65C816 in APPLE][+ and APPLE//e

On Apr 21, 11:17 pm, Steven Hirsch <snhir...@gmail.com> wrote:
> I'm a little confused... Haven't a bunch of folks reported plugging a 65816
> directly into a 6502 socket - with a pin bent out?  Or, did they all really
> mean to say 65802?

Looking at the IIe circuit, it looks like simply
disconnecting pin 1
would indeed work because the Apple IIe leaves pins 3,5,35,36,38 and
39 unconnected.
A II+ on the other hand uses pin 3 (to disable the
data bus buffers) and grounds pin 38.

If you had a card that used the uP SYNC signal (pin 39 of the
peripheral bus) then the VPA signal from the 65816 would not be a
suitable replacement. As the Apple II(+) had USER1 on that pin and the
IIgs has /M2SEL I don't think that many cards would need it.

That only leaves the question of the 65816 driving the data bus during
phase 1. This might prevent snooping the video data, preventing a
program that uses this technique to synchronize with the video
scanner. Has anyone tested this after swapping CPUs?

Otherwise, a 65816 in a IIe with pin 1 bent up should not cause
problems (provided noise on the N/C pins does not interfere with the
default state of those signals).