[sdiy] Taking a Step towards Digital Synthesis?....

[Magnus Danielson]

From: "Paul Schreiber" <synth1 at airmail.net>
Subject: Re: [sdiy] Taking a Step towards Digital Synthesis?....
Date: Wed, 7 Jan 2004 23:23:24 -0600
Message-ID: <001201c3d5a7$8ecfe5b0$0501a8c0 at bilbo>

> Getting back to the FPGA at hand:
> 
> Just looked at the dev system Jim bought. Big $$$ (like $700 or so). But the
> 300,000 gate IC (in 208-pin PQFP) is only $35 in *single* quantity!

FPGAs with chocking gate-counts is dirt-cheap these days compared to the old
days. No wonder that there is a hobby in doing strange things with these.

> This is boggling: I did a DSP emulator (OEM'd by Texas Instruments for a 'toy'
> LPC speech DSP) using 2 Xilinx XC4000 series (the top-of-the-line parts in like
> 1995). One was a 160-pin part with 4000 gates (all it was programmed for was a
> 32-bit wide 5:1 mux with latches) and the state machines (all 9 of them) ran in
> a 10K gate with 208-pins. And then there were the 2 *one-time* programmable
> serial EPROMS at $15.32 each! The 2 ICs together, in 75pc quantites, were $108
> AND $192 each, RESPECTIVELY. And they ran at a staggering 20MHZ :) I remember
> the day the Xilinx package arrived (UPS ground) and there was like $26,000 worth
> of parts in it. I didn't even want to *touch* the stupid thing.

Oh, I recall when we had the 1M-gate Virtex comming in for our emulator board
(designed to be unusable as a product - so it never became a product!) at a
cost of $5000 ... per chip! Let's say that they where a bit nervous there for
a time... ;O) Price was high since it was brand new (high speed-grade).
These days you get the equalent for almost nothing in comparision.

With new stuff comming out in 90 nm on 300 mm wavers prices is dropping as we
speak (oups, there it dropped some again). They are pretty agressive about it.
It is interesting, since for more and more stuff it becomes less interesting to
do static designs in the old ASIC trail.

> I'm getting a pain sitting here thinking about 300,000 gates for <$35.

Yeah. I got myself a 200k gates kit for $99 a few years back. That's bloody
impressive actually.

> Oh....at Tandy I got the TRW rep to *sample* me one of those MPT-16C, 16 x 16
> bipolat logic multipliers with the extruded heat sink on top. IT was for my
> 2900-bit slice Z80 emulator (it ran at 20Mhz, too and outran a VAX 11/780). I
> reacll that part was $320ea.

Nice little anecdote... and these days you cram in a bunch of those in the
corner of a FPGA.

> The good old days....sigh.....

Yeah. But on the other hand, what used to be difficult to engineer then is
fairly easy to do now. The tools we I have on my laptop where just not
concievable to have at home in the favorite couch back then. I've found that
people with a fairly basic knowledge in logic from those days need relatively
little brief information on what goes down and what to think about before
getting an initial lesson in VHDL. After that they can start to make little
projects quickly. CPLDs is another of those wonderfull advances, not as complex
but very very nice never the less (reprogramability and no external program
memory, speed and flexibility).

Oh, I recall those PAL-dreams I had back at the days... when one dreamed up a
sea of PAL-chips in a pipelined fashion (I "invented" it myself, so it was no
supprice to find it in processors, it was as natural as sliced bread)
processing data. 

Cheers,
Magnus