pciGrabber-4x4
94
PHYTEC Messtechnik GmbH 2008 L-720e_0
Determination of the number of available
pciGrabber/Decoder
WORD Max_Device_Number (void);
Returnvalue: Number of pciGrabber found
This functions specifies the number of pciGrabber-4x4 in the system,
more precisely the numbers of decoders in one system.
•
VD-012
four decoder
•
VD-012-X1
four decoder
•
VD-012-X2
two decoder
This is required, because PCI-/PCI Express-devices are not configured
with jumpers or other hardware, but are assigned automatically an
addressing region, by the PCI-BIOS. With the help of the PCI-BIOS
the address region can be determined for each Grabber card. If several
cards are installed in the system, the addresses are returned in a
sequence (see also section 2.4).
The user has not to care about addresses or address regions when
using the driver. Those are converted internally into
device numbers
(=
nDevNo
). Each pciGrabber-4x4 card in the system is assigned a
unique device number during generation of the Grabber class. It can
not be predicted for certain which number is assigned to which card,
since this depends on the topology of the bus and the function of the
BIOS.
In order to drive the different pciGrabber-4x4 independently by the
software, the device number is transferred as parameter with each
function call.
The function
Max_Device_Number()
is applied to find out how many
pciGrabber-4x4 are installed in the computer. The highest permissible
device number is returned. At the same time this is the number of
grabbers in the system, since the lowest device number =1.
If the returned value is 0, the PCI-BIOS did not find a
pciGrabber-4x4.
For
nDevNo
only values between
