Hi, I agree; I have put on my question very low items, sorry! I have in plan to use tree 16F84 as slave and one as a master. The overall lenght of the connection line is about 20 meters. Using tree wire for the connection bus, GND, TX and RX. All the slave device should be connect its RX pin at the TX wire caming from TX pin of the master. My trouble begins when I think to connect all the TX of the slave to the RX of the master. What can I do to avoid problems?? Can I use the RA4 for its open drain characteristcs? Friends, what do you think about? Ciao Leonardo -----Messaggio originale----- Da: Mark Willis A: PICLIST@MITVMA.MIT.EDU Data: gioved“ 17 dicembre 1998 2.55 Oggetto: Re: Multiple 16F84 in multidrop >I'm assuming RS485 would do here? Or do you want I2C? The problem I >have here is that I don't completely understand what you are asking; >Are these two PICs separated by 1 inch on the same PC board, or by tens >or hundreds of feet of cable? More details always helps people to help >you, I get the idea some people are waiting until you give them enough >to suggest something. > > Mark, mwillis@nwlink.com > >Leonardo De Palo wrote: >> >> Hi PICer, >> >> This is a second posting of the same problem; I resend it hoping someone >> will read it. >> >> I'm searcing ideas an comment about the necessity to connect in mutidrop, >> tree or more 16F84 on an another 16F84 functioning as a supervisor. >> >> I would use PBP functionality (serin, serout) to manage the pins for send >> and receive caracters. >> >> Anyone have suggestion to build the multidrop, connecting the 16F84 with >> the lesser count of external parts? >> >> Grazie e Ciao >> >> Leonardo >