[Fpga-synth] Try out spartan3e projects, questions

[Dave Manley]

malik martin wrote:
> Very interesting. Thanks for the info :)
> 
> On Wed, Aug 13, 2008 at 5:11 PM, Eric Brombaugh <ebrombaugh1 at cox.net 
> <mailto:ebrombaugh1 at cox.net>> wrote:
> 
>     malik martin wrote:
> 
>         I hope i'm not OT'ing your thread, but do you think spartan 3es
>         are capable of dsp functionality?
>         and what makes the dedicated DSPs different?
>         I want to get into DSPs as well. I didn't know that AD made the
>         SHARCs.
> 
> 
>     Definitely not OT.
> 
>     Yes you can do DSP with Spartan 3E parts. They're fairly good at it
>     too - witness the DSP that Scott G. has done in his various synths.
> 
>     What's the difference between a DSP and an FPGA? That's a FAQ that
>     you should be able to google. Put simply though, a DSP is a
>     specialized computer that can handle multiplies & adds very quickly
>     and usually has extra addressing modes to make certain operations
>     like convolution go fast. An FPGA is a bag of random gates, memory &
>     (these days) multipliers that you can hook up virtually any way you
>     want. They overlap in some ways, but FPGAs are better for really
>     high-speed processing, while DSPs allow for more complex but slower
>     algorithms. It's a very grey area though...
> 
>     Eric

I'll chime in with one comment: the max FPGA frequency is no where near 
the max frequency of modern processors.  I haven't looked at DSPs in a 
long time, but assume some must be able to run in the GHz range, while 
most FPGAs are going to be limited to a few hundred MHz at most (with 
any significant amount of logic).  In terms of clock speed only, what is 
the fastest DSP out there?  I see some AD Blackfin rated at 750MHz.

-Dave