Subject:
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RE: resistor pull-up help!
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 23 Mar 2000 00:12:56 GMT
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Original-From:
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Jose Luis <JLDF@MAILsaynotospam.COM>
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Viewed:
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1312 times
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Hi,
Are the general-purpose analog inputs in the exp board also connected to
the pull-up in the HB main? To use that kind of sensors the only way is to
cut the trace in the HB, no matter I have or no the ExpBoard?
Thanks
Jose Luis
--- Original Message -----
From: Fred G. Martin <fredm@media.mit.edu>
To: <lugnet.robotics.handyboard@lugnet.com>
Sent: Tuesday, March 21, 2000 10:49 AM
Subject: Re: resistor pull-up help!
> the exp bd inputs plug into the inputs on the main HB. so you still
> have to remove the pullup on the main HB.
>
> just cut the short trace on the underside of the board between the
> signal input pin and the pullup resistor.
>
> f.
>
> In your message you said:
> > Hi all,
> >
> > I'm trying to connect a pair of GP2D12 to my handyboard. I know there
is
an
> > issue with the handyboard pull-up resistors and these devices so I
figured
> > I'll try to use the unused LEGO sensor connectors on my expansion board
(I
> > don't have any LEGO sensor anyway).
> >
> > So I removed the resistor pack RP2 on my expansion board. According to
my
> > understanding of the expansion board layout, those are the one
providing
the
> > pull-up for the 4 LEGO input, RP2 is a 10Kx5 used only for this
purpose.
> >
> > And of course it's not working :^(. I still got a 255 (251 to be exact)
> > readout on analog 28-31 without anything connected and I was expecting
to
> > read 0 from there... And because of that my GP2D12 are still not
working
> > correctly.
> >
> > What did I miss? What else should I do to transform these into floating
> > inputs?
> >
> > -- Eric
> >
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Message has 1 Reply:
 | | Re: resistor pull-up help!
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| basically, yes. the inputs from the expansion board feed into the inputs on the main board. if you need a high impedance input, your best bet is to cut a trace on the main board and use one of those inputs. the exp bd takes over main board inputs 0 (...) (24 years ago, 23-Mar-00, to lugnet.robotics.handyboard)
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