Dalsa PC2-CamLink, User Manual

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Part I: PC2-CamLink Board PC2-CamLink User's Manual
Case 1: Line size below 4KB
If the camera line dimension is smaller than 4096Bytes, the average line bandwidth must be used to
evaluate if the camera’s bandwidth is acceptable for a FIFO-based frame grabber, such as the PC2-
CamLink.
Bpp * lines pixel/ nb size Line
=
where Bpp is the number of bytes required to store each pixel. 8-bit pixels require 1 byte/pixel while
the pixel depth of 10, 12, 14 or 16-bit/pixel requires 2 bytes/pixel.
Subsequently, the average line bandwidth can be obtained by the following formula:
Bpp * (Hz) rate Line * lines pixel/ nb bandwidth line Average
=
Example:
Camera Model: JAI CV-M4+
Resolution: 1380x1030
Line Frequency: 25.43KHz
Bpp : 10-bits/pixel = 2bytes/pixel
Average Line Bandwidth = 1380 pixels * 25430Hz * 2 Bytes/pixel = 70MBps
We can see that the line averaged bandwidth reaches 70MB per second. This is acceptable if the PC2-
CamLink gets installed in a system with a chipset of good quality.
Case 2: Line size higher than 4KB
When the camera line size exceeds 4KB, the peak bandwidth concept has to be used to compute the
camera bandwidth and once again see if it respects the PCI bus bandwidth capabilities:
Bpp * channel data nb * PClk bandwidth line Peak
=
Example:
Camera Model: Dalsa P2-21-6144
Resolution: 6144 pixels
Pixel Clock: 40MHz
Nb Channel: 2
Bpp : 8 bit/pixel = 1 byte/pixel
Peak Line Bandwidth = 40MHz * 2 channels *1 Bpp= 80MBps
We see that the peak line bandwidth reaches 80MB per second. With this bandwidth, the system has to
maintain a transfer rate of 80MB per second to avoid loosing any information. PC2-CamLink can
sustain this rate with a good PCI chipset.
Note: When installing multiple PC2-CamLinks on the same PCI bus, the total 133MB per second
bandwidth gets split between the boards, resulting in a lower effective bandwidth per card.