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Message
From: Mark McDougall<markm@v...>
Date: Mon Jul 30 02:39:30 CEST 2007
Subject: [oc] Help with choosing a FPGA
a2e@i... wrote:> My fist question is
> that if the onboard osc of the dev board is 50 MHz will that have any
> bearing on the maximum frequency I can clock in at?
No, FPGAs have internal PPLs that can synthesize a whole range of
frequencies from an external clock input. One caveat - a quick experiment
with the Quartus II megawizard reveals that you can't produce _exactly_
48MHz from a 50MHz clock - at least on Cyclone II - the dividers and
multipliers don't pan out. Might be safer to use 24MHz in your case...
> Looking ahead my next question is about the hard drive interface, I
> know there are cores out there to implement IDE interfaces, but what
> about a file-system? I am guessing that I am going to have to deal
> with that in the soft-cores software?
If you want a file system, then yes, there are free FAT filesystems
available that are highly portable. I've used "FatFs" on a NIOS-II with
the opencores IDE controller.
Regards,
--
Mark McDougall, Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266
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