From owner-freebsd-hackers Tue Jan 30 19:27:46 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id TAA06437 for hackers-outgoing; Tue, 30 Jan 1996 19:27:46 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id TAA06430 for ; Tue, 30 Jan 1996 19:27:38 -0800 (PST) Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id OAA17213; Wed, 31 Jan 1996 14:04:31 +1030 From: Michael Smith Message-Id: <199601310334.OAA17213@genesis.atrad.adelaide.edu.au> Subject: Re: Watchdog timers (was: Re: Multi-Port Async Cards) To: jgreco@brasil.moneng.mei.com (Joe Greco) Date: Wed, 31 Jan 1996 14:04:30 +1030 (CST) Cc: terry@lambert.org, msmith@atrad.adelaide.edu.au, hsu@clinet.fi, hm@altona.hamburg.com, freebsd-hackers@freebsd.org, brian@MediaCity.com In-Reply-To: <199601301914.NAA05659@brasil.moneng.mei.com> from "Joe Greco" at Jan 30, 96 01:14:38 pm MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org Precedence: bulk Joe Greco stands accused of saying: > > I was thinking about tackling the problem myself by putting an 8751-class > microcontroller on a PC card and writing a quick'n'stupid bit of timer code > for the 8751 that would do all the dirty work (mainly because I would hate > trying to wire all the digital logic for a traditional watchdog counter, > and I'm not familiar with any of the Maxim-type monolithic watchdog chips). > I don't have PC board facilities available to me and the prototyping cards > are expensive$$$$$. Hmm. I wouldn't bother with the micro, too expensive. Use an 8254 and a 1MHz crystal, with a GAL decoding the 8254 off the bus. The card would be small enough to not need a backpanel insert either. (You would use two timers cascaded as a prescaler to give you a mximum run period of a bit over 2000 seconds, and the third to time the reset pulse.) This would be _reasonably_ straightforward, but don't shoot me if I've missed something obvious. If this is something that would be popular, (as I said already...) I'll have a look at doing it. > ... Joe -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] "wherever you go, there you are" - Buckaroo Banzai [[