From owner-freebsd-hackers Sun Oct 27 11:19:17 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 878BB37B401 for ; Sun, 27 Oct 2002 11:19:16 -0800 (PST) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 36A2243E4A for ; Sun, 27 Oct 2002 11:19:16 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.5/8.12.5) with ESMTP id g9RJJFFC091314; Sun, 27 Oct 2002 11:19:15 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.5/8.12.5/Submit) id g9RJJFEm091313; Sun, 27 Oct 2002 11:19:15 -0800 (PST) (envelope-from dillon) Date: Sun, 27 Oct 2002 11:19:15 -0800 (PST) From: Matthew Dillon Message-Id: <200210271919.g9RJJFEm091313@apollo.backplane.com> To: David Nicholas Kayal Cc: nbari@unixmexico.com, freebsd-hackers@FreeBSD.ORG Subject: Re: i am looking for a 5 volt signal References: Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG : :Shouldn't the fact that the signal is in a while loop keep the 5 volt :signal going? Isn't the parallel port being blasted with the :value 255 over and over again? : :The serial port will not fulfill what i am ultimately trying to achive. I :am trying to have the parallel port to control 8 relays each turing :on/off based upon which bit i send out to the port. : :.. :> try using also the serial port and a logical buffer :> :> the 5 volt signal is very fast and your multimeter is maybe not to fast :> :> > I'm looking for a 5 volt signal. Uh guys. Parallel port digital outputs do not generally have a whole lot of drive. I really doubt a parallel port output could drive a relay. And it's probably TTL level equivalents, not CMOS. Even if you ganged the output bits together I doubt you would get enough drive out of them. A serial port output (+/-12 but you may see +/-10 or -5 and +12 or other out-of-spec combinations) is far more likely to be useful in driving a relay, though again there will not be much drive. It would be far better to supply the power you need from another source, like a +5V power supply. Or just get a wallwart with DC output and run it through a linear regulator. At least then you aren't likely to burn the house down :-) -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message