RE: PCI slot lost on power up?

[Ivor Bowden <ivor@peritek.com>]

Well, I was wrong. The clock is not there. What happens is at power on
the clock comes up and runs for a few seconds, then turns off if there
is no card in the slot. And the process repeats on a hard reboot. I
guess I was confused.

So now I am trying to make the clock be there regardless. The PRSNT#
pins on the motherboard seem to not be connected. I tried shorting them
to ground on the extender board, right at the motherboard PCI bus
connector, with no effect.

And I looked in the BIOS settings, I can not find anything that looks
like it would enable this.

Any other ideas? Thanks!

Ivor

At 12:34 PM 6/6/01 -0700, you wrote:
>Well, I was going to say the BIOS might be turning off the clock to unused
>slots, but you said you checked that.  Did you check it real closely?  - I
>was once working with a peripheral board that had a PLL clock buffer on it;
>during the POST sequence, the PCI clock would be present long enough for the
>PLL to sync, but then it was being turned off without my realizing it and
>the PLL just kept right on going from its last sync.  Of course, strange
>things started happening because the free running PLL wasn't exactly
>matching the bus traffic all the time.  Sometimes there was enough residual
>signal on the PCI clock line to keep the PLL in sync most of the time.
>-- BrooksL
>
>> -----Original Message-----
>> From: Ivor Bowden [mailto:ivor@peritek.com]
>> Sent: Wednesday, 06 June, 2001 10:05
>> To: pci-sig@znyx.com
>> Subject: PCI slot lost on power up?
>> 
>> 
>> Hi PCI experts,
>> 
>> I wonder if any one else has seen this problem and knows of a 
>> workaound:
>> 
>> We are making a test station for PCI boards.
>> We are using a Catalyst PCIBX64 "intelligent" extender board.
>> It is a passive board with bus and power switching, that can
>> be accessed via a parallel port.
>> 
>> The problem is, if there is no board in the slot, or if the extender
>> is turned off, AT POWER UP, then the slot is essentially dead.
>> 
>> It is not a BIOS problem, I load the BARS after boot up. It does not
>> make any difference which board is in the slot, as long as it is a
>> valid PCI board. I can even do a "hard" reset and reboot without a
>> board in the slot and it works, it is only on initial power up that
>> the board must be there. It is like there is a hardware circuit that
>> determines if the board is there at power up and defeats the slot if
>> it is not. I did scope the PCI clock line, it is there in both cases.
>> 
>> The motherboard is a VA-503+ with the VIA APOLLO MVP3 chipset and a
>> Pentium MMX 233MHz processor.
>> 
>> Any ideas?
>> 
>> Thanks!
>> -Ivor
>> 
>> Ivor Bowden
>> Peritek Corp
>> 5550 Redwood Road
>> Oakland, CA 94619 USA
>> phone: (510) 531-6500
>> FAX: (510) 530-8563
>> url: www.peritek.com
>> email: ivor@peritek.com
>> 
>
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