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Theory of Operation
X64-AN Quad User's Manual
acquired frame. In such a situation, an
X64-AN Quad
board with more memory would store more
onboard frames without loss. The Sapera event value is
CORACQ_VAL_EVENT_TYPE_FRAME_LOST.
Start/End of Field/Frame/Odd/Even
Acquisition events are available to indicate the start and end of field (odd or even), even field, or odd
field (interlaced acquisition), and for the start and end of frame (progressive acquisition).The
corresponding Sapera event values are:
CORACQ_VAL_EVENT_START_OF_FIELD, CORACQ_VAL_EVENT_START_OF_ODD,
CORACQ_VAL_EVENT_START_OF_EVEN, CORACQ_VAL_EVENT_START_OF_FRAME,
CORACQ_VAL_EVENT_END_OF_FIELD, CORACQ_VAL_EVENT_END_OF_ODD,
CORACQ_VAL_EVENT_END_OF_EVEN, CORACQ_VAL_EVENT_END_OF_FRAME,
Vertical Timeout
A vertical time event is generated if a vertical sync is not detected following an
external/internal/software trigger within the period specified by
CORACQ_PRM_VERTICAL_TIMEOUT_DELAY.
For analog cameras, if the WEN signal is used, the beginning of the WEN must be detected before the
programmed delay expires. If syncing to blanking signals ,the end of the blanking signal must be
detected before the programming delay expires.
The Sapera event value is CORACQ_VAL_EVENT_TYPE_VERTICAL_TIMEOUT.
Transfer Events
Transfer events are the ones related to the transfer module. Transfer events provide feedback on image
transfer from onboard memory frame buffers to PC memory frame buffers.
Start of Frame
The Start of Frame event represents the beginning of a full frame transfer from onboard memory into
PC memory. For interlaced video, there is one Start of Frame interrupt for each pair of fields. The
Sapera event value is CORACQ_VAL_EVENT_TYPE_START_OF_FRAME.
Start of Field
The Start of Field event is only available for interlaced scan cameras. There is a Start of Field event at
the beginning of each field transferred from onboard memory into PC memory (two per frame). The
Sapera event value is CORACQ_VAL_EVENT_TYPE_START_OF_FIELD.
