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Old August 17th, 2016   #7
Task Group Member
Join Date: Aug 2008
Posts: 369

You should be able to attach PDFs to a post using the "Go Advanced" button under the "Quick Reply" window. You can also attach small images, but the resolution limit is usually too small to be useful. Just remember that everything you post is visible to the whole world.

When you say Carrier Detect, do you mean that you're detecting whether the 485 line is driven, vs. floating, and then making the direction decision based on that? That makes me a little nervous. You're basically relying on the analog characteristics of the signal. Can you reliably determine a weakly driven line (long cable, heavy loading, low power line driver, etc.) vs a strongly biased line? Make sure you test with with a variety of both 5V and 3.3V line drivers, and different terminate schemes.

I'm mostly a digital person, Bob's done some analog work on the 485 signal and may have better advice if he reads this. It's the real-world performance that matters. Try it, it might work!
ericthegeek is offline   Reply With Quote