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Flare 12M CXP User's Manual
is set in microseconds. The frame period command has no effect in this mode. The range of
the exposure time will be set according to the maximum frame period allowed for the current
output format. The timing for this mode, with High Dynamic Range exposure modes disabled,
is shown in Figure 9.
Exposure starts when the active edge of the input trigger is seen. The active edge can be set
to rising or falling (
Trigger Edge
register). The trigger used can be the CoaXPress input
trigger received on the uplink signal (
Trigger Source
register, value 0x00000000) or the TTL
input on the power connector (
Trigger Source
register, value 0x00000001). There is a Frame
Overhead Time (FOT) period after the exposure ends, same as free-run mode, and then
readout of the frame begins.
The minimum pulse width of the input trigger is 200 ns. The delay from the active edge of the
trigger to the start of exposure is approximately 200 ns.
Exposure of the next frame cannot start until the readout of the current frame begins. Also
exposure cannot end during the readout of the previous frame. The camera will not look for a
new trigger pulse until N microseconds have elapsed after readout begins, where N =
Readout Time - Exposure Time, if the exposure time is less than the readout time. With large
swings in exposure time it is likely that a trigger will be ignored to keep the correct timing on
the sensor.
3.3.3 Edge-triggered level-controlled exposure
In edge-triggered level-controlled exposure mode the exposure of the frame is controlled by
the active state of the input trigger. The frame period and exposure commands have no effect
in this mode. The High Dynamic Range exposure modes are not available in this mode. The
timing for this mode is shown in Figure 10.
In this mode exposure starts when the input trigger transitions into the active state. Exposure
continues until the trigger transitions into the non-active state. The active state can be set to
low or high (
Trigger Edge
register).
IO Industries Inc.
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Revision 2.0
Figure 9. Edge-triggered programmable exposure timing
Readout Time, Frame N-1
Input Trigger
(rising edge)
Exposure Time, Frame N
FOT
Readout Time, Frame N
Frame Period
Exposure Time, Frame N+1 FOT