Daryl Rictor has come up with a low profile 65816 to 6502 adapter that
should work on the Apple II series computers. These boards are not tested
but other people have done tests to get the idea working. The board is about
the same size as the 6502 so there are no worries about space requirements.
Check his website for more details. Also the 6502.org thread about this
project. Imagine running a 65816 on a II+ or IIe! Volunteers are needed so
check it out.

Daryl's web site information on this:
http://65c02.tripod.com/conv.html


6502.org discussion thread:
http://www.6502.org/forum/viewtopic.php?t=186&postdays=0&postorder=asc&start
=0


What do you guys think?

Vince
--
Replica I
The Apple I clone

http://www.applefritter.com/apple1/members/replica1/index.htm





>     You win!!  I am curious.  Do you own "Understanding an Apple II+ &
Apple
> //e" manuals?  Please tell me how did you make 65C02 and 65816 CPU to work
> with Apple II+?  Did you plug 65816 CPU into Apple II+'s motherboard
> already?  The problem is that Apple II+'s ROM must be located in Bank $FF
> because it is where $FFFC is pointing in Bank $FF.
>

This is not my project, it's Daryl Rictor's. The tests they have done are on
older systems like the Oric. I'll gladly test one on my replica 1 and Apple
II plus. Board runs haven't been done yet and this is still a work in
progress. I assume when you refer to $FFFC you are referring to the reset
location that the 6502 jumps to on a reset cycle? This is the same across
the 6502, 65C02 and 65816. I'm getting a couple of these board and trying
them out. A 65C02 is essentially a 6502 with improvements such as added
instructions, lower power draw, and other features and can't think of off
the top of my head. The 65C02 is a straight drop in replacement for the 6502
but you shouldn't need to swap those out unless you require the added
enhanced instruction set of the 65C02 for some reason.

No, I don't own "Understanding an Apple II+ & Apple //e manuals". I sold off
my //e some time ago and now I'm left with my many II+ computers. Keep in
mind the adapter Daryl developed is still in its early stages and not all
machines have been tested. This is why he is looking for people to get
together and order a run of boards. You then must get the components and
solder them on this tiny board (IC's are SMD and require a reflow oven or
other method).

Cheers,

Vince

--
Replica I
The Apple I clone

http://www.applefritter.com/apple1/members/replica1/index.htm





Bryan Parkoff wrote:
> Ouch!!
>     I am sorry to state.  Unfortunately, 65816 CPU will NOT WORK on Apple
> II+ nor Apple //e because 65816 CPU's and 6502 CPU's timing are not EXACT
> the same.  They have different nanosecond measurement.  For example, 6502
> CPU requires 400 ns to run while 65816 CPU runs 250 ns (I can't remember
> exactly.)
>     "Understanding an Apple //e" manual stated that someone tried to plug
> 65C02 CPU into Apple II+, but very several instructions work while often it
> crashes at all times.

You might be interested in this site
http://home.hccnet.nl/g.baltissen/02to816.htm
I've built and used this adapter and it works quite well in a IIe
or II+.

Jim Sather did limited experiments with a few different 65C02 in the
II+. He certainly didn't try them all.
A couple of 65C02 that I've used for years in the II+ are the
GTE G65SC02P-1 and the R65C02

Wayne