BH1710FVC

Technical Note

11/15

www.rohm.com

2009.06 - Rev.A

© 2009 ROHM Co., Ltd. All rights reserved.

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Adjust measurement result for influence of optical window.

BH1710FVC is including in adjust measurement result function for influence of optical window. Adjust is done by changing

measurement time. For example, if transmission rate by optical window is 1 / N, then adjust is done by measurement time is

set to "initial value * N".

Measurement time register (Mtreg) is 10bit register. Initial value is "01_0010_1100" (12Cxh). Please change this register

value via to I

ex) Case of transmission rate is 50%.

Please change Mtreg value from "01_0010_1100" to "10_0101_1000".

1)Changing High bit of Mtreg

ST

Slave Address

R/W

0

Ack

010_10010

Ack

SP

2)Changing Low bit of Mtreg

ST

Slave Address

R/W

0

Ack

011_11000

Ack

SP

3)Input Measurement Command.

※

This example is High Resolution mode, but it accepts the other measurement.

ST

Slave Address

R/W

0

Ack

0001_0000

Ack

SP

4)After about 240ms, measurement result is registered to Data Register. (High Resolution mode is typically 120ms, but

measurement time is set twice.)

Supported Mtreg value is seeing below.

Parameter

Min.

Typ.

Max

Supported value (hex)

00110_00100

(transmission rate 153%)

01001_01100

(transmission rate 100%)

11111_11110

(transmission rate 29.4%)

For example BH1710FVC is possible to detect min. 0.35 lx when Mtreg value is “11111_11110” at H-Resolution mode.