Subject:
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Re: expansion board problems
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 10 May 2000 23:03:34 GMT
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Reply-To:
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GLIVICK@PACBELL.avoidspamNET
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Viewed:
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870 times
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Claudia,
Without a lot more detail, it will be difficult to solve this one over the
internet. If you can take a few minutes and regroup, maybe someone will have an
idea.
The kinds of things it would be good to know, interspersed with my comments:
1. It is not likely that a series of expansion boards all have the same problem,
although if there is a design problem at work it's at least possible. When you
experience the wierd analog signals, exactly which ports are they occuring on?
Some ports are pulled high with pullup resistors on the expansion board, some are
not.
2. Do the strange signals stop and stay fixed at some value when the input signal
is unplugged from the board? In short, is it the input sensors or the board that
is going whacky?
3. Have you reseated all the IC's on the main board?
4. What does the + 5 volt power line look like when these strange things are
happening? Is is stable? The analog signal is read by comparing the input
voltage to the power on the board (5 volts).
5. Have you tried another Handy Board?
6. Is the voltage regulator on your Handy Board getting too hot? Are any other
chips warm to the touch?
There are just a few of the things it would be nice to know. Be as specific as
you can when you respond, in terms such as "when I watch the input signal at
analog input 17 by reading it's value from the command line in IC, I see it
float. However, when I check the signal right at the input pin on the expansion
board with a voltmeter, it is stable at 2.5 volts." That way we have a chance to
help you with this very strange problem. And as likely and not, you'll find the
problem on your own by being so thorough in your investigation. Let us know
either way.
Gary Livick
Tiny HC11 products for your robot
http://www.teleport.com/~raybutts/
Claudia Bernett wrote:
> a follow-up to my own message - it seems that this problems occur WHILE i am
> actually running the application and using the project. if anyone can help at
> all - i would be very grateful, i am at a loss and urgent to get this working.
>
> i have built sixteen very simple mats which are made of vinyl, copper, and
> foam - it is a simple contact which, when stepped on, drops the value downt to
> nearly 1. i had a small model of this working for months, and only after a
> while using the actual size project, did this start occuring. there is no
> problem with the handyboards, but the expansion boards, one after one, seem to
> be flipping out. suddenly - the values begin skipping all over the place, or
> in the latest case, 6 of them just rest at 4.
>
> does anyone have any ideas for me? i have tried different code and different
> boards, nothing works, and i am at a loss to understand.
>
> thanks in advance,
> claudia
>
> In lugnet.robotics.handyboard, Claudia Bernett writes:
> > hello.
> >
> > i seem to be having an expansion-board problem which is very puzzling. i am
> > using all sixteen ports, and am in the process of putting together a project
> > which requires that it be stored with all sixteen ports occupied for a week or
> > two at a time - but unpowered. after this period of storage, it has (two
> > times now, with two different expansion boards) begun to behave in a very
> > strange way. the values are essentially all over the place, jumping from 255
> > to 25 to 4 to 115 etc...
> >
> > has anyone encountered this - and does anyone have any idea what could be
> > causing the problem? this has occurred with two expansion boards in a row.
> >
> > thanks in advance,
> > claudia
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Message is in Reply To:
 | | Re: expansion board problems
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| a follow-up to my own message - it seems that this problems occur WHILE i am actually running the application and using the project. if anyone can help at all - i would be very grateful, i am at a loss and urgent to get this working. i have built (...) (25 years ago, 10-May-00, to lugnet.robotics.handyboard)
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