PCI to compact PCI converter? (looking for one)

Nov 10, 2005 3 Replies
R

I'm looking for a converter that will allow me to hook up a compact PCI expansion chassis to a PCI based machine. (basically a CPCI board, a PCI board, and a cable to go between the two.)



I figure it may be that simple since CPCI is electrically identical to PCI, just on a different form factor, right?



Anybody know of somebody who makes such a thing?



Also, how would hot-swap capable boards be affected by this? I seem to recall from reading that whenever a hot-swap capable card is inserted, the #ENUM line gets hit and the bus gets enumerated. Would this cause a PCI device to be detected at this point by a windows box (2K for instance), or would hot swap not work right in this situation?



I already tried a Ziatech adapter card designed to allow a 3U CPCI board to plug into a PCI slot, this didn't work for me. I was using it with a 6U card, and it would power up partway but wouldn't come up fully. (I sort of wonder why, since I thought the secondary connector that 6U boards use was just for transition (ie back card) signal use.



Anybody have any ideas?



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T

Check out the following link.

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S

I think Catalyst have all that kind of thing...

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R

On a 3U cPCI board, both P1 & P2 are sharing the PCI bus. (upper part of

64bit bus is on P2, plus a slot address (GA), and there is also a 'system slot' identifier pin that may be looked at by combined master/slave cpu:s, to determine if they should power up or wait for an external master giving the go-ahead, as part of the hot-swapping logic.

(You may need to look at your individual board spec to find out what's needed, but the bus specs are at picmg.org)

On a 6U cPCI board, the P3 is for the rear transition panel, but I've not seen any rear I/O used with standard 3U boards. Custom I/O could be differently made I expect.

One thing I've seen when using a cPCI board in a PC, is that some PC power supplies isn't really suitable to cPCI; modern cPCI relies mainly on +3.3V supply, while modern ATX PSU:S are mainly supplying +12V power. Also the +3.3V regulation is often dependent on +5V load, so one may have to introduce a dummy load to get within tolerable +3.3V levels. The +3.3V requirement is also marginal in some cases due to differences in precision, ATX is +/-5% on +3.3V, while cPCI wants +5% -3% accuracy, and if the cPCI bord is marginally designed, it can be a problem.

If you have older 33MHz 32 bit cPCI board, it's +5V VI/O on the pci bus, not +3.3V as the newer 66MHz 64bit boards; this too must be considered, as not all adapters can be configured to work with either voltage; i.e. you can burn off some copper traces if mismatched.

/Rolf

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