Subject: Standards

From: Bernie Roehl <[email-masked]>
Date: Tue, 22 Oct 91 11:10:39 EDT

Some micellaneous thoughts on standards:

After some careful thought, I've come to the conclusion that the various
VR input devices will be too varied to make a single, universal interface
practical.

What I suspect we'll see are increasing levels of data abstraction; the
glove routines we have now well work as currently defined, and a higher-level
routine will map glove movements, gestures and buttons to a more generic
form.  Don't make the lower levels more complex; instead let them do what
they do well and let the higher levels process the results.

Since we wll probably have a set of routines for each VR input device we
develop, I would propose a naming convention: all the routines related to
the glove we love will have names prefixed with "glove_".  Thus our
initialization routine would be glove_init(), our reading routine would
be glove_read(), and our wrapup routine would be called glove_quit()
(which, as an earlier poster pointed out, is probably more meaningful
than "glove_reset()").

As to the issue of external microcontrollers... I think it would be nice
to standardize a protocol for talking to them.  Even though I don't have
one (yet; we have a 68HC11, and I'm just waiting for the person who has
the code to post it), here is what I propose:

Host sends 'H' to board to put glove in hi-res mode
Host sends 'P' to board to poll it for a 6-byte packet
Host sends 'C' to board to tell it to send full 12-byte packet continuously
Host sends 'S' to board to stop continuous sending
Host sends 'D' to board, followed by a 1-byte byte count, followed by
     that number of bytes of data to load into a buffer and execute

-- 
	Bernie Roehl, University of Waterloo Electrical Engineering Dept
	Mail: [email-masked] OR [email-masked]
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