ADNS-3090 Datasheet, PDF (31/38 Pages) Pixart Imaging Inc. – High-Performance Optical Mouse Sensor

PixArt Imaging Inc.
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Shutter_Upper
Access: Read
Address: 0x0f
Reset Value: 0x00
Bit
7
6
5
4
3
2
1
0
Field
S₁₅
S₁₄
S₁₃
S₁₂
S₁₁
S₁₀
S₉
S₈
Data Type: Sixteen bit unsigned integer.
USAGE: Units are clock cycles. Read Shutter_Upper first, then Shutter_Lower. They should be read consecutively. The
shutter is adjusted to keep the average and maximum pixel values within normal operating ranges. The shutter value
is checked and automatically adjusted to a new value if needed on every frame when operating in default mode.
When the shutter adjusts, it changes by ± 1/16 of the current value. The shutter value can be set manually by setting
the AGC mode to Disable using the Extended_Config register and writing to the Shutter_Maximum_Bound registers.
Because the automatic frame rate feature is related to shutter value. It may also be appropriate to enable the Fixed
Frame Rate mode using the Extended_Config register.
Shown below is a graph of 800 sequentially acquired shutter values, while the sensor was moved slowly over white
paper.
Shutter Values (White Paper)
Z =2.4mm, Circle@7.5" diameter, Speed = 6ips
100
90
80
70
60
50
40
30
20
10
0
1
101 201 301 401 501 601 701
Counts
Figure 28. Shutter Value (white paper)
95
90
85
80
75
70
65
60
55
50
1.6
Shutter vs Z (White Paper)
Resolution = 3500cpi, Circle@7.5" diameter, Speed = 6ips
1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4
Distance from Lens Reference Plane to Navigation Surface, Z (mm)
Avg-3sigma
Avg
Avg+3sigma
Figure 29. Mean shutter vs. Z (white paper)
The maximum value of the shutter is dependent upon the setting in the Shutter_Max_Bound_Upper and Shutter_
Max_Bound_Lower registers.
All rights strictly reserved any portion in this paper shall not be reproduced, copied or transformed to any other forms without permission.
PixArt Imaging Inc.
31
E-mail: [e-mail]