RE: Re: Rabbit 2000

["Paul Smith" <ukha@xxxxxxxxxxxxx>]

>=20
> Looks a bit better!
> If I was you, I would use an interrupt driven input rather than
> polling. Polling can be made to work, but you must sample at at least
> twice the frequency of the pulse you are looking to measure, and it
> can all get a bit messy if your mark-space ratio is not even (which is
> pretty likely in a measuring meter led pulse scenario).
>=20
> For details on setting up an edge triggered interrupt, see here:
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> http://www.rabbitsemiconductor.com/documentation/docs/manuals/Rabbit2000/=
U
> sersManual/index.htm
>=20
> section 7.9.1 is the relevant bit
>=20
> If I remember correctly, the rabbit sample code that comes with the
> compiler also includes some examples of how to do this too (or
> something pretty close to it)?
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> PPS. Do publish the finished design, quite fancy one of these myself
:-)
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> Cheers
> Patrick

Hi Patrick,

That=92s a problem for me as what I am trying to do is monitor at least 3 =
inputs and the TN note from rabbit which hi-lights the 2000 module
interrup=
t problem and says "This is done by using an interrupt routine that is
driv=
en continuously by a timer, and using that
routine to examine a number of input lines that can be considered to be
int=
errupt requests. The synthetic
interrupt can be edge or level sensitive. When a condition is detected
requ=
iring a synthetic interrupt, the
routine calls the interrupt service routine.
This technique is more robust and requires less hardware than using hard
in=
terrupts. It is especially good
for counting pulses and can be used to count a number of input pulse
stream=
s at the same time. Experience
shows that counting pulses by using an interrupt input is an endless
source=
of trouble because of ill-conditioning
of the pulses and exceptions that often happen at the start and end of the
=
pulse train."

I've contacted rabbit for an example but they've not come back to me :-)

Any ideas ?

Regards,

Paul


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