Re: [Gumstix-users] Re: INT0, Port D, Robostix

[Ed C. <eca...@gm...>]

I'm actually using your int6 sample code.  I was getting similar
results with my own code, but your code was useful since it outputted
to serial as well (its hard to debug using only LED's =3DP).

I'm definitely connected to the right ports.  Shorting between 5 and 0
generated interrupts appropriately.  I guess it will take some playing
around to find cap values that don't dampen the response I want too
much, but that eliminate the noise.

When connecting the cap, what considerations do I need to take into
account?  The cap goes in parallel with my input(from the input to
ground), right?

On 2/20/06, Dave Hylands <dhy...@gm...> wrote:
> Hi Ed,
>
> On 2/20/06, Ed Camacho <eca...@gm...> wrote:
> > Ok...so I'm getting just a TON of interrupts.  Even when I'm not
> > turning the encoder, I'm getting interrupts.
>
> So, I'd try disconnecting the encoder. Use a jumper wire and short the
> input to ground and then to +5. You should get a bunch of interrupts
> when connecting/disconnecting but should get no interrupts when in
> steady state.
>
> Are you sure you're connected to the correct pins? Read the labels on
> the bottom of the board, not the numbers on the top of the board
> (these differ by one from the ones on the bottom). Unconnected CMOS
> inputs will tend to follow the signal next to it and can make it look
> like something is kind of working even when you have it hooked up
> wrong.
>
> > My understanding of these encoders (HEDS 5700) is that they are logic
> > hi/low at 5v/0v.  I was measuring the voltage that was causing the
> > unlimited interrupts and it seemed to be 5v.  Can I debug this without
> > a scope?  Is there some component I'm missing which will smooth out
> > what the robostix is interpreting as an edge?
>
> Can you send us the code you're using now? It would be worth double
> checking everything.
>
> Putting a 0.1uf or 0.01uf cap may help if there is noise being picked
> up on the input signal.
>
> Did you enable the pullups?
>
> --
> Dave Hylands
> Vancouver, BC, Canada
> http://www.DaveHylands.com/
>
>
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