23 Mar
2014
23 Mar
'14
4:51 a.m.
At 06:55 PM 3/22/2014, Philipp Hachtmann wrote:
Everything about bus drivers seems to be said. And has
been said long before I
even had the idea to build something like the USB board.
All that could be interesting in that area would be practical experience with
different drivers, hardware configurations....
--- Hi Philipp, I agree with you that info on practical experience with various
configurations and modern bus interfaces would be interesting. However, I for one, have
benefited from discussion here of bus drivers/receivers. As a result of the questions
raised, I did the additional research which revealed that DEC had made prominent usage of
ordinary TTL gates as Omnibus receivers. I believe that fact wasn't widely known.
Since the modern bus transceivers meet or exceed the output current, output voltage levels
and input loading of the best DEC parts, the only remaining questionable specs were the
receiver input levels. Showing that DEC endorsed TTL input levels for Omnibus receiving
established modern transceivers as fully qualified for the RAM Board project.
The positive result which has emerged is that there is no reason to suspect that Omnibus
interfacing with modern parts (at least in applications similar to the RAM Board) is at a
disadvantage relative to DEC practice.
Steve Lafferty