SpectraVideo Camera User’s Manual
Digital Control Board
18
☞
An Exposure Gate pulse of 25
µ
s minimum width must be provided to this board
to trigger exposure as discussed below.
A Line Blank and Frame Blank pulse are provided in addition to the Data Valid
strobe. The Line Blanking pulse is high for the parallel shifts. Line Blanking is
only active with a Region of Interest (ROI) selected. Frame Blanking is low
during the exposure period, high during the after exposure delay and then low
during the readout. In this way the I/O channel to the PC can sense the internal
exposure gate timing.
EG=Exposure Gate
DV=Data Valid
LB=Line Blanking
FB=Frame Blanking
Figure 6 Camera Control Timing for Internal Exposure Mode
NOTE: For external
exposure mode, EG must be high the entire exposure period.
Parallel mode is used with the parallel data input option and serial mode is used
with the serial fiber optic input option.
6.2.1.
F
LUSH
M
ODE
After readout or after rebooting the DSP, the CCD is kept flushed of charge
indefinitely by a parallel transfer, serial readout sequence. The only way to get out
of this mode is to trigger an exposure.