On Wed, 09 Feb 2005 12:03:12 +0100, Alexander van Heukelum <[EMAIL PROTECTED]> wrote: > On Tue, 8 Feb 2005 11:19:12 -0500 > Timothy Miller <[EMAIL PROTECTED]> wrote: > >If we use a block RAM in 18-bit mode, that's better because we don't > >disable the associated multiplier. It wouldn't be a big deal to treat > >the RAM as a single-ported unit, 36x512 (which is using both 18-bit > >ports together) and just treat the output as 3 12-bit numbers. The > >problem then comes down to being able to look up two at a time. > > I wasn't aware of this. Thanks. > > I found this doc on Xilinx' website, however (released September > 2002): http://www.xilinx.com/bvdocs/appnotes/xapp228.pdf > It describes how to use the block-rams effectively at double the > clock frequency. From the doc: "Because of over-clocking, the > frequency of operation of the block RAM is effectively reduced. > However, the quad-port RAM will work with clocks of up to > 125 MHz in a Virtex-II -5 speed grade device, and up to 80MHz > in a Virtex-E -7 speed grade device." Would it be possible to > get two values per clock (and per port) from the block-rams > at ~200MHz rate on 'our' Spartan-3?
I've just barely managed to get 200Mhz ot of those RAM blocks myself. I could tinker with it, but I'm not optimistic. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
