ADNS-7700-H4MY Avago Technologies US Inc., ADNS-7700-H4MY Datasheet - Page 41

• Manufacturer Part Number: ADNS-7700-H4MY
• Description: USB SoC Lsr Snsr 3B+TW
• Manufacturer: Avago Technologies US Inc.

Specifications of ADNS-7700-H4MY

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

SQUAL
Access: Read Only
Data Type: Upper 8bits of a 10-bit unsigned integer
USAGE: SQUAL (Surface Quality) is a measure of ¼ of the number of valid features visible by the sensor in the current
Figure 23. SQUAL Values (white paper)
Figure 24. Mean SQUAL vs. Z (white paper)
41
Bit
Field
40
30
20
10
40
30
20
10
0
0
1
frame. Use the following formula to find the total number of valid features. The values range from 0 to 144.
Number of features = SQUAL register value * 4
Since small changes in the current frame can result in changes in SQUAL, slight variations in SQUAL on one
surface is expected. The graph below shows 800 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 typi-
cally maximized when the navigation surface is at the optimum distance from the imaging lens (the nominal
Z-height).
1.6
51 101 151 201 251 301 351 401 451 501 551 601 651 701 751
7
SQ
1.8
Distance from Lens Reference Plane to Navigation Surface, Z (mm)
7
2
Z = 2.4mm, Circle@7.5" diameter, Speed = 6ips
1000cpi, Circle@7.5" diameter, Speed = 6ips
6
SQ
2.2
6
SQUAL Value (White Paper)
SQUAL vs Z (White Paper)
2.4
Count
Address: 0x08
Reset Value: Undefined
5
SQ
2.6
5
2.8
4
SQ
4
3
3.2
3
SQ
3
3.4
2
SQ
2
Type: Device
Avg-3sigma
Avg
Avg+3sigma
1
SQ
1
0
SQ
0