How about the MAX485 series from maxim. If you'd like galvanic isolation, check out the burr-brown (TI) ISO485. Also there is the TI SN75ALS176A. Nat Semi appnotes AN-409, AN-979, and AN-1057 are helpful, along with with these app notes from TI: http://www-s.ti.com/sc/psheets/slla036b/slla036b.pdf http://www-s.ti.com/sc/psheets/slla112a/slla112a.pdf http://www-s.ti.com/sc/psheets/slla070c/slla070c.pdf Dave Challis -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Lawrence Lile Sent: Monday, February 14, 2005 8:12 AM To: piclist@mit.edu Subject: RE: [PIC] RS232 vs RS485 Yes, more precisely what I am looking for is a level shifter. My PIC will be a master and the devices on the RS485 side are all slave devices, i.e. they shaddap unless they are told to talk, so there is no problem with collissions. There is a well known protocol/language/command set what have you that talks to these devices that I need not bore you guys with there. If you are curious, they are ADAM 4015 temperature transmitters reading RTD's. (yes I know I could probably read RTD's with a PIC but I don't want to reinvent the wheel) You have already probably anticipated my next question - is there a simple chip that accomplishes this level shift ala' the venerable MAX232? --Lawrence >From: Jan-Erik Soderholm >Reply-To: "Microcontroller discussion list - Public." >To: piclist@mit.edu >Subject: RE: [PIC] RS232 vs RS485 >Date: Sat, 12 Feb 2005 16:23:50 +0100 (MET) > >Byron A Jeff wrote : > > > Here's how I read Lawrence's question: > > > > "Can a PIC UART talk RS-485 (RS-232) without a protocol converter of > > some sort (like a MAX232)?" > >Is a MAX232 a "protocol converter" ? >I thought it was a *level* converter/shifter between >TTL/CMOS and RS232 voltage levels. That has nothing >to do with any protocols, if I understand correctly what >a "protocol" is. > >IMHO, the answer to Lawrence is "it depends". >If there's only one RS232 and one RS485 "node", you could probably live >with just a level converter. But if it's a full RS485 "network" with >multiple "nodes", you must probably add some "protocol" to cope with >bus conflicts and collisions. > >So, we (or rather Lawrence) need to know more about the >RS485 node(s) at hand. What does the actual signal/protocol used look >like ? Is it a single RS485 node on "the line" ? > >Jan-Erik. > > > >-- >http://www.piclist.com PIC/SX FAQ & list archive >View/change your membership options at >http://mailman.mit.edu/mailman/listinfo/piclist _________________________________________________________________ Don't just search. Find. Check out the new MSN Search! http://search.msn.click-url.com/go/onm00200636ave/direct/01/ -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist