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USB BACKGROUND
The Universal Serial Bus (“USB”) standard was originally
developed by computer manufacturers in 1995 to minimize the number of
ports in the back of a PC. The major goal of the creators of USB was to
create an external expansion bus, which makes adding peripherals to a
PC more convenient and transparent to the user. USB 2.0 is the 2000 update
of the original USB1.1 standard incorporated into most PC motherboards.
The USB 2.0 specification extends the maximum speed of the connection
from 12 Megabits per second (“Mbps”) for USB1.1 up to 480 Mbps (60MBytes/sec).
This enables the real-time transfer of data for high-definition video
conferencing or for example 500 frames of 320x240 images per second (“fps”)
for high-speed analysis or video motion analysis. While some of the other
interfaces such as Camera Link are faster, this speed often is unnecessary
due to the limitations of PC host processing and storage. USB 2.0 also
provides bi-directional serial communication for camera setup, control,
triggering, strobing, and other I/O signaling.
USB VENDOR SUPPORT
Intel has released a family of chipsets starting with
the 845 support chipset family for the Pentium-4- based family of processors.
These chipsets, which include the ICH4 South Bridge chip, all have an
embedded USB 2.0 enhanced host controller interface and hub, capable of
supporting up to 6 high or low speed ports. Similar support chips for
the AMD processors and other bridge manufactures also incorporate the
USB 2.0 standard into their silicon. At present, more than 80% of all
new motherboards incorporate USB 2.0, resulting in USB2.0 domination of
the market. Because the ICH4 connects directly to the memory controller
(a.k.a. “the North Bridge chip”) over a 266MB/s (32bit/66MHz) hub interface,
it can simultaneously move data from the USB 2.0 at maximum rates without
reducing the bandwidth capacity of the 32bit/33MHz PCI bus. Thus, USB
2.0 is the preferred connection for most PC peripherals, and currently
is on virtually all Pentium and Athlon system boards. Even Apple has installed
USB 2.0, along with IEEE 1394b, in its new G5 machine.
USB
SOFTWARE SUPPORT
Microsoft has released a driver for Windows XP and has
upgrades for Windows ME and Windows 2000. However, Microsoft has stated
that it will not provide USB 2.0 driver support for Windows 9x or earlier
Windows operating systems. the Linux community has recognized the imminent
growth of USB 2.0, and has already released driver support in its latest
kernel.
FASTVISION'S
USE OF A USB2.0 PORT
Due to the advantages above, some camera manufacturers
use USB 2.0 as the primary interface. This has the advantage of making
virtually any computer a frame grabber with no cost. Another approach
is taken by FastVision's high-speed “smart” CMOS cameras (“FastCamera40”
and “FastCamera13”) use USB 2.0
either as a 30-40 Mbytes/sec secondary video port, or to download the
results of the in-camera-processed images or data. Thus the FastCamera
Series can be interfaced with virtually any computer or use any computer
as a secondary video monitor for camera setup and low-speed data collection
of raw or in-camera processed data.
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