Silicon Imaging SI-3300 MegaCamera, Инструкция по эксплуатации

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Silicon Imaging , Inc. 2004 Page 6 of 39 Company Confidential
3.) Digital Clock Synthesizer
A wide range a master clock frequencies (eg. 20 to 80MHz) can by precisely generated using the Digital Clock
Synthesizer. The Frame Grabber, which is used with the camera, must be capable of receiving 12bit at 40Mhz for
standard cameras or up to 80Mhz for the High-Speed (-H) model to achieve the highest data rates. Without any byte
packing of the 12-bit word the data rate would be 160MHz (2pixel x 2bytes/pixel x 80MHz). In standard 32Bit/33MHz
PCI computers the maximum data rate directly to host memory is usually below 120Mbytes/sec (from 132MB/sec
bus) without system interrupts. However, 100MB/sec is more reasonable rate to achieve with other system devices
operating (eg. display, clock, mouse etc.). Under these condition the 12-bit data can be mapped to 8-bits/pixel to
reduce the bus traffic or the clock rate can be reduced to and still maintain 12bits/pixel. The frequency of the clock
synthesizer can be set by serial command. A table with associated clock frequency is found in the serial
programming section of the manual. Due to minimum frequency restriction on the digital transmission link, the pixel
clock frequency cannot be lower than 20Mhz.
4.) Embedded Microprocessor
A microprocessor in the camera provides the control interface between the PC and the functional block in the camera
(Sensor, Clock Synthesizer, Register Memory, Channel Link Interface & Serial port (CameraLink). The
Microprocessor receives commands thru the LVDS level serial port and issues commands to the other devices. It
also can store preset values for camera setting, which can be recalled with single ASCII character commands.
Several digital I/O or analog sampling signals are available on the processor from PCB header points for custom
OEM applications.
5.) 12-Bit CameraLink Interface (Base Configuration)
Camera Link is a new digital transmission method designed by imaging component manufacturers as an easy and
standard way to connect digital cameras to frame grabbers. The Camera Link specification includes greater than
1.2Gb/sec data transmission as well as camera control and asynchronous serial communications all on a single
cable with high-density 26pin connector. Only two connections are required to quickly interface your digital camera
to a multitude of frame grabbers. This standardization will ultimately reduce cost of high performance digital cameras
through open market competition and a simple migration path to faster and higher resolution systems.
As a standard that has been defined by industry members, Camera Link provides the following benefits:
•
Standard Interface: Every Camera Link product will use the same cable and signaling. Cameras and frame
grabbers can easily be interchanged using the same cable.
• Simple Connection: Only two connections will be required to interface a camera and frame grabber: Power
and Camera Link.
•
Lower Cost: Because Camera Link is an industry-wide standard, consumers will be able to take advantage
of lower cable prices.
•
Smaller connectors & cables: The technology used in Camera Link reduces the number of wires required
to transmit data over traditional LVDS or RS-422 parallel interfaces, allowing for smaller cables. Smaller
cables are more robust and less prone to breakage.
•
Higher data rates: The technology used in Camera Link has a maximum data rate of 2.3GB/s, for use in the
most demanding high definition, high frame rate and line scan.