Re: TI-H: Multiple device control


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Re: TI-H: Multiple device control



Damien wrote:

> I'm not sure if this may be of any help or not, but, I have a splitter
> for my walkman and I notice that it takes more power to run both
> headphones (obviously). I'm assuming that this will be the same with the
> calcs but not as severe. I don't know what the resistances on the
> splitters are either, but, I first thought of remedeing the prob by
> suggesting a powered hub to amplify the signal, then I realized that
> each calc in the chain could be used as an amplifier. One calc transmits
> a signal to the next calc in the chain, it checks if its for that calc,
> and resends it to the next one. Maybe this is a possible suggestion for
> getting a network together, then again maybe not (too slow?)
> 
> Damien

The resistance of the cables is hardly a problem, and if it is, it can
be easily solved by adding a pull-up resistor to 5V somewhere (a
SPinTerface on a calc or an external battery source). But there might be
a problem with the capacitance. I haven't got the experience to tell how
much the capacitance would disturb the transfers. If it turns out to be
a problem (this should be quite obvious, it stops working with long
wires), the routines have to be slowed down. In fact, speed adjusting is
a feature I will add to the routines in the near future, because without
it they probably cause problems when mixing turboed and unturboed calcs.
Also, as it seems that an IR link won't be as fast as a wire link, there
has to be an option to slow down the bit rate if we ever use IR links.
In fact, I tried speed adjusting in a development version but then
removed it from the release version because I wanted to do it better and
they worked without it, at least with unturboed calcs. (Nobody I know
has a turboed calc, so I can't test it with one.)

The amplifier chain you suggested doesn't solve the capacitance problem,
so I think it's useless for now...also, it'd make the routines even more
complex.

-Ozone

-- 
*** Osma Suominen *** ozone@clinet.fi *** http://www.clinet.fi/~ozone
***


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