VCNL4020C

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Vishay Semiconductors

Rev. 1.1, 20-Mar-18

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Document Number: 84350

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Example: read register “Ambient Light Result Register” #5 and #6:

Addressing:command: 26h, 85h (VCNL4020C_I2C_Bus_Write_Adr., Ambient Light Result Register #5 [85])

Read register #5:command: 27h, data (VCNL4020C_I2C_Bus_Read_Adr., {High Byte Data of Ambient Light Result register #5

[85])}

Read register #6:command: 27h, data (VCNL4020C_I2C_Bus_Read_Adr., {Low Byte Data of Ambient Light Result register #6

[86])}

3.3 Continuous Conversion Mode in Ambient Light Measurement

In the following is a detail description of the function “continuous conversion” (bit 7 of register #4)

Standard mode (bit 7 of reg #4 = 0):

In standard mode the ambient light measurement is done during a fixed time frame of 100 ms. The single measurement itself

takes actually only appr. 300 μs.

The following figures show examples of this measurement timing in standard mode using averaging function 2 and 8 as

examples for illustration (possible values up to 128).

Fig. 15 - Ambient Light Measurement with Averaging = 2;

Final Measurement Result = Average of these 2 Measurements

Fig. 16 - Ambient Light Measurement with Averaging = 8;

Final Measurement Result = Average of these 8 Measurements

Note

•

≥ Independent of setting of averaging the result is available only after 100 ms.

Continuous conversion mode (bit 7 of register #4 = 1):

In continuous conversion mode the single measurements are done directly subsequent after each other.

See following examples in figure 17 and 18

Fig. 17 - Ambient Light Measurement with Averaging = 2;

using Continuous Conversion Mode

Fig. 18 - Ambient Light Measurement with Averaging = 8;

using Continuous Conversion Mode

50 ms

100 ms

Start

22315

12.5 ms

Start

100 ms

22316

460 μs

Start

1.5 ms

22317

460 μs

Start

4.2 ms

22318