From owner-freebsd-hackers Sun Oct 5 11:27:31 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id LAA03234 for hackers-outgoing; Sun, 5 Oct 1997 11:27:31 -0700 (PDT) Received: from proxy3.ba.best.com (root@proxy3.ba.best.com [206.184.139.14]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id LAA03228 for ; Sun, 5 Oct 1997 11:27:29 -0700 (PDT) Received: from shellx.best.com (shellx.best.com [206.86.0.11]) by proxy3.ba.best.com (8.8.7/8.8.BEST) with ESMTP id LAA26722; Sun, 5 Oct 1997 11:26:00 -0700 (PDT) Received: from localhost (mdean@localhost) by shellx.best.com (8.8.6/8.8.3) with SMTP id LAA08835; Sun, 5 Oct 1997 11:25:59 -0700 (PDT) Date: Sun, 5 Oct 1997 11:25:58 -0700 (PDT) From: mdean To: Mike Smith cc: freebsd-hackers@FreeBSD.ORG Subject: Re: A world of unexplored pain. In-Reply-To: <199710050846.SAA00411@word.smith.net.au> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk The fastest I can run a KA series is at Crystal Freq = 16Mhz, EClk = 4Mhz, so if you look on page 10-12 of the hc11 reference manual you see that a divisor of rtr1=0 and rtr0=0 does E/2^13 netting a 2.05ms period between interrupts (this is only half of what I need) Ever seen a stepper motor controller that can be retargeted as it moves? > Uh, excuse me. A 1kHz interrupt gives you 2000 machine cycles between > You should re-read the HC11 reference, particularly the section where > they discuss interrupt priority. Yes, you can make any single interrupt the highest priority. Thats just it, I wouldn't be using an interrupt it have to be a tight loop running in the busy wait state monitoring the system clock reg that increments with every. >From what I've seen, not gates with outputs that go to a shared bus have a single input and a tristate enable? input, if the enable is off the output becomes a very high impedance input. Makes it so that the output has no effect on that line. Now I'm not really sure about wired-or, but I get the idea that it allows you to hook a whole bunch of stuff to the same interrupt line without using or gates, if any one output goes high the others don't interfere.