Dalsa PC2-CamLink, User Manual

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Part I: PC2-CamLink Board PC2-CamLink User's Manual
Interrupt-Related Definitions
Interrupt
An interrupt is an electrical signal sent by the PC2-CamLink board to the
computer CPU to indicate an event on the frame grabber. The PC2-CamLink
driver has excellent reaction time to interrupts since interrupts are processed
inside an interrupt service routine (ISR) at kernel level.
Event
An event is a WIN32 object that can take two states: signaled and non-
signaled. It is used for thread synchronization. In this context, an event is
associated with an interrupt so that a WIN32 thread can be unblocked when
the event it is waiting for gets signaled. For example, when an interrupt is
received, the corresponding event is signaled and the thread waiting for this
event resumes execution.
Interrupt event
object
Under IFC, an interrupt object is an IFC virtualization of an event associated
to an interrupt.
Start of Trigger
The Start of Trigger interrupt is generated when the selected external trigger pin is asserted, usually
indicating the start of the acquisition process. In IFC, this is represented by CL2_INTR_SOT . In
Sapera, this is represented by CORACQ_VAL_EVENT_TYPE_EXTERNAL_TRIGGER.
PC2-CamLink is equipped with a debounce circuit that allows the user to define the minimum
acceptable pulse width programmatically.
Note: There is no Start of Trigger interrupt for a software trigger. This particular interrupt is only
asserted for a pulse on the selected external trigger pin.
Start of Capture
The Start of Capture interrupt family indicates a FVAL or LVAL has been detected. Note that this
does not necessarily mean the image will be captured. For instance, if you have a free-running camera
at 30fps with external trigger enabled, you will get 30 interrupts per second even though the PC2-
CamLink waits for an external trigger to actually capture the next image. This allows the application
program to count frames or lines coming from the camera.
Start of Frame
The Start of Frame interrupt represents the beginning of a full frame output by the camera. It is also
generated on the start of a virtual frame. It is asserted on the FVAL pulse (at the beginning of the
frame). In IFC, this is represented by CL2_INTR_VB . In Sapera, this is represented by
CORACQ_VAL_EVENT_TYPE_VERTICAL_SYNC.