Re: Microsoft Softcard and IIgs

[David Wilson <mcs6502@gmail.com>]

On Mar 13, 11:58 am, mdj <mdj....@gmail.com> wrote:
> On Mar 13, 4:55 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> > Actually, any DMA device in the Apple II must "let go" frequently
> > to prevent the 6502 from losing its dynamic state.  Woz did some
> > experiments and found that typical 6502s could tolerate much longer
> > "holds" than were specified, but the time was temperature- (leakage-)
> > dependent, so holding it longer than factory specs is iffy.
>
> That only applies to the older NMOS 6502's though, right?

The Rockwell R65C02 data-sheet says:

phi2 cycle time Max: R65C02 and R65C102 minimum operating frequency is
limited by phi2 low pulse width. All processors can be stopped with
phi2 held high.

phi2 Low Pulse Width: Max 5000ns