From owner-freebsd-hackers Sat Nov 1 18:59:52 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id SAA23717 for hackers-outgoing; Sat, 1 Nov 1997 18:59:52 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from word.smith.net.au (ppp13.portal.net.au [202.12.71.113]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id SAA23711 for ; Sat, 1 Nov 1997 18:59:45 -0800 (PST) (envelope-from mike@word.smith.net.au) Received: from word.smith.net.au (localhost [127.0.0.1]) by word.smith.net.au (8.8.7/8.8.5) with ESMTP id NAA00542; Sun, 2 Nov 1997 13:25:58 +1030 (CST) Message-Id: <199711020255.NAA00542@word.smith.net.au> X-Mailer: exmh version 2.0zeta 7/24/97 To: "Jamil J. Weatherbee" cc: hackers@freebsd.org Subject: Re: 7400 gates effected by probe routine In-reply-to: Your message of "Sat, 01 Nov 1997 13:53:05 -0800." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 02 Nov 1997 13:25:56 +1030 From: Mike Smith Sender: owner-freebsd-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > During a device probing routine I noticed that it is possible for the > outputs of two 7400 TTL gates one in the high state and one in the low > state to be connected together for not more than 10 microseconds. I was > looking at a transistor level diagram of a 7400 and would like to verify > the following. That this should not damage the gate itself, just pull > about 10 times the normal current. I don't see anyway to get around this > without just removing the probe routine. Jamil, during the "probing routine" it is more likely that crazed mice will be copulating on your motherboard than that two 7400 devices will actually be present in your system, let alone have their outputs in contention. Can you perhaps clarify the realities of the situation and what the actual problem that you believe that you have is? mike