AVR-Chat

On Thu, 2005-08-18 at 14:10 -0500, Don Jackson wrote:
> Here's a problem I have that maybe some of the gurus on this list can
> help with...

   Well, perhpas a little extra hardware is in order, since the noise
problem could lead to loss of synchronization.

   You can obtain single chip filters that could be easily ruend using
external R-C va;ues to your two frequencies, then use Schmidt Trigger on
the output of thefilter to generate a trigger pulse everytime the signal
is at that frequency.  Just run those to a pair of interrupt enabled
inputs on your AVR, and count the pulses.  Since you know what the bit
timing is, it should be fairly easy to distinguish noise, and to
identify mutliple bits of the same freqency.

  Granted, external hardware may not be the ideal solution either, but
it occurs to me off the top of my head to be a way around the problem of
losing sync.

Tom