Programming Manual
PHYTEC Messtechnik GmbH 2008 L-720e_0
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program has to be specified according to each problem, which implies
that the RISC-program is created during run time of the user program,
since often the parameters (for example the size of the image) which
control the RISC-program, are variable or not available prior to this
time.
The software driver delivered with the pciGrabber-4x4, creates the ap-
propriate RISC-program automatically with the adjustment of the im-
age size. This process is transparent to the user program.
Nevertheless this feature should be in the conscious of the
programmer using this driver software.
Figure 42
depicts this scheme. For image size and data format
selection the user program applies the function
set_image()
of the
driver. The driver starts two actions: first the image size is set in the
VideoScaler
by values in the local registers of the Grabber via the
PCI-bus. This implies, that the pciGrabber-4x4 creates the correct
image size and the data flow has the correct format and provides the
appropriate
synchrony
signals.
In
the
same
way
the
DataFormatConverter
is adjusted to the correct format. This implies
that the flow of pixel data to the FIFO has the correct format
(for example RGB).
The second action of the driver software is the creation of a data flow
appropriate to the RISC-program, which is stored in the main memory
of the PC. The DMA-controller of the pciGrabber-4x4 is notified of
the starting address of this program. During digitization, the
DMA-controller receives the RISC-commands in sequence by DMA
from the main memory and executes those commands and stores the
data according to those instructions.
