a classiccmp electronics project?

From: Tom Jennings <tomj_at_wps.com>
Date: Mon Aug 2 14:42:28 2004

> > A cute trick commonly used in the CP/M days (and later) was to put a
> > boot EPROM board in the same (conflicting) memory space with RAM; ...
> > EPROM board read access generated many wait states; the trick was the
> > EPROM board ignored write cycles but the underlying RAM didn't. I forget
> > how we handled the EPROM 'read' cycle but it was buss-safe (S100) and
> > simple.

On Sun, 2004-08-01 at 18:56, Bill Sudbrink wrote:

> I believe that was the "PHANTOM" line... pin 67 (according to _THE_S-100_
> AND_OTHER_MICRO_BUSES_ by Poe and Goodwin).

Ugh! I remember now! >shudder< S100 interfacing dribbles back into
brain... not good! :-)

(I should go buy an S100 book though for reference. I have nothing from
that era at all except one WordStar book.)
Received on Mon Aug 02 2004 - 14:42:28 BST