localtalk, was Re: pcmcia ethernet card support for m68k?
On Wed, 12 Aug 2020, Michael Schmitz wrote:
>
> The bit about bus delay should be possible to figure out from timing
> access to the SCC data port and compare to RAM access. That might
> already decide the issue.
>
The Guide to Macintosh Family Hardware says that SCC accesses are paced by
the GLUE logic.
"The SCC requires 2.2 uS between accesses for its intemal lines to
stabilize; in the case of back-to-back accesses to the SCC, the GLUE
holds off the second access for that amount of time."
That's 454545 accesses per second (peak).
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