Re: GS 65816 Chip??

[nathan@cco.caltech.edu (Nathan Mates)]

In article <3qetpp$ql4@triode.apana.org.au>,
Andrew Roughan <posty@triode.apana.org.au> wrote:
>Nathan Mates (nathan@cco.caltech.edu) wrote:
>:    I wouldn't recommend this at all. The 65816 and 6502/65C02 are not
>: pinout compatible, and you can't replace earlier chips with it,
>: according to my Lichty & Eyes manual on the 6502, 65C02, 65802 and
>: 65816.

>Well, I've placed my 65816 into my platinum //e. (I use it to run Merlin16).
>So I'd like to hear the electrical reasons why this should not be done.
>Can someone explain exactly what damage is being done?

   Well, looking at the pinouts printed in Lichty & Eyes, it seems
that most of the pins are the same, but a few pins have changes. The
65816 takes a few pins and puts them to dual use, such as pumping the
bank address out on the data pins during fetch and the like. The rest
look mostly like timing things (I'm not a EE) that got replaced by
stuff like Abort, hooks for external Virtual Mem support, and such.
Whether these signals are in any way compatible with the 6502 pins,
I really can't quite tell.

   If a 65816 is working in a 6502-designed motherboard, good for you.
As to damage or anything else, I really can't comment further. Maybe
some of you Electrical ENgineers can comment further.

Nathan Mates



-- 
<*> Nathan Mates http://www.ugcs.caltech.edu/~nathan/      <*>
# And he said to them, "To you has been given the secret of the
# Kingdom of God, but for those outside, everything comes in 
# parables" Mark 4:11, NRSV