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Subject: Re: stupid question
From: George Styles (
Date: 2002-08-19

Cool... can I ask the 'gurus' one more question please?

is it current-overload protected? ie, if I go mad and connect the +3.3v to
ground by accident, am I gonna 'cook' the SH2?

If its protected, I may get my soldiering iron out tonight...


----- Original Message -----
From: "Nielsen Linus (ext)" <>
To: <>
Sent: Monday, August 19, 2002 1:15 PM
Subject: RE: stupid question

> > I am assuming that the serial line can be configured from
> > software to be a simple digital input, which is bi-directional.
> Yes it is.
> > If this is the case, can we do the following:
> >
> > Usually have it set as an output, with 1 (+3.3v) on it.
> > Connect a capacitor across it and ground, to store some 'juice'
> > Use a simple push-to-make switch to ground it through a
> > potential divider
> > Each (say) 1/100s we could flip the digital line to an input,
> > and read it.
> > If its 0, the switch is down, if its 1, the switch is not down
> > Bingo! we have an input, with just a couple of passive
> > components, and no battary
> Sounds feasible, yes.
> > Can someone who has studied the schematics/ knows the SH2
> > processor tell me if this is possible?
> I can't see a reason why it shouldn't work.
> /Linus

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