 flicker channel (ALS and Flicker mode). The

RGB - IR- visible channels can be sensed in ALS mode while AC flicker mode is configured with the clear

channel. Note that in this configuration, the selected channel routed to the AC light flicker module (i.e. clear)

cannot provide an ALS value at the same time.

Exposure time (EXTIME) is defined by the user and is identical for all channels in ALS operation. EXTIME can

be set from 1.6 ms up to 1.6 s. After each EXTIME duration, a fixed period of time of ~6 ms takes place to allow

counts to be converted into digital information. This housekeeping time must be considered in the overall ALS

speed framerate.

Individual analog gain (AGAIN) can be applied by the user for each channel, including the channel routed to the

AC light flicker module.

3.3

Operating modes

The VD6283 can stream the following data continuously: ALS color data over the I2C and raw flicker data over

the GPIO2 ball. Streaming starts when the host microcontroller sends a “start/stop” command. Then, the N-1 data

measurements are automatically overwritten in the I2C registers with the latest N measurement batch.

The user can set an intermeasurement period through the software driver. This goes from 0 to 5.1 seconds, in

steps of 20 ms (256 steps). This can be useful to reduce sensing frame rate and power consumption, without

having the master microcontroller host awake during the inter measurement period.

ALS and flicker sensing are totally independent and can be activated/stopped individually.

The VD6283 can also work in a "continuous gated” way. Once measurement N is finished, the VD6283 waits

for the microcontroller handshake to carry on to measurement N+1. I2C data are not refreshed until the next

acknowledgment, whilst the PDM data are still streaming over the GPIO2 ball. The handshake mechanism is

performed via I2C polling.

VD6283TX

System description

DS13735 - Rev 1

page 6/59

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