Date   : Sun, 28 Aug 2005 13:20:44 +0100
From   : Sprow <info@...>
Subject: Re: 80186 co-pro

In article <1125229499.6156.13.camel@...>,
   Phil Blundell <philb@...> wrote:
> On Fri, 2005-08-12 at 07:35 +0100, Sprow wrote:
> > A small FPGA with distributed RAM is the way, then a can make the FIFO a 
> > few kB long!

> It turns out that suitable FPGAs are not quite as common as one might
> hope. 

Indeed. I've trawled all the usual candidates, and Xilinx quickly got
eliminated since the sensible-package-5V-tolerant-distributed-ram equation
didn't work out.

Tried
 Xilinx
 Lattice 
 Quicklogic
 Actel
 Altera
 Atmel
 
> Most of the newer ones (Spartan-3 and the like) lack 5V
> tolerance, which would be a pain.  My first idea was to use a
> Spartan/XL, but on further investigation it seems to be difficult to get
> synthesis tools for those. 
>
> So, the best compromise seems to be a Spartan-2.  These need both a 2.5V
> and a 3.3V supply, and they aren't available in PLCC packaging, but
> other than that they seem like they fit the bill.

The ARM coprocessor design has a AT40K05AL from Atmel on it now, though if
the software turns out to be as awful as it looks at first glance my only
other "ticks all my boxes" part is from the Altera Acex family.

PLCC would have been nice based on the pin pitch, but actually I find those
stupid J leads harder to solder than a quad flatpack,
Sprow.