Date: Sat, 16 May 1998 08:04:21 -0400 (EDT) From: Peter Dufault <dufault@hda.com> To: dmlb@ragnet.demon.co.uk (Duncan Barclay) Cc: winter@jurai.net, freebsd-hardware@FreeBSD.ORG Subject: Re: interesting stuff Message-ID: <199805161205.IAA07702@hda.hda.com> In-Reply-To: <XFMail.980516090704.dmlb@computer.my.domain> from Duncan Barclay at "May 16, 98 09:07:04 am"
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> 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
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