Allison: 2910c version of z80

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sun May 6 13:50:11 2001

In 1990, when the 3000-series parts were new, the 3030's cost around $300, each,
in thousands, the 3042's, a bit more, and the 3090'w which were the biggest at
the time, cost about $650 in the <2k units per year we were buying.

There are still plenty of XILINX parts that, say, AVNET wants >$1k for in small
quantities. I agree, however, that the SPARTAN series, which seems to be the
most accessible series of XILINX parts, are quite reasonable, and the PLCC-84 is
far and away the most reasonable package for prototyping.

However, if you want to use the >300-pin packages that some devices force you to
use, the adapters for applying them to a prototype board, cost >$500. True,
this is for a socketed part, and the bulk of the cost is for the socket.
However, I have a tough time justifying a prototyping adapter for each of
several devices in the same package, particularly since they're so difficult to
solder by hand. (I'm gradually going blind ... ) Moreover, the BGA prototyping
sockets required for the really high-pin-count parts cost some real money.
Making an adapter PCB for these is not a trivial process either, since there's
no way to rework the BGA's if their contacts don't all "make" and I'm not
willing to gamble with the high cost of these devices.

It's just as difficult accomodating the smaller parts from other vendors, with
their odd-fraction-of-a-millimeter pin pitch, etc. Eventually I'll figure out
how to manage the problem. For now, however, I'm going to complain every time I
get a chance.

XILINX, as I said before, is VERY generous with support of all sorts,
maintaining an active presence on the comp.arch.fpga newsgroup to help with all
sorts of questions. Once you've bought even the cheapest support software,
they'll help you all you want. Moreover, their free WEBPACK software is
adequate for many tasks. The higher-end tools required to do a proper job on a
BIG task cost some dough, though.

Dick

----- Original Message -----
From: "emanuel stiebler" <emu_at_ecubics.com>
To: <classiccmp_at_classiccmp.org>
Sent: Sunday, May 06, 2001 11:19 AM
Subject: Re: Allison: 2910c version of z80


> Sorry Richard, I have to jump in here ;-)
>
> Richard Erlacher wrote:
> >
> > I'd not be afraid to give the SPARTAN series a try for building an
experimental
> > version of a '70's-'80's generation CPU. They are relatively (choke)
> > inexpensive
>
> $20 for the xcs10, plcc84 package.
> What did you pay for your 3k gates 3030 before ?
>
> > and available in versions with sufficient on-board RAM that you
> > might not need the higher pin counts required to interface external memory.
> > Unfortunately, the high-pin-count parts are hard to prototype.
>
> There really many prototype boards out there. And cheap ones ...
>
> > The solution is to go to a gun show and buy a pistol, then stop at the local
> > liquor store to make a withdrawal.
>
> Student license is $100 & the small prototype board around $150.
>
> Still much cheaper than a good gun ;-)
>
> > Then you'll be able to afford the
> > prototyping sockets, normally costing $400-500 or so when built onto a
> > wire-wrap-compatible adapter. Life is easier when one simply uses the
84-pin
> > PLCC versions.
>
> Cheers
>
>
Received on Sun May 06 2001 - 13:50:11 BST