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Paul,
In one of you earlier posts on this thread, you mention that you use a 20ppm crystal, can you share your source for this crystal. All the crystals I have found have a 50ppm tolerance at 25 deg and then a another 50ppm over temperature or then a worst case frequency tolerance of 100ppm, I would like to stay away from using a TXCO and 20ppm would be the right amount of acceptable tolerance for my project.
thanks,
Terry
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Hi Terry,Originally Posted by Terry
I am not near my lab so I cannot check right now ... however, I know I got them at either Digi-Key or Mouser. I just saw this part http://www.mouser.com/Search/Refine....t=815-ABL-4-B2
and will check in my lab and confirm if that is what I used. Back when I posted this example I let my trial circuits run for months and found the tolerance to always be +/- 20ppm or less with the xtals I used. I will let you know here shortly.
Paul Borgmeier
Salt Lake City, UT
USA
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I use the Abracon line. They have both SMT and through hole packages @20 ppm. They have some higher speed @ 10 ppm. Very reasonable, besides!
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Shouldn't it HzTimer be initialized to $7A120 (dec500000), rather than to $7A12 (dec31250)? And incremented by the same $7A120 for 1/2 second.
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Never mind; now I see you're dividing by $10.
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Err, Did you realise you ignored the author of your one second timer when he posted here?
Anyway, I was looking around for an explaination of why my clock drifts out
a couple of seconds in a few hours. Now I know.
I didn't know you could buy different qualities of crystals. Perhaps I should chase a better one.
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