ADNS-2080 Avago Technologies US Inc., ADNS-2080 Datasheet - Page 21

• Manufacturer Part Number: ADNS-2080
• Description: Low Power Wireless LED Sensor
• Manufacturer: Avago Technologies US Inc.

Specifications of ADNS-2080

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 516-2309-5

SQUAL
Squal Quality Register
Access: Read
Data Type: Upper 8 bits of a 9-bit unsigned integer.
USAGE: SQUAL (Surface Quality) is a measure of the number of valid features visible by the sensor in the current
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frame.
The maximum SQUAL register value is 180. Since small changes in the current frame can result in changes in
SQUAL, variations in SQUAL when looking at a surface are expected. The graph below shows 250 sequentially
acquired SQUAL values, while a sensor was moved slowly over white paper. SQUAL is nearly equal to zero, if
there is no surface below the sensor. SQUAL is typically maximized when the navigation surface is at the opti-
mum distance from the imaging lens (the nominal Z-height).
Figure 9. Squal values (white paper)
Figure 14. Mean squal vs. Z (White Paper)
Field SQ7
-10
60
50
40
30
20
10
60
50
40
30
20
10
0
0
Bit 7
1
-0.8
55 109 163 217 271 325 379 433 487 541 595 649 703 757 811 865
-0.6
Address: 0x05
Reset Value: 0x00
6
SQ6
-0.4
Delta from Nominal Focus (mm)
-0.2
5
SQ5
Mean SQUAL vs Z
Squal
Count
0
4
SQ4
0.2
0.4
3
SQ3
0.6
2
SQ2
0.8
Avg-3sigma
Avg
Avg+3sigma
1
1
SQ1
0
SQ0