🚀 go-pugleaf

In article <1049@castle.ed.ac.uk> dil@lfcs.ed.ac.uk (David Laurenson) writes:
>I am trying to build a transputer link analyser that passively
>monitors the communications link between two transputers, and produces
>a high level (hopefully) form of debugging/performance monitoring.  I
>am currently trying to find a suitable differential driver/receiver
>pair that I can use that will not introduce more than 3nS skew.

Can someone from INMOS please tell me why the skew spec for 20
Mbits/sec is so tight?  6% of a bit makes things very difficult for
link buffers as the above user has discovered.  Why does the skew
become more important at higher rates?  30 ns @ 5 Mbits/sec, 10 ns @
10 Mbits/sec and 3 ns @ 20 Mbits/sec seems like a strange relationship
to me.  Using INMOS link switches, which do bit regeneration, is
obviously the thing to do, but these *do* slow down transfers, despite
what the documentation says.

-- 
Hubert Matthews      ...helping make the world a quote-free zone...
hjm@cernvax.cern.ch   hjm@vxomeg.decnet.cern.ch    ...!mcvax!cernvax!hjm

In article <1049@castle.ed.ac.uk>, dil@lfcs.ed.ac.uk (David Laurenson) writes:
: I am trying to build a transputer link analyser that passively
: monitors the communications link between two transputers, and produces
: a high level (hopefully) form of debugging/performance monitoring.  I
: am currently trying to find a suitable differential driver/receiver
: pair that I can use that will not introduce more than 3nS skew.
: 
: I am currently looking at the uA9637AC and uA9638C pair, but I am
: unsure of their skew tolerance.   Has anyone already buffered the
: links successfully, and if so what chips did you use?

I'm probably being niave but, would C011 chips make this sort of thing
fairly easy?  I have to admit that I don't know what perfomance loss
they cause.

Lindsay Patten            "People are package deals - No substitutions allowed"
Pattern Analysis & Machine Intelligence Group                   lindsay@watnext
Department of Systems Design Engineering           lindsay@watnext.waterloo.edu
University of Waterloo              {utai|decvax|uunet}!watmath!watnext!lindsay