Re: Fully unrolled RC5 on FPGA

John L. Bass wrote:
> None of these devices which have a practical size are easily socketed.
> Most are ball grid arrays (BGA), or fine pitch quad flat packs (QFP).
> The price per performance doesn't favor a bunch of small fpga's, but
> may well favor a few mid to large sized fpga's.

Okay, if sockets aren't practical that's cool too. I'll just have to
save up more up front...

> As for card chassis, server PC's are still the cheapest, and most usable
> chassis ... far better than some VME kludge. A typical mid end PII or
> PIII PC server motherboard has a bunch of slots, including a couple 64bit
> 3.3V PCI slots, can be had for small change. Some more interesting boat
> anchors, like older high end servers, typically have a large number of
> PCI slots (up to 12), including a large number of 64 bit slots.

Like the quad pent pro ALR monstrosity I have? :) I'd love to slot half
a dozen full length PCI cards w/crunchers into that box. And agreed, VME
would probably be an ugly kludge from the logic side of things, I was
thinking in terms of easy to invest in hardware for those interested but
not quite hardware hackers.

(BTW - a little off topic, anyone seen a wiring diagram and perhaps some
easy assembly instructions for building adapters to plug 533Mhz celerons
into ppro sockets? :) I'm kinda looking, and wasn't interested in paying
the silly amount some site wanted for those things...)

> It might not be unreasonable to make a card so that it can passively
> occupy a 5V PCI slot (take power and mounting from it), but not interface
> to the 5V PCI. Or to put a 5V tollerant CPLD on a 5V PCI card to pick
> off ISA emulation I/O ports with a narrow (8/16) bit bus width, as an
> interface to the fpga array. Or, use some older XC4K fpga's as the bridge
> to the newer fast/cheap fpga's. 5V PCI capable XC4K parts frequent Ebay
> for chump change, as do the CPLDs.

Build a small PS patch on the card to step down the 5v pci to 3.3v and
opto isolate the I/O lines? *shrug* not my area of expertise here, but
it's an idea.

--Gerald


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