Re: Microsoft Softcard and IIgs

[vladitx <vladitx@nucleusys.com>]

On Mar 12, 12:17 am, "Michael J. Mahon" <mjma...@aol.com> wrote:

> The clocking of the Softcard is very clever, and a very unusual
> "syncopated" clock.  It interacts with the Apple II by stealing
> DMA cycles, and therefore exercises areas of slot timing to their
> limits.
>
> The timing margin limits of some cards go beyond the timing margin
> limits of some Apple II's--particularly post-][+ Apple II's.

My guess too, some timing violation must occur. Softcard must have
been designed around 1980-1981, so is based around the venerable II+.
Sather has investigated the change in slot timing between II and IIe,
including the changes 65C02 introduces. But this card works in an
enhanced IIe, so the changes in IIgs must be even bigger. Or DMA
handling in IIgs is stumbled by the card.

Any II / IIe cards using DMA known to be working ok in IIgs?