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CPU consumption of IEEE 1394b IMAQ?

Hi.
In search of vision equipment with good performance/$ ratio I came across IEEE 1394 (Firewire) cameras. For processing and storage, I would use a PC with an off-the-shelf Firewire controller board (PCI based).
In a number of places I read that Firewire consumes quite an amount of host computer CPU (for example in http://digital.ni.com/public.nsf/websearch/ED092614FCCC900D86256D8D004A3B0C?OpenDocument  --"...IEEE 1394 cameras also require processor control to move the image data, which limits available processor bandwidth for image processing.")

Does this also apply to the newer IEEE 1394b-2002? As the controller hardware would allow for DMA, does NI-IMAQ for IEEE 1394 Version 2 (which actiually supports IEEE 1394b) make use of DMA capabilities? If yes, how much is CPU burden reduced?

If these questions should be silly, please forgive. I am "at home" more on the optical side of a detector, not at the electronical side.

Philipp


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Hi Philipp,
 
the KB you have found is very old 🙂
Generally, the newest driver (IEEE 1394 2.0.1) works with occurrences (events), independent of "a" or "b" standard! This driver also supports DMA! I estimate that the CPU burden averages 2-3%!
It's possible to connect a cam with "b" standard to a 1394 board with "a" standard (e.g. CVS). NI has tested the following 1394b cams with our 1394a boards successfully: Sony XCD-V50 and XCD-V50CR
 
regards,
ThSa
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Hi ThSa,

thanks for your helpful (and encouraging) reply. One more question in case I got you wrong:
You mention NI CVS, but is it so that independent of "a" or "b", using *any* controller board sticking to 1394 OHCI 1.1, the NI driver can make (automatically makes?) use of DMA? I guessed that OHCI 1.1 is the requirement because I read that there is a DMA engine included in this standard.
I just ask because at the moment I wasn't planning to buy a CVS (which doesn't mean I wouldn't like to if I had the money 😉 ).

regards
Philipp



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You are right, it depends on OHCI!
Btw, here is a nice document for it:
 
regards
ThSa
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