1394b bandwidths, Requirements for pc and 1394b – ALLIED Vision Technologies Guppy PRO F-503 User Manual
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FireWire
Guppy PRO Technical Manual V4.0.0
29
1394b bandwidths
According to the 1394b specification on isochronous transfer, the largest
recommended data payload size is 8192 bytes per 125 µs cycle at a band-
width of 800 Mbit/s.
For further details read Chapter
How does bandwidth affect the frame rate?
Requirements for PC and 1394b
One Guppy PRO camera connected to a PC’s 1394b bus can saturate the stan-
dard PCI bus.
1394b also requires low latency for data transmission (due to small receive-
FIFO). In order to get the most out of your camera-to-PC configuration, we
recommend the following chipsets for your PC:
•
For Intel-based desktops, chipset 945 (or higher)
•
For non-Intel based desktops (e.g. AMD), PCI Express compatible chip-
set
For multi-camera applications one of the following bus cards is needed:
•
PCI ExpressCard with potential 250 MByte/s per lane (up to 6 supported
by chipset) or
•
64-bit PCI-X card (160 MByte/s)
Note
Certain cameras may offer, depending on their settings in
combination with the use of AVT FirePackage higher packet
sizes.
Consult your local dealer's support team, if you require addi-
tional information on this feature.
www
For more information:
Caution
As mentioned earlier, it is very important not to exceed an
inrush current of 18 mJoule in 3 ms. (This means that a
device, when powered via 12 V bus power must never draw
more than 1.5 A, even not in the first 3 ms.)
Higher inrush current may damage the physical interface
chip of the camera and/or the phy chip in your PC.
Whereas inrush current is not a problem for one 1394b cam-
era, supplying bus power via (optional) HIROSE power out to
circuitry with unknown inrush currents needs careful design
considerations to be on the safe side.