On Wed, Jun 23, 2004 at 09:02:21AM +1000, Trungie*! wrote: > Thanks for the replies! It amazes me whats out there! I'm excited about this > project! > > To answer Bryon's questions > > > 1) Do all of the PICs have to be able to communicate at the same time? > Not necissarily but i'd like to send data each second from each pic about > it's status. Not a problem. > > > 2) Is the communcations required going to have to be bidirectional? > Yes. I'd like to be able to communicate to the PICmicro. Not a problem. But if it's one way it's simpler to implement. > > It seems from a consensus so far most engineers recommend the multidrop! > Which sounds like fun! Cool. > > The multidrop is a totally new concept to me. Where would you recommend i > start? Are there any recommended books which i could buy and then make a > small network with a multidrop? Or perhaps a project website? > Jan Axelson's Lakeview Research is a treasure trove of information: http://www.lvr.com/serport.htm Her Serial Port Complete is an excellent book on the subject. You can take a read of her chapter one before deciding to purchase. > Upon connecting them to the PC, i'd like to somehow give them ip addresses > (fun factor). I was thinknig about using iptables. Will using a multidrop be > hinderous to this goal? Helpful. If you really want to tackle IP then SLIP (Serial Line IP) is the fastest ticket. It's really little more than a thin wrapper over raw IP that sent over the serial port. It's a project that's also on my vast list of things to do, but it's further down than most. I'm still trying to figure out if there needs to be an intermediate gateway between the PC and the rest of the network. > > Would anyone know a ball point mark how much the XPort embedded Device > servers cost? I'm still awaiting their reply :( > http://www.lantronix.com/products/eds/xport/ No clue. > > It would seem they would solve my problem, but im thinking they cost $50 > each. I'm trying to keep costs fairly low. > > Thanks guys, i'm amazed with all this! Glad to help. BAJ > > > ----- Original Message ----- > From: "Byron A Jeff" > To: > Sent: Wednesday, June 23, 2004 6:22 AM > Subject: Re: serial port dilemma - design advise requested > > > > On Wed, Jun 23, 2004 at 01:44:11AM +1000, Trungie*! wrote: > > > I have a PIC device that connects to my PC via serial port for constant > > > communication. > > > > OK. > > > > > > > > I would like to have over 10 PIC devices connected to my PC somehow for > > > communication. > > > > Well that's a challenge. A couple of questions: > > > > 1) Do all of the PICs have to be able to communicate at the same time? > > 2) Is the communcations required going to have to be bidirectional? > > > > > However, i would not like to buy some sort of expensive multi serial > port > > > card for it. > > > > That could be painful. > > > > > > > > What sorts of things can i do to over come this problem? Potentially i > would > > > like to use over 10 of these PIC devices at once. > > > > Well it gets back to the questions above. If each and every PIC needs to > be > > able to independently communicate at the same time, then you're pretty > much > > stuck with having a serial port per PIC and the multi-serial solution. > > > > However if you can arrange so that the PC can pick which PIC to talk to, > then > > you can arrange what is known as a multidrop network where all of the PICs > > share the same serial connection. > > > > The most popular hardware interface for multidrop serial is EIA485 (also > known > > as RS485). It's cheap and reliable. However there's no specified protocol > that > > sits on top of it to talk to each of the individual PIC nodes. So you'll > have > > to fish around for ways of doing it. > > > > Hope this gets you started on the subject. > > > > BAJ > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > > > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.