Data interface
Goldeye Technical Manual
V2.2.0
48
Timing (FVAL, LVAL, DVAL, PCLK)
The Camera Link specification provides three synchronization signals:
•
FVAL (Frame Valid) – HIGH during transmission of valid lines of an image.
•
LVAL (Line Valid) – HIGH during transmission of valid pixels of a line.
•
DVAL (Data Valid) – HIGH in case that valid pixel data are present.
The gross pixel rate at the InGaAs sensor is 10.5 MHz.
However, the maximum available bandwidth of the Camera Link Base configu-
ration is not nearly exploited, on the contrary, the transmission components
require a minimum clock frequency for a safe operation. For this reason the
internal clock frequency is artificially increased before being output as Camera
Link clock signal.
As a consequence an unnecessary high data rate would occur at the grabber,
and because of this a multiple of the really needed data volume ought to be
moved within the storage of the receiver. Now the DVAL signal offers the oppor-
tunity to explicitly mark particular data words as valid so that only the really
needed pixel data are stored in the grabber memory.
GigE feature name
(AcquisitionControl)
Feature visibility Description
TriggerMode
Beginner
Modifies the trigger mode of the camera. When the
trigger mode is
Off
, the camera will generate
frames independently.
When the trigger mode is
On
, the camera is
switched to the image-on-demand (IOD) mode. In
this mode the camera waits for an external trigger
signal or an timer pulse. To control exposure and
dark time trigger, mode must be switched to
On
.
Table 24: Camera special feature: Trigger mode
Note
When selecting a grabber and developing software, ensure that
the grabber does not only evaluate the signals FVAL and LVAL
but also supports DVAL.
