cvs commit: src/sys/net if.c

[Daniel O'Connor]

On Mon, 27 Sep 2004 19:01, Peter Jeremy wrote:
> On Mon, 2004-Sep-27 12:43:29 +0930, Daniel O'Connor wrote:
> >Hmm, MS have a circuit diagram ->
> >http://www.microsoft.com/whdc/system/CEC/dmpsw.mspx
>
> I bumped into that as well.  The innards of the PAL aren't documented
> anywhere that I could see and there seems to be quite a lot of logic
> when the only inputs are the PCI clock and the NMI switch.  (Bloated
> design and undocumented internals - sounds familiar :-).

Heh, I'd say it's not that complex.

You have to hold #SERR down for 1 PCI clock and then tri-state it. I think you 
can do it with a basic 16V8 or so.

I'm thinking of making such a board at work :)

> >Pin 42 is #SERR and the other side of it in ground.
>
> Does anyone with knowledge of the PCI spec know if just shorting #SERR
> to ground will work?  (Assuming that the BIOS/chipset maps #SERR to NMI).

You're supposed to hold it low for 1 clock and tri-state (according to the 
PCI2.0 spec)

> I've used a screwdriver on an ISA slot on several occasions but haven't
> tried it on a PCI bus yet.

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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