Dalsa Piranha 2 Series, Руководство пользователя

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59 Piranha 2 User’s Manual
03-032-00493-14 Teledyne DALSA
Appendix A
Camera Link™ Reference
Cam era Link is a com m u nication interface for vision ap p lication s.
For years, the scientific and ind u strial d igital vid eo m arket has lacked a stand ard m ethod
of com m u nication. Both fram e grabbers an d cam era m anu factu rers d evelop ed p rod u cts
w ith d ifferent con nectors, m aking cable p rod u ction d ifficu lt for m anu factu rers and very
confu sing for con su m ers. A connectivity stand ard betw een d igital cam eras an d fram e
grabbers is long overd u e an d w ill becom e even m ore necessary as d ata rates continu e to
increase.
Increasingly d iverse cam eras and ad vanced sign al an d d ata tran sm ission s have m ad e a
connectivity stand ard like Cam era Link a necessity. The Cam era Link interface w ill
red u ce su p p ort tim e, as w ell as the cost of that su p p ort. The stand ard cable w ill be able to
hand le the increased sign al sp eed s, and the cable assem bly w ill allow cu stom ers to
red u ce their costs th rou gh volu m e p ricing.
LVDS Technical Description
Low Voltage Differential Signaling (LVDS) is a high -sp eed , low -p ow er general p u rp ose
interface stan d ard . The stand ard , know n as AN SI/ TIA/ EIA-644, w as ap p roved in March
1996. LVDS u ses d ifferential signaling, w ith a nom inal signal sw ing of 350m V d ifferential.
The low sign al sw in g d ecreases rise an d fall tim es to achieve a theoretical m axim u m
transm ission rate of 1.923 Gbp s into a loss-less m ed iu m . The low signal sw ing also m eans
that the stand ard is not d ep end ent on a p articu lar su p p ly voltage. LVDS u ses cu rrent -
m od e d rivers, w hich lim it p ow er consu m p tion. The d ifferential sign als are im m u ne to ±1
V com m on volt noise.
Camera Signal Requirements
This section p rovid es d efinitions for the signals u sed in th e Cam era Lin k interface. The
stand ard Cam era Link cable p rovid es cam era control sign als, serial com m u nication, an d
vid eo d ata.
Video Data
The Chan nel Link technology is integral to the tran sm ission of vid eo d ata. Im age d ata
and im age en able sign als are transm itted on the Ch annel Link bu s. Fou r enable sign als
are d efined as:
• FVAL—Frame Valid (FVAL) is defined HIGH for valid lines.
• LVAL—Line Valid (LVAL) is defined HIGH for valid pixels.
• DVAL—Data Valid (DVAL) is defined HIGH when d ata is valid.
• Spare— A spare has been defined for future use.
All fou r en able signals m u st be p rovid ed by the cam era on each Channel Link chip . All
u nu sed d ata bits m u st be tied to a know n valu e by the cam era. For m ore inform ation on
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