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iPORT CL-GigE External Frame Grabber User Guide
Case 2: FVAL and LVAL are Edge-Sensitive
In this case, FVAL and LVAL are edge-sensitive.
•
Start of frame/line is signaled by:
A rising (or falling) edge on FVAL, which signals the start of a
frame
. A rising (or falling) edge on LVAL, which signals the start of a
line
.
•
End of frame is signaled by:
•
The next FVAL valid edge (rising edge when rising-edge sensitive or falling edge when falling-
edge sensitive) occurs.
•
Or, when all of the pixels have been acquired (as set in the image height and width settings)
AND
an end-of-frame (EOF) occurs.
Note: EOF occurs at LVAL rising edge (when rising-edge sensitive) or LVAL falling edge (when
falling-edge sensitive). This is an additional LVAL edge, in addition to the configured/expected
number of lines. See the EOF indicator in the illustration below.
•
Line Missing status and Partial Line Missing errors:
Partial Line Missing indicates lines are ending
early (the next LVAL valid edge occurs before all of the pixels have been acquired). Full Line Missing
indicates that the frame is ending early (the next FVAL edge occurs before all of the lines have been
acquired).
(1,0)
(N-1,
0)
t
LI2LV
PB_FVAL
PB_LVAL
PB_DVAL
t
FV2LV
t
FI2FV
t
LV2LI
(1,1)
(N-1,
M)
PB_DATAx]
(0,0)
(N,0)
(0,0) (1,0)
(0,1)
(N,M)
Don’t Care
Window Size = N x M
t
FV2DV
t
LV2DV
t
FV2FV
t
FV2FI
EoF
