Re: [N8VEM-S100:1032] A new S-100 6502 CPU Board

[Paul Birkel <pbi...@gmail.com>]

I'd be interested in taking this on in a year or so once "other business" has been taken care of.  In the meantime I've been slowly proceeding down the ECB-based path, although currently focused on the 6809 side of that PCB (http://n8vem-sbc.pbworks.com/6809-host-processor) rather than the 6502.

I'd certainly prefer to take it on using the upwards-compatible chip :->.  I haven't looked into the available open-source tooling (but would of course start from: http://www.z80.eu/dos65.html).  Perhaps Douglas can enlighten us?

Regarding a SBC, I'd prefer the S100-based bus master-slave solution -- yes, with the associated speed limitations ...

On Wed, Aug 8, 2012 at 10:00 AM, Douglas Goodall <douglas...@mac.com> wrote:

The 65816 was the CPU in the Apple ][ GS (I have several).

Apple considered it a good upgrade from the plain 6502.


Douglas

On Aug 8, 2012, at 6:10 AM, Ian May <fps1...@gmail.com> wrote:

I think the CPM like OS would have been Richard Leary's DOS/65. I know
that I would need Richard or someone else to produce a modified DOS/65
to make use of the memory beyond 64k, it would take me a very long
time to do it! I started out with 6800s and 6809s so the first time I
had to program a 6502 type machine (it was a Rockwell R6511 in the 64
pin QUIP package) I also found those 8 bit index registers a little
confining.

I'd agree that if nobody else is interested in the 65816 stick with
what you have now. It may be better to build a board in the n8vem
group something like Sergey's ZETA and run the 65816 flat out at 14
MHz. According to the timing information in the data sheet the address
to data access time needs to be 30nS or faster at 14MHz, so it will
need fast static ram chips very close to the CPU. On an S100 card the
addresses probably won't even have made it to the edge connector in
30nS!

Cheers,
Ian.

Douglas Goodall