RE: [N8VEM-S100:1069] A new S-100 6502 CPU Board

["Andrew Lynch" <LYN...@YAHOO.COM>]

Hi!  For the life of me I can't find it right now but I've seen a simple
schematic that uses latches and transceivers to extract the full 16 bit data
bus and 24 bit address bus from the W65C816S.  Basically it is the CPU plus
a couple support chips -- basically similar to how the 8086 does it!  It is
a full blown 16 bit computer with 24 bit address bus. It is a natural fit
for the S-100 bus, IMO.  Basically I recommend finding one of the many
W65C816S home brew projects and reviewing it.  Maybe discuss with the folks
at 6502.org also I know Dan Werner is very knowledgeable about the W65C816S
so maybe he can shed some light on this.

Thanks and have a nice day!

Andrew Lynch

> -----Original Message-----
> From: n8vem...@googlegroups.com [mailto:n8vem-
> s1...@googlegroups.com] On Behalf Of David Riley
> Sent: Monday, August 20, 2012 10:49 PM
> To: n8vem...@googlegroups.com
> Cc: <n8vem...@googlegroups.com>
> Subject: Re: [N8VEM-S100:1069] A new S-100 6502 CPU Board
> 
> On Aug 20, 2012, at 21:48, "Andrew Lynch" <LYN...@YAHOO.COM> wrote:
> 
> > Hi!  At this point since the W65C816S is an 8/18 bit chip I would
> > suggest a
> > 16 bit S-100 CPU board built around it.  Then the board could use the
> > S-100/IEEE-696 16 bit extensions and be purely 16 bit rather than
> > tweaking the S-100 6502 CPU V2 board which is a fundamentally 8 bit CPU
> design.
> 
> My memory of the 65c816 is a bit rusty, but isn't it only an 8-bit data
bus with
> an ALE equivalent pin to latch the upper 8 address bits from the data bus?
> 
> I'm thinking that might make it difficult to make a true 16-but board out
of it; I
> seem to recall that the primary benefit of the 65C816 was that it behaved
as
> an 8-bit CPU to the outside world (much like the 8088 as opposed to the
> 8086).
> 
> Or I could be remembering completely wrong. Either way, I'd be interested
in
> a 65C816 CPU board!
> 
> 
> - Dave=