cPCI compatibility questions

I'm a software person that is in over my head. I have to select
a 1553 interface card for a 6U cPCI chassis that has a PowerPC
board running vxWorks.  Unfortunately, I don't know anything
about cPCI, except for some reading I've done today.

My problem is that I don't know what I need to check so I can be
reasonably certain that a cPCI interface card will be compatible
with our chassis & processor board.

First the size question:  The cards I've found that meet our
requirements are all 3U.  AIUI, I can plug a 3U cPCI board into
a 6U cPCI chassis.  It will use the bottom 110 pin connector
and there will be a couple of inches between the top of the
board and the top of the chassis.  Is this correct?

Do I need to worry about any of the following issues:
3.3V vs. 5V?  32-bit vs. 64-bit?  33 Mhz vs. 66 Mhz?

Anything else I should check?

Thanks!
Kevin

"Kevin J. Phillips" <knp@abs.net> wrote in message
news:U4GdnUT9BLbozkzZnZ2dnUVZ_umdnZ2d@charm.net...
>
> First the size question:  The cards I've found that meet our
> requirements are all 3U.  AIUI, I can plug a 3U cPCI board into
> a 6U cPCI chassis.  It will use the bottom 110 pin connector
> and there will be a couple of inches between the top of the
> board and the top of the chassis.  Is this correct?

It is true that you can plug a 3U card into a 6U slot, but I believe an
additional card guide might be required. Frequently 6U chassis have 3U slots
allowing two 3U cards on the top of each other with a guide in between...

> Do I need to worry about any of the following issues:
> 3.3V vs. 5V?  32-bit vs. 64-bit?  33 Mhz vs. 66 Mhz?

Yes, these are all valid concerns. cPCI has a system of color keys installed
in the backplane connectors as well as a system of front panel keys to code
all possible combinations. I don't know though how well manufacturers follow
these, especially the front panel keying system.

> Anything else I should check?

Hot swap capability if you care.

You might want to check out the cpci reflector:
http://www.picmg.org/compactpci.stm

/Mikhail