ADM3073 (RS485 full duplex) problem

[meysam_abbasinia]

hi,

I designed RS485 bus by ADM3073 full duplex driver, but I have bad problem, when I use one slave and one master every things OK but when I use it for 2 slave I have problem and I don't receive data from one slave, my code is OK and I test my boards whitout RS485 driver and every things OK but when I use this IC one slave data missed.
note: I use termination resistor(120 ohm)
why?

 

[KlausST]

Hi,

How did you control driver_enable?

It should be easy to check the signals with a scope...what does it show?

Klaus

 

[betwixt]

Are you using a termination resistor at each slave maybe? You should only have one terminator in the chain, preferably at the slave furthest away from the master.

Brian.