User Manual

BH1750FVI
Technical Note
12/17
www.rohm.com
2009.04- Rev.B
© 2009 ROHM Co., Ltd. All rights reserved.
●H-Resolution Mode2
H-resolution mode2 is 0.5lx ( typ. ) resolution mode. It is suitable if under less than 10 lx measure ment data is necessary.
This measurement mode supports " Adjust measurement result for influence of optical window ". Please refer it. It is possible
to detect min. 0.11 lx by using H-resolution mode2.
○ Instruction set architecture for H-resolution mode2
Instruction Opecode Comments
Continuously H-Resolution Mode2 0001_0001
Start measurement at 0.5lx resolution.
Measurement Time is typically 120ms.
One Time H-Resolution Mode2 0010_0001
Start measurement at 0.5lx resolution.
Measurement Time is typically 120ms.
It is automatically set to Power Down mode after measurement.
○ Measurement sequence example from "Write instruction" to "Read measurement result"
ex) Continuously H-resolution mode2 ( ADDR = 'L' )
① Send "Continuously H-resolution mode2 " instruction
ST 0100011 0 Ack 00010001 Ack SP
② Wait to complete 1st H-resolution mode2 measurement.( max. 180ms. )
③ Read measurement result.
ST 0100011 1 Ack
High Byte [15:8]
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
Ack
Low Byte [7:0]
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
-1
Ack
SP
How to calculate when the data High Byte is "00000000" and Low Byte is "00010010"
( 2
3
+ 2
0
) / 1.2 ≒ 7.5 [ lx ]
from Master to Slave
from Slave to Master