From owner-freebsd-hackers Thu Oct 9 18:00:31 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id SAA11886 for hackers-outgoing; Thu, 9 Oct 1997 18:00:31 -0700 (PDT) (envelope-from owner-freebsd-hackers) Received: from alpo.whistle.com (alpo.whistle.com [207.76.204.38]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id SAA11865 for ; Thu, 9 Oct 1997 18:00:24 -0700 (PDT) (envelope-from julian@whistle.com) Received: (from daemon@localhost) by alpo.whistle.com (8.8.5/8.8.5) id RAA09611; Thu, 9 Oct 1997 17:54:54 -0700 (PDT) Received: from current1.whistle.com(207.76.205.22) via SMTP by alpo.whistle.com, id smtpd009607; Fri Oct 10 00:54:52 1997 Message-ID: <343D7C95.52BFA1D7@whistle.com> Date: Thu, 09 Oct 1997 17:53:42 -0700 From: Julian Elischer Organization: Whistle Communications X-Mailer: Mozilla 3.0Gold (X11; I; FreeBSD 2.2-CURRENT i386) MIME-Version: 1.0 To: mdean CC: freebsd-hackers@FreeBSD.ORG Subject: Re: Reliable probing techiniques for isa bus? References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk mdean wrote: > > If I have an isa card which occupies 16 ports but only uses 9 of them, I've > put in some debugging code to see what can be read from the card at boot > time. The read/write ports are random depending on what the card in > connected to, the control ports are write only, and so I am only left with > the other 5 ports on the card that aren't used and the pattern they are in. > Is it expected that you will always read 0xff from an unused port, because > that is what I am getting? welcome to the pleasures of ISA there is no answer.. yes the ports will read ff they will also read ff for any other device that does not use them :)