Date   : Mon, 29 Aug 2005 15:58:10 +0100
From   : Phil Blundell <philb@...>
Subject: Re: 80186 co-pro

On Sun, 2005-08-28 at 13:20 +0100, Sprow wrote:
> 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.

Ah, right.  I was scared off the Atmel ones by the "DSP optimised"
claim, but maybe I was too hasty there.

I spent a little while yesterday playing with the Spartan-3 toolchain.
Judging from the synthesis reports, the free6502 core implemented in an
XC3S50 should be capable of 30MHz or so, with enough room left over for
the Tube bits.  You'd still need an external RAM, and driving that at
30MHz might prove tricky, but something around 25MHz ought to be
feasible.

So, my view now is that the w65c02s is a waste of time, and the original
"soft core in an fpga" approach was the correct one.

> 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,

Yeah, true.  Though, of course, you can use a socket with PLCC.

p.