Re: Attached PDF of work in progress FPGA PCB

Gerald Richter <[email protected]> wrote:
	> John L. Bass wrote:
	> > Missing is a PLD and a compact flash socket on the bulkhead
	> > end for configuration loading. Plan to use the open cores
	> > configuration PLD for the design ... other suggestions
	> > welcome. The 8 fpga's need a configuration bus wired, I left
	> > the D0-D7 pins open for that.

	> I've not bothered to look at how these things are actually configured 
	> and whatnot, but I do like the layout. I do have plenty of room in any 
	> target cases I might use for full length PCI cards - actually have a 
	> couple full length PCI raid controllers in use. What's it look like with 
	> a compact flash socket attached? How big a compact flash card would be 
	> needed?

I plan to place it at the IO port end, and sticking out enough to easily
remove with fingers. The sockets I have do not have ejectors. The configuration
bit stream for these devices isn't very big .. a few megabytes, or less
if compressed. With CF cards in the hundreds of MB easily available for
a few dollars, this doesn't seem an issue.

	> I'm thinking the CF socket could be oriented opposite the host bus 
	> interface - leave the CF to stick off the edge just a little bit if it's 
	> small enough. Not being the professional here, someone feel free to tell 
	> me it's a bad idea. :)

That would require an open case to access. Easy in the lab, but painful
otherwise.

	> > PII, PIII and P4 server cards with 3.3V 64Bit PCI slots are
	> > dead cheap, and probably make a better host and enclosure than
	> > any other choice. If needed, we can always use an older 5V
	> > fpga for the PCI interface if 5V slot access is really needed.
	>
	> Guess i'll have to pick up one. :) I've only got 32bit pci slots 
	> available at the moment, but i'm not opposed to picking up a newerish 
	> server board.
	>
	> I need to get some newer boxes for misc linux duties anyway. :)

I've been using both Tyan and Supermicro dual boards for some time. I have
about 30 Tyan Dual P3 S2510 and S2518 boards racked in 1U cases for an
MPI/PVM cluster for my research. At $80/each the are very cost effective
processor and memory cycles (60 P3 CPUs at 1GHz and 1.26GHz), and they
will each host a single 66MHz 64bit PCI slot with a riser card. I also have
a mix of other Tyan and Supermicro dual boards in tower cases up to several
GHz, none of which cost more than $50 on ebay, although the CPUs and memory
can be more expensive.

Have fun,
John
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