Re: 65C816 adapter for 6502 computers (aka Apple II)

["Bryan Parkoff" <bryan.nospam.parkoff@nospam.com>]

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.
    It would be ideal to redesign motherboard that it will have Apple I's
Apple II's, Apple II+'s, unenhanced Apple //e's, enhanced Apple //e's, and
Apple //c's ROMs to be BUILT in one motherboard using 65816 CPU.  Do not
worry that nanosecond measurement may not be the same, but the measurement
of MHz will match.  All Apple Models can share single 16MB RAM.
    You can be able to run all Apple Models continuously in the same memory
without needing to switch back and forth.  I like Vince Briel's idea to
replica Apple I, but I suggest him to do the same what my suggestion states.
    My project allows to have 6502, 65C02, and 65816 CPUs to be built in
software simulation.  My software simulation does support 6502's Bug with
invalid ADC & SBC's N, Z, and C flags however it is undocumented until I
notify when it is ready.  It would be great for the experts to be very
curious to experience with 6502's Bug.

-- 
Bryan Parkoff
"Vince Briel" <vbrielnospamme@comcast.net> wrote in message
news:WpN3c.135$i76.3008@attbi_s03...
> 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
>
>