Because RS-485 is an electrical specification and not a hardware or protocol specification, as such, it does not describe any method for collision detection. However, for this circuit I have added it. Also, I've included an "anti-chatter" circuit (basically a charge pump) to the "talk enable"; in the event that the PIC goes south while talking to the bus, the device can not tie up the bus (note: the interface circuit does not require the use of the anti-chatter circuit). Douglas Wood Software Engineer dbwood@kc.rr.com Home of the EPICIS Development System for the PIC and SX http://epicis.piclist.com ----- Original Message ----- From: "Ruben Jvnsson" To: Sent: Sunday, August 18, 2002 2:02 AM Subject: Re: [PIC]: CAN or RS-485 ? > If you are interested in a full-duplex, multi-drop RS-485 circuit with > collision detection, I have in a 17C756 reference design (does not > rely on using the 17C756). > I was under the impression that RS485 can not handle collision detection reliably. Does this really work? Ruben ============================== Ruben Jvnsson AB Liros Elektronik Box 9124, 200 39 Malmv, Sweden TEL INT +46 40142078 FAX INT +46 40947388 ruben@pp.sbbs.se ============================== -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body