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Old July 24th, 2006   #5
Join Date: Jun 2006
Posts: 11

Hi Scott,

Yes, I believe I have seen this occur. It stumped us for a few days in fact. It happens if you have just the right 3 UID's that are numerically close to one another. The "wire-or" that makes A&B look like C changes the checksum perfectly, as it is only one bit that changes in the message and one bit that changes in the checksum. A's UID is one bit off of that of C and B's UID is also one bit off of C. We're using a very high speed processor with interrupt driven serial algorithms so the response synchronization across multiple responders is very tight.

We'll deal with it by having the controller notice when its happening and continue to branch. I hope -- unless I'm totally mistaken somehow -- that this thread will some day save someone some frustration.

-John Sondericker
Wybron, inc.
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