September 8, 2010
about 5 years ago
Has anyone tried to connect one of these to the RS-485 Breakout sku: BOB-09823?
I have an RS-485 Breakout connected to a Fez Domino and I am trying to communicate through RS-485 to a PC.
We have scoped out the RS-485 line and transmitted data in both directions looks fine.
If we connect a different RS-485 device from a different manufacturer then we can communicate to it in both directions.
So the issue seems to be communicating between two SP3485 based devices.
We have tried adding additional bias resisters similar to those on the other device. But it does not help.
Our best guess is that the issue is related to the 3.3V operation and the fact that each one has a terminating resister. Since an RS-485 network should really not have multiple termination resisters we wonder if this is the problem. Before I start modifying a board I wanted to see if anyone else had sucess with this setup.
As a product suggestion: a switch or jumper to disconnect the termination resister.
No public wish lists :(
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