From owner-freebsd-hackers Sun Sep 7 23:28:47 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id XAA11484 for hackers-outgoing; Sun, 7 Sep 1997 23:28:47 -0700 (PDT) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id XAA11479 for ; Sun, 7 Sep 1997 23:28:36 -0700 (PDT) Received: from word.smith.net.au (lot.atrad.adelaide.edu.au [203.20.121.21]) by genesis.atrad.adelaide.edu.au (8.8.5/8.7.3) with ESMTP id PAA24587 for ; Mon, 8 Sep 1997 15:58:24 +0930 (CST) Received: from word.smith.net.au (localhost.atrad.adelaide.edu.au [127.0.0.1]) by word.smith.net.au (8.8.7/8.8.5) with ESMTP id PAA01633; Mon, 8 Sep 1997 15:54:57 +1000 (EST) Message-Id: <199709080554.PAA01633@word.smith.net.au> X-Mailer: exmh version 2.0zeta 7/24/97 To: "Jamil J. Weatherbee" cc: hackers@FreeBSD.ORG Subject: Re: Speaking of device drivers. In-reply-to: Your message of "Sun, 07 Sep 1997 23:13:24 MST." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 08 Sep 1997 15:54:56 +1000 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > > > Sounds like a lot of overkill, IMHO. This isn't the sort of thing you > > want in an industrial environment. > > I didn't really have a word in this respect, I am just supposed to deliver > a working software--- people put hardware together demonstrate that it > functions correctly and then expect it all linked. Yuck. I hope you are billing the crap out of these people. Unless there's something really compelling about having multiple machines, it's basically a losing architecture. > > >From my POV I would be using one or more RS-485 links and either custom > > slaves at suitable points or off-the-shelf 485 slaves like the > > Advantech ADAM modules. The only time this breaks down is when you > > have precise timing requirements between multiple slaves, and often the > > easiest way to go then is to have a separate transmit-only time-sync > > bus. > > I actually have looked into this I've done some significant programming > on a 68hc11 board with RS485 ports We use these a *lot*. > also I am working on an unrelated > solutions to another problem on the 68hc11KA4 a truly versatile processor We mostly use the HC811E2/711E9/711E12; the '2 is an all-EEPROM part and thus great for field upgrades, the E9 is easy to get, and the E12 has loads of ROM space. > very hard to get for your run of the mill embedded solutions), in fact if > it was up to me I would of found a multiport rs485 board (i think > Industrial computer source sells some of these) and done the whole thing > with a network of 68hc11's (actually you can implement rs485 stuff on a > bus which is really neat -- and next time I design this kind of stuff I'll > keep that In mind). Heh. I have a driver for stock '485 boards (we use the Advantech PCL-740) which does the 9-bit address-prefix mode, which I keep meaning to commit. As you might guess from this, we use '485 pretty heavily. > One of the major problems with the networked embedded > design was analog ports, I have 48 12 bit analog ports and I could not > find any embedded hardware capable of sampling 256 ports at that > resolution (also 10,000 samples/second) , so I am using a analog io card > in a remotely connected > machine, plus the processing overhead for the kind of operations being > done are somewhat significant. Is that 10Ksamples total, or 10K per channel? For that sort of situation, I'd go ahead with the card-in-PC approach, but that's still just one PC. > sorry about the run on > sentences I have written that way since I was 8 years old in really long > sentences without periods or punctuation I guess just wanted to be Cognitive dissonance is all well and good, but remember that your goal here is to communicate, not to piss other people off. > In other words I needed a little more power than I could of gotten out of > some embedded hc11 system for what I am doing Not just one embedded system, but lots of them. Parallel processing 8) Speaking of which, does anyone remember the old Byte daisy-chain Mandelbrot processor? mike