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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 and 1, so don't use those.
fred
In your message you said:
> 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 is in Reply To:
 | | RE: resistor pull-up help!
|
| 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 (...) (25 years ago, 23-Mar-00, to lugnet.robotics.handyboard)
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