From owner-freebsd-hackers Sat Feb 3 05:48:28 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id FAA29761 for hackers-outgoing; Sat, 3 Feb 1996 05:48:28 -0800 (PST) Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id FAA29751 for ; Sat, 3 Feb 1996 05:48:19 -0800 (PST) Received: (from bde@localhost) by godzilla.zeta.org.au (8.6.9/8.6.9) id AAA16215; Sun, 4 Feb 1996 00:41:27 +1100 Date: Sun, 4 Feb 1996 00:41:27 +1100 From: Bruce Evans Message-Id: <199602031341.AAA16215@godzilla.zeta.org.au> To: msmith@atrad.adelaide.edu.au, phk@critter.tfs.com Subject: Re: Watchdog timers (was: Re: Multi-Port Async Cards) Cc: hackers@FreeBSD.ORG, jgreco@brasil.moneng.mei.com Sender: owner-hackers@FreeBSD.ORG Precedence: bulk >> > All this is a little hypothetical just now, as I'm concentrating on the >> > watchdog card. If it works out, it should do the basics, and with a TXCO >> > on it should give a good, stable frequency reference. Accessing it >> > won't be fast, sorry Bruce 8( >... >Bruce has the 8254 data, I suspect that you would as well. Yes, you can >latch everything inside it all at once. Actually I don't have the data sheet and haven't seen it for a few years. I seem to remember that there is an 8254 feature (automatic latch?) that we should be using. >Would having two counters (32 bits) be enough? The tap points on the Can you easily latch multiple 8254 counters at once in hardware? I think it would work to put them at the same address for writes and at different addresses for reads. Is the slowness only the usual slowness for multiple 8-bit reads? Bruce