From owner-freebsd-hardware Sun May 17 05:08:24 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id FAA14000 for freebsd-hardware-outgoing; Sun, 17 May 1998 05:08:24 -0700 (PDT) (envelope-from owner-freebsd-hardware@FreeBSD.ORG) Received: from hda.hda.com (hda-bicnet.bicnet.net [208.220.66.37]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id FAA13995 for ; Sun, 17 May 1998 05:08:19 -0700 (PDT) (envelope-from dufault@hda.hda.com) Received: (from dufault@localhost) by hda.hda.com (8.8.5/8.8.5) id IAA07702; Sat, 16 May 1998 08:05:36 -0400 (EDT) From: Peter Dufault Message-Id: <199805161205.IAA07702@hda.hda.com> Subject: Re: interesting stuff In-Reply-To: from Duncan Barclay at "May 16, 98 09:07:04 am" To: dmlb@ragnet.demon.co.uk (Duncan Barclay) Date: Sat, 16 May 1998 08:04:21 -0400 (EDT) Cc: winter@jurai.net, freebsd-hardware@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL25 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > It's usually easier to do these on the parallel port (god knows how many phase > locked loops I've programmed down that!). I have a version that works with either a parallel port or the Philips I2C controller chip. I put it up on the multimedia list a little while ago - I have a new version so I'll put it up later today. > One "problem" with the I2C is that it > is not a TTL compatible bus, so a bit of hardware is need to convert the logic > levels. RS232 isn't TTL. I2C is TTL but uses weak high bidirectional clock and data lines that everyone on the bus has to be able to drive low. When I played with it on the parallel port I had some diode protection and used independent input and output pins for each bus line. Peter -- Peter Dufault (dufault@hda.com) Realtime development, Machine control, HD Associates, Inc. Safety critical systems, Agency approval To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message