Re: Universal Card

[reynoldst@mobilian.com (Todd Reynolds)]

Forget that comment about the Universal motherboard socket. That's just 
something I think should be done.
I was confusing my server board, which has both, with the universal card. 
The rest of the commentary still applies.

Does anyone know why this hasn't been done (the universal socket)?
It seems more useful than making card manufacturers build universal cards 
and would help speed migration to 3.3V cards.

-Todd

At 10:10 AM 9/6/2002, Jeffrey Journey wrote:
>Todd,
>
>I have always been told that there are no Universal connectors...only
>universal cards. Your note below speaks of a universal slot. Is this
>something new?
>
>Thanks,
>Jeff
>
>----- Forwarded by Jeffrey Journey/Charlotte/IBM on 09/06/02 01:07 PM -----
> 
>
>                       reynoldst@mobilia 
>
>                       n.com 
> (Todd              To:       Grbic@mosaid.com 
>
>                       Reynolds)                cc:       pci-sig@znyx.com 
>
>                                                Subject:  Re: Universal 
> Card
>                       09/06/02 12:47 PM
>
>Mr. Grbic,
>I am currently using a 3.3V card in a universal slot successfully. Part of
>the role of a universal board socket is to allow the use of both 5V Only
>and 3.3V Only cards.
>
>My design uses the 5.0V and the 3.3V supplies but is set-up as a 3.3V only
>card with the Vi/o pins being 3.3V based on the motherboard detecting the
>3.3V card and using 3.3V for the Vi/o pins.
>
>What you want to do is design a 3.3V only card(3.3V Keyed Only!) since that
>
>is your I/O requirement.
>
>If you wanted to be able to use your card in both 3.3V and 5.0V motherboard
>
>sockets, then you would need to get an FPGA that could handle both or get a
>
>very good/fast level translator/buffer. The second is not recommended and
>not allowed by the specifications but if it is a prototype or test board
>you may be able to get away with it but it will be very difficult and you
>will spend a large amount of time designing it - unless you can find a chip
>
>that someone has already designed to do the translation for you (Maybe a
>universal Bridge Chip?). I have never tried it but there should be others
>on this list with more experience in this area.
>
>FYI: You are never supposed to add components to the signal lines. They
>should be point-to-point connections though the specification allows stubs
>within tolerances.
>
>-Todd
>
>At 09:02 AM 9/6/2002, you wrote:
> >
> >
> >  Dear PCI
> > experts,
> >
> >
> >
> >  The electrical spec (Pci rev 2.2) recommend that PCI components on a
> > universal board must use dual voltage I/O buffers, powered from
> >  "I/O" designated power
> > pins.
> >
> >
> >
> >  In  my  PCI  universal card I'm using a PLD (FPGA device) which is
> > powered by 3,3V supply and can not drive and be driven by 3.3V or
> >  5.0V
> > devices.
> >
> >
> >
> >  Any comments about this
> > matter?
> >
> >
> >
> >  Now my question is: in a new universal board can I leave unused
> > dedicated Vi/o pins on the PCI edge connector (properly decoupled to
> >  the  ground  plane)  and  use only the 3.3V supply from the PCI
> > connector (or 5V supply with a regulator) to power up the PLD? Also,
> >  regarding  I  am  using  PCI edga universal connector, and not dedicated
>
> > 3.3V PCI connector, do I have to add some serial resistance
> >  onto the signal lines to compensate for the clamping
> > diodes.
> >
> >
> >
> >  Thanks for any
> > suggestions.
> >
> >
> >
> >  Goran
> > Grbic
> >
> >  Senior H/W Apps
> > Engineer
> >
> >  MOSAID
> > Technologies
> >
> >  p:
> > 613-599-9539/1481
> >
> >  f:
> > 613-591-8148
> >
> >
> >