50
•
X64 Xcelera-HS PX8 Reference
X64 Xcelera-HS PX8 User's Manual
•
Line Trigger Too Fast
Event which indicates a previous line-trigger did not generate a complete video line from
the camera. Note that due to jitter associated with using shaft encoders, the acquisition
device can delay a line trigger if a previous line has not yet completed. This event is
generated if a second line trigger comes in while the previous one is still pending. This event
is generated once per virtual frame. The Sapera event value is
CORACQ_VAL_EVENT_TYPE_LINE_TRIGGER_TOO_FAST.
•
Shaft Encoder Reverse Count Overflow
Event which indicates that the shaft encoder has travelled in the opposite direction expected
and that the number of pulses encountered during that travel has exceeded the acquisition
device counter. The acquisition device will thus not be able to skip the appropriate number
of pulses when the expected direction is detected. The Sapera event value is
CORACQ_VAL_EVENT_TYPE_SHAFT_ENCODER_REVERSE_COUNT_OVERFLOW
Transfer Events
Transfer events are the ones related to the transfer module. Transfer events provide feedback on
image transfer from on-board FIFO memory to PC memory frame buffers.
•
Start of Frame
The Start of Frame event is generated when the first image pixel is transferred from the on-
board FIFO into PC memory.
The Sapera event value is CORXFER_VAL_EVENT_TYPE_START_OF_FRAME.
•
End of Frame
The End of Frame event is generated when the last image pixel is transferred from the on-
board FIFO into PC memory.
The Sapera event value is CORXFER_VAL_EVENT_TYPE_END_OF_FRAME.
•
End of Line
The End of Line event is generated after a video line is transferred to a PC buffer.
The Sapera event value is CORXFER_VAL_EVENT_TYPE_END_OF_LINE.
•
End of N Lines
The End of N Lines event is generated after a set number of video lines are transferred to a
PC buffer. The Sapera event value is CORXFER_VAL_EVENT_TYPE_END_OF_NLINES.
•
End of Transfer
The End of Transfer event is generated at the completion of the last image being transferred
from the on-board FIFO into PC memory. To complete a transfer, a stop must be issued to
the transfer module (if transfers are already in progress). If a transfer of a fixed number of
frames was requested, the transfer module will stop transfers automatically. The Sapera
event value is CORXFER_VAL_EVENT_TYPE_END_OF_TRANSFER.
Trigger Signal Validity
External trigger signal noise is easily ignored by the ACU with its programmable debounce control.
A parameter is programmed for the minimum pulse duration considered as a valid external trigger
pulse. Refer to Note 3: External Trigger Input Specifications for more information.
Supported Transfer Cycling Methods
The X64 Xcelera-HS PX8 supports the following transfer cycle modes which are either synchronous
or asynchronous. These definitions are from the Sapera Basic Reference manual.
•
CORXFER_VAL_CYCLE_MODE_SYNCHRONOUS_WITH_TRASH
Before cycling to the next buffer in the list, the transfer device will check the next buffer's
state. If its state is full, the transfer will be done in the trash buffer which is defined as the
last buffer in the list; otherwise, it will occur in the next buffer. After a transfer to the trash
buffer is done, the transfer device will check again the state of the next buffer. If it is
empty, it will transfer to this buffer otherwise it will transfer again to the trash buffer.
•
CORXFER_VAL_CYCLE_MODE_SYNCHRONOUS_NEXT_EMPTY_WITH_TRASH
Before cycling to the next buffer in the list, the transfer device will check the next buffer's
state. If its state is full, the next buffer will be skipped, and the transfer will be done in the
